markov

3 Articles

Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Copycat Keyboard

December 30, 2024 by 1 Comment

This is Crater75, an almost completely from-scratch row-staggered wireless split board that [United_Parfait_6383] has been working on for a few months. Everything but the keycaps and switches is DIY.

The Crater75 split keyboard, which features OLEDs on the Function row.
Image by [United_Parfait_6383] via reddit
As cool as a keyboard full of screens might seem, can you imagine what it would be like to type at speed on a sea of slick surfaces? Not very nice, I’m thinking. But having them solely on the Function row seems like the perfect compromise. Here, the Function row keys interact with foreground applications, and change with whatever has focus. For the curious, those are 0.42″ OLEDs from Ali with a resolution of 72×40.

I’m not sure what’s going on internally, but the two sides connect with magnets, and either side’s USB-C can be used to charge the board. Both sides have a 2100 mAh Li-Po battery, and the average current of the OLED displays is low enough that the board can run for months on a single charge.

The switches are Gateron low-profiles and are wearing keycaps recycled from a Keychron, which add to the professional finish. Speaking of, the enclosures were manufactured by JLC3DP using the Nylon Multi-Jet Fusion process, but [United_Parfait_6383] says the left side feels too light, so the next revision will likely be CNC’d aluminium. Be sure to check out this short video of Crater75 in action.

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‘Bit’ Installation Combines Art, Markov Chains

December 17, 2018 by 7 Comments

A Markov chain is a mathematical concept of a sequence of events, in which each future event depends only on the state of the previous events. Like most mathematical concepts, it has wide-ranging applications from gambling to the stock market, but in this case, [Jonghong Park] has applied it to art.

The installation, known simply as ‘bit’, consists of four machines. Each machine has two microswitches, which are moved around two wooden discs by a stepper motor. The microswitches read bumps on the surface of the disc as either a 0 