M A K E B U I L D H A C K C R E AT E

hsmag.cc September 2019 Issue #22

OPEN
WORM MAKE AN
INSTRUMENT,
UGO VALLAURI
We all have the right to repair
– if you can’t fix it,
A 3D-printed wriggler MUSICAL CLOCK, you don’t really own it
designed for science OR ALARM

Robotic
Music
+
CIRCUITPYTHON
CONNECT TFT DISPLAYS
COLOUR SENSING
HAPPY TUNES
FOR HARDWARE
HACKERS
BUILD A LIGHT THAT
CAN EMULATE COLOURS
TOOL STORAGE LORAWAN
LASER-CUT YOUR OWN Connect sensors to the internet
WORKSHOP SHELF Sept.2019 from almost anywhere
Issue #22 £6

UMBRELLAS AI 3D PRINTING CALLIPERS

 Infrared Thermopile Semiconductors
Triboelectric Passives
Magnetic Position Electromechanical
Gesture Control Power
Interconnect Circuit Protection
Rectenna Automation
Connected Cloud Connectors
Decoupled Network Interconnect
Hybrid Envelope-Tracking Signal Hyperfast
Re-Entrant Leveraged Design IoT
Embedded Logic Switches
TEGs RFID
Passives TMR Magnetic Sensors
Logic Eco-System RF Directional Couplers
Third-Order Sensor Bipolar Digital Latching Sensor
Clock/Timing Logic
Memory Digital Omnipolar
Filters Crystals
SoC Augmented Reality
Thermal Management Earth-Friendly Display
Class-G Amplifier Embedded Cellular
Decimated Power-Efficiency IO-Link
Microwave Solenoids
Bluetooth Proximity Sensor
Remote Control Capacitive Touch
FPGA Embedded Computers
DDS Thermocouple Interface
Batteries PIR Sensor
Betavoltaics SPI Interface
MiWi Transceiver Linear
Nanogenerators Ultra Low-Power
AMR Narrowband
Recycling Radiowaves Mesh-Networked
Ask Receiver Virtual Reality
Transformers Keyfob
Solar Isolators
Sensor MCUs
2-Way Remote RF Evaluation
Simplex Transmission Dev Boards
ADC RF Antennas
Potentiometers Axis Tilt
Interface Zettabyte Era
NFC I2C
Frequency Synthesizers Robotic Process Automation
Oscillators Microservice Architecture
Low Energy Rezence Compatible
We Make It Easy. PMIC
Relays
WPC-Certified
XCVR
Immersive Experience
Artificial Intelligence
Smart Devices Internet of Things
Capacitors Na-TECC
Electromechanical 3D Alteration
Optoisolators Quantum Computing
ZigBee Shunt Sense
Semiconductors Touchless
EMI Smart Home Technology
Tools 5G Mobile
Hardware Energy Harvesting
Cable MotorData Acquisition
 EDITORIAL
Editor
WELCOME
Ben Everard
ben.everard@raspberrypi.org

Features Editor
Andrew Gregory
andrew.gregory@raspberrypi.org

Welcome to Sub Editors

David Higgs, Nicola King

HackSpace magazine DESIGN

Critical Media
criticalmedia.co.uk

Head of Design
Electronic music is a great way of playing with electronics, Lee Allen

but what if – like me – you prefer the sound of acoustic music Designers
Sam Ribbits, Ty Logan
made by plucking strings and hitting instruments? Does that Photography
mean that electronic music isn’t for you? No! It just means you Brian O’Halloran

have to get a little creative with your electronics. This month, CONTRIBUTORS
Lucy Rogers, Andrew
Matt Bradshaw is taking us on a journey of robotic music by Huang, Jo Hinchliffe, Matt
Bradshaw, Cameron Norris,
building a glockenspiel that plays itself with the help of a Tom Portegys, Mayank
Sharma, Jo Hinchliffe,
couple of servos and an Arduino. A very similar approach can Andrew Lewis, Poppy
be used to robotize almost any instrument, though it’s perhaps Mosbacher, Bob Knetzger,
Gareth Branwyn, Les
a little easier with those from the percussion section. You Pounder, Glen Horan, Daniel
Hollands, Marc de Vinck
can use this to build your own orchestra, or just add a little
PUBLISHING
musicality to your builds. Publishing Director
Russell Barnes
If sound isn’t your thing, we also take a look at visual output russell@raspberrypi.org
this month as I take a look at hooking up TFT screens to Advertising
Charlie Milligan
microcontrollers using both in CircuitPython and Arduino (see charlotte.milligan@raspberrypi.org

page 76). Also, Jo Hinchliffe investigates LoRaWAN to send data DISTRIBUTION

to the internet from the remote Welsh countryside (page 82), Seymour Distribution Ltd
2 East Poultry Ave,
and Dr Andrew Lewis helps you make sure all your cutting tools London EC1A 9PT
are kept sharp (page 108). Turn the page and let’s get making. +44 (0)207 429 4000

SUBSCRIPTIONS
BEN EVERARD Unit 6, The Enterprise
Centre, Kelvin Lane, Manor
Editor ben.everard@raspberrypi.org
Royal, Crawley, West
Got a comment, Sussex, RH10 9PE
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3
Contents 100

06 SPARK 35 LENS
06 Top Projects 36 Robotic music
What’s impressed us this month Replace musicians with reliable funky robots

16 Objet 3d’art 54 How I Made: OpenWorm

Everything 3D-printed in its right place Create life in the form of a C. elegans nematode

18 Meet the Maker: Jen Fenner 58 Soundscapes to Landscapes

How to build a business out of a makerspace Citizen science to monitor the sound of wildlife

22 Columns 62 Interview: Ugo Vallauri

Has Moore’s law run its course? Why we should all repair, re-use, and recycle more

24 Letters 70 Improviser’s Toolbox Umbrellas

How a no-blame culture saves lives Stay dry and entertained with these foldable membranes

26 Kickstarting
Harness the power of the sun with cheap hardware
Tutorial
30 Hackspace Makerspace Hull
Inspiring creativity in the city of Wilberforce Hold on

Cover Feature

Robotic
Music 88 Impose order on
your workbench

Build, program,
and play your 124
own unique
instruments

36
4
 CONTENTS

Direct from Shenzhen

Third hand 122
Interview
Ugo Vallauri
98

114 Third hands – for when two

hands just aren’t enough

75 FORGE
76 SoM TFT screens
62 Meet the co-founder of the Restart
Project – fighting for your right to fix 06
Simple displays for data feedback

78 SoM CircuitPython
Animate pixels to create a moving mammal 113 FIELD TEST
82 Tutorial LORAWAN 114 Direct from Shenzhen Third hand
Extend the range of the Internet of Things Augment your puny human hands with extra holding power

88 Tutorial Get a grip 116 Best of Breed

Advanced workbench techniques from the pros The best keyboard add-ons for clicky inputs

122 Can I Hack It?

94 Tutorial Colour sensing Will the PlayStation Classic bend to our will?

70
Build a chameleonic ornament

98 Tutorial Digital callipers 124 Review SparkFun Edge

Bring internet-free artificial intelligence to your builds
Measure work with digital precision

100 Tutorial Cable organiser 126 Review Creality Ender 3

Cut, bend, and craft acrylic into useful shapes Get a working, solid printer out of the box for £200

104 Tutorial Temperature control 128 Review Sonoff Mini

Keep food at a constant temperature – with rubbish Turn stupid devices into smart ones with this switching unit

108 Tutorial Stay sharp 129 Television Review Blown Away

Keep your blades sharper than Sean Bean Enter the world of artisan glass-blowing

Some of the tools and techniques shown in HackSpace Magazine are dangerous unless used with skill, experience and appropriate personal protection equipment. While we attempt to guide the reader, ultimately you
are responsible for your own safety and understanding the limits of yourself and your equipment. HackSpace Magazine is intended for an adult audience and some projects may be dangerous for children. Raspberry
Pi (Trading) Ltd does not accept responsibility for any injuries, damage to equipment, or costs incurred from projects, tutorials or suggestions in HackSpace Magazine. Laws and regulations covering many of the topics
in HackSpace Magazine are different between countries, and are always subject to change. You are responsible for understanding the requirements in your jurisdiction and ensuring that you comply with them. Some
manufacturers place limits on the use of their hardware which some projects or suggestions in HackSpace Magazine may go beyond. It is your responsibility to understand the manufacturer’s limits.

5
Top Projects

REGULAR

Wine barrel
speaker
By Philipp hsmag.cc/GyFYGW

W
hen he came across an empty wine barrel in
his late grandfather’s house, Philipp knew it
was ripe for a project. He removed the rings,
sanded the wood, and finished it with linseed
oil before putting it back together again. Oh,
and he also installed a Bluetooth speaker unit,
cutting an extra hole in the base for the speaker.
We like the simplicity of this project. The electronics may be ‘off
the shelf’, but it’s a unique object that looks great and does a job.

Right
Recycling is good,
but reusing is better
– turn to page 62 for
more on this theme

6
SPARK

7
Top Projects

REGULAR

Above
The clever thing
about this is that the
positive and negative
wires don’t touch
until you slot the
battery in

8
 SPARK

Free-form
LED bow-tie
By Clarissa Kleveno hsmag.cc/MsCABC

A
s soon as I saw Czech-based artist Jiří Praus’
beautiful creations, I knew I wanted to make
my own version. While I will never be able to
top the Freeduino, I created this LED bow-tie as
my own first attempt into exploring free-form
circuits. While circuit boards are commonly
used to mask complicated wirings, free-form circuits turn it into
a feature, and highlight just how beautiful circuitry can be. With
some careful planning and soldering, I turned a handful of 3M
LEDs and some wire into a fabulous accessory. The subtle orange
glow is perfect for proms, weddings, or your next formal event.

9
Top Projects

REGULAR

DrumCube
By Franco Molina hsmag.cc/wCgqnt

T
he DrumCube is an Arduino-based robot
drummer. It replicates the sounds a regular
drum kit would make, with an arrangement of
servos hitting both a small can and a pair of piezo
transducers. It also uses a transistor white noise
generator that imitates the cymbal sounds.
I’m a Chilean artist/musician and also a maker,
self-taught on electronics, Arduino, and in most things I do,
really. I developed this project as a way to complement
my music gigs without any help from other
musicians, big drum kits, or digital tracks. This
is a musical machine that you can enjoy
watching, as well as hearing.

Above
For more from
Franco, follow
him on Instagram,
or listen to him
on Spotify

10
SPARK

11
Top Projects

REGULAR

Binary scarf
By Sam Meech smeech.co.uk

O
n the hottest day ever recorded in Britain,
we bought a scarf. Not just any scarf though:
this one has a quotation from Ada Lovelace
encoded into it. Creator Sam Meech is an artist
based in England’s creatively fecund North West,
who among many other endeavours has made
a small range of knitwear with techy messages knitted into them.
As Sam puts it, “Binary scarves are a series of knitwear informed
by the ASCII text system of encoding text to binary. Each design
contains a quote related to either computers, binary, patterns,
digital art, or repetition. The designs are presented within the
constraints of a standard 24-stitch punchcard pattern repeat. The
scarves have been produced in collaboration with a factory in
Manchester, ironically named Unique Knitwear.”
Our scarf carries the message, “The Analytical Engine weaves
algebraic patterns just as the Jacquard loom weaves flowers
and leaves. Ada Lovelace, 1843”.

Right
We love the
symmetry of the
Jacquard loom
(which is close
enough to a knitting
machine) coming
back to computing

12
SPARK

13
Top Projects

REGULAR

WW2 radio
broadcast
time machine
By Adam Clark hsmag.cc/SvkMVj

M
y name is Adam Clark (aka Ajax Jones), and
I have listened to quite a few of the archive
broadcasts from WW2 online, but wanted
to listen to them on something more fitting
and physical. To this end, I bought a very
old, non-working valve radio, and replaced
the internals with a Raspberry Pi Zero on a custom 3D-printed
chassis. The dial is used to select different years of the war, and
the relevant radio broadcasts are then played out. To read the
dial, I used an MCP3002 analogue-to-digital converter (ADC),
and for the audio, I used a MAX98357 I2S Amplifier. Keeping the
original speaker in use was a great stroke of luck, as the reward
was an amazingly authentic sound.

Right
Like this brilliant
Raspberry Pi-based
build? We’ll feature
it in more depth
in a forthcoming
issue of HackSpace
magazine

14
SPARK

15
Objet 3d’art

REGULAR

Objet 3d’art
3D-printed artwork to bring more beauty into your life

B
ack in the olden days, people
used to listen to music on
flat plastic discs covered
in tiny grooves. A needle
on the end of an arm would
bounce around in these tiny grooves as the
disc span, and the vibration was amplified
electronically to produce music. It was the
best of times, it was the worst of times.
Amanda Ghassaei used a UV-cured
resin printer called the Objet Connex500,
which has a resolution of 600 dpi in the x
and y axis, and 16 microns in the z axis to
create a playable record (a film of WD-40
is about 17 microns deep). Despite that,
the grooves on the 3D-printed record are
about ten times deeper and ten times wider
than those on a pressed vinyl record, so
the 3D-printed record can’t hold anywhere
near as much audio as a pressed record.
Amanda has published a detailed
explanation of using the Python
programming language to extract useful
data from an audio file, turning the data
into an STL file and, from there, into a
printed resin object, along with the ups
and downs of getting the process right.
She’s also released recordings of
3D-printed sample tunes, including Nirvana’s
Smells like Teen Spirit, Daft Punk’s Around
the World, Debaser by Pixies, and songs by
Joy Division, New Order, and Aphex Twin.

hsmag.cc/0eHpoX

16
SPARK

17
Meet The Maker

REGULAR

Meet The Maker:

DefProc Engineering
Making dreams come true

I
f you’ve got an idea for a world-beating Liverpool, which had started the year before. Pat
product, but you don’t quite know how to went and learned how to use a laser cutter, how to
get it off the ground, you’ll need someone design for laser cutting, how to design for 3D printing,
to help you out. Someone who can design a all sorts of little electronic bits. Somebody offered him
PCB for you before it goes to the factory, write a piece of work – they asked him about a device they
software, establish a proof of concept that you were trying to make, but didn’t know how to get
can take to investors, or build a prototype that you started making it. They had the idea, but they just
can use to iron out the creases before you make that were having difficulty executing it.
first factory run.

”
That’s exactly what DefProc Engineering, run by
Jen and Patrick Fenner, does. This pair work with We basically set up a
clients big and small to make one-off and small-run
electronics-based products – and they started out in business to make things
their local makerspace using the same equipment as
for people within

”
the rest of their local maker community. We spoke to
co-founder and managing director Jen Fenner to find the makerspace
out what it takes to go from sharing soldering irons to
working on government contracts.
“We started our business in 2010. We didn’t have “He started offering advice to people, and eventually
full-time jobs; we had some money to live on, and we they just asked him: ‘would you be able to make it for
just started. We were only 27, so we didn’t know us?’. We basically set up a business to make things for
what we were doing, but we started it in my mum and people within the makerspace. People would come to
dad’s spare room. We initially had this idea to design a us and ask us to make things. That’s how it started.
human-powered vehicle – they were all the rage at the “Our business has changed over time. We still do
time, but there wasn’t a really good, affordable fundamentally what we did when we were there; we
version. So we had this big idea that we were going to just do it for slightly higher-paying clients, and we’ve
produce a human-powered vehicle and design this kit, got our own equipment now. The shared equipment
Right and we worked on that for about a year or so. is good, but you want your own professional tools.
Made Invaders is a “We found that when it came to building our first We’ve got quite high-end soldering irons now,
real, physical version
of the classic Space prototype, none of the manufacturers would talk to whereas the space we were in, it was good at the
Invaders game. We us. They either didn’t get back to us with a quote, or start, having access to all that equipment – I think we
would have had
a go if it hadn’t the one that did get back to us took eleven weeks to actually bought some equipment and put it in the
been surrounded
by children. Those
get the quote, and it was astronomically expensive. space so everyone could use it. We really loved it
pesky kids! So, we decided to scale back. We found DoES there, and we wouldn’t have the business we have

18
SPARK

19
Meet The Maker

REGULAR

Right
The river sensors that
DefProc built for the
Environment Agency
have recently gone
out into the fie d and
are being tested

now if it wasn’t for us being at DoES Liverpool. They

gave us a break.
“One of the things I like is that we still refer people
to the makerspace as well. If a potential client comes
to us with an idea, we will sometimes say, ‘You don’t
want to spend loads and loads of money with us, but if
you go to the makerspace, there will be someone
there who can support you while you start off.’ It’s a
supportive community, and it doesn’t cost very much
to join.

CLIENT WORK
“Everything we do is tailored to the client. We don’t
particularly invent things. We have one project, Push
to Talk, which is our in-house product that we’re
developing with Liverpool City Council as part of the
Council’s 5G project, and that’s going out to
people’s homes.
“The Environment Agency project that we’re
working on is a live level sensor. Because of the way
the Environment Agency monitors its rivers, they have
a big base station where you can see at that particular
point what the level is, but you don’t necessarily know
what the water level is like ten miles down the river,
because there isn’t any data being gathered until the
next base station.
“They wanted us to develop some smaller sensors
that they could tap into, through which they could
monitor the water levels along the length of rivers.
We’ve been using a new technology called NB-IoT
(Narrowband IoT ), which is a bit like LoRaWAN signal.
We started developing that while we were at DoES,
and we’ve done various different versions of it. We’ve
also created some bespoke sensor hardware for them,
so that they can train their staff on how to use these
small devices so that they can get the data they want
out of those sensors. We’ve done quite a lot of work
with the Environment Agency, including a national
training scheme for these devices.
“We’re currently at a staff level of five. We do a lot
of stuff for how small we are. This week we’re just
finishing off a build for the National Science and Media
Museum in Bradford. We’re putting together all the

20
 SPARK

interactive side of four lunar landing exhibits. You we’ve formed a business within the makerspace,
touch something and then it lights up and plays video, providing a complementary skill to some of the other Above
“Sometimes people
or you put an RFID tag on something and it plays people that were there. We’ve grown from there over will go to other
audio into a specific space. We do all the electronic the last five years. It’s been serendipitous. companies with ideas
but aren’t able to get
side of that. “A lot of it’s been driven by Patrick and his interest exactly what they
“Patrick’s a design engineer; his degree was in in new problems. One of the things that stands out want; they’ll come to
us, and we’re often
automotive engineering and structures, and he’s for us, as a business, is that we’re willing to take a a e to u fi what that
person wants”
migrated into this field of electronics. My background punt with a client. Even if we don’t know how
is in textile design; I do a lot of the creative design. something works, we know that it must be possible.
Made Invaders, for Whereas we know that a

”
example, is my design, lot of businesses, unless
and then Patrick works We’re doing much it fits into their formula,
on how to make it they won’t be willing to
function. I don’t know bigger projects now, take it on. It comes back
much about the
still working with the to the time when we

”
electronics, but I do wanted a prototype
know what they should Environment Agency – there was no-one who
look like: the design was willing to do a proof
rigour that needs to go of concept, or a
into things. We have quite a nice partnership of skills. prototype. ‘No, we don’t want to make one of
“We’ve got a product designer now who does all something; if you want 10,000, come back.’
the CAD for us and makes everything look good. It’s “I think our biggest run has been 200 things for a
nice to have people to support us. When it was just client. If you go to somewhere that’s got the big
the two of us, Patrick was doing the electronics and pick-and-place machines, and ask them to make you
the software, and we’ve now got a software engineer 200 of something, they’ll tell you it’s not worth their
and a product engineer as well. time to set up the machines to do that. We can
“Gradually, we just built up and built up. We’re doing manufacture things in small runs that big places just
much bigger projects now, still working with the don’t want to do. It’s almost like the bigger the
Environment Agency. We didn’t go to the makerspace company, the less likely they are to want to deal with
to design a product to then start a business out of it; you. We try to fill that void.”

21
Lucy Rogers

COLUMN SPARK

Nine squares
Making time for the important things in life

H
ave you ever used the is my life”, is that if they lose that job
wrong tool for a job when or partner, then their life is empty and
you have the proper tool meaningless. She suggests making a grid
elsewhere, but the wrong of nine squares and writing part of your
one just happened to be life in each. Then, spend equal amounts
handy? I often use a junior of your thoughts/efforts on each square.
hacksaw to cut small things, when I have I have made one of these grids – and
a workshop full of wood-saws, jig-saws, I’ve been using that to help me focus on
fret-saws, and a band-saw – any of which what ‘rocks’ I want to put in my jar.
would make neater cuts. My top three squares are for family,
Having tools is great, but sometimes home, and friends. The next three are

Lucy Rogers
the right tool is just the one nearest income, health, and learning. And then
to hand. I have the things I love to do – making,
There’s a time storytelling, and
@DrLucyRogers management tool outdoor activity.
– it’s an analogy So now I am putting the These are not rigid
Lucy is a maker, an engineer, about rocks, pebbles, definitions. Some
and a problem-solver. She is
‘rocks’ into my calendar
sand, and water in things will tick two
adept at bringing ideas to life. a glass jar. Fill the jar – and giving myself or more boxes at
She is one of the cheerleaders with rocks permission to do the once – for example,
for the maker industry, and is (important projects, kayaking with
Maker-in-Chief for the Guild e.g. family, health, fun ones too friends, or selling one
of Makers: guildofmakers.org and income) and of my makes.
there is still room for However, just like
pebbles (nice projects such as hobbies knowing there’s a better tool in the
and friends , and then still room for filler workshop, knowing that I have large
projects’ (watching TV or social media) rocks to put into my jar is not the same
– and even then, there’s still room for as doing them. Sometimes it’s just easier
liquid refreshments ut fill it with sand to procrastinate on social media.
or liquid first and there’s no space time After I went freelance, I spent years
left for more important things. telling myself that I couldn’t do the ‘fun’
This is a great tool’, but one I had filed things until I’d done the ‘work’ things.
under ‘useful’ rather than ‘use’. Which meant that even if I did do a fun
So, I have taken some time to think thing, I spent the time guilt-wracked,
about what my ‘rocks’ and ‘pebbles’ are – which killed the enjoyment.
or should be. What areas of my life do I So now I am putting the ‘rocks’ into my
want to be important? In her book, Feel calendar – and giving myself permission
the Fear and Do It Anyway, Susan Jeffers to do the fun ones too. And weirdly, I am
mentions that the problem of someone still finding time for social media and
saying, “my job is my life”, or “my partner watching a bit of TV!

22
Bunnie Huang

COLUMN SPARK

The quantisation
of Moore’s Law
It’s 2019 – where are our faster chips?

O
ne of the most remarkable TSM , Samsung, and Intel. Progress has
aspects of Moore’s Law is been halting; instead of a continuum of
how smooth the rate of performance improvements, the industry
improvement had been is forced to contend with quantised
up until a few years ago. leaps in performance. Intel’s absence
or five decades, ma or in the 1  nm and  nm nodes has been
industries could count on regular notable, leaving P manufacturers
improvements to performance and cost. struggling to give consumers reasons
In hindsight, this smoothness was a to upgrade their existing computers.
result of do ens of foundries ockeying for ecently, TSM has filled the leadership
pole position. If one foundry stumbled, vacuum in the  nm node, and everyday

Bunnie Huang another would take its place. owever, as

transistors became much smaller than the
consumers have felt this in the form
of AMD’s Ryzen renaissance.
si e of the photons used to draw them, hat’s beyond  nm? The industry is
@bunniestudios shrinking dimensions was no longer ust a finally about to embark on a huge
matter of better paradigm shift from
Andrew ‘Bunnie’ Huang is a optics or clever using 1  nm deep
hacker by night, entrepreneur computational optics ultraviolet light, to
by day, and writer by
EUV is hard in so many
tricks. t  nm, 1 .5 nm extreme
procrastination. He’s a something ways; it’s reported to ultraviolet (EUV) light.
co-founder of Chibitronics, fundamental had to EUV is hard in so
gobble a megawatt of
troublemaker-at-large for the change: the industry many ways; it’s
MIT Media Lab, and a mentor moved to double- power to produce just reported to gobble a
for HAX in Shenzhen. patterning and 200 watts of EUV light megawatt of power to
FinFET transistors. produce ust
This was a difficult watts of V light,
transition that fundamentally changed the and it requires landing a bullseye – not
structure of transistors. p until  nm, once, but twice – with a powerful 2
laser
things had gotten better and cheaper, so on droplets of ultra-pure tin that are 25
ust about every conceivable circuit rode microns in diameter, falling at a rate of
the Moore’s Law train for free. owever, 5 , times per second. The big news is
from  nm onwards, transistors got that TSMC has recently gone into
denser and better, but stopped getting production with V, marking the
cheaper. Thus, only applications that could beginning of a new quantum for Moore’s
ustify the higher cost continued to ride Law. This should hopefully unlock a trickle
the Moore’s Law train, marking the of incremental improvements over the
beginning of the end of Moore’s Law. next couple of years – and then we’ll have
In recent years, the number of players to wait again, until the next quantum of
has continued to dwindle to ust three: Moore’s Law.

23
Letters

REGULAR

Letters ATTENTION
ALL MAKERS!
If you have something you’d
like to get off your chest (or
even throw a word of praise
in our direction) let us know at
hsmag.cc/hello

TETRIS MICROWAVE GLASS

I’d seen LED animations such as I have to take issue with you. Popty-ping is
the Tetris matrix in [issue 21’s not Welsh for microwave [as we implied in
animated clock] but never thought the contents of issue 21]. The correct word
I’d be able to make one myself. It is microdon. ‘Don’ means wave in Welsh.
turns out you don’t have to – just It’s also prototype Celtic for water, which is
download the right bit of code, and why there are so many rivers in Europe
it's done for you. Truly, this is the called the Don.
lazy man’s way to program things. .
dam
Frank Caerdydd
Edinburgh
Ben says: e have enough trouble with
Ben says: You say tomato, I say nglish, so it s cra y that we d even
tomato you say la y, say efficient, attempt any elsh in the mag. ither way,
intelligent, and leaving plenty of we had good, clean fun with microwaving
time to get other things done. glass, and it was pretty cheap too.

24
 SPARK

BUZZWORDS
The corporate companion (issue 21,
Top Projects) tickled me. I used to
work with a chap like that. I wonder
if management realised how much
money they could have saved if only
they’d reproduced him with an
empty suitcase, a Raspberry Pi, and
a speaker?

Dan
Bath

Ben says: xperts have been telling

us for decades that automation is
going to turn the world of work
upside down, so we shouldn t be too
surprised that a middle manager
can be replaced by a script and a
computer. heck out its and
a yte s ou ube channel for more
excellent daftery like this.

ENGINEERING CULTURE a mistake, you’d make every effort to

Project Egress (mentioned in our keep that mistake secret, putting people
interview, issue 20) seems like a niche in danger. It’s a tragedy that something
thing to focus on, but it shows the got lost between the moon landing and
importance placed on safety by any the Challenger explosion, which was
serious engineer. In aerospace, there’s a caused by a known, reported issue with
no-blame culture where failures are O-rings that was ignored for years before
reported rather than brushed under the it caused the explosion. We often hear
carpet, and it’s all to make things safer. If that getting things wrong is essential,
you knew you’d get the sack if you made and it is, but only if we learn from it.

andy
Texas

Ben says: ndeed so. e ve tried to get

a few people to speak in the maga ine
about failure, but while many are
willing to say failure is essential in the
abstract, not everyone is comfortable
talking about specific mistakes they ve
made. ail often, and fail small that s
our motto.

25
Crowdfunding now

REGULAR

CROWDFUNDING
NOW
makerPower Solar
Release your projects from the confines of the power grid

From £35 crowdsupply.com Delivery: November 2019

S
olar power can seem like a really simple solution to
providing electricity for remote projects. Take a panel,
hook it up to the power port and you’re done, right? Well,
not quite. Photovoltaic cells (aka solar panels) provide a
varying supply of power to your project that also requires
a varying supply of power (unfortunately they aren’t varying at the
same rate). You therefore need something that you can put between
the two to absorb the fluctuating power from the photovoltaic cells
and distribute it smoothly to your project – a battery. However,
batteries introduce their own complexities. They can’t be charged
too fast or allowed to drain too low. It might also be useful for your
project to understand the power level of the battery so it can ration
power appropriately.
The makerPower Solar board is designed to combat exactly these
problems. It takes 12 V solar cells (which don’t actually output 12 V)
and uses this power to charge a 12 V lead-acid battery. This is then
used to power a 5 V regulator that can produce up to 2 A of current
through either a USB port or solderable headers. Up to 3 A of 12 V is
also accessible via a header.
So far, so normal. However, makerPower Solar also lets you read
the current status of the battery and charger via an I2C interface.
There are libraries for both Arduino and Raspberry Pi that let you
look at the different voltages and currents flowing through the
controller board. This can be used to intelligently manage the power
you have available. For example, you can stop non-essential
activities below a certain power, or perform high-power activities
when the battery is fully charged and there’s still power arriving
from the sun.
While we haven’t tested out the makerPower Solar, if it lives up
to its claims, it will be a great addition to the toolkit for remote,
solar-powered projects.

26
BUYER
BEWARE !
When backing a crowdfunding
campaign, you are not purchasing
a finished product, but supporting
a project working on something
new. There is a very real chance
that the product will never ship
and you’ll lose your money. It’s
a great way to support projects
you like and get some cheap
hardware in the process, but if
you use it purely as a chance to
snag cheap stuff, you may find
that you get burned.

Above
You can use the
makerPower Solar to
power a Raspberry
Pi, and then use this
computer to monitor
the makerPower Solar

Left
A camera powered
via a makerPower
o ar  har er

27
 WELCOME

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MAGAZINE
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TRICKS, AND MAKES

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Build a touch-activated
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Join us as we lift the lid
on video games

Visit wfmag.cc to learn more

Space of the month

REGULAR

Space of the month:

Makerspace Hull

I
“
t’s a bit of a cliché to say that you want
your space to be for everyone, but being
part of a library, it’s really true – we’re
quite publicly visible and accessible, so we
can, and do, get all types of people
walking through the door.
Makerspace Hull “We want to provide an environment where people
can feel comfortable coming to just explore and have
hcandl.co.uk a play without necessarily having a ‘project’ to work
makerspacehull on. Again, it’s that library thing of wanting it to be a
really friendly space which is genuinely open to all.
@makerspacehull
“There’s a real mix of members from artists looking
makerspacehull into new techniques and new ways of getting their
work out there, to your more traditional makerspace
hacker, and lots in between. Recently, we’ve had
members laser-cutting things like earrings to sell on
their market stall, and lino blocks for their artwork.
3D printing for cosplay and tabletop gaming seem
to be really popular uses of the space as well.
“Funding was secured from Arts Council England
to set up the space, with additional money from the
James Reckitt Library Trust. Part of the original aim
was to capitalise on the enthusiasm generated by
Hull being the UK City of Culture 2017, and give
people the opportunity to develop their skills and
have access to new technologies.

Right
Makerspace Hull
holds regular
metalworking
workshops

30
 SPARK

Yes, it’s in a library

– but that doesn’t
mean there aren’t
laser cutters and 3D
printers to play with

31
Space of the month

REGULAR

Right
These lino prints We’ve been open just over six months now, so it
were made by still feels fairly new, and we’re learning as we go,
Sean Azzopardi,
who’s a member of but it feels a very exciting thing to be a part of.
Makerspace Hull
(image credit: Sean
“In terms of gear, we’ve got a laser cutter, two
Azzopardi) 3D printers, a large format printer, a digital cutter,
a dye sublimation printer with heat press, a digital
embroidery machine, as well as all the usual hand
and power tools, soldering irons, and lots of
electronics stuff like Arduino starter kits. There is
also a suite of computers with programs such as
Fusion 360 and the full Adobe package installed
which help people go from idea, through design,
to fabrication under one roof.
“The 3D printers are in fact built in the area, and it’s
really important to us to try and use local companies
and suppliers wherever we can. There are plans to
expand in the near future with a dedicated room for
a CNC machine and also a woodworking room,
which is something a lot of the members have
CONTACT US been requesting.
We’d love you to get in
“Anyone over the age of 16 can become a member
touch to showcase your
makerspace and the for a small monthly fee – we really try and keep the
things you’re making. costs low to reduce barriers to entry as much
Drop us a line on Twitter as possible.
@HackSpaceMag, or
email us at hackspace@
raspberrypi.org
with an outline of what
makes your hackspace
special, and we’ll take it
from there.

32
 SPARK

“The best way to find out more is just to pop in and

have a chat when we’re open; there’ll always be staff
on hand to show you around and help get you started
on whatever creative journey you want to embark on.
“Workshops are a big part of what we offer,
including lots of ‘Introduction to…’ style ones in
subjects like Arduino, 3D printing, and laser cutting
to help people get started. We’ve also started
running ‘Family Maker Days’ to get younger people
exploring their creativity in the space with a series of
taster activities, and these have proved very popular,
so much so that we’re looking at doing something
similar with adults in the near future.
“Outreach work is something we want to do a lot
more in the future, getting out to schools, community
centres and the like to spread the word and create a
community of makers across the city.”

More important than

the physical space
or the tools are the
open-to-all activities
that take place at
Makerspace Hull

33
LENS
HACK MAKE BUILD
Uncover the technology that’s powering the future
CREATE

PG

54
HOW I MADE: PG
36
OPENWORM
Build and code a C. elegans
nematode – the first organism to
have its whole genome mapped ROBOTIC
MUSIC
PG

58
SOUNDSCAPES Play happy tunes with
TO LANDSCAPES home-hacked hardware
Tracking wildlife through citizen
science, volunteer ecologists,
and open hardware

PG
PG

62 70
INTERVIEW: IMPROVISER’S
UGO VALLAURI TOOLBOX:
We meet the co-founder of the UMBRELLAS
Restart Project – a man who’s Intriguing builds inspired
passionate about our right to repair by portable hand-held tents
Robotic Music Glockenspiel

FEATURE

Robotic
Music:
Glockenspiel
Build a musical instrument
that plays itself

W
hen you think about using The design will consist of a cheap glockenspiel
electronics to create music, and an arm with a beater on the end, which will
you might think of drum rotate to reach the different notes. The arm’s
machines and synthesizers, movement is powered by a large servo motor, while
with their sound generation the beater is powered by a small servo motor. The
technology hidden inside a servos are controlled by an Arduino Uno, and the
black box. However, electronics can also be used to circuitry is housed on a breadboard so that we can
control acoustic instruments. In this tutorial, you will easily modify it later on. The glockenspiel, arm,
learn how to build a robot arm with two motors Arduino, and breadboard are all mounted to a piece
which can play a tune on a glockenspiel. of plywood.
Our aim for this project is to take a glockenspiel This project can be approached in a number of
and add every possible extra feature we can think of. different ways, depending on what resources are
In the main part of this tutorial, we will build a basic available to you. We have 3D-printed quite a few of
robotic arm to play a preprogrammed melody. Once the parts for this build, but if you don’t have access
that works, we will add other features such as to a 3D printer, you could achieve the same results
controlling the instrument from an external keyboard using wood, a bucket full of screws and, of course,
or via the Internet of Things. a roll of duct tape.

36
 LENS

Above
he finished
instru ent an
e used without
ein onne ted
to a o puter

37
Robotic Music Glockenspiel

FEATURE

Right
he de au t ode p a s
eetho en’s de
to o ut ou an
pro ra an e od
ou an thin o

YOU’LL NEED
 Glockenspiel
the smaller the better

 Plywood for the base

approx 60 cm × 40 cm

 Wood for the arm

approx. 25 cm × 3 cm × 2 cm

 Arduino Uno
 Breadboard
 Jumper wires
 Tactile button
 LED
 Resistor
220 Ω

 2 × Electrolytic capacitors
10 µF

 olt e re l tor
7805


 r ino in
power supply

 t n r er o

 ll er o

 Access to a 3D printer
or decent woodworking skills!

 Wood screws
 riet o M
 hine
screws and nuts

 i
 oo or in tool

38
 LENS

Quick Tip
This project assumes
some basic knowledge
of the Arduino platform
– if this is your first
time playing with an
Arduino, start here:
hsmag.cc/iSwUtN.

A SOLID BASE external power to drive motors, it is important to

To start, find yourself a piece of plywood or similar make sure that there is always external power
to act as a base for your instrument. As you can see available to the Arduino. Throughout this project,
Above
in the photos, it needs to be wide enough that you make sure that you don’t turn off the external power he rai is ed
can mount the glockenspiel firmly at one end, and unless you have already unplugged the USB cable, ro a ains
trans or er ia a
long enough to also contain the arm, breadboard, otherwise the Arduino will attempt to power the o ta e re u ator
and Arduino.
Next, mount your Arduino and breadboard next to
each other on the base, with the Arduino’s USB and The circuit contains a
power ports nearest the edge of the base.
Breadboards often come with a sticky underside,
making them very easy to mount. The Arduino can button, which will be
be secured in place by screwing wood screws
through its mounting holes, but be careful not to
over-tighten them and crack the board.
used to start and stop
On your newly secured breadboard, build the
circuit shown in the diagram above. The circuit the melody, and an LED
contains a button, which will be used to start and
stop the melody, and an LED, which is useful for
debugging (and aesthetics!). motors via USB, which provides insufficient current
The circuit also contains a 5-volt regulator chip. and could cause damage.
The Arduino can’t provide enough current for our With the servos connected, as shown in the
somewhat chunky main servo, so we have to think diagram, and the external power supply turned on, try
laterally. Our Arduino is going to be powered by a 9 V out the Arduino example sketch found in File >
mains transformer, which has plenty of current, and Examples > Servo > Sweep. Upload the sketch to
the Arduino lets us access this 9 V power feed
directly, via the ‘Vin’ (voltage input) pin. The 5 V Controlling servos
regulator chip takes the 9 V input and steps it down
to 5 V, giving us enough power (at the correct
A servo is a special type of motor which has a built-in feedback mechanism, meaning that
voltage) to run our servos. The capacitors are there the motor ‘knows’ its current position (or, sometimes, speed). Our servos read a signal from
to keep the voltage stable – make sure you get them the Arduino and then move to a particular angle, between 0° and 180°. The Arduino sends a
the right way around. pulse of a specific length, and the servos interpret this as an angle and rapidly move to the
correct position.
FIRST MOVEMENT You don’t need to worry about what pulse length to send, because there is a ready-made
library called ‘Servo’ which handles all the calculations. You just need to tell the Arduino
Plug the 9 V power supply into the Arduino and turn
which motor is connected to which pin, and what angle you want each motor to move to.
it on, before plugging the Arduino into your PC with
the USB cable. With a project like this, that requires

39
Robotic Music Glockenspiel

FEATURE

Right
hie ds sta on top
o the rduino to
add un tiona it

Below
reatin a asi
ode o the ser o
itse in ree
was he p u when
desi nin a
ser o ount

long, ungainly parts. The sketch plays Beethoven’s

Timing troubles Ode to Joy when the button is pushed once, and
stops playing when the button is pushed again. The
The arm takes a finite time to reach a note before the beater can hit it, which needs
to be taken into consideration in the code. After some trial and error, we found that a LED is lit while the melody is playing.
preHitDelay of 150 ms was enough time for the arm to reliably reach its destination
before triggering the beater, but feel free to adjust this value up (for increased reliability) UNDER THE HOOD
or down (for a faster maximum speed). There is also a postHitDelay value of 50 ms, which Go to hsmag.cc/issue22 and open the glock_main
can be tweaked to give a nice clean hit of the beater – if this value is too short, the beater sketch. The code starts by including two libraries: one
won’t reach the keys; too long and it will dampen the note, rather than letting it ring.
called ‘Servo’ to control the servos (obviously), and
one called ‘Bounce2’, which makes it easier to handle
button presses. Bounce2 is not included by default in
the board, and you should see one of the servos move the Arduino software, so go to Tools > Manage
back and forth. Take a look at the code, and try editing Libraries, search for ‘Bounce2’ and install it – if you
it. See if you can change the speed of the sweep, or don’t do this, the compiler will complain and won’t let
move both servos at once – the code that we will use you upload the sketch.
to play the glockenspiel is similar to this example. We then declare objects to represent the two
Although it seems a little counter-intuitive at this servos and the button, before defining various
early stage of the build, now is a good time to variables which will be used in the code, such as the
upload the main sketch, since we can see if the possible angles of the beater, the amount of time to
circuit is working properly before we start attaching wait for the arm to reach its position, and the
sequence of notes that you want to be played. In the
setup function, we tell the Arduino which pins
correspond to the servos, button, and LED, and we
Quick Tip set the delay between notes based on the tempo.
In the main loop, we continuously check whether
Some useful pedantic the button has been pushed. The updateButton
knowledge: many people function listens for a button press and sets
will mistakenly call this
sequencePlaying to either true or false. When
instrument a xylophone,
but a xylophone’s bars sequencePlaying is active, notes are played in order.
are made of wood, The playNote function (see code extract) handles the
not metal. process of moving the arm to the correct note,

40
 LENS

Long arm of the law

Getting the length of the arm right is important – too short,
and its arc of movement will be very small, meaning you
won’t be able to reach many notes on the glockenspiel
(which are laid out in a straight line). If you make it too
long, however, it may require too much force for the servo
to move the arm, even with the external power supply. For
our build, we found that 28 cm from the large servo’s shaft
to the tip of the beater was about right, with the actual
wooden part of the arm measuring 23 cm. This gave us a
wide enough arc to reach a whole octave of notes, without
appearing to stress the motor unduly.

waiting until it is in position, moving the beater

downwards, waiting a few fractions of a second,
moving the beater back up, then finally pausing until
the next note, according to the desired tempo.

void playNote(int thisNote) {

if(thisNote >= 0 && thisNote <= 7) {
// note is valid, play note
bigServo.write(notePositions[thisNote]);
delayWhileUpdating(preHitDelay);
littleServo.write(beaterHitAngle);
delayWhileUpdating(postHitDelay);
littleServo.write(beaterRestAngle);
} else {
// delay instead of playing note
delayWhileUpdating(preHitDelay +
postHitDelay);
}
delayWhileUpdating(tempoDelay);
}

Upload this sketch to the Arduino, making sure the ARMED AND DANGEROUS
external power supply is connected first, and press You can now work out where to position your
the button. If all is well, the LED should come on and glockenspiel and your large servo. Cut a piece of
the two servos should start twitching independently. wood to the desired length for your arm, and attach Top
he eater was printed
If this doesn’t happen, double-check your wiring. an appropriate servo horn. Horns are the (usually at on one side un i e
plastic) pieces that come with a servo and fit snugly a re u ar o enspie
eater to a e it
onto the servo’s shaft. Find an appropriately shaped easier to print
horn and screw it to the underside of your wooden
Above
arm at one end. Mount the wooden arm on the ou find a desi n
servo so that it is parallel with the long side of the aw a ter printin a
part it’s o ten possi e
baseboard, aligning with the middle of the to od e it unti ou
et around to printin
glockenspiel. Make sure the servo is at its 90° a etter one
position when you do this (the sketch defaults to the
Left
big servo being at 90° when it starts up). t’s possi e to
The arm would work like this, but it’s best to secure od e an e istin
o enspie eater
it down to the servo if possible. Some servos have an to wor with this
M3 thread inside the shaft, allowing you to screw the ui d i ne essar ut
3 printin a usto
arm directly to the shaft. Alternatively, you might be one wor s etter

41
Robotic Music Glockenspiel

FEATURE

drill pilot holes quite precisely so you know where to

place the screws. Another four screws hold the servo
itself in the mount. The small servo mount clamps
the motor to the arm using M3 machine screws,
although you could also use wood screws.
The custom glockenspiel beater features a recess,
into which you can place one of the horns from the
small servo. As with the large servo, you need some
way of holding everything in place – small servos tend
to come with a tiny screw for this purpose, but this
will likely be too short to reach through the stem of
the beater, so you will require some ingenuity. We
used a longer screw with the same diameter, but you
could modify the design to allow you to use the
original screw, or come up with another solution.

able to use a carefully chosen wood screw (be careful TUNING UP

Quick Tip not to crack the servo shaft with an oversized screw), If you run your sketch at this stage, you will hopefully
or you could resort to glue. If you are going to screw find that the robot arm functions, but it is very unlikely
Make sure you know
what position each servo through the arm, you’ll want to drill a hole through the that it will play the tune correctly. This is because the
is in before attaching wood, starting in the centre of the horn.
parts to it, or your Since one end of the arm is hovering a few
machine might try and
tear itself apart when
centimetres above the base, you may want to add a The large servo mount
vertical support, as seen in the pictures. You could
you run the sketch.
possibly get away without it if the arm is secured
tightly to the servo – it’s up to you. We 3D-printed our is held in place from
support, but it’s a very simple piece that could
certainly be fashioned from wood.
under the base with
THE THIRD DIMENSION
Speaking of 3D printing, the vertical support is one of wood screws
several parts of this build that you can either 3D-print
or make yourself from scratch – the other parts are a
mount for the large servo, a mount for the small arm positions have to be dialled in for the individual
servo, and a custom glockenspiel beater. We layout of your instrument. While the low C position
designed the 3D parts in FreeCAD, a free, open- on our build was at 109°, yours is likely to be at least
source 3D design program which is worth a few degrees lower or higher, depending on the size
downloading. The STL files are available from and position of both your glockenspiel and your arm.
Above hsmag.cc/issue22 – you can either use them as they
o ta e re u ators are, edit them, or create your own.
o ten ha e a ho e
so ou an atta h a If you don’t have a 3D printer yourself, you could
heat sin i re uired check out your local makerspace, or order the parts
Right from an online 3D printing service. It’s certainly
his pre ious possible to build this project without any 3D prints
ersion o the ro ot
o enspie was – you could achieve identical functionality with some
tri ier to ui d ut
has a wider ran e
wood, glue, screws, a saw, and a drill – but we’re
o notes going to continue the tutorial on the assumption that
Far Right you’re using the printed parts.
ou an use u e
wrap to ute the
o enspie whi e TIGHTEN UP
testin i our The large servo mount is held in place from under the
house ates don’t
appre iate the noise base with wood screws – you’ll need to measure and

42
 LENS

Other approaches
The build detailed here is one relatively simple way to
make an electronically controlled glockenspiel, but there
are plenty of other methods, each with their own pros and
cons. One alternative strategy is to use a solenoid for each
key of the glockenspiel, as shown in the ‘Glock-O-Bot’
made by the Mather family at Fab Lab Manchester – this
design allows for multiple notes to be played at once
(polyphony) and is more space-efficient than our design,
although there is a lot more wiring!
Another approach that we tried previously, with some
success, is to remove the metal bars from the glockenspiel
and rearrange them in a semicircle, meaning that more of
the notes are within range of the beater’s arc of movement,
including the sharps and flats.

To ‘tune’ your instrument, make a copy of the

current sketch and adapt it to help you figure out
which note is at which angle. Try replacing the Ode
to Joy melody found in the noteSequence array with a
simple repeating scale, then start tweaking the values
in the notePositions array until you get a good result.
For reference, the number 0 in our build corresponds
to the lowest C on the glock, while the number 7 is
an octave higher. The number -1 denotes a pause in
the melody.
Finally, mount the glockenspiel itself on the
baseboard using wood screws. You now have a robot
glockenspiel that can play any melody you can think
of! But wait, there’s more…

43
Robotic Music Glockenspiel

FEATURE

Extending
your robot
glockenspiel
How to take your
instrument to the
next level
H
opefully, your glockenspiel can now
play a melody at the touch of a button,
but there’s a lot more we can do! Here
are a few extension projects to help you
learn more about your robotic instrument, but there
are almost endless ways it can be adapted to new
uses. The only limit is your imagination – it sounds
like a cliché, but it’s true!

44
 LENS

Big Ben chiming clock

This first modification is a nice one to start with,
YOU’LL NEED
because we can make it without any extra ‘BIG BEN’ CLOCK
components. By making some changes to the code
 othin e tr
in the Arduino sketch, we can tell the instrument to
play a melody at a specific time, rather than on the INTERNET OF THINGS
push of a button. M
We’re going to trigger a melody every 15 minutes,
Arduino Ethernet

making a chiming clock à la Big Ben (although Little shield
Ben might be a more apt name for our tiny clone).
Download the glock_clock sketch and have a look at  Ethernet cable
it – the code starts off pretty similar to the main build, M T
but there are a few additions and changes. Optoisolator

6N138

We’re going to trigger 5-pin DIN


M o et
breadboard-compatible

a melody every 15 Resistors


220 Ω 0Ω 0 Ω

Diode

minutes, making a 1N4148

chiming clock
The single, long noteSequence array in the previous
version has been replaced by a two-dimensional array
containing four separate lists of notes – these are the
four different melodies played by Big Ben. Below this
we have also defined variables representing the
current time in hours and minutes – you need to set
these manually to the current time before uploading
your sketch (e.g. if the time is 3:47 pm, set
startTimeHours to 15 and startTimeMinutes to 48,
then upload the code to the Arduino just as the
minute hand ticks over from 47 to 48). Once your
sketch is running, it should stay approximately in time,
and the chimes can be turned on or off by pressing
the button.

Adding a display
The next logical addition for either the chiming clock or
the Internet of Things alarm clock would be a display to Left
show the time. Perhaps the most obvious component for he o enspie
an e pro ra ed
this would be a four-digit, seven-segment display, as used to i i i en’s
in digital clocks since the 1970s, although a more modern a ous e od
OLED display could also be cool, as could Nixie tubes or
Credit
edge-lit LED displays, sometimes known as ‘Lixies’. a id i
3

45
Robotic Music Glockenspiel

FEATURE

Internet-connected alarm clock

Go to the Arduino library manager, install the
Adafruit MQTT Library, then open the sketch found
in File > Examples > Adafruit MQTT Library >
mqtt_ethernet. Read through the code – this sketch
subscribes to a simple binary feed called ‘onoff’,
reading changes from an on/off button in the Adafruit
IO web interface. The sketch also sends dummy data
to a feed called ‘photocell’, and the data sent from
the Arduino can then be seen live on a web interface
called a ‘dashboard’.
Set up these two test feeds, ‘onoff’ and ‘photocell’,
within your account, and create a dashboard with a
button to send data to the ‘onoff’ feed, and a graph
to read data from the ‘photocell’ feed. This is a
little complex, so check out these sites –
hsmag.cc/HRSKql and hsmag.cc/GF0brB – to get an
overview of what feeds and dashboards are all about.
Once you think you’re up to speed, enter your
Our ‘clock’ will now chime the same four patterns username and key in the mqtt_ethernet example
every hour, which is cool, but nothing that couldn’t sketch, and upload the code to your Arduino. Open the
have been achieved using clockwork in the 19th serial monitor in the Arduino software and, with luck,
century. Let’s bring things up to date by making our you should see details of a successful connection to
clock read the correct time from the internet, and the Adafruit server. Try playing with the dashboard –
allow an alarm to be set with a custom melody via a you should now have two-way communication
website. By adding an Ethernet shield to the Arduino, between the dashboard and your Arduino.
we can connect the robot glockenspiel to the Internet
Above of Things. SOUND THE ALARM
n Ethernet
shie d a ows our
The Ethernet shield is perhaps one of the simplest If that works, you can download the glock_iot_alarm
rduino to ta to and cheapest ways to connect an Arduino to the sketch, which is a mash-up of the previous example
the outside wor d
internet. To add it to your circuit, simply remove the and our glockenspiel code. As before, enter your
Below jumper wires from the Arduino, insert the shield into Adafruit IO username and key, and make sure that
he o p eted
o enspie an the Arduino’s pins, and then reconnect the jumper timeZoneOffset and daylightSavingsOffset are
e ontro ed ia wires in the same pin sockets as before. Now, plug correct for your region (if you want an advanced project,
the internet or
ro a e oard the shield into your router using an you could try to obtain these settings automatically
Ethernet cable. somehow). Next, on the Adafruit IO site, create a new
At this stage, both the previous dashboard called ‘alarm glock’ and populate it with
sketches should still work – you three new feeds: ‘alarmtoggle’ (a toggle button),
should try them out to verify that ‘alarmtime’ (a text block), and ‘alarmmelody’ (another
the circuit is intact. text block).
We’re going to use a service Upload the code to the Arduino and check the serial
called Adafruit IO, which facilitates monitor to see whether everything appears to be
IoT projects. Go to adafruit.io and running smoothly. If the sketch is working, you should
sign up (it’s free). Adafruit IO be able to set an alarm from the dashboard. Changing
consists of a series of ‘feeds’ which the alarm time or melody on the dashboard should
can be read or written to. There is an cause the alarm time or melody to be changed on the
Arduino library which handles the Arduino (and cause the LED to flash briefly), while
process of either reading or writing the toggle button should activate or deactivate the
data, so we want to install that and alarm (with the LED either on or off to show the
try an example. current state).

46
 LENS

MIDI input
MIDI (which stands for ‘Musical Instrument
Digital Interface’) is a technology used extensively
in studios and live gig situations to connect
synthesizers, drum machines, sequencers, and
more. For our final feature, we’re going to add a MIDI
input to the glockenspiel so that it can be played
digitally by another instrument.
MIDI outputs are relatively simple to wire up, since
you’re just sending an electrical signal down a wire, Left
but MIDI inputs are a little more complex. Since you in e the ar has a
i ited ran e on the
can’t really trust signals coming from external idd e o ta e o the
e oard a e ts
devices, a MIDI input uses an optocoupler which the o enspie
converts the incoming signal into pulses of LED light,
Below
then immediately back into an electrical signal again. he rest o the ir uit
Add the extra components to your existing circuit. re ains in p a e
ut addin a
In the Arduino software, install the ‘MIDI Library’ by port we an ontro
Forty Seven Effects and upload the sketch. You may the ro ot ar ro
another instru ent
actually need to disconnect the jumper wire from
pin 0 in order to do the upload, because the Arduino
gets confused between the computer’s USB signal
Switching brains
Since this project was already based around an Arduino Uno, a plug-and-play Ethernet
shield made sense, but there are loads of different ways to add internet connectivity to an
electronics project. You could swap your regular Arduino Uno for an Uno WiFi with wireless
capability, although it’s about twice the price of a regular Uno.
A Raspberry Pi would also be a good choice for this project, since many models come with
WiFi. You could either connect a RPi to the Arduino via USB, or run the whole build solely
from a Raspberry Pi. There’s a huge number of options for small controller boards at the
moment, and this project should work on most that can control servos (which is the majority).

and the keyboard’s MIDI signal – you can replace the

jumper after the sketch has been uploaded.

GETTING THERE SLOWLY

If everything is working properly, pressing certain keys
Signing off on the keyboard (middle C, and the octave of keys
above it) will now cause the servos to move. The code
You might notice that some numerical values in these is written so that holding down a key will move the
sketches are of the type ‘unsigned long’, rather than arm into position, and releasing the key will cause the
just ‘int’ (integer). The Arduino usually deals with time in
beater to strike. While this is a little counter-intuitive, it
milliseconds, but the number of milliseconds in a day is too
large to be stored as an ‘int’ value, so instead we use ‘long’
actually makes the instrument easier to play accurately Quick Tip
variables which can contain much larger integers. – if the Arduino attempted to move to a note and hit it
The ‘unsigned’ part means that the value can only be as soon as a key was pressed, there would be a If you made changes
positive, and allows for even larger numbers. If you find noticeable delay before each note while the arm to the note positions or
any strange behaviour while writing or modifying code for delay times in the main
moved into position. With this method, as long as the
your glockenspiel, think about whether any of the variables sketch, remember to
player can get used to playing ‘in reverse’, the latency copy these over to the
need to be ‘long’ or ‘unsigned long’ instead of ‘int’.
is much better, and it’s possible to play along in time to other sketches.
a piece of music.

47
Robotic Music Glockenspiel

FEATURE

Awesome
musical
instrument
hacks
Building your own
instrument gives
you a unique sound

T
here is a vibrant, worldwide
community of makers working on
exciting, fun, and often bizarre
homebrew musical instruments. By
thinking about the underlying design of an
instrument, makers often end up creating fascinating,
unusual music which would not be possible with
‘normal’ instruments.

48
 LENS

,
Marble Machine
First up, the terrifyingly complex and impressive ‘Marble
Machine’ by Martin Molin of the Swedish band Wintergatan.
This instrument uses a hand-powered mechanism to raise
hundreds of marbles to the top of a ramp, before gravity
transports them onto a glockenspiel in a preset pattern
determined by, what looks like, a system of Lego pegs. On top
of this, the machine (which is over six feet tall) has a built-in
‘drum machine’ with kick, snare, and hi-hat, plus an entire
semi-automated bass guitar. It’s impossible to adequately
describe, so go and add to the Marble Machine’s 100 million-
plus YouTube views and see for yourself.

wintergatan.net

Furbinator Above
he ar e a hine’
is a reathta in
one an and o
A somewhat more terrifying aesthetic can be found in an instru ent
Psychiceyeclix’s circuit-bent instruments. Circuit-bending
Credit
is the practice of altering an electronic device to generate a ue ester ren
sounds beyond what was originally intended, such as adding
a pitch-shift knob to a children’s piano. Psychiceyeclix has Left
a nderwood and
an active and fascinating YouTube channel, where he shows raha unnin
off his ability to make almost any piece of electronics sound p a in the a oth

Mammoth demonic. He has hacked everything from a Sega Mega Drive eat r an i e at
upersoni esti a
to a Thomas the Tank Engine sound book, and sells a lot of his

Beat Organ
creations through his Etsy store. Below
he ur inator’ a
ir uit ent ur
psychiceyeclix.wordpress.com s hi e e i

A similarly ambitious instrument to the Marble Machine,

the ‘Mammoth Beat Organ’ has been created by
Sam Underwood and Graham Dunning in England.
They describe the instrument as “a two-player,
semi-autonomous musical instrument” which plays
“unusual, sometimes erratic compositions drawing
on drone music, minimalist repetition, and fairground
organ techniques”. The mechanical design is modular,
allowing a combination of melodic and percussive
sounds to be triggered from a central drive shaft.

mammothbeatorgan.co.uk

49
Robotic Music Glockenspiel

FEATURE

Instrument
Sematary
Lia Mice is another maker who likes to modify existing
instruments, and puts them to use both in her live shows
Right
ho as rua ’s
and in the studio. Her ‘Instrument Sematary’ project involves
orni ator instru ent taking old, broken acoustic instruments and combining them
is i arre ut ersati e into new, Frankensteinian creations. The project was inspired
Below by the zombie animals in Stephen King’s story Pet Sematary,
e en ei h’s and its message is that musicians and instrument designers

Hornicator
o e is desi ned to should be aware of the environmental impact of their choices
e ade ro s rat h
e inners – recycling (or ‘upcycling’) is a common theme for a lot of
the makers mentioned here. The double-headed harp-guitar,
One musician who is particularly known for his homemade pictured, will be exhibited in London at the V&A’s Digital
instruments is Thomas Truax. His surreal songs take place Design Weekend, 21–22 September.
in the fictional setting of Wowtown, and are soundtracked
by his ‘Hornicator’ (an unholy union of a gramophone horn, liamice.com
several microphones, and numerous acoustic instruments)
and a variety of mechanical drum machines. He shows that
DIY instruments can become a signature part of a musician’s
sound and aesthetic – his creations have a steampunk style,
which elevates his stage show to another level.

thomastruax.com

MINI.MU Glove
Helen Leigh is another maker who uses
microcontrollers to make original instruments.
She has created a musical glove called the
MINI.MU, which uses a micro:bit. It was inspired
by the much more complex MI.MU glove, a
gestural MIDI controller which was designed for
the musician Imogen Heap. Helen took that idea
and created a low-cost wearable instrument with
a built-in speaker. The micro:bit’s accelerometer can
be used to trigger chiptune sounds, and the whole thing
is available as a kit which can be sewed and coded by
kids. The MINI.MU, along with Helen’s other projects
such as the beautiful ’sonic circuit sculpture creatures’,
can be found on her website.

doitkits.com

50
 LENS

Monolith
Take a look at the huge and ambitious ‘Monolith’ synth,
created by Ross Fish (Moffenzeef Modular), Darcy Neal (Lady
Brain Studios), Ben Davis (Malekko), and Paul Stoffregen
(PJRC). The synth is based on a Teensy 3.6 microcontroller
(basically a more powerful Arduino, capable of high-quality
audio), with a clear acrylic case mainly fabricated on a laser
cutter. The 40 arcade buttons act as a drum sequencer,
while the two end panels produce bass lines, arpeggios, and
textures. The instrument weighs around 40 kg, looks amazing,
and was designed as an “interactive sound sculpture” to be
exhibited at Maker Faires and other events. If you’re looking to
make your own synthesizer from scratch, the Teensy’s intuitive
drag-and-drop interface (which automatically generates
Arduino code) is a great place to start.

pjrc.com/monolith-synth

Chaotic Pendulum The projects mentioned here are just a tiny sample Above
he ono ith was a
of all the amazing musical instruments being hacked, o a orati e e ort
Some of the most fascinating homebrew musical instruments
modified, or built from scratch right now, so get onto etween our a ers
combine both mechanical and electronic elements, and a
great example of this is Mike Cook’s ‘Chaotic Pendulum’. The YouTube and find some more inspiration. If you want Below
i e oo ’s
design is based around a pendulum which is free to swing in to start building your own instruments, there are lots
instru ent uses
two dimensions. The pendulum has a magnet on the end, and of good places to start. If you’re interested in haos theor to
there are a number of magnetic switches (known as ‘reed enerate notes
circuit-bending, there is an excellent book on the
switches’) laid out underneath it. When the pendulum swings subject by Nicolas Collins called Handmade Electronic
close to one of the switches, the magnet on the end briefly
Music: The Art of Hardware Hacking, and you should
closes the switch, triggering a note via the MIDI output port.
The tiny amount of energy required to close the reed switch also check out Look Mum No Computer online. If
also causes a slight variation in the pendulum’s path, creating you’re not yet familiar with modular synthesizers,
a chaotic, ever-changing, mesmerising pattern. This project that’s an excellent rabbit hole to go down.
uses an Arduino to generate music, a subject that Mike For those who would rather build something digital,
literally wrote the book on: Arduino Music and Audio Projects there are loads of great platforms: Teensy, Bela, and
is available to buy online and is a great reference. Mike’s
Raspberry Pi are all great ways to build your own
website is also a brilliant resource, as he publishes detailed
build instructions for a lot of his instruments. audio inventions, and even an Arduino can be coaxed
into producing (lo-fi) sounds using the Mozzi library.
hsmag.cc/fvMipr Also, don’t discount the idea of designing instruments
in software on a PC first – it’s often a good way to
test out your ideas before bringing them into the
physical world.
If you’re more inspired by mechanical or acoustic
projects, you should look into the instruments
commissioned by Björk for her Biophilia show. It’s
also worth getting some background knowledge of
‘proper’ musical instrument building, perhaps by
binging on the satisfying guitar build/repair videos on
StewMac’s YouTube channel.
Whatever you do, make sure to have fun, and if you
come up with something cool, share the details of
your instrument online so that others can build on it in
the future.

51
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A food-foraging C. elegans robot

FEATURE

How I Made

A FOOD-FORAGING
C. ELEGANS ROBOT
Converting biology into computer science

By Tom Portegys

I
’m a member of the OpenWorm awareness through crossover education in
open science organisation biology, robotics, and coding (a popular
(openworm.org). Our aim is to approach in many educational
create a virtual worm. The worm environments). For OpenWorm, this meant
is C. elegans, a tiny (1 mm) building robots that approximate the real
nematode. Biologists have worm. The downside of this is that C.
been very fascinated with this elegans is, of course, not a
worm for many years, basically robot. However,
because it is so easy to study, simulating the worm in
with only about 1000 cells robotic form manifests
– 302 of those cells are a tangible aspect that
neurons (nerve cells). pure software models
C. elegans was the first do not possess. Also, a
organism to have its worm robot sidesteps
genome mapped out. working with actual
Another goal of worms, which requires
OpenWorm is to special conditions and
promote scientific equipment, such as
lighting and microscopes.
In early 2017, some of
us set about how to make a
In motion robot that tries to stay true to
the biology of C. elegans.
Videos of the robot can be found here: There were other C. elegans
Moving without sensor: robots around. For example, we
hsmag.cc/SdFcjJ talked to a researcher at the
University of Leeds, who had made a
Foraging food to right:
hsmag.cc/gXzGfl tube-like robot: hsmag.cc/bjCmdv. We
also were aware of a project by a former
Foraging food to left:
OpenWorm member that runs the worm
hsmag.cc/mjrTTV Above
The unpowered nervous system, called the connectome, in
wheels let a Lego robot: hsmag.cc/ehJ0Zn. We also
the robot
wiggle forward were guided by a couple of scientific

54
 LENS

Future implementations
These could include:

• Touch response. C. elegans responds to

touch on its nose by reversing direction.

• A Jupyter Notebook to provide a

programming interface to the robot. This
might also support software exercises
related to C. elegans, such as how the
neural network can be optimised to
achieve sensorimotor coordination for
touch response.

printing services are typically easy to

Above LOCOMOTION obtain, and in hindsight, dealing with the
The worm body designed
and ready to be 3D-printed The first version was based on a Raspberry challenges of DIY printing, building, and
Pi board, and accomplished one of the operating a printer did delay the completion
papers that proposed how the worm goals: locomotion. of the robot (personally speaking!).
moves (locomotion), and forages for food. The robot consists of nine articulated The Raspberry Pi Zero W is a full-fledged
Since no existing robot incorporated both segments, which is a simplification from microprocessor that included wireless
these ideas, it seemed like a good plan to the twelve segments in the real worm. communication capability. A PWM board
build a robot that modelled them. Each is segment mounted on a pair of
In the spring of 2017, Australian wheels. Locomotion is achieved, as it is in
robot-builder Shane Gingell joined the C. elegans, by moving in a snake-like
project, and he and I proceeded to forge manner that relies on surface friction. The
ahead. We ended up with two versions of wheels are hence not powered and exist
the C. elegans robot. The first is a to provide a suitable contact surface with
Raspberry Pi processor implementation, the ground.

Since no existing robot incorporated both

these ideas, it seemed like a good plan to
build a robot that modelled them
and the second is an ESP32 MicroPython Each segment is a 3D-printed component
system on a chip (SoC) implementation. that articulates with its neighbours via
Both implementations are a combined servos. The electronic components are
effort. Shane spearheaded the design and mounted on platforms fastened to several
initial build, and I built the versions used for of the segments. We both purchased and
external demos, as well as supplying assembled Tarantula 3D printers to print Above
The head section of the worm holds
software to run the simulation. the parts. However, considering that 3D the distance sensors

55
A food-foraging C. elegans robot

FEATURE

distributes power and controls signals from [219,-0.63,-0.65,-0.62,-0.58,-0.55,-0.51,-

the Raspberry Pi to the servos. Each servo 0.48,-0.44,-0.41,-0.37,-0.34,-0.30],
Resources is capable of maintaining a specified [375,-0.63,-0.65,-0.62,-0.58,-0.55,-0.51,-
angular position that translates to 0.48,-0.44,-0.41,-0.37,-0.34,-0.30],
The 3D models, code, assembly instructions, intersegment angular positioning. [531,0.63,0.00,-0.62,-0.58,-0.55,-0.51,-
and parts lists are available at:
We designed the parts and exported 0.48,-0.44,-0.41,-0.37,-0.34,-0.30],
github.com/openworm/robots
them as STL files so they could be printed [672,0.63,0.65,-0.62,-0.58,-0.55,-0.51,-
Both implementations of the robot can be on most 3D printers. The head is designed 0.48,-0.44,-0.41,-0.37,-0.34,-0.30],
constructed by someone with moderate to support sensors for food foraging and [812,0.63,0.65,0.00,-0.58,-0.55,-0.51,-
technical skills, after obtaining the parts from
touch, while segments support wheels and 0.48,-0.44,-0.41,-0.37,-0.34,-0.30],
various vendors.
parts of the electronics. [937,0.63,0.65,0.62,-0.58,-0.55,-0.51,-
The segments are articulated. A servo 0.48,-0.44,-0.41,-0.37,-0.34,-0.30],
is mounted on the front top of the [1047,0.63,0.65,0.62,0.00,-0.55,-0.51,-
segment, with its geared shaft extending 0.48,-0.44,-0.41,-0.37,-0.34,-0.30],
into an aperture in the next forward
segment. An arm secured to the gear The recording is transferred to the
sits in a recession in the segment that Raspberry Pi via the scp (secure copy)
transfers the angular movement of the command. To run the robot, the user logs
gear into angular movements between in via SSH, and executes a Python script
the segments. that initialises the servos and executes the
As previously noted, the locomotion of recorded file line by line.
the worm was described in a paper that A short video of the robot in action can
specified a fine-grained model of the be viewed here: hsmag.cc/TjaLNi.
worm’s neuromuscular system.
Unfortunately, the model entails a V2: FOOD FORAGING
computation-intensive physics engine that The RPi version supported locomotion,
is too demanding for the Raspberry Pi, however, we also wanted to have the robot
hence the recording/replay procedure. forage for simulated food. C. elegans
The robot replays a recorded sequence forages for bacteria in its environment by
of segment angle positions, that are sensing and following salt gradients

For the robot, a sensor that can provide

a proximity signal to a simulated food
source was needed as a counterpart

generated by an offline run of the model. produced by the bacteria. For the robot, a
Each entry in the recording is processed sensor that can provide a proximity signal
at a fixed interval of time, and contains a to a simulated food source was needed as
set of angles that are directly distributed a counterpart. A chemical sensor was not
to the servos. The anterior (forward) deemed to be feasible. Several other types
segments receive signals of greater of sensors were tried: sound, laser
magnitude than the posterior (rear) distance, and sonic.
segments. The overall effect is to Unfortunately, we found it difficult to use
achieve an undulating forward motion the Raspberry Pi to both read the sensors
that simulates actual worm locomotion. and drive the servos. So, for the second
Sample recorded angular movement data: version, a new processor was selected,
the ESP32 system on a chip (SoC).
Above [78,-0.63,-0.65,-0.62,-0.58,-0.55,-0.51,- The ESP32 provides a MicroPython
One segment assembled and ready
to be inserted into the worm 0.48,-0.44,-0.41,-0.37,-0.34,-0.30], interface that can run numerous general-

56
 LENS

Left
he first iteration
powered by a
Raspberry Pi

purpose services, such as WiFi. It was The following algorithm accomplishes

also very beneficial that the board contains locomotion combined with distance sensing:
both control and power distribution
connections for the servos, as well as turn_angle_delta = 0 turn_angle_delta = right_turn_
connections to support other peripherals, for each step: angle_delta
such as sensors. This simplified the print(“food right”)
design by dispensing with the PWM # Set servo angles. else if left_ping_distance < right_ping_
and voltage regulator boards required by for each segment: distance:
the RPi implementation. Another servo_angle = angles_array[step] turn_angle_delta = left_turn_
enhancement for the ESP32 version was [segment] + turn_angle_delta angle_delta
the use of laser-cut body parts. Although set_servo(segment, servo_angle) print(“food left”)
the 3D-printed body parts remained fully else:
compatible, the laser-cut parts made for # Check right sensor distance. turn_angle_delta = 0
a sturdier body. if head swing moving right and head print(“food forward”)
An ultrasonic distance sensor was angle is 45 degrees:
settled upon (after some stiff competition right_distance = activate_sensor() With this, we can study the movement
with a laser rangefinder) to allow the robot of the worm as it seeks out food in its
to forage for simulated food by seeking it # Check left sensor distance. simulated environment.
out by proximity. The food source was if head swing moving left and head angle
simply then any object that can reflect is -45 degrees:
sound, such as a cardboard box. This left_distance = activate_sensor()
approximates how C. elegans follows
chemical gradients in its environment to # Determine turn direction.
Worm robot
find the nearest food source. The worm if right_distance <= goal_distance or on the move
with the ultrasonic sensor mounted on the left_distance <= goal_distance: The C. elegans robot was demonstrated
head is shown at the start of the article. print(“food found”) as part of a public program of events
The ultrasonic sensor has a wide (30+ break associated with the conference that
degrees) view field. To achieve successful else if right_distance > max_valid_ was hosted by OpenWorm at the
navigation toward the nearest object, a distance and Sainsbury Wellcome Centre for Neural
Circuits and Behaviour in London, UK on
distance measurement is taken at 45 left_distance > max_valid_
31 January 2018. In May 2019, it went on
degrees from centre as the robot swings distance:
display at the Ars Electronica Center in
its head from side to side. An increment is turn_angle_delta = 0 Linz, Austria.
added to the segment servo angles, print(“food forward”)
depending on which side the object is to else if right_ping_distance < left_ping_
force a turn in that direction. distance:

57
Soundscapes to Landscapes

FEATURE

Soundscapes
Mapping bird diversity with citizen science and open-source

S
oundscapes to Landscapes is a algorithms to predict the distribution of bird species
citizen science project that uses based on environmental data gathered by NASA’s
open-source hardware – including remote sensors.
AudioMoth, a low-cost, full-
spectrum acoustic sensor, 351,692 MINUTES OF RECORDINGS
developed by Open Acoustic Devices The data collected by these systems can be used to
Cameron Norris here in the UK – to map bird diversity across determine the physical structure of vegetation over
Sonoma County, California. vast areas, such as the heights of trees and plants, as
@CameronSNorris
By comparing the research of citizen scientists with well as the canopy chemistry, which can be used to
environmental data gathered by NASA, the assess ecosystem productivity and habitat quality.
Cameron is a
technology and
Soundscapes to Landscapes project aims to advance “In my PhD research in the early 2000s, I explored
communications the use of remote sensing satellites for monitoring, these technologies in a wet tropical forest with the
specialist, passionate predicting, and conserving animal diversity on Earth. goal to map tree species and estimate forest structure
about the use of
open-source hardware “It is recognised that the data collected by citizen and biomass. These were some of the first
for social innovation. scientists can be much larger and even more accurate applications of these two types of sensors in tropical
than by paying a team to do the work,” says forests,” says Matthew.
Soundscapes to Landscapes project lead, Dr Matthew To complete their prototype phase in 2017, Matthew
Clark, a professor at Sonoma State University. and his team of local volunteers partnered with the
SENSING Matthew and his team of volunteers capture Pepperwood Preserve, a 3200-acre site that acts as a
SOUND ‘soundscape’ recordings at audible and ultrasonic refuge for over 750 species of plants and 150 species
frequencies, which are then used by experts within of wildlife in North California’s Mayacamas Mountains.
An acoustic sensor can
the birding community to identify bird species within While at Pepperwood, they collected AudioMoth
be any combination
of recorder, detector,
a particular area. These bird diversity maps make sound recordings from over a hundred different
microphone, or it possible to test the accuracy of models that use locations. The team also completed their species
hydrophone, designed
to detect and record
sounds in the
environment. They are
often small, increasingly
affordable, and can be
deployed in the field
for extended periods
to monitor wildlife
and its response to
human activities.

Images
Soundscapes
to Landscapes

Right
Citizen scientists
place audio recorders
in the fie d to apture
bird calls

58
 SPARK

to Landscapes
distribution modelling code in R (an open-source
software and programming language commonly used
for data analysis) and developed bird call identification WIDE
models and species distribution probability maps for
REACH
nine different species of bird.
‘ARBIMON’ stands
for Automated
ANIMAL BIODIVERSITY MONITORING
Remote Biodiversity
Initially, the project used Android smartphones to
Monitoring Network.
capture audio recordings but quickly switched to ARBIMON is a web-
based bioacoustics
analysis platform that
“WE WERE THRILLED enables anyone with
an internet connection
to access soundscape
WITH THE EASE OF bird calls. Citizen scientists can then quickly validate if
the bird call is really present or not.”
recordings. So far, the
research platform has
USING AUDIOMOTHS” Once that data is validated and labelled, it is passed
to a research team at the University of California that
collected over one
million recordings from
is using deep learning to identify bird calls. “We are monitoring stations in
AudioMoth due to the hardware’s simplicity and currently working on having a single convolutional Puerto Rico, Hawaii,
Arizona, Costa Rica,
low-cost per unit. “We were thrilled with the ease of neural network classifier that will identify 32 bird
Argentina, and Brazil.
using AudioMoths,” says Matthew. “We have also species in all of our recordings… currently 350,000
found the sound fidelity is much better than with the minutes in total,” says Matthew.
smartphone, which was designed to record human Despite the project’s growing support, there are still
conversations, not environmental sounds.” many areas of Sonoma County that are difficult for the
Following success in Pepperwood and surrounding team to access. “In the next field season, we will be
areas, Soundscapes to Landscapes received funding stepping up our effort to mail out flyers to targeted
from NASA’s Citizen Science for Earth Systems property owners in these areas, and hope to send Above
Capturing bird calls
Program (CSESP), which put the project on track to recorders out to these landowners for deployments in the fie ds
map all of Sonoma County, a vast area of over 1760 on their properties,” Matthew explains.
Below
square miles, by 2021. To find out more about the Soundscapes to Dr Matthew Clark and
a team of volunteers
Since the beginning of March this year, student Landscapes project and get involved in next year’s field conduct a survey in
interns and community volunteers have already season, visit soundscapes2landscapes.org. Sonoma County
collected recordings from more than a hundred sites,
totalling over 175,000 minutes of audio. “We could not
have had this productivity if it was not for the energy
and passion of our new project coordinator, Rose
Snyder, based at Point Blue Conservation Science,”
says Matthew. “Our team worked with Rose to create
a whole new process for managing citizen scientists
into teams, tracking AudioMoths, organising sound
recordings, and identifying properties to visit.”
Matthew believes that there is still work to do in
regards to providing NASA-funded citizen science
projects with more detailed guidelines on how to
promote and run projects with the general public.
“We worked with Sieve Analytics to create a new
Citizen Science interface to ARBIMON,” he says.
“This will allow us to find soundscapes with potential

59
Soundscapes to Landscapes

FEATURE

AudioMoth
A
udioMoth is a low-cost, open-
source, full-spectrum acoustic
sensor capable of recording
uncompressed audio to a
microSD card for environmental
and biodiversity monitoring in
remote habitats. It was designed by Andrew Hill
and Peter Prince, two computer science PhD
FLYING students at the University of Southampton, along
MAMMALS with Alex Rogers, a computer science professor at
the University of Oxford.
The Bat Conservation
These palm-sized devices are currently being
Trust is currently using
AudioMoth technology used to help researchers “move away from
to develop an automated passive continuous recording by individual, expensive
end-to-end system for devices, towards using multiple low-cost, smart
monitoring bats in devices that flood large and inaccessible
Britain. The system ecosystems,” says Andrew.
includes an app that Above
In addition to monitoring wildlife populations by The AudioMoth companion app can be used to schedule
enables volunteers to recordings, customise the gain and sample rates, as well as
send audio recordings recording sounds made by target species at a calculate the device’s approximate remaining battery life
to a central server for sampling rate of up to 384kHz, AudioMoth can also
processing, algorithms be used to detect potential threats to protected accurate track of time for recordings scheduled using
to automatically detect habitats by listening for poachers’ gunshots or the the companion smartphone app.
and classify bat calls to sound of chainsaws used in illegal logging. The companion app also enables users to
species, and an online
customise the gain and sample rates, as well as
portal to share the
survey results with
GUNSHOTS AND CHAINSAWS calculate the device’s approximate battery life with
volunteers and members “Until now, professional ecologists typically had been any given configuration. The size of a fully assembled
of the public. On top of surveying wildlife with commercial equipment. The AudioMoth is just 58 mm long, 48 mm wide, and
that, as much of the cost advantage of AudioMoth completely changes 18 mm thick, which is slightly bigger than a box of
technology as possible the science people can do,” says Alex. “Previously, safety matches. This means that over a hundred
will be open-source. if an ecologist had a small budget, they could devices can fit into a standard 25 l capacity backpack.
maybe only deploy three or four recorders. Now “From the beginning, we were looking to create
they can potentially deploy a hundred recorders, a minimal device we could run smart algorithms on to
meaning different types of wildlife surveys can only record when hearing a sound of interest,”
be conducted.” explains Alex. “With the Gecko MCU, we can do
The system is built around an energy-efficient nearly all the listening while the processor sleeps,
EFM32 Gecko 32-bit MCU, which includes up then it can wake up to run the detection algorithms
to 128kB flash and 16kB RAM. It also across a four-second sound buffer.” This feature
features an analogue MEMS microphone makes it possible to deploy AudioMoths in the field
(similar to the microphone inside your for up to twelve months, with each device listening
smartphone) and preamplifier with adjustable continuously for twelve hours per day.
gain. Power is supplied by “We have a lot of deployments in remote jungles
three AA-cell batteries or an and forests with extremely limited internet access,
Left
An AudioMoth ready to external 6 V lantern battery, but we are still planning to add low-power wireless
e dep o ed in the fie d while an RTC (real-time connectivity to new versions of the device for alerting,
to gather important
acoustic data clock) is used to keep an streaming, and research purposes,” adds Alex.
 SPARK

Right
PRICE DROP
The main mission
of Soundscapes to The bill of materials
Landscapes is to cost for the AudioMoth
advance the science is around £35 per unit,
of global biodiversity
monitoring from but researchers can get
sensors in space their hands on working
devices just as cheaply
by joining online

“THEIR TASK WAS collective purchasing

groups to bulk order
devices from web-
TO SURVEY A SINGLE Although no native cicada was identified during the
study, the detection capabilities of the device were
based PCB assemblers,
such as CircuitHub. The

1 KM SQUARE” tested by playing cicada recordings captured in

Slovenia (where the Cicadetta montana is commonly
most popular site so far
is GroupGets, which has
found) along with background noise captured in the run several successful
‘group buy’ campaigns
New Forest. Impressively, the detection algorithm
for the device, priced
LAST SEEN OVER 20 YEARS AGO achieved a true positive rate of 0.98 and a false around £40 per unit.
The first field study using AudioMoth aimed to identify positive rate of only 0.01.
the only cicada species native to the UK, the Cicadetta As AudioMoth is capable of recording the highest
montana, which was last seen in the New Forest frequency bat echolocation calls in the UK, which
National Park over 20 years ago. Cicadettas spend come from the lesser horseshoe bat at over 100kHz,
most of their lives underground as nymphs, emerging they also make ideal tools for organisations working to
as adults every seven years or so, and the high-pitched conserve bat populations. Since launching the British Left
Be part of a team of
call of the adult, at 14kHz, is out of the hearing range of Bat Survey in 2017, the Bat Conservation Trust has
volunteers and hike
most adults, making it difficult to search for in manual freely provided AudioMoths to volunteers participating to predetermined
sites on public and
surveys. As a result, 87 AudioMoths were deployed in in the annual study each year. private land to deploy
four New Forest locations for up to three months at a This year’s survey focused on discovering sound recorders, and
retrieve them after a
time from spring 2016 until early summer 2017. how much time is needed to collect the amount of few days
data required to estimate population trends for rarer
Below
bat species in South West Britain. Volunteers received Volunteers are busy
a survey kit containing an AudioMoth, a waterproof deploying AudioMoths
throughout
case, and memory cards for as many Sonoma County
non-consecutive nights as possible between
1st July and 11th August 2019. At the end of
the survey, participants are provided with a
list of all the bat species that they detected
and the data is used to determine the best
survey methods for a large-scale roll-out of
the British Bat Survey next year.
If you would like to get your hands on an
AudioMoth for the 2020 British Bat Survey,
visit bats.org.uk for more details. Or, if
you’d like to build your own AudioMoth from
scratch, visit openacousticdevices.info to
find all of the open-source documentation
you need to get started.

61
 o
Ugo Vallauri

INTERVIEW

g
U l
HackSpace magazine meets…

Ugo Vallauri
Focusing on openness in the repair economy

al
M
ost people who like
making things also like
to take things apart. We
love to see how things
work, and the best way to
do that is to break them,
then put them back together again. It’s
like a puzzle game, but one in which you
win a prize of an ‘extra’ nut or bolt.
However, this simple joy is at risk
of being extinguished. Appliance
manufacturers all too often use hard-
to-find screws, or glue things together,
meaning that it’s getting harder to fix the
things that you own. And in some cases,
you’re not even legally allowed to fix your
own stuff.
Thankfully, there are a number of
organisations fighting against this rising
tide of waste, ignorance, and restriction,
including the Restart Project, a London-
based organisation campaigning in the
UK and Europe to protect our right to
repair. We spoke to Restart’s co-founder,
Ugo Vallauri, about the green economy,
recycling, and why it’s essential that
we have the freedom to repair the stuff
we own.

Right
Two advocates for
re-use and recycling,
at the estart o fi e in
Brixton, London

62
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lauri
63
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Ugo Vallauri

INTERVIEW

g
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HackSpace The United Nations says that 80% of the overall greenhouse gas Of course, when you’re buying a new
the UK is the second highest producer emissions linked to the whole life cycle of product, it makes sense to consider energy
of e-waste per capita. What are we the product have to do with the efficiency as one of the criteria. It is a
doing wrong? manufacturing stage. It becomes very useful way to understand how much
obvious that the only thing we can do to money you might save during the use
Ugo Vallauri It’s obvious that a country reduce the environmental impact of using phase, but this does not take into
with the kind of economy of the UK would all these products is to make fewer of consideration how much energy and
be one of the highest producers of e-waste. them. Obviously when you’re talking materials are employed during the
Yes, we are consuming too much and about a fridge or an oven, there’s a manufacturing phase.
too fast, but we’re also not very efficient, significant amount of energy used in the This is why we are campaigning for the
compared to some other countries, at use phase, but when you compare it with right to repair, which among other things
collecting the products we no longer use small battery-powered products, during involves pushing for better regulations

l
for recycling. At the Restart Project, we the use phase you’re going to be using that prevent manufacturers from making
first believe that we should consume maybe 15% of the overall carbon products that do not meet minimum
more slowly than we do now, and that emissions of the overall life cycle of requirements of repairability, such as being
when products are no longer used by the that product. near-impossible to disassemble for repair;
first user, we should try to reuse them, Which means that the only providing as many spare parts as possible
by reselling them, giving them away. environmentally sound option is to for as long as possible; and providing

a
When certain products reach the access to repair manuals and

”
end of their useful lifespan, we are instructions to facilitate repair for
extremely inefficient – around the At the Restart everyone, and not just for
world generally, but in the UK in professional repairers, which for a lot
particular – at collecting all kinds of
Project, we first of products no longer exists widely
electronic products. believe that we in our communities.
This is particularly true for smaller should consume I don’t mean smartphones, tablets,
products that a lot of people are still
more slowly than and other IT products – they’ve
adding to their non-recycling waste, generated a thriving repair
we do now

”
so they end up in landfill because community. But for many other
they’re small. Obviously, it wouldn’t products that people tend to bring to
be possible to do this with a washing repair events like our Restart Parties
machine, but it’s perfectly possible to do keep using, repairing, reusing, and or to Repair Cafés, such as kettles, toasters,
with a kettle or a toaster. extending the lifespan of that product as printers, headphones, hair straighteners,
On average, around the world, we are much as possible, before it reaches the hair dryers, and many other products.
still very inefficient at recycling recycling phase.
electronics, and a high proportion of them HS Yes! We visited a Repair Café earlier
simply don’t get recycled at all – more HS I’ve seen the argument that modern this year. It’s amazing how many simple
than half of all electronics are not recycled. appliances are more energy-efficient, appliances are designed to stop you from
On top of that, there is a misconception and therefore it’s more environmentally fixing them when they break.
that recycling is always the best thing responsible to upgrade your laptop,
to do. Many critical raw materials used for example, for something that uses UV That’s exactly why we’re campaigning,
in smartphones aren’t recycled at all, less energy. with our partners across Europe, to push
such as beryllium (used in connectors), for a European-wide movement for right to
gallium (in integrated circuits), indium UV That is absolutely wrong. This only repair. We know that for many products
(in touchscreens) and silicon metal applies to things like your fridge and there simply is no regulation whatsoever
(in microchips). other larger appliances. All evidence limiting the power of manufacturers to just
For other materials, the amount of points to exactly the opposite. If you were do whatever makes the most sense to
recycling is extremely low, including to look at the energy consumption in use them, irrespective of the environment.
graphite (used in batteries), neodymium for a laptop, in order to make up for the For some products, some regulation
(in microphones) and tantalum proportion of environmental damage exists, and we’ve actually pushed the
(in microcapacitors). caused by that product during the option of initial minimal right to repair and
It gets worse than that. In the life cycle manufacturing phase, you would have to repair provisions in European legislations.
of a smartphone, for example, the iconic keep a laptop in use for ten years to make From 2021, new televisions, electronic
product of this generation, approximately up for that. screens, dishwashers, and fridges that

64
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lauri
Right
On average we in the
UK each produce 24.9kg
of e-waste per year (the
worst offenders are the
Norwegians)

65
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INTERVIEW

g
U l
come to the EU market will have to have a professional or not, which is fairly repair and reuse of products and less of a
list of spare parts available for at least worrying, because it could potentially throwaway economy.
seven years after the product is taken out create the conditions for only authorised
of the market, as well as access to repair repairers performing certain types of HS That’s European lobbying that you’ve
manuals and design that allows accessing repairs agreed by the manufacturers, been doing — have you done much with
those spare parts without further which is pretty much what’s happening the UK government? I know that you’ve
damaging the appliance that you’re trying right now. won the backing of the Green Party
to fix, which unfortunately is very and the Liberal Democrats. How have
frequent. You need to be able to fix the HS Still, a start though, to have the you been getting on with Labour and
things you own: if you can’t fix it, you don’t need recognised? the Conservatives?
really own it.
Unfortunately, the manufacturers have UV Absolutely, it’s a start, and that’s why UV Last October, in Manchester, we

l
been able to water down our proposals. we want to use this precedent to push for gathered 59 repair activists from across
Access to the wider set of spare parts and much wider adoption of measures that the UK who took part in Fixfest, our
to repairer information will be restricted translate this concept to all kinds of other national gathering. We co-wrote the
to what are called ‘professional’ repairers, products. The case of smartphones is Manchester Declaration, which has been
which would leave a lot to be desired. For quite shocking – we’re talking about signed by over 40 community repair
example, this means that if you need to globally over 1.5 billion new devices sold groups and 15 organisations supporting

a
replace the light bulb within your fridge, per year. We see that there’s a very recent it, asking for all barriers to repair to be
you as an ordinary citizen might taken down. [The Greens and

”
not be able to buy the light bulb for the Liberal Democrats already
your fridge, but a professional You need to be support this.] We received
repairer might be able to do that endorsement for the Declaration
for you. Which doesn’t make any
able to fix the from our first two Labour MPs:
sense to us. things you own: Helen Hayes in Brixton and
Obviously there will be if you can’t fix it, Tulip Siddiq from Hampstead
manufacturers that provide you
you don’t really and Kilburn.
with better access, but we need We have groups around the
own it

”
regulations to be more ambitious. country that are actively reaching
This is a good start, but we need it out to their MPs from all parties
to be more universal in terms of to invite them to community
what you can access and in terms of trend of people wanting to keep products repair events and ask them to endorse
what kind of products are included in in use for longer, and we’re pretty sure the Declaration, so we foresee a lot more
these measures. The biggest target for our that if conditions were simplified for cross-party support on this front.
work in campaigning on the right to repair people to extend the useful life of a If it is true that the UK government is
is to have smartphones be regulated product by making it easier to access aiming to do better than what Europe is
as well. repair when a button goes wrong – or a trying to achieve, then this is a very good
speaker, or a camera, or a charging port, opportunity to ask any manufacturer of
HS If access to spare parts is limited which we see quite frequently, or more any product that’s sold in the UK market
to professionals, what constitutes a reliable battery replacement – this trend to make spare parts and repair manuals
professional? Who decides who’s a will be more prevalent, and we will see a available to everyone, right away. There’s
professional person? longer lifetime for this product, which will an opportunity to lead in their area, if
be win-win for the environment, and also only there were the willingness to do it.
UV The regulations state that member for providing a more vibrant local That’s what we’re working towards.
states will have to have a register of economy for repair. The UK, Germany, and Italy have
professional repairers, which includes Repair jobs are the original green jobs. historically had large manufacturing
repairers that are insured for the work that They provide jobs for individuals in local sectors, and perhaps it shouldn’t come as
they do. Where such a register doesn’t communities, as opposed to continuing a surprise that when the regulations for
exist, it will be up to the manufacturer to to buy and upgrade to new products refrigerators, washing machines,
accept or reject a request for spare parts or that rely on poor working conditions dishwashers and the like were discussed,
access to manuals for professional repairs. elsewhere in the world. At a time of there were three countries that were
So, it will be up to the manufacturers to climate emergency, we have a chance seen to be blocking the regulations: the
determine whether someone is a to put things right by promoting more UK, Germany, and Italy. And so we put

66
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lauri
Left
Repair activists from
around the world will
convene at the global
Fixfest happening
in Berlin from 20–22
September

67
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INTERVIEW

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68
Above
The Restart Project practices what it
preaches – there’s an old printer in the
o fi e that wou d ha e een thrown
away years ago anywhere else; here it’s
being kept alive by a Raspberry Pi
al
o
LENS

ri
pressure specifically on these countries,
to prevent further watering down.
And by the way, this is not just in the

u
interest of consumers; it’s also in the
interests of repairers of all kinds, because
repairs will be faster, better, and easier. And
it’s also in the interests of the work done at
the end of the product’s life, by the

a
recyclers: if a product is designed for
disassembly, it’s designed so that more of Left

l
Toasters are often
the components that still work can be built to be thrown
removed. It’s in everyone’s interest. away, even when they
can be made whole
Proper regulation will mean a level with a tin fi
playing field, so manufacturers can
compete without undermining consumer for longer – or TVs for that matter – how after a certain day. There are
rights and the environment. Until this can we justify manufacturers making two consequences to this. However, that said,
happens, they will always try to defend the or three years of security updates and then the trends we’ve seen in computers
status quo. Also, they use the argument abandoning products? It’s contributing to preventing any hardware upgrade –
that repairs shouldn’t be allowed because premature obsolescence. because RAM is soldered on the
it is not safe for other people to access Why is it that Google doesn’t provide ten motherboard, SSD drives are soldered as
the product they have made. We think years’ worth of security updates to the well, or they are provided for some models
that, actually, lack of documentation phones that it provides software updates with proprietary connectors so they
access to the official precise repair to? It has the capacity to do that, so why cannot be found in the market, and a lack
documentation might create cases where doesn’t it? of ports – is certainly something that we
repair becomes less safe, because people Could we think of devices with a kill see as extremely worrying.
might use alternative sources that might switch, so the moment the smart element At the end of the day, we’re talking
be less reliable. of the device is no longer secure, we can about creating an economy that makes
more sense for people and the

”
HS I remember that argument planet. To repair and reuse can be
from John Deere [US maker of an essential part of this. No data
tractors, combine harvesters, and
Use your amazing would contradict what I’m about
other agricultural equipment], that skills to contribute to say that it is environmentally
allowing non-authorised repairs to a future where more efficient to extend the
would be dangerous.
people and use case of the current product,
rather than recuperating some
planet are a lot

”
UV The John Deere case is materials and some components
interesting because it opens happier to make a brand new product
up the other big issue, which is to be sold again in the market.
that of software. In the United You can create a lot more
States, a big part of the fight for the right turn it off and use it as a non-smart device, jobs by having proper maintenance
to repair is intellectual property. In the the way we used to use devices before, and reuse economies to prevent
case of John Deere, the question was: without compromising safety or security unnecessary recycling and unnecessary
‘can a company lock access to a product depending on the product? throwing away of products that are
by installing a piece of software that will These are some of the trends we have already manufactured.
make it impossible for a product repaired seen. Software is increasingly the reason Make use of whatever resource you
by a third party to be used again unless people give up on a product, and it’s not already have; keep using and making the
it’s verified again by the manufacturer?’ repairable unless it can be substituted with most of the component that you already
This is a really big issue and, more broadly, a free and open-source alternative, which have – this should be at the heart of every
extended firmware support and security is the case for quite a lot of products. tinkerer. Use your amazing skills to
updates for products is one growing It’s a real decision by a manufacturer to contribute to a future where people and
cause of concern that’s not yet tackled by stop supporting a product. This is not about planet are a lot happier, by preventing
regulation either. At a time when people conspiracy theories; it is a real decision waste and ensuring that everything is
already want to keep their smartphones and there is a plan to say no more support used to the fullest that is possible.

69
Improviser’s Toolbox: Umbrella

FEATURE

UMBRELLA Looking for inspiration? The brolly’s got you covered

O
Mayank Sharma ne of the oldest pieces of handheld umbrella affordable to everyone later in that century.
accessories, the umbrella was Leather made way for lighter textiles such as silk,
@geekybodhi
invented over 4000 years ago which became quite popular. These days you can find
in Mesopotamia. Archaeologists many different types of umbrellas; some are easier to
Mayank is a Padawan
maker with an have found evidence of umbrellas operate, and others can double up as a walking stick.
irrational fear of drills. in ancient digs all over the world, Several hundred million of these are made in the
He likes to replicate
electronic builds,
including Egypt, Greece, India, and China. The word Chinese provinces of Guangdong, Fujian, and Zhejiang
and gets a kick out ‘umbrella’ is Latin in origin, and means ‘shade’ – the which house over a thousand umbrella factories.
of hacking everyday contraptions were originally designed to provide The use of the umbrella was rather unpopular in
objects creatively.
protection from the sun. The rainproof versions, England in the 1700s. It was thought of as a tool for a
made with treated paper, popped up poor man who couldn’t afford the luxury of a carriage.
in China only about 1500 years It was serial philanthropist, traveller, and writer Jonas
ago. The brolly made its way
into Europe thanks to
the Silk Road – it
“ The rainproof versions,
became popular made with treated paper,
with the Romans popped up in China only
as a guard against
the heat.
about 1500 years ago “
Back in the
day, umbrellas Hanway who helped establish the umbrella as part
used to denote of everyday Londoner’s attire around 1750, after
wealth and status. enduring much ridicule. The prejudice didn’t evaporate
History is littered with text until the 1850s. But gradually, umbrellas gained
and drawings of kings, priests, and acceptance, and stands for them became a common
high-ranking officials being accompanied item of hallway furniture.
by umbrella-bearers. Not only do we carry our Over time, umbrellas have unfurled their way into
own umbrellas now, but it’s also no longer many aspects of our lives, and are used for all sorts
regarded as an accessory just for women, like it of creative purposes. They are a popular form of
was for several centuries. decorating exotic drinks and cocktails; the security
Frenchman Jean Marius is often credited for detail of former French President, Nicolas Sarkozy,
introducing the folding umbrella to Europe in 1710. has also used a Kevlar-coated one as a defensive
Manufacturing advancements and access to newer, device. Here are some less exotic, but equally
and relatively cheaper, raw materials made the creative hacks for your portable hand canopy.

70
 LENS

SOUND DOME
Project Maker
Matthew Ebisu
Project Link
M atthew is fascinated by umbrellas.
On the lookout for ways to use them
to their full creative potential, he came
across the umbrelAudio unidirectional
hsmag.cc/ZRhOU0
speaker, and decided to create one
of his own using an umbrella. Instead of a plastic
bowl, Matthew uses a dome umbrella as a parabolic
unidirectional speaker that’s able to direct audio,
such as music, to one

“ The original hack is specific location. You’ll

need several bits and
almost a decade old, and bobs to replicate his
Matthew suggests using build. The laborious

Bluetooth speakers now “ process involves creating

and attaching a mount
for a battery-powered
speaker, and running wires from the speaker to your
audio source. Matthew used a couple of hooks
to hang his umbrella speaker on
his dorm’s light bowl fixture to get
the true Cone of Silence feel. He
suggests you place the speaker
at least 5” from the top of the
umbrella to maximise the sound
space. The original hack is
almost a decade old, and
Matthew suggests using
Bluetooth speakers now
to save a lot of hassles
soldering wires and keep
the build clean, adding that
he’ll now “probably go with a
Above programmable field sound array
Besides detailed build
instructions and videos of to disperse the sound across the
audio tests, Matthew’s also entire umbrella, as opposed to just
shared details about the
physics of the sound domes one location.”

71
Improviser’s Toolbox: Umbrella

FEATURE

SMARTPHONE
CAMERA
EXTENDER
L
Project Maker isa runs a DIY blog – she was out
Lisa Richards of ideas to make something for her
husband for Father’s Day when she
Project Link
hsmag.cc/pyZAFk saw a picture of a camera extender.
“I needed something that telescoped
in on itself, but was strong enough to support the
camera,” writes Lisa. A little research later, she
decided to use an old umbrella. She first removed
the canopy from the umbrella and then used pliers
to strip away all the metal support ribs to leave
just the main pole. She then drilled a hole in the

“ the DIY selfie

Left
One weird trick to spam
social media with
pictures of your face
stick doesn’t have a
mechanism to trigger
the camera’s shutter “

top to fit in a screw. Lisa made sure the hole was

long enough to leave some threads of the screw
exposed. Here she screwed a mini tripod camera
holder. After shaving off some of the
plastic cover of the umbrella, she
was done. Remember though,
the DIY selfie stick doesn’t
have a mechanism to trigger
the camera’s shutter. Lisa
suggests using a camera app
with a long enough timer to allow
you to set up the shot. If you can
live with this minor inconvenience,
Lisa says you can save yourself quite
a lot of money, even if you had to buy
everything for the hack.

72
 LENS

BACKPACK COVER
A
Project Maker gatha’s backpack bore the brunt of the
Agatha Lee rainfall as she and her son walked to
the Handmade Movement Fair in the
Project Link pouring rain with a small umbrella.
hsmag.cc/JwhsKp
That’s when she decided to upcycle an
old unused umbrella into a waterproof cover for her
backpack. The first step is the trickiest, and involves
removing the canopy from an umbrella without any
damage to the fabric. Agatha used a kids’ umbrella
that had a thread that connected the canopy to the ribs
and was relatively easy to dismantle, but your mileage
may vary, depending on the type of umbrella you use.
It was fairly simple from here on. Agatha is a textile
artist – she details the entire process of sewing a tube
around the canopy with a needle and thread, and some
chalk and measuring tape. She then uses a safety pin
to pass a length of elastic through the tube, before
sewing the ends to complete the cover.

UMBRELLA
PARACHUTES
B
rian loves making parachutes from Above
old damaged umbrellas. He starts by You can even use the
umbrella’s original
Project Maker cutting out the canopy from the umbrella fastener to fold the
Brian Wente using a box cutter – in a similar fashion cover when it’s not
in use
to Agatha’s (above). If you do it carefully
Project Link enough, you can get it done without cutting off Left
hsmag.cc/eHzixx Brian created one
the tip, which then comes in handy to tie a length of these for his
of nylon cord. Brian’s canopy has eight tips, so he daughter’s Hunger
Games -themed
takes a cord that’s about 1.5 times the radius of the birthday party
umbrella, and doubles it into eight strands before
tying off one end into a knot. He then cuts the other a sewing machine. Finally, attach a piece of weight.
end and attaches each of the eight strands to the Brian suggests using a heavy weight for a good
tips of the canopy. If you don’t have tips, you can show. Now gather your chute, roll it up, and throw it
knot each end, and stitch them to the canopy with as far up in the air as you can.

73
3 ISSUES from £5
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FORGE
HACK MAKE BUILD CREATE
Improve your skills, learn something new, or just have fun
tinkering – we hope you enjoy these hand-picked projects

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82
LORAWAN
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76
Get into the long-range
Internet of Things
SCHOOL OF
88
PG

MAKING
HOLD ON Start your journey to craftsmanship
with these essential skills
Get a grip on your work with
our top workbench techniques 76 TFT screens
78 CircuitPython
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94
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100
SENSING CABLE ORGANISER
Build a smart ornament that
mimics the world around it Cut, heat, and shape acrylic to create
order out of cable chaos
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104 108
DIGITAL CALLIPERS
Measure twice – not because you TEMPERATURE CONTROL STAY SHARP
love accuracy, but because digital Create constant temperatures Keep your tools sharper, safer,
callipers are so lovely out of recycled materials and needing less effort to use
Graphical output for (almost) any board

TUTORIAL

Graphical output
for (almost) any board
Add an ILI9341-powered screen in Arduino and CircuitPython

S
ometimes you need a little bit of • MISO (Grand Central pin 50)
graphics or text output for your • MOSI (Grand Central pin 51)
projects and, for this, TFTs are a great • CLK (OR SCK) (Grand Central pin 52)
solution – they’re cheap, available in a • CS (or SS) (Grand Central pin 53)
range of sizes, and well supported by
maker hardware. TFT stands for The following aren’t SPI pins, but also need to be
thin-film transistor – essentially, TFTs are liquid crystal connected. As they’re not part of SPI, it doesn’t
Ben Everard
display (LCD) screens with fast refresh rates. The matter which pins you connect them to, provided
@ben_everard main thing you need to know when looking to get one they’re digital IO. The pin numbers we’ve used
is the driver chip it uses. There are a few that are easy could easily be changed.
Ben loves cutting stuff, to use; in this tutorial, we’ll look at ones driven by the
any stuff. There’s no
longer a shelf to store
ILI9341 chip. The driver should come on the TFT • DC (Grand Central pin 49)
these tools on (it’s now board, so we don’t need to worry about wiring the • RST (Grand Central pin 48)
two shelves), and the two together. Instead, we just need to connect the
door’s in danger.
module to our microcontroller. That’s all there is in terms of physical setup.
This connection uses SPI (plus a couple of other Let’s now take a look at what code we need. The
wires), so the first thing we need to do is to connect Grand Central can use either Arduino or CircuitPython,
the four SPI pins to an SPI bus – it’s quite high speed, so let’s take a look at how to use it in both these
so it’s best to make sure it’s on a hardware SPI. Most languages. First, we’ll look at Arduino.
microcontrollers have one of these, so look up where You’ll need to install the Adafruit GFX library –
Above yours are. The following connections go from the that’s a high-level graphics library that can work
Your TFT board
should have the pins relevant pins on the microcontroller to the labelled pin with a range of displays. You’ll also need the
labelled to make it on the TFT screen. We did this on an Adafruit Grand low-level Adafruit-ILI9341 library that handles this
easy to connect up to
your microcontroller Central, so the numbered pins are the ones we used. specific driver chip.

76
 FORGE

In the File > Examples menu, you’ll find Adafruit

ILI9341 > graphics test. This is, as you may guess, a
test for this particular TFT. There are a few
configurable options on this. Above the setup
method, you’ll need the following code:

#include “SPI.h”
#include “Adafruit_GFX.h”
#include “Adafruit_ILI9341.h”

// For grand central. Other boards might need

different pins
#define TFT_DC 49
#define TFT_CS 53
#define TFT_MOSI 51
#define TFT_CLK 52
#define TFT_RST 48
#define TFT_MISO 50

Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS,

TFT_DC, TFT_MOSI, TFT_CLK, TFT_RST, TFT_MISO); This creates a display object that you can draw to. For
more information on what to do with this, take a look Above
The wiring is the
With that saved, you can upload it to your board and at the CircuitPython tutorial that builds on the display. same whichever
you should see various different graphics tests appear However, for the purposes of this article, we just language is used

on the screen. That’s the screen running. What you need a simple test to make sure everything’s wired
do with it is up to you. If you have a look through the up properly and working. For this, you can enter the
example code, you should get an understanding of following code under the above:
how to use the GFX library to display whatever
graphics you want. splash = displayio.Group(max_size=10)
display.show(splash)
GETTING SNAKEY
Now let’s try with CircuitPython. First you’ll need to color_bitmap = displayio.Bitmap(320, 240, 1)
flash your board with CircuitPython 4.1.0 or later. color_palette = displayio.Palette(1)
There are two sections to the code. The first part color_palette[0] = 0xFF0000
sets up the display. You’ll need to use this whenever bg_sprite = displayio.TileGrid(color_bitmap,
you’re using this screen. It is as follows: pixel_shader=color_palette,
x=0, y=0)
import board splash.append(bg_sprite)
import displayio
import adafruit_ili9341 while True:
from time import sleep pass

displayio.release_displays() If everything’s worked properly, the display turns red.

That’s how you get your ILI9341 display wired up
display_bus = displayio.FourWire(board.SPI(), and running in both languages. There are pros and
command=board.D49, cons to both. You’ll get much better performance
chip_select=board.D53, from the Arduino language, but it can be quicker to
reset=board.D48) get started with CircuitPython. Your choice may also
display = adafruit_ be determined by the hardware, as almost all hobbyist
ili9341.ILI9341(display_bus, width=320, boards run Arduino, while a smaller (but growing)
height=240) number run CircuitPython.

77
Control a screen with CircuitPython

SCHOOL OF MAKING

Control a screen
with CircuitPython
Help otters frolic through the fields on a PyPortal

T
he displayio framework first wide and high. The following code will display a
appeared in CircuitPython running otter on the screen:
4.0.0, but the performance
was slow and it could only
import board
really be used to display static
import displayio
images. However, in version 4.1.0
from time import sleep
Ben Everard the performance has improved vastly, and it’s
now possible to use this language to display
@ben_everard display = board.DISPLAY
animations. Let’s take a look at how this works.
group = displayio.Group()
We’ve used a PyPortal for this, but other
Ben loves cutting stuff,
CircuitPython devices should work. If your device
any stuff. There’s no with open(“/images/otters.bmp”, “rb”) as otters_
longer a shelf to store doesn’t have a screen built-in, you can attach one
img:
these tools on (it’s now (see the page 76).
two shelves), and the otter_bitmap = displayio.OnDiskBitmap(otters_
door’s in danger.
Displayio is made up of multiple levels:
img)
otter_tile = displayio.TileGrid(otter_
Display This is what controls how the screen is
bitmap,pixel_shader=displayio.ColorConverter(),
connected to the microcontroller. It displays a Group.
width=1, height=1, tile_width=96, tile_height=96)
Group This pulls together the graphical elements into
group.append(otter_tile)
a scene. It’s made up of other Groups and TileGrids.
counter = 0
TileGrid This contains one or more images that can
direction = 1
be displayed (but aren’t necessarily all displayed at
while True:
the same time). They’re used to control Bitmaps.
for image_num in range(4):
Bitmap This is a grid of pixels and associated
counter = counter + (3 * direction)
colours. Bitmaps are the lowest-level primitives that
otter_tile[0] = image_num + 8
your images are built up from.
otter_tile.x = counter
display.show(group)
This all sounds a bit abstract, so let’s build up an
sleep(0.2)
animation and see them all in action. Firstly, we’ll
if counter > 320 or counter < -96:
need some images to build up our bitmap. You can
direction = direction * - 1
draw your own if you like, but we took a look at
otter_tile.flip_x = not otter_tile.flip_x
opengameart.org to find some we could use; we
came across an adorable otter at hsmag.cc/UfAfne
– it’s the otters.png image you need. You can As you can see, adding a display is simply a case of
download this as a PNG, but we need a bitmap, so pulling it from the board module. If not running on a
you’ll need to open it in a graphics program and save board with a built-in screen, you’ll need to set this up
it in BMP format. We need this file as otters.bmp in more fully. See the page 76 for details.
an images folder on the CircuitPython device. A bare group can also be created with a simple
If you have a look at this image, it’s made up of 16 line. Most of the graphics setup is done with
smaller images in a 4×4 grid. Each image is 96 pixels the lines:

78
 FORGE

with open(“/images/otters.bmp”, “rb”) as otters_

img:
otter_bitmap = displayio.
OnDiskBitmap(otters_img)
otter_tile = displayio.TileGrid(otter_
bitmap, pixel_shader=displayio.
ColorConverter(),width=1, height=1, tile_
width=96, tile_height=96)
group.append(otter_tile)

This opens the otters bitmap and uses the file

object to create a bitmap object. The TileGrid object
takes a few more parameters:
otter_tile[0] = image_num + 8 Above
OpenGameArt is
otter_tile.x = counter a fantastic resource
otter_bitmap is the bitmap that the grid is
display.show(group) for graphics for
taken from. embedding in your
projects (whether
pixel_shader: Bitmaps contain a grid of colours; as game-related or not)
we’ll see later, these aren’t necessarily actual RGB The first line is probably the oddest. We’ve got our
colours, so we need a way of converting between TileGrid called otter_tile that only displays one tile
the bitmap and the display colour. This is the (at index ‘0’), but contains 16 source tiles from our
pixel_shader, and in this case we can use the bitmap. We have to decide which of these source
built-in one. tiles to put on the screen. This is in a for loop that
width and height define how many tiles will be iterates between the numbers 0–3, and we want the
displayed in the TileGrid when it’s on the screen. displayed image to rotate between images 8–11. We
As we only want one of the otter images on a also have the variable counter that we increment and
screen at any one time, this is ‘1’ in both cases. decrement to move the x position of the TileGrid
tile_width and tile_height are the size of each along the screen. Finally, we have to display the
tile in the source bitmap. group in order to make our changes visible.
If you upload this code, you should see an otter
At this point, we’ve got all our images loaded into running backwards and forwards across your screen.
memory, and sliced up, but we haven’t actually put However, it will be in a white square on a black
any of them on the screen. We do that in the while background. Otters don’t run in white squares, so
loop, particularly in these three lines: the next step is to get ours running joyfully across a
natural background.

ENTERING THE FOREST

Our source image has a transparent background, but
this gets lost when we convert it to a bitmap image.
We need a way of importing our image which
preserves this. The alternative way of bringing
images into displayio is by setting the data points in
the bitmap directly and creating a palette.
Each pixel in a bitmap is stored as a single
number. The palette then links these individual
numbers to an actual RGB value. As such, it uses
far less memory because there’s only one number
per pixel rather than three (one for each RGB value).
We need to process our image in the right format.
It’s a bit CPU-intensive to do this on the
CircuitPython device, so we’ll do it on our main
Left
computer using Python. You’ll need Python 3 with Our lo-res otter
gives us a good
NumPy and Python Imaging Library (PIL) installed – hit of nostalgia for
we recommend using Anaconda, but you can also 16-bit consoles

79
Control a screen with CircuitPython

SCHOOL OF MAKING

#need to print the pallette data differently as the

hex values are stored in strings
#and will be outputted with quote marks unless we
do this
print(“otter_pallette_data = [“,)
for colour in outpallette:
print( colour, “,”)
Right
The Mu editor is the print(“]”)
easiest way of
programming
CircuitPython – some
other text editors This opens a file called otters.png (located in the same
cause problems directory that you’re running this script from) and
outputs, to the terminal, the Python data structures
install them manually (or via your package manager if holding the bitmap and palette. We pushed this straight
you’re on Linux). into a Python file by running it with the following:
The code for the conversion is:

python convert.py > otter_data.py

import numpy
from PIL import Image
This will create a PY file that we can copy to our
CircuitPython device and import – but before getting to
#NumPy magic to convert image to Python list
that point, let’s take a look at what the script does.
img = numpy.asarray(Image.open(‘otters.png’)).
We won’t dwell on the line that does some magic
tolist()
from NumPy and PIL to create a 2D list containing the
RGBA (the final A is the Alpha or transparency) values
pallette = []
for each pixel. It just uses some built-in methods to do
outbitmap = []
the hard work.
strippedbitmap = []
We then have to loop through this and, for each
outpallette = []
pixel, see if that colour is already in the palette and, if it
is, link that pixel to the index of the colour. If it isn’t,
#convert array of RGBA values to bitmap and pallet
add the colour to the palette, then link it to the index of
for i in img:
the colour.
line=[]
for j in i:

”
try:
colour = pallette.index(j) This gives us our
line.append(colour) transparent image, but we
except ValueError:
pallette.append(j) need something for it to be

”
colour = pallette.index(j) transparent against
line.append(colour)
outbitmap.append(line)

We finally have to convert the RGB values, which

#strip transparency & convert to hex
are stored in lists to a hex string, and strip out the parts
for colour in pallette:
of the image that we don’t want (as we’re pushing the
outpallette.append(‘0x%02x%02x%02x’ %
memory limits of the PyPortal as it is).
(colour[0],colour[1], colour[2]))
This gives us our transparent image, but we need
something for it to be transparent against. We used
#strip down to just the running otter
the trees and bushes images from hsmag.cc/
for x in range(96):
rtasZA, but scaled to be 320×240 pixels to match
strippedbitmap.append(outbitmap[2*96+x])
the dimensions of the screen. We saved this as
background.bmp in the images folder on
print(“otter_bmp_data =”, strippedbitmap)
the PyPortal.

80
 FORGE

The final image for our running otter is as follows:

import board
import displayio
from time import sleep
import otter_data
display = board.DISPLAY
group = displayio.Group()

otter_bitmap = displayio.Bitmap(384,96,18)
background_file = open(“/images/background.bmp”,
“rb”) if counter > 320 or counter < -96:
background_bitmap = displayio direction = direction * - 1 Above
The otter running
OnDiskBitmap(background_file) otter_tile.flip_x = not otter_tile.flip_x across our PyPortal
background_tile = displayio.TileGrid(background_
bitmap, pixel_shader=displayio.ColorConverter())
As you can see, this loops through the data structures
our script created to add the pixels to the bitmap and
#load the otter pixel data
the colours to the palette. The only bit the script didn’t
counter_x = 0
do is extract which colour on the palette relates to the
for line in otter_data.otter_bmp_data:
transparency. We can tell from looking at the data that
it’s the first entry in the palette, so we use the
counter_y = 0
following code to mark that as a transparent colour:
for pixel in line:
otter_bitmap[counter_y,counter_x] = pixel
counter_y = counter_y + 1 otter_pallette.make_transparent(0)
counter_x = counter_x + 1

Once the transparent bitmap is created, we can use it

#load the otter pallette data
in a TileGrid as usual.
otter_pallette = displayio.Palette(18)
As we’re now using two TileGrids in our group (one
counter_colour = 0
for the background and one for the image), the only
for colour in otter_data.otter_pallette_data:
thing we need to be careful of is the order they’re in.
otter_pallette[counter_colour] = colour
Displayio will put them on the screen in the order they
counter_colour = counter_colour + 1
are in the group, and we want our otter to appear on
otter_pallette.make_transparent(0)
top of the background, so we append that to the group
otter_tile = displayio.TileGrid(otter_bitmap,pixel_
after we add the background. You should recognise the
shader=otter_pallette, width=1, height=1, tile_
rest of the code from the initial test.
width=96, tile_height=96)
That’s all there is to it. Displayio is a powerful way of
controlling the graphics on your screen, and now runs
group.append(background_tile)
fast enough to control animations. This otter should run
group.append(otter_tile)
at about ten frames per second on a SAMD51 device.
That’s just about enough to make animations look like
counter = 0
animations rather than stuttering images. If you reduce
direction = 1
the size of the animation, you should be able to get it
to run even faster.
otter_tile.y=144
You now know enough to take this and embed it in
while True:
your own projects. You could use this to display
for image_num in range(4):
information relevent to your project, add a little
counter = counter + (9 * direction)
graphical spice or create an added bit of interest in a
otter_tile[0] = image_num
prop or costume.
otter_tile.x = counter
Whatever you choose to do, let us know about your
display.show(group)
makes via Twitter @HackSpaceMag or email
sleep(0.2)
hackspace@raspberrypi.org.

81
Let’s learn LoRa!

TUTORIAL

Let’s learn LoRa!

Explore LoRa and LoRaWAN and transmit
temperature and humidity to an online dashboard

Figure 1
The Things Uno wired up
to a DHT11 sensor that
can sense temperature
and humidity

I
t seems that the terms LoRa and the first thing is to download and install the latest
LoRaWAN are everywhere at the moment, Arduino IDE software from hsmag.cc/APNJVV.
but what are they? LoRa is a platform for To test that The Things Uno board is working,
sensors to communicate wirelessly over long let’s upload a simple program to check the board.
range; LoRaWAN is essentially the same, but Connect your The Things Uno to your computer
Jo Hinchliffe
when the receiver receives something from using the micro USB cable. In the Arduino IDE, click
@concreted0g a LoRa sensor device, commonly called a ‘node’, it Tools > Board, and then check it’s set to ‘Arduino
acts as a ‘gateway’, sending the information onto Leonardo’. Next, click Tools > Port, and select the
Jo is a contributor the internet. In this tutorial, we’re going to work port that includes the label ‘Arduino Leonardo’ to
to the Libre Space
Foundation, and is
through some simple LoRaWAN activities and ensure the Arduino IDE is communicating with the
passionate about all connect a LoRa node to ‘The Things Network’, a correct port.
things DIY space. He crowdsourced network of gateways. This enables us Next, click File > Examples > 01.Basics > Blink,
loves designing and
scratch-building both to receive data from a node and transmit some data and then click the verify button (looks like a tick on
model and high-power across the internet to a nice dashboard displaying the top left of the screen), and then click the upload
rockets, and releases
our data. button (the right-pointing arrow button next to the
the designs and
components as open- We are going to work with The Things Uno, which verify button). All being well, after a few seconds
source. He also has is essentially an Arduino-shaped board that has the your The Things Uno should have a flashing LED
a shed full of lathes,
milling machines, and
LoRa communications chip built into it. We can also that is connected to pin 13 on the board (one of the
CNC kit! program The Things Uno using the Arduino IDE, so four green LEDs next to the micro USB port).

82
 FORGE

Figure 2
Using the
Arduino IDE
library manager
to install the
libraries we need
for our project

”
PUBLIC NETWORK
The Things Network is a community-hosted network We are going to work with The Things Uno, which
that consists of gateways connected to the internet.
LoRaWAN devices, in our case a The Things Uno,
is essentially an Arduino-shaped board that has

”
can be received by any gateway, and their data the LoRa communications chip built into it
packets are then forwarded to an account registered
by the device owner on The Things Network website.
The website application can be set up to integrate
or forward those pieces of information to other GOING LOCAL
systems, allowing the user to create a visual web The next job is to upload an example sketch from
dashboard, a phone application, an SMS alert, an The Things Network library we just installed. Click
email, or other options triggered or populated by File > Examples > TheThingsNetwork > Device
the data from the device or devices in the field. The
info in the sketch that is open – we need to make
Things Network website has a map of gateways –
check and see if you have one locally that you may one small change before we can use this sketch.
be able to connect to. The Things Uno frequency for Europe is 868MHz,
so we need to replace some text. Edit the sketch
so that the ‘REPLACE_ME’ is replaced with ‘TTN_
Next, we need to install some libraries we are FP_EU868’. Readers in other regions will need
going to use in this tutorial. We’ll install two of to replace it with the example that matches the
them using the Arduino IDE libraries manager, and frequency available in your region – it can be found
download and manually install one from the internet. on a sticker on the reverse of your The Things Uno.
Open the Arduino IDE and then click Tools > Manage Double-check your board is still connected and
libraries (Figure 2). The first library we are going set to Arduino Leonardo, and the port is correct.
to install is called ‘The Things Network’, so type Verify and upload the device info sketch to your The YOU’LL NEED
that into the ‘filter your search’ bar at the top of Things Uno. Once uploaded, you need to open the The Things
the library manager. You should find a library whose serial monitor in the Arduino IDE, this can either be Uno
description begins ‘The Things Network by Johan opened by clicking the Magnifying Glass icon at the
DHT11 or DHT22
Stokking, Ludo Teirlinck…’ – select this library and top right-hand side of the screen or clicking Tools temperature and
click Install. Repeat the above process, searching for > Serial monitor. In the serial monitor after a few humidity sensor
‘cayenne LPP’ to install a library called ‘CayenneLPP seconds, you should see some details appear that
Some
by Electronic Cats’. Finally, to install the third library, are unique to your The Things Uno – copy and paste breadboard
we need to download it from hsmag.cc/pEDXUY. these details into a text document somewhere on connector wires
Click the large green ‘Clone or download’ button your computer for later use.
Micro USB
and then click the Download ZIP option. Once We’ve now got the hardware set up and cable
downloaded in the Arduino IDE, click Sketch > configured, it’s time to take a look at the networking
Access to a LoRa
Include Library > Add .ZIP Library, and then navigate side of things. This is what gives us some where to gateway (see
to where you downloaded the zip file, and select it. send our data to. tutorial for details)

83
Let’s learn LoRa!

TUTORIAL

TO THE THINGS NETWORK The last two input boxes should be as we want
Figure 3 We’ll use The Things Network as the glue to hold them, with ‘Application EUI’ set to ‘EUI issued by
Adding an application
to our The Things
our sensor together with dashabord (which we’ll The Things Network’, and ‘Handler registration’ set
Network account look at in a bit). Navigate to hsmag.cc/BtGluJ and to ‘ttn-handler-eu’. Leave these as they are and click
Figure 4 register an account. Once registered and logged in, the turquoise ‘Add application’ (Figure 3) button in
Registering a device you should see a link for ‘console’ in a drop-down the lower right-hand side of the page.
into an application on
The Things Network is list when you click your username. Navigate to the The application should now be created and you
essentially introducing console and you should see two large icons: one will be pushed on to the Application Overview
The Things Network
to our The Things that says applications and one that says gateways. page. If you scroll down this page, you should find
Uno so that they are
connected and enabled
We are (hopefully) going to rely on you being in a section called ‘Devices’ which will show there are
to communicate with range of a gateway, so we are interested in setting no registered devices. So let’s add a device, which
each other
up an application: click the Application icon. will be our The Things Uno, so that our hardware can
An application, in terms of The Things Network, connect to this application. On the upper right-hand
can be thought of as the area to which your devices

”
or nodes (in this case, your The Things Uno) will
send their data. It is here that the The Things For now, we are going to
Network will choose where to send and what to do create one simple application
with the data it receives. An application can receive
to receive data from our

”
data from multiple nodes or devices and can also
be integrated into other online services that allow The Things Uno
you to do things with the data (for example, send
a text message when a temperature gets too high,
populate a dashboard, send key information to an side of the devices box, click ‘Register device’.
online spreadsheet). In the resulting Device Registration page, give the
For now, we are going to create one simple device a device ID and then copy the ‘Dev EUI’
application to receive data from our The Things Uno, from the text document we made earlier when we
which will be the humidity and temperature from our got the device information off our The Things Uno
DHT11 sensor. Click the ‘Add application’ button in via the device info sketch. Leave the App Key field
the top right-hand corner and give it an application on this page as it is (set to be generated by The
name – note that these have to be in lower case Things Network) and click the turquoise ‘Register’
and also have to be unique, so if you try ‘test’ for button in the lower right-hand corner (Figure 4).
example, you will probably find when you try to You should now end up on the ‘Device Overview’
QUICK TIP
add the application, it has already been used. As page for the device you just registered. There is a lot
Use The Things
instructed in the second section, add some human- of information on this page, including the activation
Network website
map to see if you readable text to remind you what this application is; method (which should be OTAA) and the various
are close to any for example, ‘HackSpace tutorial temperature and keys that the device has or needs to communicate
LoRa gateways. humidity example’. with the application. If we scroll down to the

84
 FORGE

Figure 5
Success! Data
from our device
successfully being
received by our
application on The
Things Network

bottom of this page, we should see a box called made some changes and added the keys, we need
‘Example Code’. to allow it to communicate with the application on
The Things Network. Download the sketch from
IT’S ALL IN THE CODE hsmag.cc/issue22 and open it in the Arduino IDE.
Rather wonderfully, this is a snippet of code There are only a couple of changes we need to
containing the two key pieces of information an

”
Arduino sketch on our The Things Uno needs to
connect it to our application on The Things Network. The data pin on the
Copy these (either select and right-click and select
DHT11 sensor needs to be
‘copy’, or press the copy button in the upper right-
connected to pin A0 on The

”
hand side of the box) and paste them into a text
document or a blank Arduino sketch. Before we Things Uno
move on to the next part of the tutorial, we are
going to make one last change to the application
we have made on The Things Network. Return to make. The first is to check the frequency plan is
the Application Overview page – navigate here by correct for our The Things Uno; this is the same
clicking ‘Applications’ in the upper right-hand side bit of code we replaced earlier in the device info
of the page near your profile name – then select sketch. In our code, it is set as the ‘TTN_FP_EU868’
the application we just created. Once back in the European version and will only need changing if you
Application Overview, click the ‘Payload Formats’ tab are using the US frequency plan.
on the upper right-hand side. On the resulting page, The second change is that you will see a section
you should see a box called Payload Format, and it in the code which is similar to the code we copied
should show ‘Custom’ in it. Click on this box. In the from the ‘Example Code’ box on the Device
drop-down menu, there should only be one other Overview page on The Things Network earlier. (It’s
option, which is CayenneLPP; select this and then
make sure to click the Save button in the lower right-
hand corner of the page.
SPICY MESSAGES
Cayenne is an IoT platform by a company called
LET’S GET CONNECTED myDevices. CayenneLPP (Cayenne Low Power
Connecting our DHT11/22 sensor board to The Payload) is a format for data packages over LoRa that
Things Uno is pretty straightforward. Connect allows for some key types of sensors to be integrated QUICK TIP
into the Cayenne IoT platform simply via The Things Remember, an
breadboard wires between the DHT11/22 and The
Network. Put simply, if we can send sensor data in a application on The
Things Uno 5 V and GND pin sockets. The data pin on CayenneLPP format, a lot of the work to unpack this Things Network can
the DHT11 sensor needs to be connected to pin A0 data and present it in a straightforward and readable support multiple
on The Things Uno (as seen in Figure 1). way is done for us in The Things Network and the devices – perfect for
Returning to the Arduino IDE, we will now upload Cayenne myDevices environment. large, remote sensor
the sketch for our sensor to The Things Uno; having array projects!

85
Let’s learn LoRa!

TUTORIAL

Figure 6
Beginning to set up
a dashboard on the
myDevices site

Figure 8
Selecting the
CayenneLPP options
for our dashboard

Figure 7
Select The Things Network from the left-hand menu

upload the sketch to The Things Uno. Leave The

Things Uno plugged into your laptop for power after

”
the sketch has uploaded.
Our payload is decoded and is nicely displayed, You now have a LoRaWAN node with a sensor
hopefully transmitting its payload of the sensor data
labelled correctly ‘temperature’ and ‘humidity’, on humidity and temperature, if you are within range

”
instead of just a raw collection of bytes of a gateway (it’s worth taking your laptop and The
Things Uno outside to increase chances!) Returning
to The Things Network website, click the applications
tab and select the application you created, and then in
the two lines under the comment ‘//Replace these the Application Overview page, select the ‘Data’ tab
with your AppEUI and AppKey‘) So, of course, from the upper right-hand side. Wait for a short while,
copy and paste those entire two lines from your and you should start to see data packets appear
Device Overview Example Code box to replace the with some information about the data, and most
similar ones in the Arduino sketch. importantly, the payload in the end columns stating
the temperature and humidity readings from your
DECODING THE PAYLOAD sensor (Figure 5). As we set the application to read
Save your sketch and then click Verify. If the code the payload as being of the CayenneLPP type, our
Above compiles correctly, then double-check that your The payload is decoded and is nicely displayed, labelled
The standard
dashboard showing
Things Uno is still attached correctly as an Arduino correctly ‘temperature’ and ‘humidity’, instead of just
our data Leonardo, and the correct port is selected, and then a raw collection of bytes. If you click on a particular

86
 FORGE

data packet, you get a drop-down with more it should reveal only one option ‘Default key’ next
information, such as the signal strengths and which to two buttons that say ‘Devices’ and ‘Messages’.
gateways the device sent the data through. Click on ‘Default key’ to select this into the ‘Access
As things stand, we have our sensor data going Key’ box, then click the blue ‘Add integration’
to The Things Network, but you might notice that button in the lower right-hand corner.
if you refresh the Applications Data page or close If you now switch back to your myDevices page
it and reopen it, it doesn’t keep the data there. we left open in another tab, as soon as myDevices
Simple applications on The Things Network don’t receives some data from your The Things Uno, it
retain data; they act as a holding area that can should automatically make a dashboard for you
send and forward data to other places. We are now and display the data. It should create a dashboard
with RSSI (received signal strength indicator), SNR

”
(signal to noise ratio), and, of course, our sensor
The myDevices dashboard humidity and temperature data. This dashboard
will update with the latest data and will store the
elements can all be edited data it receives, meaning you can come back and
and customised so you check it anytime – or, if you take your The Things
Uno offline, it won’t lose all the existing logged
can swap the icons or the

”
data. The myDevices dashboard elements can all
type of graph be edited and customised, so you can swap the
icons or the type of gauge or graph by clicking the
settings menu for each widget.
going to create a simple dashboard for our device
to which our application will send the data, and the TIME FOR ANOTHER PROJECT
dashboard will keep our data more permanently so Congratulations on setting up your first LoRaWAN
we can review it when we need to. device and application. There are dozens of
different platforms for devices, and innumerable
LET THERE BE DATA sensors that can be developed and added to them.
Apart from it making it simple to get a payload in a In addition, as a rapidly growing community, there Below
Our altered
readable form on The Things Network, we used the are lots of tutorials to explore online to help you dashboard showing
CayenneLPP library and payload format as it makes develop your next projects. data in visual form
it very trivial to create a dashboard for our device
online that will collect and display all the data from
our The Things Uno device. To set this up, we first
need to register a free account on the Cayenne
myDevices website: hsmag.cc/YlgAGf.
Once logged in, select the large LoRa icon
(Figure 6) and then select ‘The Things Network’
from the lower end of the menu bar on the
left (Figure 7). Then scroll down and click the
CayenneLPP option (Figure 8); in the settings
window that should appear, you need to give the
dashboard/device a name, and then add the Device
EUI in the DevEUI box – leave the Activation
mode set to ‘already registered’, and the tracking
box locations as ‘this device moves’. Save these
settings and leave this tab open in your browser.
Finally, we need to go back to The Things
Network site, and in our Applications Overview we
need to select the ‘Integrations’ tab and click ‘Add
integration’. Scroll down and click the myDevices
icon; in the Process ID box, give this a name such
as ‘hackspacedashboard’, and in the ‘Access Key’
drop-down menu, when you click on the empty box,

87
The delicate art of holding on

TUTORIAL

The delicate art

of holding on
Learn to get a grip on your project
and make your workshop a safer place

A
lmost everyone is familiar with you a good idea about which vice you need to
the function of clamps and vices. choose. For basic forms like bar and sheet, the
They’re a staple of every workshop, process of clamping is very simple, and it doesn’t
shed, garage, and factory. However, really need to be described in detail for this
not everything fits neatly into a tutorial. There are some simple tips that can
bench vice, or lends itself to easy save you from problems with any material, and
Dr Andrew Lewis clamping. Knowing how to hold your work securely these tips apply to work-holding in general.
is an important skill, especially if you are using power Firstly, check the vice jaws and the threaded
@monkeysailor
tools or sharp hand ools that could do damage if you bar are clean. Clamping onto a workpiece when
slip. In this tutorial, you’ll learn some basic work- there are pieces of grit or swarf on the jaws will
Dr Andrew Lewis
is the owner of holding tools and techniques, and some sneaky tips almost certainly leave a mark on your work. Grit or
Shedlandia.com, a for getting a grip on more awkwardly shaped objects. bits of swarf on the threaded bar will wear the vice
restorer of old tools,
mechanism and make it more difficult to clamp.
a fabricator for hire, a
research scientist, and BARS AND VICES Grease on the jaws will make it more difficult
a founder member of If you want to hold onto something, you probably to hold your work securely without slipping.
the Guild of Makers.
need to put it in a vice or a clamp of some kind. If you are worried that clamping might damage
The secret to successful work-holding is knowing your work, you can protect it with a layer of masking
what type of vice of clamp you need to use. tape and fit a pair of soft jaws onto the vice. Soft
Most vices have sensible names, like ‘engineer’s jaws are made from soft metal or plastic and should
vice’ or ‘woodworking vice’, that should give be softer than the item you are trying to clamp.

88
 FORGE

SPLIT NUT

Threaded bar, bolts, and machine screws are very

difficult to clamp effectively without damaging the
threads, even if you are using soft jaws. Last month we
looked at how to make a stud clamp for just this
purpose, but another option is to use a split nut. To
make a split nut, you will need an ordinary nut with the
same thread as the workpiece that you need to clamp.
Hold the nut in the vice with one of the high points at
the top, and cut down to the middle with a hacksaw,
parallel to the direction that the bolt fits. Clean up any
DOGS AND COOKIES
Holding work flat onto a surface poses a different set Above
rough edges, then screw the nut onto your workpiece. A pipe vice typically
Tightening one or more of these nuts into the vice with of problems, particularly if you need to work all the has different-sized
the cut part between the jaws will deform it slightly, way along the edge of the material. Clamps are an inserts that let you
hold different sizes
gripping the threaded bar firmly without damage. effective strategy in some cases, but the jaws of a of pipe. They’re
relatively cheap and
clamp can get in the way of tools you’re using. If you are very useful if you
have a workbench, it might be worth investing in some work with lots of
hollow stock
You can make your own soft jaws, or buy them bench dogs. Although the name might not be familiar,
ready-made for popular brands of vice. You can also you’ve probably seen a bench dog before on a portable
buy ‘universal’ soft jaws that fit onto existing vice jaws workbench. Bench dogs are the small stoppers that
using magnets or tape, although these are less secure fit through regularly positioned holes in a workbench
than replacement jaws that bolt onto the vice body. and butt up against the edge of a piece of wood
Clamping tube or hollow stock is tricky, and you to stop it sliding around. You can make these quite
really only have two good options to avoid deforming easily with a 3D printer, or by gluing a piece of dowel
the part. You can either use shaped jaws that match into a wooden block. Bench dogs won’t stop your
the profile of the object you’re working with (a work from flipping upwards, but they will keep it in
dedicated pipe vice is an example of this), or you can position on the table when you apply a lateral force.
increase the rigidity
of the part before QUICK TIP
you clamp it by filling Silicone mats or
the hollow part with baking grips are
useful for holding
something solid. Musical
and moving hot
instrument repairers metal objects.
sometimes use low-
temperature plastic as a
packing material in brass
instruments. The plastic
is heated, pushed into Left
the desired section of This work area is
drilled with holes that
the instrument, and then accept bench dogs
allowed to cool. When and holdfasts. It can
be removed from
the repair is finished, the workbench and
they warm up the plastic replaced with a blank
piece of wood when
again and remove it. it isn’t needed

89
The delicate art of holding on

TUTORIAL

NORTH AND SOUTH

You can use magnets to hold non-magnetic, thin, flat
materials together. This is particularly useful in cases
where you need to glue smaller items into place on a
large sheet of material. Simply place a magnet on each
side of the material and use them to hold the pieces in
contact while they dry.

Alternatively, holdfasts can be used instead of

Above
ou an fi our bench dogs. Holdfasts are steel bars with a hooked
workpiece more foot at one end, very much like the end of a walking
fir onto the en h
fittin do s on stick or shepherd’s crook. Like a bench dog, a
every side, and then holdfast fits into a hole in a workbench and the
hammering wedges
between the edge of hooked part rests on top of the material you want
the workpiece and to keep in place. Tapping the top of a holdfast with
the dogs
a mallet causes it to sit crookedly in the hole and
Right
A homemade wedges the workpiece in place. Although holdfasts
holdfast made from are quite expensive, you can make a small version
a large nail can be
very effective and very quickly using a large nail. Heat the head of the
only takes a few nail and flatten it into a spatula, then bend a curve
minutes to make.
Larger cast holdfasts near the spatula to make the familiar shepherd’s
are e pensi e to u crook shape. You might need to experiment with the
but can be a valuable
workshop tool size of hole you need to drill in the workbench.

QUICK TIP
If you need to apply
pressure on an
uneven surface, a
sock or bag filled
with ball bearings
makes a useful
deformable weight.

90
 FORGE

Standard holdfasts are around 18 mm in diameter, It might sound strange if you’ve never tried
but a nail will be considerably smaller. If you it, but masking tape and superglue can hold flat Above
A hand vice makes
find the holdfast slips too easily, try roughing sheets like brass or PCB blanks in place for light it easy to hold small
the sides with some coarse sandpaper. milling or engraving. Apply the masking tape parts safely on a drill-
press. You can use a
If that all sounds like too much effort, or you to the bed of the machine and to the back of pair of pliers, some
string or wire, and a
don’t have access to a workbench that you can the sheet material, then apply superglue to the lollipop stick or long
drill holes into, bench grippers make an excellent tape, and join both tape surfaces together. As nail to do the same
job, but make sure
alternative. Bench grippers (also commonly called an aside to this, double-sided tape on cardboard it’s secure enough
cookies) are plastic discs coated in a non-slip or plywood can be very useful for holding small
rubber material, and they are great for holding flat parts in place for spray painting or fine detail
materials in place for planing, sanding, or carving. work. Having the parts fixed on an easily movable
If you need to drill into the end of a bolt or a surface really speeds up the process of painting.
short piece of bar, you can use a spare drill-chuck
to hold the work perpendicular to the bed of your IF ALL ELSE FAILS, GLUE IT
drill-press. This is also a great way to keep hold of The topic of work-holding is huge, and there simply
short pieces that need to be polished or worked on a isn’t room to write about all of the techniques
grinder. The drill-chuck makes a comfortable, weighty out there for clamping and fixing objects to QUICK TIP
handle that makes it less likely you’ll inadvertently work on. For some projects, the vast majority of Parallel jaw pliers
launch the part you’re working on across the room. the work can be creating an appropriate tool to close equally,
For light machining, you can hold small parts in hold the thing you need to cut, drill, mill, or turn. leaving a parallel
wax to make them more manageable. The wax won’t Whether it’s bulldog clips or custom-made jigs, gap along the entire
jaw. This makes
last very long if the part starts to heat up, but for light there is always a tool or method that will solve
them good for
engraving or scribing, the wax (or low-temperature the problem. Hopefully, you will be able to use holding delicate
plastic) should give even the most irregularly some of the tips in this article to save some time, parts without
shaped object enough support to work with. and also make your workshop a safer place. leaving marks.

91
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Rustic lamp with colour-sensing lights

TUTORIAL

Rustic lamp
with colour-
sensing lights
Create glowing mushrooms that change colour to match an object

C
olour sensors are a novel way 20×12×12 cm works well. If necessary, use a band-
to create mood lighting. Place an saw to adjust the size and create a level base.
object over the sensor and this lamp On the underside, choose where to hollow out
will shine with the matching colour. a space for the electronics. It needs to be close to
The sensors are easy to use with an where your mushrooms will stand so that a drill
Arduino, and are widely available. bit will reach through from the top, and at least
Poppy In this tutorial, we’ll embed a colour sensor in a log 8×6×3 cm to fit an Arduino Uno. Use a chisel and
Mosbacher and use biodegradable plastic and multicoloured LEDs to hammer, or power tools, to create the recess. Sand
@PoppyMosbacher make mushroom lights. The instructions use an Arduino any rough edges to avoid splinters.
Uno for the electronics because it’s a popular board for Put the Arduino in position to see where the
Poppy loves getting beginners, but it can also be made with a Nano, ESP, or power cord needs to go, and chisel a channel
tech into the hands Flora, which are smaller and easier to enclose. through the wood for the cord to come out the
of people who do
back of the lamp.
traditional crafts. She
is helping set up a A BIT OF WOODWORK Decide where the mushrooms will stand and drill
makerspace in Devon Find a piece of wood that you could imagine a hole for each one. Also, choose a position for the
and was a director
of Build Brighton seeing mushrooms growing on, with enough bulk colour sensor and drill two holes close together for
MakerSpace. to hide the electronics. A section approximately the wires to go through.

94
 FORGE

YOU’LL NEED
Arduino Uno
preferably a version
with a row of holes
alongside the pins

RGB colour sensor

(TCS34725)

3 × RGB LEDs with

a common anode
re i tor
re i tor
Small perfboard
Red, green, blue,
orange, and black
insulated wires
ello
heat-shrink
ol orph
plastic granules
ie e o oo
e fire oo p rt
of fallen branch or
driftwood

USB A-Male to
B-Male lead with
on/off switch
Mould the Polymorph into a flat rectangle and (printer cable)
Above
easoned wood su h as firewood is idea e ause it is dr wrap it around the legs of one of the LEDs to Lithium-ion
and any cracking will have already happened
create a stalk. As it sets, the clear plastic will turn battery with USB
connector such as
white, hiding the LED legs inside. If the Polymorph po er n or
CUT AND STRIP becomes stiff before you’ve finished moulding it, mains adapter
Cut 4×10 cm wires of each colour, except black. just drop it back in the water to soften. It doesn’t Insulating tape
These are for the LEDs. Also cut 1×10 cm strip of matter how wet the LED gets.
Two small screws
each of the black, orange, blue, and green-coloured Mould another lump of Polymorph into a ball. Push (optional)
wires for the sensor. Using wire strippers, expose your thumb into it to make a cone and then place it on
Dry moss from
approximately 5 mm of wire from all the ends. top of the LED, squeezing gently to join it to the stalk. twigs (optional)
Each of the RGB LEDs have a tiny red, blue, and Continue moulding until it resembles a mushroom.
Cup and tray of
green light inside, and a corresponding wire, called Top up the hot water as it cools down, and add hot water
a leg, to control them. The fourth leg provides a extra Polymorph granules to make the rest of
Teaspoon and
common anode, which will be the positive wire in the mushrooms. spatula
the circuit. The legs for each colour are different
Band-saw
lengths, so before you start soldering, check which
Chisel hammer
is which from the LED data sheet. Solder matching
colour wires to the tips of each leg on the LEDs and rill ith
drill bit
orange wires to the anodes. Then cover the whole
of each leg with separate bits of yellow heat-shrink Soldering iron
and solder
to prevent the wires from touching. A darker colour
could show through the mushroom stalks. Hot glue gun and
glue stick

MOULDING THE MUSHROOMS Rolling pin

To make the mushrooms, drop about six teaspoons Hair-dryer
of Polymorph into a cup of hot water, above 60°C. Wire cutters
The granules are ready to use after a few seconds,
Above Wire strippers
when they turn clear and clump together. Use a If you choose a log that has been chopped into quarters
spoon to remove a blob of Polymorph, and wait until lengthwise, you can use a band-saw to make grooves along Sandpaper
the intended opening. Then tap the thin wafers of wood out
it’s just cool enough to touch. with a hammer Scissors

95
Rustic lamp with colour-sensing lights

TUTORIAL

Legs on the RGB LED*

Blue
Green
100
220

100

Red
220Ω
330Ω

220Ω

Anode (positive)
Ω
Ω

Ω
*the order may be different
for your LEDs.

Above
This wiring diagram shows
how the components
Ground connect together to create
Power the circuit

Position the mushrooms on the log and poke Solder the orange wires attached to the LEDs
Top the wires through the drilled holes. Remelt the to an unused area of the perfboard and join them
Polymorph looks a
bit like frogspawn the mushrooms slightly with a hair-dryer to mould them together using solder. This will become a shared
first ti e ou e t it to the contours of the log. That may be enough to power connection. Red wires are often used for
Above stick them to the bark. If not, use a hot glue gun. power, but that colour has been used, so orange has
When Polymorph is
heated, it becomes
been chosen to avoid confusion.
malleable like clay CREATE THE CIRCUIT From the underside of the perfboard, poke the
Perfboard has predrilled holes and copper pads on remaining green wire next to the 330 Ω resistor and
one side, which make it easy to arrange components secure in place with solder, making sure the solder
and attach solder. For this tutorial, we will refer to touches the resistor too. Do the same with a red and
the side with the copper pads as the top. blue wire for the other resistors. These wires will

”
attach to the Arduino later.

Many clones of Arduino Uno boards (available on ADDING MAGIC TO THE MUSHROOMS
Although there are seven pins on the colour sensor,
eBay) have a line of holes as well as pins, which

”
you only need to attach wires to four of them. Solder
makes it easy to solder wires to one end of the remaining orange strip of wire to Vin
(voltage in) for power and do the same with black to
GND (ground). Connect the blue wire to SDA (serial
With the top of the perfboard facing down, poke data) and the green to SCL (serial clock), both of
QUICK TIP the three resistors into any holes. Turn the board which will communicate with the Arduino.
Glue dried moss over, solder them into place, and cut the legs off with Connect the other end of the orange Vin wire to
from twigs onto wire clippers. All the green wires share the 330 Ω the shared power area on the perfboard, created in a
the log for extra resistor, so push the ends of the wires through the previous step. The rest of the wires from the colour
texture, or to hide perfboard close to the resistor and solder from the sensor will go straight to the Arduino board.
the sensor’s circuit
underside. All the red wires go to one of the 220 Ω Connect the black GND wire from the colour
board. Make sure
the tiny sensor and resistors, and the blue wires go to the other 220 Ω sensor to one of the GND pins on the power section
on-board LED are resistor. Use solder to create a bridge from each of of the Uno. Also connect the blue SDA wire to
left uncovered. the wires to the relevant resistor. Analog pin 4 and the green SCL wire to Analog pin 5.

96
 FORGE

PRINT YOUR OWN

Instead of using Polymorph, you could 3D-print
the mushrooms. A search for ‘Mushroom LED’ at
thingiverse.com brings up free designs, ready to resize
and print. Buy diffused RGB LEDs, or cover clear ones
with masking tape or a blob of Polymorph, to make the
colours blend evenly.

check out the guide at hsmag.cc/shYSMW, which

walks you through how to select the board and Left
Colour-coding the
port settings. wires makes it easier
if you need to do any
Install the colour sensor library by going to Sketch trouble-shooting
Many clones of Arduino Uno boards (available on > Include Library > Manage Libraries. Search for
Above
eBay) have a line of holes as well as pins, which Adafruit TCS34725 and click Install. For help on Play around with
makes it easy to solder wires to. If yours only has installing libraries, go to hsmag.cc/zmXjEI. coloured objects
to explore the
header pins, you could remove them or use jumper Open the ColorView example code that comes different effects
wires instead of regular wire. with the sensor library by going to File > Examples >
Connect the red wire beneath the perfboard to Adafruit TCS34725 > ColorView.
Digital pin 3 on the Uno, the green wire to Digital Upload the code to the Arduino, by going to
pin 5, and the blue wire to Digital pin 6. Make sure Sketch > Upload. Remove the power cord from the
that the components are dry before connecting computer and attach it to a USB power supply, either
to power. mains or battery powered. Then hold a colourful
object over the sensor. After a few seconds, the
HIDE THE WIRES LEDs should shine the same colour as the object.
Fill a tray with hot water, and sprinkle a layer of Place a different object on the colour sensor and the
Polymorph granules on top to create a thin sheet. LEDs will change colour too.
Remove with a spatula to keep it flat and use a rolling
pin to create a roughly rectangular shape, a little larger
than the gap you hollowed out of the log. Return it to
the water when necessary to keep it flexible.
Hold the Polymorph over the electronics to check
the size, then cut and bend into shape. While it’s
pliable, thin pieces of Polymorph can be cut with
scissors. If you can’t cut it, reheat and roll a bit more. Left
Perfboard is put
Use the glue gun or screws to keep it in place. between the log
and the Arduino.
Cover the USB port
LET THERE BE LIGHT with insulating tape
Open the Arduino IDE software and connect the if there is a risk of
components
Arduino to your computer. If you are new to Arduino, short-circuiting

97
How to use digital callipers

TUTORIAL

How to use
digital callipers
Learn to get a grip on your project and make your workshop a safer place

T
here is a reason why ‘measure your tool, for under US$40 you can get a surprisingly
twice, cut once’ is a golden rule of high-quality set. We recommend the iGaging
making. Getting accurate Absolute Origins. They deliver everything you need in
measurements is critical to the such a tool at a really reasonable price. They even
success of many projects. While the have a data-out port. With an additional special cable,
measuring abilities of a common you can send your measurements directly into a CAD
imperial/metric ruler are sufficient for many program. Unfortunately, the cable will cost you twice
Gareth Branwyn
measuring situations, sometimes you need much as much as the callipers (but you can sometimes find
@garethb2 higher precision (like when measuring parts to feed them cheaper on eBay).
into a computer design for 3D printing). That’s the So, what can digital callipers do for you? All models
Gareth has been a time that you need a set of digital callipers. of such callipers are designed to provide four basic
lifelong practitioner
(and chronicler) of
You might think that getting a set of digital callipers types of measurement:
DIY tech, media, and in your toolbox is an expensive proposition, and not
culture. He is the author worth it for the few times most of us might need Outside Diameter The main jaws of the callipers
of ten books, including
Tips and Tales from such an instrument. Not exactly. For under US$10, at (called the ‘outside measuring faces’) are designed to
the Workshop, and online stores and discount tool markets, you can get a measure the outside diameter of objects (usually up
is a former editor for
worthy set of callipers that can reliably measure at a to 6”/150 mm). Many models of callipers have a
Boing Boing, Wired,
and Make:. 0.0005”/0.01 mm resolution. Many of these cheap zeroing function. To do a measurement, you close the
callipers work just fine, once you learn to work around jaws, press the Zero button, and then spread the jaws
their eccentricities. If you want higher confidence in to take your measurement.

98
 FORGE

1 2 4

The results appear on the LCD. Most calliper sets

have imperial and metric selections. Some also
include a fractional measurements mode.

Inside Diameter The smaller ‘faces’ at the top of the

callipers are for measuring the inside diameter of an
object. The jaws here are inverted from the main
ones, but work in the same fashion. You open them
to the walls of whatever inside area you are to convert, then press the Mode button to switch
measuring and find the reading on the LCD. between millimetres, inches, and fractions (if your set Figure 1
The top faces
has this mode). Digital slide-rule! are used for
Depth On the back end of callipers’ ruler/scale is inside diameter
measurements
found a depth gauge (or ‘depth bar’). This is used to Measuring the balance thickness of a ‘blind hole’
Figure 2
measure, for instance, the depth of a hole. Simply Let’s say you have a blind hole (a hole that does not The bottom ‘jaws’,
extend the bar into the distance to be measured, and go all of the way through) in a workpiece, and you known as ‘faces’,
are used to measure
read the results on the display. want to know the difference between the depth of outside diameters
that hole and bottom edge of your piece. Simply use
Figure 3
Step You can measure the difference between two the depth bar to measure the depth of the hole, zero You can use the
surfaces using the outside measuring face (main out your callipers, and then measure the overall distance between the
edge of the inside
jaws). You simply place the outside edge of the sliding height of the piece. The result shown will be the face and the outer
edge of the outside
jaws against one of the edges you are measuring and balance of the blind hole. face to measure the
the outside edge of the inner, fixed jaw against the distance between
two edges
other edge. The display will reveal this distance. Measuring centre-to-centre distance When
Some models of callipers have a fine adjustment measuring the centre-to-centre distance between two Figure 4
The ‘depth bar’ found
screw that allows you to move the jaws more holes, first measure the hole diameter. Then zero out on the opposite end
precisely. Some also have a set screw so that you can your callipers and measure from near-edge to from the faces is
used to take
tighten to hold a measurement. Knowing how much near-edge of your two holes. (The hole diameter, depth measurements
pressure to apply when taking a measurement takes which you zeroed out, will be automatically
some practice. It’s often a good idea to take several subtracted). This gives you your centre-to-centre
measurements along an object and average them out distance. This is particularly useful when trying to
to get closer to a reliable number. figure out where to place PCB mounting posts when
designing project enclosures.
Other uses and measuring tricks: Callipers are also known as a vernier, which is a
short scale made to slide along a graduated YOU’LL NEED
Using callipers like a funky slide rule You can use instrument for indicating divisions. A set of digital
callipers as a conversion calculator. Simply move the callipers
fine adjustment wheel (if you have one) on your Thanks to Something
callipers to the number along the scale that you wish Lenore Edman, Jeff Worley, Richard Gould, Jake Hildebrandt to measure

99
Laser-cut cable rack

TUTORIAL

Laser-cut
cable rack
Cut and thermoform a one-piece cable organiser

I
f your shop or workspace is like ours, you charred edges, acrylic melts like butter, and the laser
probably have a snarl of assorted cables leaves a perfectly smooth edge, similar to the
on hand: audio patch leads, proprietary flame-polished display cases seen in museums. You
camera cables, various vintages of USB may even come to like the ‘sweet’ smell of melted
and FireWire, ¼” guitar leads, HDMI, MIDI, acrylic (but of course, always use proper ventilation
AC power cords… and what is that odd, when laser cutting).
Bob Knetzger mystery cord from?! Here’s a simple design for
cable storage to organise such a mess. It’s made
Bob Knetzger is from a single piece of laser-cut acrylic,
a professional toy thermoformed into shape. When the rack is
designer/inventor and
has created dozens of mounted on the wall, the cords hang down for easy
products for Mattel, identification of plug types and cord lengths. It also
Hasbro, Spin Master,
has a shelf to hold other little bits and bobs.
and many others. He
is the author of Make: You could cut out this acrylic rack using hand or
Fun! Create Your power tools, but the comb shape means laboriously
Own Toys, Games,
and Amusements. scoring, drilling, and scraping – and fearing cracks
Makerfunbook.com and chipping at each operation. Laser cutting makes
for easy and worry-free fabrication. Unlike laser-cut
wood and fibreboard, with its burnt smell and ugly

100
 FORGE

GET READY
01 We used a Glowforge laser cutter, so the
basic size of the flat shape fits nicely onto a single,
full-size sheet of Glowforge’s own Medium
Proofgrade Acrylic. For any other laser cutter, use
a 12” × 20” sheet of 1/8” thick acrylic. Choose the
speed and power setting for a clean through-cut
on your laser cutter; there are no engraves in this
design. The Glowforge’s built-in camera reads the
YOU’LL NEED
Proofgrade’s QR coded stickers to automatically set
the power and speed for the material to be cut, but thi r li
heet
on your machine, you may have to set it up manually.
e to
l er tter

piece of material). And you can freely change the file or the
MAKE ADJUSTMENTS e i n o online t
02 Because you’ll be bending the corners, there
sizes and locations of the holes for mounting
fasteners to match your installation. hsmag.cc/issue22)

are no worries about kerf allowances and finger Leave the protective paper label on both sides of trip he ter
joints. In fact, none of the dimensions is critical, so the acrylic when laser cutting to avoid ‘flare’ and
Mo ntin re
you can adjust the size or change the proportions to smoke marks. Remember to remove the label before or hollo
fit your particular needs (or to optimise for a scrap strip-heating! ll tener

101
Laser-cut cable rack

TUTORIAL

Above
a in the first end

Below
hin a out the order ou need to per or our ends in

Above
si p e wooden
frame for the heater
to sit in

”
formed carefully in position over the strip. The strip
A strip heater is ideal. If you don’t have access very gently and slowly warms the plastic. You’ll see
to a commercial heater, there are inexpensive a slight deformation in the surface when it’s nearly

”
ready. Test by gently bending: when ready, the
units available as kits material will bend easily. Remove the material and
make the desired bend, then hold in position as the
plastic quickly cools into the new shape. Unlike
THE STRIP HEATER
03 Once the basic flat shape is cut out, you’ll
slump moulding, where the material is heated all
over, the strip heater softens the plastic only where
next heat and bend the corners. For that, a strip you’ll actually bend it, so it’s easy to get nice-looking,
heater is ideal. If you don’t have access to a accurate corners.
commercial heater, there are inexpensive units
available as kits. We like the BriskHeat strip heater
element. It comes pre-wired and ready to use. You
MAKING BENDS
build a simple wooden frame for the heater to lie in.
There are more details in the kit’s instructions, but
05 To make the slight angle on the tips of the
here’s a useful sketch (above). comb, first soften the plastic and then press down
QUICK TIP firmly with a piece of wood as you hold the tips to
I used self-adhesive make the bend. Hold in place until the plastic cools.
aluminium foil tape
Consider which side of the material to place on
to line the channel
GETTING BENDY
and to tape down
the fraying edges of
04 The strip heater is easy to use. After the
the strip heater. Place the side of the outside of the
corner face down, directly on the heater. The plastic
the fibreglass mat. heater has warmed up, place the material to be there has to be softer, to stretch more to make the

102
 FORGE

larger, outside radius of the corner. The cooler

Above
side (away from the heater) is the smaller inside ounted and read
for storage
radius corner.
Plan your sequence of bends so that the edge to Left
ou an use an
be heated can reach and lay flat on the strip heater. o our o a r i
Place the strip heater of a worktable and near the
edge to help position and heat multiple bends in a
tricky shape.
Sometimes a shape will require a backward bend,
where the side facing the strip heater will become an
inside corner. In that case, leave the material over the
strip for some extra time to soften thoroughly so that
the plastic bends without cracking.
MAKING MORE
The laser cut-and-bend method of fabrication is
quick, easy, and highly versatile. Once you get the
hang of making accurate bends, you’ll find a wide
range of things that you can make.
WALL MOUNTING
06 To mount the finished rack, use wood
screws or hollow wall fasteners. If needed, drill
new mounting holes in the rack to match your
installation requirements.
You can now store your knick-knacks, cables,
and assorted doodads on your wall where they’ll
be easy to find. Now, go forth and declutter your
workshop with your own wall-mounted storage rack.
Let us know how yours turns out @HackSpaceMag
on Twitter, or email hackspace@raspberrypi.org.

103
Controlling temperature in the kitchen

TUTORIAL

Controlling temperature
in the kitchen
Reuse waste plastic to make a fermenting box

T
emperature control is hugely The first real decision is what voltage to run your
important in working with food. system at. Many off-the-shelf heating components are
Sometimes we want to heat it to a high designed to run at mains voltages. For example, some
temperature, and for this we have ovens people use filament light bulbs. However, we wanted
and microwaves. Sometimes we want to to run ours at a lower voltage, so we didn’t have to
chill it, and for this we have fridges and worry too much about the electrical safety. However,
Ben Everard freezers. However, sometimes we want to warm it a if you go too low in voltages, you need a high current
little, and for this there are fewer options. For example, to get enough power to provide enough heat for your
@ben_everard
you might want to warm bread dough to help it rise, or box, and that introduces its own problems. We went
keep milk at the right temperature for yoghurt to form. with a 12 V system.
Ben loves cutting stuff,
any stuff. There’s no To help with this, we’re going to build an insulated, For heating, we went with a 12 W silicon heating
longer a shelf to store heat-controllable box. pad. These are available cheaply from a variety of
these tools on (it’s now The mechanics of a heat-controllable box are pretty sources (ours cost £2.78, including delivery).
two shelves), and the
door’s in danger. simple. We need something to heat it, something to For temperature and control, we could have used
sense the temperature, and something to turn the more or less any microcontroller and programmed our
heater on or off, depending on what it reads from the own interface, but we wanted to make this project
sensor. There are lots of options for all of these and, in super-simple, so opted for an off-the-shelf temperature
many ways, there’s not a ‘best’ option. control unit. This has a temperature probe, a display,
and a relay. You can set a temperature you want it to
hold, and it will turn the relay on and off to help you
THERMAL CUT-OFF achieve this. You just have to wire the heating pad into
the relay.
Our temperature controller claims to have a built-in
thermal cut-off, but it’s still relying on a single unit
to ensure that it never overheats, and we don’t have
a good idea of how reliable this unit is yet. The risk
is that the unit somehow jams on and continues to
push power into the heat pad, even when it’s too
hot. Whether or not this is a problem depends on
how hot your unit can get with the heating element
permanently on. It’s a good idea to test this scenario
out by putting your heat pad on permanently while you
monitor it for temperature to see what the risk is.
If you’re concerned about it getting to a dangerous
temperature, you may want to consider putting a
separate heat monitoring unit in there that can cut
off the supply to the first unit. This could be as simple
as another identical temperature controller that’s set
to the same temperature with both relays rigged in
series. That way, as long as one of the two units is
working properly, it will cut off the power once it gets
above the predefined temperature. Above
Insulating our box with shredded plastic
packaging – just make sure it’s all clean

104
 FORGE

The other item we need for the build is a 12 V power

supply (we pulled this from our big box of spare power Above
The wiring for our
supplies) – the only requirement is that it can supply box puts the relay in
line with the power
just over 1 A of current (1 A for the head pad, and a for the heat pad
bit for the controller). A 1.5 A power supply should be
Left
plenty. We attached this via a 5.1 mm jack, but you The temperature
could also wire it directly in if you’d prefer. controller displays
both the current
That’s all the electrical gubbins sorted; we just temperature and the
need a box to house it in. As we’re trying to hold a desired temperature

warm temperature, we need insulation to help it stay

warm so we don’t waste electricity. Insulation also
helps keep the temperature even inside the box.
There are a few options here. The simplest is to use
an insulated box like a cool box, but this is also the
most expensive option. The most hacky solution is to THE BUILD
use a simple Tupperware box, and wrap it in a blanket The first part of the build is to get the electronic
when it’s running. However, we opted to build our own gubbins mounted into the outer box. The temperature
insulated box using two plastic boxes, one smaller controller is panel-mounted with clips to hold it
than the other. With the small box held inside the large in place, so you need to cut out a rectangle the
box (more on this in a bit), we filled the gap between appropriate size from the outer box. We used a rotary
them with insulation. There’s loads of stuff you can tool with a cutting disc, but a hot knife would also do
use for insulation, but we used old plastic packaging. it if you don’t have a rotary tool. You’ll also need a hole
Anything that can be scrunched up and cut to size can for the power to go through (we used a panel-mounted
be jammed between the two boxes to help keep our 5.1 mm jack port; you could equally just have a hole for
heat in, and our insulation consisted of everything from the wires to go through, but you may want to consider
bubble wrap to (clean) crisp packets. We used scissors using hot glue as strain relief if you do this (this will
to cut it all into little bits, and jammed it in place. also help with insulation).

105
Controlling temperature in the kitchen

TUTORIAL

Right
While it may not
look pretty, our
temperature-
controlled box is both
insulated and helps
reuse waste plastic

You’ll also need a hole through to the smaller box for box upwards. We happened to have some modelling
the wires for the heater. foam left over from a previous project, so in the spirit
The second step is to mount the smaller box so that of reducing waste, we used this. Really, you can use
it’s held in place while the insulation is packed around any moderately stiff plastic sheet. We tried a few
it. We did this with some 18 mm-wide wood that fitted options for holding them in place, but found that
in perfectly; however, you will have to improvise as T-Rex tape worked best. It doesn’t have the most
your gaps are unlikely to be the same as ours. We aesthetically pleasing look, but we’re building with
screwed the wood to the smaller plastic box, then rubbish, so aesthetics aren’t our top priority. We built
positioned this box at the appropriate place inside the the walls up as high as we could without blocking

”
the lid.
You’ll also need insulation on the lid. We just
You’ll also need insulation on the lid. We just happened to have an Amazon Prime padded envelope
happened to have an Amazon Prime padded the same size as the lid. We filled this with more cut-

”
up plastic to add extra insulation and taped it to the
envelope the same size as the lid inside of the lid. This padding on the lid should push in
and fit snugly with the padding around the side of the
larger one, and screwed it to that as well. This held the main box.
smaller box off the bottom of the larger box and with It’s worth noting that we’re not worrying about if
gaps all around it. We filled these gaps with cut-up bits any of this is food-safe – this is because whatever
of plastic. We packed it in quite densely as this should food we put in this heat box will be in its own food-
provide more insulation. safe container, and this contraption shouldn’t come
The insulation should also cover the top half of the into contact with any foodstuffs.
box, so we need to extend the sides of the smaller That’s everything in the right place; it’s time to wire
up the electronics. Your 12 V input should go into the
temperature controller, but it also needs to go to the
REDUCING WASTE heat pad – the temperature controller doesn’t power
We could have built this temperature-controlled box in many ways, but we chose to the heat pad directly, it just turns a relay on and off.
use otherwise waste plastic as the insulator. Humanity is currently producing huge The wiring goes like this: 12 V goes into one side of
amounts of single-use plastic that then ends up littering the planet for generations the relay. One heat pad connection goes into the other
to come. As makers, we can find ways of using this resource rather than just side of the relay (it’s not polarised so can go in either
consigning it to landfill. This build was one attempt to do that.
way around), and the other heat pad connection goes
If you’ve got other ideas for how we can reuse rather than waste plastic, we’d
love to hear them. Drop us an email at hackspace@raspberrypi.org or message us to ground. You can do this using the screw connectors
on social media. in the back of the temperature control unit, so no
other soldering or wire joints are necessary.

106
 FORGE

The only bit left is to mount the temperature sensor

in the box and have something to rest our food on, as
YOGHURT
we don’t want it sitting directly on the heat pad. We’ve Yoghurt is a form of cultured milk. To make it, you
used three bits of 18 mm wood – one with a hole inoculate some milk with the appropriate bacteria,
drilled in it to hold the temperature sensor. These are and then keep the milk at the right temperature for the
in the bottom of the small box, with the temperature bacteria to thrive. What temperature this is depends on
sensor configured so it’s between the food and the the particular cultures you’re using, but most common
cultures want between 40 and 44 °C.
heat pad. This means the food should never go above
The traditional method of creating yoghurt has the
the set temperature. rather unappetising name of ‘back slopping’. This is
That’s the box built and ready to power on. When where you take a couple of spoonfuls of live yoghurt
you first turn it on, be aware that there may be a few and add it to milk before putting it in your temperature-
different modes that the controller can be in – for controlled box. You can start this with any commercial
example, ours came configured to work with a chiller live yoghurt; however, the bacterial colonies in
commercial yoghurt aren’t very virile, and you’ll
rather than a heater, so it would have left the heater
probably find that after a generation or two of yoghurts,
switched on permanently. Follow the instructions on it stops working. We’ve had the same experience with
your temperature controller to make sure you’ve got it commercially produced ‘yoghurt starters’.
set up properly, and make sure you keep it supervised If you want an ongoing supply of yoghurt, the best Above
so you’re sure it’s working properly the first few times. bet is to acquire an ‘heirloom’ yoghurt starter. These Internet deliveries
can lead to huge
That’s your temperature-controlled box built. You’re cultures should continue to grow indefinitely if you look amounts of plastic
after them well. waste, so make sure
now ready to help your bread rise and make yoghurt, ou find wa s to
tempeh, or all manner of other fermented goodness. reuse it

107
Staying keen

TUTORIAL

Staying keen
Learn how to stay at the cutting edge with your workshop tools

T
here’s an old saying that a blunt whetstones tend to be double-sided, with a coarse
knife is more dangerous than a sharp and a fine abrasive side. The coarse side is used to
one. The reasoning behind the saying grind out more noticeable nicks and blemishes from
is that you need to apply more force a blade, while the fine side is used to hone the edge
with a blunt knife to make it bite into to a sharper point. Whetstones are graded, just like
the surface, so it’s more likely that you sandpaper. The finer a whetstone, the higher its
Dr Andrew Lewis will slip while you’re using it. The same thing can be number will be, with a coarse stone being 400 or
said about most workshop tools, and keeping the 1000 grit, and finer polishing stones going up above
@monkeysailor edge on your tools is important if you want to keep 30,000 grit.
using them effectively. Blunt tools can overheat, slip, To use a whetstone, apply a little bit of oil to the
Dr Andrew Lewis shatter, and can delay or even completely ruin the surface, and move the blade across the surface so
is the owner of
Shedlandia.com, a project you’re working on. In this article, you’ll be that the edge of the blade is touching the stone
restorer of old tools, taking some of the most common workshop tools evenly, with light pressure. For the best results,
a fabricator for hire, a
and finding out the best way to keep them in working always try to move the blade so that the sharp edge
research scientist, and
a founder member of condition, with the minimum amount of effort. is being pulled along the stone, rather than pushed
the Guild of Makers. Sharpening a blade is something that’s easy to do onto it. The blade of a knife is usually a V-shape when
by hand with a little practice, and there are a few viewed end on, so you’ll need to flip the knife over
different tools out there that use automation to let every couple of strokes so that you sharpen each
you get the job done quickly. The simplest method of side equally, and keep a steady angle between the
sharpening a blade is with a whetstone. A whetstone stone and the blade. You want to match the existing
is an abrasive stone made wet with oil. Modern angle that the blade makes, so keep an eye on the
edge as you work to see whether you have the knife
tilted too far up or down.
If you have nicks or gouges on the blade, start with
the coarse side of the whetstone and keep working
the blade steadily until you’ve got them out. Once
you have a smooth edge, switch to the fine side of
the stone and continue honing the blade until it’s as
sharp as you need. Some tools like planes, chisels,
and scissors don’t sharpen to an equal V in the centre
of the blade; the sharpest point of these blades is on
the very edge of the metal. For these blades, you

HOW SHARP?
The internet is full of videos where people sharpen
their knives to a razor edge, and then use them to cut
through tissue paper or a single human hair. This is
definitely something that you can do if you have the
time and equipment, but it’s entirely unnecessary for
general workshop tools. A razor-sharp blade is easy
to nick and will blunt quickly on harder materials.
You’ll probably find yourself stopping to sharpen it
every few minutes.

108
 FORGE

YOU’LL NEED
Whetstone

Scythe-stone

Mill file

Three-point file

Angle guide
or protractor

only really need to sharpen the angled side of the material from your blade in a very short time. Finer
blade, unless there are any burrs that stick up from belts or discs are much better for sharpening tools on
the flat side of the blade. For planes and chisels, in a grinder. The high speed of the grinder also results in
particular, you might find it easier to sharpen the more friction, and that heats up the part that you’re
blades if you use a wedge to help you keep the working on. If your blade gets too hot during grinding,
correct angle between the stone and the blade. it can ruin the tempering and hardening of a blade.
The trickiest types of tool to sharpen with To help stop this from happening, you can apply some
whetstones are scythes, sickles, and bill-hooks. light oil to the blade before you start grinding. Move
Unlike knives that might have a convex curve near the blade evenly across the abrasive surface applying
the end of the blade, these tools have a concave a minimal amount of pressure, and keeping a fixed
curve that makes it hard to get good contact angle between the edge of the blade and the wheel
between a normal whetstone and the edge of the or belt. Remember that even a small bench grinder
has enough power to pull a blade from your hands

”
and fire it at high speed across the room. Safety is
You should carefully very important with these types of machine.
consider the type of
QUICK TIP

”
grinding wheel you use A 400/1000 grit
double-sided
whetstone is a good
choice in a general
blade. For this type of tool, you can buy conical workshop.
barrel-shaped whetstones that will better match the
curve of the blade.
The technique for these shaped stones is the
reverse of a normal whetstone. You hold the blade
stationary while working the stone along the length
of the blade.
Above
The right amount of
AVOID THE DAILY GRIND oi and i ht fin er
If you want to sharpen your tools more quickly, you pressure will help
keep the blade
might consider using a bench grinder, wet and dry moving smoothly
without dripping all
grinder, or a linisher (a belt sander) instead of a over the table
whetstone. Aside from the obvious ferocity of
Left
grinders and linishers, you need to take a lot of care Finding a comfortable
when using them to sharpen a blade. You should position to sharpen
a curved blade is
carefully consider the type of grinding wheel you use. half of the battle. You
Grinders and linishers move an abrasive belt or should always have a
fir rip on the too
disc at very high speed, and that will remove a lot of handle and the stone

109
Staying keen

TUTORIAL

” Sharpening a drill
bit isn’t as daunting

”
as it looks

Begin the sharpening process by putting your saw

into a vice with the teeth facing upwards, and use the
mill file to flatten the tops of the teeth so that they
are all the same height. If you find that the blade is
too flexible to file, use some pieces of scrap wood to
support it on either side of the vice. You’ll know
you’re done when you can see shiny metal on the top
of every tooth. It might seem counter-intuitive to do
this, but saw blades do not always wear evenly, and
flatting the tops (also called jointing) makes sure that
you’ll be sharpening the teeth evenly in the next step.
With the tops of the teeth level, run some masking
tape a couple of millimetres below the bottom of the
existing teeth (the bottom of the saw tooth is
sometimes called the gulley or valley). You’re doing
this so that you have a straight edge to work to, so
MAKE A WHOLE HOLE pay attention and keep the measurement as close as
Above If you have a bench grinder, you can use it to sharpen you can. Use your triangular file to recut the teeth.
Use the rest on the
grinder to support your drill bits. Sharpening a drill bit isn’t as daunting Start at one end of the saw, and keep filing the gulley
our fin er not the
drill. You’ll get more as it looks, as you only really need to set the point until you reach your tape line. Looking at the top of
control that way angle of the drill (the angle of the cone at the end of the teeth, the flat spots you made with the mill file
Right the drill), and make sure the centre of the drill is should now be spikes again.
It feels very unnatural even. Most general-purpose drills have a point angle
to run a fi e a ross
the top o a saw ut of about 118 degrees, which is an angle of 59
it’s the only way to
degrees per side. This angle is fine for most wood,
get the top of the
blade level metal, and plastic drilling needs. Use an angle guide
to set 59 degrees, and then begin grinding the point
of the drill evenly on one side, checking against your
angle guide regularly. If you’re struggling to set your
angle, you can either cut a template out of card or
plastic, or even just get the angle from a drill that’s
already sharp. When you’re happy with the angle,
switch to the opposite side and grind that in the
same way. Keep watching the point of the drill, and
make sure that you don’t grind it off-centre.

A SAW POINT
Saw blades are probably the most time-consuming
SHARPENING STATION
type of blade to sharpen, and the sharpening process
QUICK TIP has several different steps. To sharpen a saw blade, As an alternative to a bench grinder, you can get
Ripsaw teeth you’ll need a mill file (a flat file) and a three-square small desktop sharpening stations from most DIY
have an angle of stores. Typically, these sharpening stations will
(triangular) file. You’ll also need a special tool called
95 degrees from come with a small diamond grinding wheel on a
a saw-set, which you’ll use to set the position of the
the blade, while low powered motor, and they have several jigs and
cross-cut saws teeth to either side of the saw. Once you have those guides to help you hold different tools in the right
have an angle of things, you need to know whether you’re sharpening position while you sharpen them.
about 75 degrees. a cross-cut saw or a ripsaw.

110
 FORGE

The final step in the process is

sharpening the teeth using your Left
You don’t always
three-point file. If you’re sharpening have to reshape the
a ripsaw, you’ll file the teeth teeth on your saw.
If the blade isn’t too
perpendicular to the blade. Cross-cut worn ou an ust
saws usually have a slight angle to go ahead and set
the teeth then
the blade, so they will be about sharpen them
75–80 degrees (with the point of the
blade cutting when the saw pushes),
rather than the 90 degrees of a
ripsaw. Again, it’s easiest to work
down one side of the blade first,
sharpening all of the teeth on the left
side before flipping the saw over and
sharpening the right side. If you’re
having trouble judging the angle of
the file, you can create a simple
The teeth are now shaped correctly, but they’re guide by part-cutting through a scrap of wood at the
not sharp yet, and they’re not in the right position appropriate angle. Just place the wood onto the
relative to the blade. You’ll need to use the saw-set blade and use this to guide you.
to push the teeth to the left and right of the blade. You can also use this technique to sharpen an
The easiest way to set the blades is to work all the electric reciprocating or oscillating saw. The
way down the saw, setting the position of every replacement blades for these saws are quite
other tooth, and then flip the saw around to do the expensive, so it can be worth the time it takes
other teeth. Make sure you don’t skip a tooth, as it to set and sharpen a blade in this way.
can be very frustrating to go back and correct your Hopefully, you’ll find that sharpening your tools
mistake later on. using these techniques will get your projects
You can fine-tune how much you bend the teeth running much more smoothly. Blunt tools are
to suit different tasks. Wider spacing will increase very frustrating to use, and just a little extra
the width of cut, but the saw will be less likely to effort with a whetstone can save you from
bind. A general rule of thumb is to set the teeth hours of extra work, and allow you to breathe
about 1/3 of the width of the blade on either side. extra life into expensive consumables.

QUICK TIP
You can sharpen
old files by soaking
them in vinegar
for 24 hours,
then rinsing
and oiling them.

Left
The numbers on a
saw-set represent
the number of teeth
per inch of the
saw you’re setting.
t’s ust a uide
thou h so ou an
experiment with
different settings

111
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FIELD TEST
HACK MAKE BUILD CREATE
Hacker gear poked, prodded, taken apart, and investigated

PG

114
DIRECT FROM SHENZHEN:

THIRD HAND
Only four limbs? Lack of digits
getting you down? Why not
PG
116
invest in a helping hand?

BEST OF
BREED
PG

122
CAN I
HACK IT? The best mini keyboard to add easy
inputs to your project
A PlayStation Classic, bought
at a bargain price, is the latest
hardware to fear our Dremel

REVIEWS
124 SparkFun Edge 128 Sonoff Mini
AI development board Create the Internet of Things for £6.40

126 Creality Ender 3 129 Blown Away

A 3D printer out-of-the-box for £200 Let glass-blowing battle commence!
Direct From Shenzhen

REGULAR

DIRECT FROM
SHENZHEN Third hand
Make soldering easier and avoid gassing yourself

By Ben Everard @ben_everard

T
hird hands are wonderful. They’re
devices for holding your work while
you solder. Typically, they include two
or more crocodile clips on movable
arms that can hold not only the
PCB, but also a component in place.
They’re so useful, we’d be tempted to call them
an essential part of an electronics tool-kit.
There are a few basic differences between
different models – how they attach to the
work surface, how many arms they have, how
flexible they are, and what extra attachments
they have. Let’s explore these a bit.
We’ve never had much luck with third hands
with suction cups to stick them down. These
never seem reliable enough in our experience.
Hands with screw clamps (similar to G-clamps)
can work, but only if you have a work surface they
can clamp to, and even then, they can only be on
the edge of the surface. Our favourite option, by
a significant margin, is those with a large, heavy
base that doesn’t need additional clamping.
Two arms work well: that gives you one to hold
the PCB and one to hold what you’re soldering,
provided you’re only soldering one thing at a time
and the PCB is light enough to be held by one arm.
For more complex soldering, three or four arms are
much better. Above about four arms, there seem
to be diminishing returns – we very seldom find
ourselves not able to hold our work in place with four.
There are two common types of arms: those
made out of metal rod with two or three joints, and
those that are almost endlessly flexible. There are
advantages and disadvantages to both. The rod-
and-joint style can be a bit tricky to get into position,
but usually can be locked with screws and are then
Above
Five extra hands and a
fixed in position. The more flexible arms are easy to
fan make soldering easier get into position, but can then wobble and move.

114
 FIELD TEST

Left
The plastic pads
on the handles are
prone to coming
off, but they’re not
functional anyway

There are a few extra attachments you can place for your particular piece of work, but it has
get – magnifying glass, fan, and light are all the downside of feeling quite flimsy. The USB
common. Magnifying glasses can be useful for cable isn’t particularly long, so you’ll either need a
fine work, but we find that only the rod-and-joint- power source very close by, or a USB extension
style third hands are capable of holding work still lead. We put our laptop on our desk and used
enough to be useful for this level of fine work. that, but for more regular use we’ll splice in a bit
Of course, depending on your eyesight, you may more cable to make it long enough to be useful.
find magnifying lenses more or less useful. The crocodile clips are covered in heat-shrink

DIRECT FROM SHENZHEN

Whether or not a light is useful to you will depend tubing to protect the component being held, and

”
on your workshop lighting. plastic covers on the
Since switching to arms. The latter are
The arms do have a certain
lead-free solder, we’ve prone to falling off, but
found soldering fans wobble in them, but no more this doesn’t matter as
to be essential parts of than we’d expect for fully they don’t do anything

”
our desktop. Even with anyway. Overall, the clips
leaded solder, there are flexible arms are big enough to hold
quite a few fumes given most things we want
off, and that stuff is not good for your health. to solder, and firm enough to hold them securely.
With all that in mind, we set off to find The base is just heavy enough to hold itself
our perfect third hand on a direct-from-China in place. Any lighter and we’d worry about
website to see what it would cost. it moving about too much. We would feel a
We got a NEWACALOX Multi Soldering Helping bit more confident if it were heavier, but we
Hand Third Hand Tool from the NEWACALOX official haven’t had any problems with it in use.
store on AliExpress for £20.93, including delivery The base includes recesses that can be used to
to the UK, and set out to do some soldering. hold components, but we find it a bit fiddly to use
The arms do have a certain wobble in them, as the arms are quite close together and you
them, but no more than we’d expect for fully risk knocking them when trying to pick something up.
flexible arms, and the number of arms means Having external component bins works far better.
you can double up to minimise this. Overall, this third hand is a great tool for
The fan is a computer fan with a USB connection soldering with, especially if you hack the USB
that has an M3 bolt through one corner, attaching cable on the fan to be a bit longer. Fortunately,
it to one of the arms. This has the advantage of we’ve got just the thing to hold it in place
making it easy to position in the most effective while we solder up the new cable.

115
Tactile inputs

BEST OF BREED

ONLYTHE
BEST
Tactile inputs
A surprising variety of keyboards for your
next electronics project

Below
By Marc de Vinck @devinck If you’d rather go the
full DIY route, you
can build your own
keypads from scratch

S
ometimes old school is cool. And
you can’t get more old school than
keyboard inputs. And that’s what
we’ll look at in this Best of Breed.
There is something enduring about a
simple key press. Just ask any gamer
about their keyboard and you’ll most likely get into a
lively conversation about the best layouts
and specific brand of keys they like to
use. Even in the DIY electronics world,
we know it’s important. Just look at
Pimoroni’s Keybow: it’s available in
different ‘feeling’ keys, both
clicky and non-clicky.
Keyboards are also
incredibly useful and
extensible. And you don’t
need to simply input
characters. They can be
used for entering code patterns,
movement, and – this author’s favourite use
– programmable displays for creating sequenced
music. Another nice thing about having a keyboard
input with your project is it’s very natural for humans.
OK, maybe not natural, but at least it’s very familiar. If
your project requires user input or feedback, you
won’t need to explain how to use a keyboard.

116
 FIELD TEST

Keybow 12-key Kit vs

Adafruit Trellis Monochrome Driver
Hackable mini keypads

PIMORONI $60 shop.pimoroni.com ADAFRUIT $ 9.95 adafruit.com

T
he Pimoroni Keybow is an
easy-to-build mini mechanical
keyboard kit that doesn’t require Below
A really well-made
any soldering. It’s powered by and complete kit
Raspberry Pi and includes twelve
beautifully illuminated keys.
You can customise the inputs with a variety of
macros, or just use as a simple keyboard.
Clicky or non-clicky is really the only decision you’ll
need to make when you pick up the Keybow kit. And
unlike many other kits or shields, this really includes
everything – OK, almost everything – you need to get
up and running, even a Raspberry Pi Zero WH. The
only additional item you will need is an SD card,

T
which you most likely have already. The quality of the he Trellis driver PCB assembly
keys and PCB is really good, which is what we expect from Adafruit is an open-source
from any Pimoroni kit. If you want a self-contained backlight keypad driver system.
mini keyboard, this is it. And if you are looking for It’s really easy to use, thanks to an
something a bit smaller, check out Pimoroni’s 3-key extensive tutorial from Adafruit,
Keybow kit. It’s just as good as the 12-key, but a bit and highly customisable. This
less expensive and a lot smaller. It’s a great way to Trellis PCB is made to match the Adafruit 4×4
get user input in a small form factor. elastomer keypad and has areas in the centre of
each button for customising with 3 mm LEDs.
VERDICT
You will need a microcontroller to control the Pimoroni Keybow
Below
Build and modify Trellis, as the circuitry on the board only handles the A great solution
the Trellis however background key presses and LED lighting of the tile. for adding keyed
you’d like
Any Arduino, or similar microcontroller, can handle input to your
reading of the key inputs and configuring the LEDs. Raspberry Pi.

10 / 10
Our favourite part about the Trellis is its ability to be
expanded and be customised. Each Trellis PCB has
an I2C-controlled LED sequencer and keypad reader
already on it. The on-board chip can control all of its
16 LEDs individually. The same circuitry reads any key Adafruit Trellis
presses. You can connect up to eight PCBs together Customisable,
via their edge connectors. Each board will share the affordable, and
same power, ground, interrupt, and I2C clock and extensible.

10 / 10
data pins. This makes building a huge 128-button
matrix really fun and easy! Just remember to pick
up the required matching membrane and LEDs.

117
Tactile inputs

BEST OF BREED

Adafruit 1×4
Membrane Keypad
ADAFRUIT $2.95 adafruit.com

” Use it in your next project

just like any simple

”
button or switch

ADAFRUIT 3×4
MEMBRANE MATRIX KEYPAD
ADAFRUIT $3.95 adafruit.com
Adafruit also sells a larger version of its membrane
keypads if you need extra inputs. It’s a similar hook-up
process, and is just as easy to get up and running
thanks to Adafruit’s online tutorials and projects. Just
keep in mind, this version will require a microcontroller.

T
his Adafruit 1×4 Membrane Keypad
Above has four input buttons, each with
You can easily
wipe these keys to
its own wire for hooking up to your
keep them clean project. And since all of the buttons
are wired individually, you don’t even
need a microcontroller to use it. Use
VERDICT it in your next project just like any simple button or
Easy to clean switch. The membrane has a soft touch, and it can
and affordable. easily be mounted by removing the paper backing,

8 / 10
exposing a strong adhesive. Adafruit includes a
5-pin, extra-long header strip so you can easily plug
it into a breadboard.

118
 FIELD TEST

3×4 Matrix Keypad

ADAFRUIT $6.50 adafruit.com
” Adafruit includes a
library to get your Arduino

”
project up and running

G
ot a project that requires a
stealthy code to be input? If so, 4×4 MATRIX KEYPAD
this is the keypad for you! The
Adafruit 3×4 Matrix Keypad has ADAFRUIT $5.95 adafruit.com
twelve buttons, arranged in a
Just like Adafruit’s membrane keypads, the mechanical matrix keypad
traditional telephone keypad grid.
is available in multiple sizes. The larger 4×4 matrix is also arranged in a
They are wired in a matrix, which can easily be read
telephone-style layout and will work just as easily as the smaller version
by a microcontroller using only seven pins. Adafruit with your microcontroller. With this keypad, your code can include a few
includes a library to get your Arduino project up and alphanumeric inputs, making it extra secure.
running. A row of header pins is also included so
you can easily prototype with it on a breadboard.

Left
Need more
keys? Try the
larger 4×4
matrix keypad

Left
A great way to get
fast and reliable
keypad input

VERDICT
Easy to use
and reliable.

9 / 10
119
Tactile inputs

BEST OF BREED

Button SHIM PS/2

PIMORONI $30 shop.pimoroni.com Keyboard to
TTL Serial
T Converter
he Pimoroni
Button SHIM may
be the smallest,
and most discreet,
keyboard-like
input available ADAFRUIT $17.95 adafruit.com
for Raspberry Pi. OK, it’s a
Right
A very handy button bar, but isn’t that what all
addition for

T
your Raspberry
keyboards really are anyway? The
Pi project Button SHIM gives you five he PS/2 Keyboard to ASCII
physical buttons, along with a Converter from Adafruit is a simple
handy RGB status LED. solution for producing a single TTL
An interesting aspect of this ASCII character on the ‘press’ of a
VERDICT SHIM is the ability to solder it keystroke from a standard, and
A discreet way into the GPIO pins and still allow you to use a HAT or ubiquitous, PS/2 keyboard. We’ve
to add button pHAT at the same time. Alternatively, you can solder on made a lot of different projects using old PS/2
input to your the included female header and use it as a simple keyboards, and this breakout board is a lifesaver. It’s
Raspberry Pi. standalone board. Installation of the required software designed to offload the complex keyboard decoding

8 / 10
couldn’t be easier: just one line of code typed into the of PS/2 keyboards. This allows your microcontroller,
terminal and the package will be installed. Head over to like an Arduino, to tackle other
the Pimoroni website to learn more. tasks. And as we all know, your
Arduino is always happy to
have a little extra help.
ADAFRUIT HELLA UNTZTRUMENT! All you have to
do is plug in a
ADAFRUIT $199.99 adafruit.com standard PS/2
keyboard
Is one Trellis just not enough for you? You can have more Trellis with the Adafruit HELLA
UNTZtrument! This kit includes eight Trellis control PCBs (16×8 total) and everything else in one
you need to make one cool instrument. And if this is just more fun than you can handle, end and start
you could always pick up a smaller 8×8 kit, which is still pretty big! typing, while your
Arduino receives
the specific
keystrokes via a little
code. You can also use it to
break out magstripe and
PS/2 bar code readers. It
comes ready-to-go and VERDICT
requires no soldering. A simple
solution for
adding a full-
size keyboard
to your project.

8 / 10
Above
Adding a PS/2
keyboard –
made simple

120
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A PlayStation Classic

CAN I HACK IT?

Can I Hack It?

A PlayStation Classic?
Can we hack this mini retro nostalgia console?

I
n the late 1990s, Sony released the original GENERAL CONSTRUCTION
PlayStation upon a generation nurtured The all-ABS plastic chassis is made from a firm plastic
by Sega and Nintendo. CD-based games that can be worked with hand/power tools. The top
with sprawling levels, full-motion video, and and bottom of the case are held together with five
high-quality audio became the norm. But, fast- cross-head screws that tap directly into plastic struts.
forward to 2018 and Sony released its own With the bottom of the case exposed, we can see
Les Pounder mini retro nostalgia console, following the success that there are a further four cross-head screws which
@biglesp of the NES and SNES consoles. Alas, supplies of need to be removed to enable the circuit board to be
PlayStation Classic exceeded demand, and in 2019 released. These screws also hold a large metal cover
Les Pounder loves it was put on offer as clearance. And that begs the to the board. The cover is our heat-sink, connecting
taking things to pieces question, “Can we hack it?” directly to the CPU via a 2 mm-thick thermal pad. Take
and seeing how they
work. He teaches care to remove the heat sink without damaging the
others how to be pad, as it is needed to keep the CPU cool.
makers and tinkerers
at events across the
UK. He blogs at bigl.es ELECTRONICS
The single circuit board is powered by a MediaTek
ARM (MT8167A) system on a chip (SoC), with
a quad-core ARM Cortex-A35 CPU running at
1.5GHz. This is partnered with 1GB of DDR3
RAM and a PowerVR GPU. Storage is provided
by 16GB of flash memory, enough to house the
games and the operating system. This is a
typical configuration for tablet devices,
something this chipset is designed
to work with. Power comes in
the form of a micro USB port,
so 5 V is the norm, and we
can solder connections to
the port for powering
projects. This also
means that the board
can be powered
from a USB battery
YOU’LL NEED for portable hacks.
Sony PlayStation In our tests, the
Classic
unit used 180mA
COST on average at idle;
£44 when gaming, this
rose to 320mA during
WHERE a brief bout of Tekken 3 for
hsmag.cc/ymXZkK testing… yes, testing.

122
 FIELD TEST

ROM PROBLEMS
Game emulation is a legal grey area, but the common points to note are that if you are
downloading the games, collectively known as ‘ROMs’, from the internet, then you
are breaking the law, and opening yourself up to possible viruses and malware. If you
are using your own game CDs/cartridges to create backups, known as ‘dumps’, then
this is still illegal. The whole ROMs debate has raged for many years and across many
systems, and it will continue to rage for many years to come.
Some games are ‘abandonware’, and the creators/publishers have disappeared into
the mists of time. But the majority of games have a publisher or owner who can claim
Above
The main circuit board for the PlayStation Classic is well-made copyright theft. Nintendo recently issued take-down notices to a number of websites
and provides lots of power for emulation hosting games for Nintendo consoles as old as the NES.
To blur the lines of this issue even further, in recent months there have even been
Around the perimeter of the board are large ground legally dumped ROMs on archive.org which can be downloaded for use or played
directly in the browser. Before engaging in this activity, it would be prudent to review
planes that will enable us to find good spots to
the laws for your country.
connect our projects to ground. The two USB ports We at HackSpace magazine do not condone software piracy or copyright theft.
have easy access for hacks, and can be used for the
included joypads, or for USB drives – more later.

HACKABILITY
But can we hack this? Well, yes! Cosmetically, we
can remove the board from the PlayStation chassis
and insert it into a 3D-printed case, with a small HDMI
screen, and break out the USB ports. Adding a USB
battery would enable the kit to be used on the move.
But, electronically, this is really just a single-board
computer similar to the Raspberry Pi. It’s running a
version of Linux, and so it is just a computer. The two
game controller USB ports are the gateway to fun.
Using some software called BleemSync, it is possible
to adapt the operating system on the device and
run your own games from a USB drive plugged into
port two. BleemSync also provides a neat interface
via a web browser and a direct USB connection to
your computer.

Below
he ports an e used to onne t ash stora e
externally or internally via soldering for a clean look
If you would like to add some extra tech, then the
5 V and handy GND planes mean that we can add an Above
Attaching a USB
Arduino, or other microcontroller, to control NeoPixels drive to the internal
and many other types of LEDs. USB port connectors
means that we can
When the PlayStation Classic came out, it was hide USB drives full
overpriced and featured an underwhelming game of games!

selection. But, as something that we can hack, the

PlayStation Classic offers a conveniently sized chassis
into which we can add our tech, hack the existing
software, and enhance the product to meet our
needs. Right now, this is being sold off with drastic
price cuts – it was £15.99 in Amazon’s recent sale.
At this price, it’s a great option for a hacking platform,
whether you’re looking to build a DIY handheld
gaming rig or something more adventurous.

123
SparkFun Edge

REVIEW

SparkFun Edge
Artificial intelligence stripped bare

SPARKFUN $14.95 sparkfun.com

By Ben Everard @ben_everard

A
t the moment, artificial audio to some cloud service and that cloud service
intelligence is in a transitionary works out what you’re saying, what this means,
phase where words have different and sends the commands back to the device. This
meanings to different people. has a few disadvantages – it requires a permanent
No one’s lying; it’s just that the AI connection to the internet, it sends quite a lot of
world hasn’t quite decided how to data back and forth, and it requires cloud servers
describe the various aspects of embedded AI. For to be kept running in order for it to operate.
starters, what is the Edge? Very briefly, it refers to Edge computing is the opposite of this. It means
Below AI that happens on a device itself. The easiest way that some level of AI is running directly on the
At 4 cm by 4 cm, to understand this is to look at the alternative: for device doing the sensing. So far, it all seems fairly
this shou d fit
into even space- example, the way most popular voice assistants straightforward. Where it all seems to break down
onstrained pro e ts work. When you speak to them, they upload the is what people expect these edge devices to be.
Last month we looked at Raspberry Pi 4 as an edge
device – and it is. It can do some powerful AI while
still being cost-effective and low power (at least when
compared to a traditional computer). The SparkFun
Edge, however, is an order of magnitude smaller
than this. It features an ultra-low-power ARM M4
core, a couple of microphones, and just enough
other components to keep everything running.
People will argue about which of these is the
‘true’ edge, but semantics need not bother us. They
both have niches in AI that they fill well, and we can
just look at what is the best device for our needs.

LIVIN’ ON THE EDGE

We’ll start with the issues with the SparkFun Edge.
First is that it’s not particularly easy to program. You’ll
need a USB to UART cable, and it’s programmed via
a downloadable SDK. This is pretty much par for the
course with many commercial dev boards, but anyone
used to the Arduino IDE, or similar things, will find it
a bit of a shock. That said, it’s well documented; so
as long as you’re comfortable using the command
line, you should make it through unscathed.

124
 FIELD TEST

” The hardware is very good

for a very specific set of
circumstances – AI without
mains power and needing

”
Bluetooth connectivity

This refers only to programming the device.

Programs take models (which are the matching
engines of neural networks) and tell the board
what to do depending on how the model reacts
to the input. Creating models is a separate
task from programming – it exists somewhere
between art and science. Essentially, it comes
down to throwing a lot of example data at a neural
network and attempting to ‘train’ it to understand
particular patterns. In many cases, it’s possible to
bypass this, and use pre-created models similar
to how you might use a library in programming.
Once you’ve got your code into the device, you
need a way to interact with it. This board is designed This can make sense, particularly if you’re
by SparkFun, and the team at TensorFlow, to run running a number of devices in a small area Above
There’s a battery
neural networks. These models are first trained to and power consumption is an issue, or if your holder for
recognise if an input falls into a particular category devices only need occasional connectivity. off-grid running

or not; for example, if a particular sound is a word. You need to be realistic with your expectations
On the Edge, there are two microphones, four GPIO with the SparkFun Edge. If you’re looking for
pins (that can run SPI or I2C), a Qwiic connector, high-precision matching of complex input – such
and a camera connector. As yet, there’s no camera as recognising people from images – then you’re
module available for the camera connector. probably going to struggle. However, if you’re
This is all controlled by an Ambiq ARM Cortex looking for something to run on very low power and
M4F processor with Bluetooth. The Cortex-M4F core react when it recognises one of a small number
is one of the more powerful microcontrollers around, of conditions, then this might well be the board
and this one runs at 48MHz (with a 96MHz burst for you. At the moment, the lack of pre-prepared
VERDICT
mode). What makes this stand out is that it does this models means that it’s not really suitable for casual For low-
while drawing under 2 mA of current at 3.3 V – great uses; however, given that it’s an official board by power AI with
Bluetooth
if you’re running on battery (there’s a CR2023 holder TensorFlow, we expect that there’s likely to be
connectivity,
on the back), solar, or other limited power supply. more in the future, so keep an eye out to see what
the hardware’s
models currently exist before making a purchase. here, but you’ll
CONNECTION CONUNDRUMS The hardware on this board is very good need to see
Perhaps the biggest limitation for this board as an for a very specific set of circumstances – AI if there are
edge device is the connectivity. Bluetooth makes without mains power and needing Bluetooth the models
sense from a power and cost perspective, but it connectivity. While these are quite specific, you need.

8 / 10
makes your overall system setup a bit more complex they’re not all that rare. This lets you bolt on
as it’ll need something to pair with to send data into neural networks to remote sensor deployments.
the world. For those conditions, this board stands alone.

125
Creality Ender 3

REVIEW

Creality Ender 3
Hot plastic fabrication on a budget

CREALITY around £180 creality3d.cn

By Glenn Horan @BatGlenn13

O
nly a few short years ago, the
thought of getting a consumer-
grade 3D printer, that works out of
the box, for anything under £1000
was a maker pipe dream. Today,
thanks to Creality, we’ve very nearly
got just such a printer for under £200.
The Ender 3, like many printers in this price range,
arrives as a kit. Opening the box, we are greeted with
a printer that’s around 80% assembled and includes a
full-colour manual detailing the twelve-step building
process. There’s a selection of essential tools required
to build the printer, and some additional tools that are
useful for its day-to-day operation (a selection of Allen
keys, a scraper, a microSD card, and USB adapter – to
name but a few). All of the parts are well labelled, with
the screws neatly organised into labelled bags. From
box to first print takes between one and two hours,
and there is plenty of help available online, via the
Ender 3 subreddit and Facebook pages.
Right
The minimal Our favourite thing about the Ender 3 is the frame
and solid- – it’s made entirely from aluminium extrusions, rather
looking
Ender 3 printer than wood or acrylic found in its contemporaries,
which gives it an incredibly solid feel. The level
of stability this provides means that it can
achieve very good-quality prints, even at
higher speeds. As if that wasn’t good
enough, the Ender 3 also boasts a
Bowden extruder setup. While
the debate of Bowden vs
direct-drive extruders is a lively
topic among the 3D printing
community, Bowden systems
do offer a few undeniable
advantages. A Bowden setup
has the stepper motor that feeds
the filament into the hot end mounted
on to the frame, rather than on the extruder itself. This
means there’s less weight being swung from side to

126
 FIELD TEST

Left
The Ender Dog was
this author’s first
print with the Ender 3
– it turned out great!

side as the printer operates, resulting in the ability to the sturdy frame and Bowden extruder will
print faster while maintaining print accuracy. theoretically allow you to print things quickly (or at
least quickly in the world of 3D printing).
WHAT’S IT CAPABLE OF?
This printer has a long list of excellent features that THE BOTTOM LINE
really make it a delight to use. All the wires are neatly As expected, there are a few small downsides to the
hidden away within the frame, or bundled neatly into Ender 3. The springs on the underside of the bed aren’t
the stylish black cable tidy. A spool holder, which sits very strong (more tension in the springs means less
on top of the machine, reduces the footprint that it build plate movement, and less calibration needed
takes up on your desk. The power unit itself not only between prints), but it’s both cheap and easy to replace
comes with a switch and a removable plug, but it

”
operates at 24 volts, meaning that the bed can heat
up in a fraction of the time of its competitors, which If functional prints are more your bag, the sturdy
are usually kitted out with 12 V units. There are small
frame and Bowden extruder will theoretically

”
rubber pads on each corner of the base to help
dampen the sound it makes, and there are large allow you to print things quickly
wheels on the bottom of the bed to allow very quick
and precise bed level calibration. The build plate is
also removable and flexible, allowing users to these. Printers manufactured before 2019 do not have
remove their prints easily, cleanly, and with little risk thermal runaway protection, which is a pretty important
of breakage. safety feature, so make sure that it’s enabled on your
So how does it print? Every Ender 3 comes with a printer. Unfortunately, the board running the Ender 3
pre-prepared file to do a test print of what we’ve does not have a friendly bootloader, which makes it a VERDICT
come to call the ‘Ender Dog‘, and we were very little tricky to update the firmware. While there are You won’t find
impressed with the results with no calibration or tutorials online that detail the process, it’s definitely an a better printer
tweaking (with the exception of the necessary inconvenience if you want to do additional tinkering to in the sub
Z-levelling). We’ve consistently been impressed with improve the printer. £200 range.

9 / 10
what this printer can do. The quality of prints, For the price and print quality, though, we can live
particularly when using a higher resolution, is amazing with these issues. The Ender 3 has raised the bar for
for this price. If functional prints are more your bag, budget 3D printers.

127
Sonoff Mini

REVIEW FIELD TEST

Sonoff Mini
two-way smart switch
Create your own Internet of Things

SONOFF £6.40 itead.cc

By Daniel Hollands maker.rip

I
n issue four we reviewed the Sonoff Basic, At less than half the size of the Basic,
a cheap option for people who wanted to it lives up to its Mini name, which
make their dumb devices smart by providing according to Sonoff’s marketing materials
power switching via apps and voice control means it will fit inside a standard EU switch box –
– provided they’re prepared to get their but unfortunately, when testing the device we found it
Above
hands dirty with a little DIY. Today we’re didn’t fit behind any of our test switches, so if you’re A small and
looking at its younger sibling, the Sonoff Mini, and planning on using it to upgrade the lighting in your compact unit,
living up to
discussing the differences between the two devices. home, you will need to measure the available space its name
Much like the Basic, the Mini provides the ability inside the switch box first. This is important, not only for
to add smart switching features to dumb devices. aesthetics, but because it needs to sit inside an
What’s different is the Mini has the optional ability enclosure due to the live screw terminals which are
to attach an on/off switch to it, providing two-way exposed on the unit.
switching control, letting a regular switch work Much like the Basic, the smart control via the
alongside smart control. eWeLink app works really well, and we had no issues
The classic use case for this would be adding getting it connected to our WiFi network, or added
smart control to the pre-existing lights in each room of as a device to our Amazon Echo. Among the features
your home, while keeping the ability to use your of the app are the ability to set a regular schedule,
regular light switch, allowing both to provide timers, and interaction with the IFTTT service, letting
independent control. It won’t matter which state you do things like, automatically trigger the switch
the switch is in, when you flip it, the lights will when the ISS is overhead, for example. Left
Diagram showing
toggle on or off accordingly, with the same being One new feature is that of LAN access, meaning the two wiring
true of the smart control. smart control can continue to work independently of options available
a cloud service, which solves the previously reported
issue of the cloud service occasionally going down,
VERDICT
and bypassing potential issues with an unstable
Adds smart
internet connection.
control to
Also new is a DIY mode, aimed at developers, which room lighting
provides a REST API for direct control of the device, in an elegant
which is enabled by opening the casing and attaching way, provided
the included jumper. The documentation and tools for it fits behind
this exist on a GitHub repo, but still appear in their your switch.

8 / 10
infancy. Provided you have a suitable enclosure, the
Sonoff Mini provides an easy-to-use way of adding IoT
control to existing appliances.

128
Television

REVIEW FIELD TEST

Blown Away
By Ben Everard @ben_everard

T
he format for this Netflix show is
simple – take a group of glass-
blowers and, each episode, give
them a challenge and eliminate
whoever performs worst. This
format is particularly brutal because it
doesn’t give the competitors a chance to redeem
their mistakes – one false move and they’re out.
When working with glass, it’s easy for one false
move to result in the utter destruction of the piece
you’re working on. While this can happen at any
time, a particularly risky time is getting the piece off
the punty (a metal rod used to hold the glass as it’s
worked) and into the annealer (an oven that very
slowly cools down the glass to room temperature to
ensure that it doesn’t crack). It doesn’t matter how
well your glass is worked, if your tap to break it off
the punty is a little too hard, or you don’t hold it
properly, all you’ve made is a pile of broken glass.
There are parallels to the Great British Bake Off in
Blown Away, and the strongest of these parallels are
in the medium, rather than the structure of the
competition. Molten glass, like cake batter, is in a
constant state of flux. You can influence it, you can
work with it, but you can never really control it in the
same way you can with, say, metal or wood. It
doesn’t stay still, so once you’ve begun the process
of creation, you’re thrust into a stream of work that
it’s hard to stop or pause, until you’ve gone all the
way through to a finished product in the annealer. VERDICT
Blown Away is an entertaining watch in its own Great
right, and we enjoyed getting an insight into the entertainment
process of glass-making, but we would have and some truly
preferred a slightly safer competition, where makers impressive builds.

9/ 10
were eliminated on the results of two or three
makes, rather than having just a single chance
each episode.

129
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 Transistors
Since John Bardeen, Walter Brattain, and William
Shockley created the first transistor in 1947,
these electrically controlled switches have come
out in many different forms. Here, two new old
stock germanium transistors look on with pride at
a much smaller, cheaper silicon transistor.
The smallest transistor created so far was just
2.5 nanometres wide. You could fit approximately
9,273,600,000,000,000 of them on this page.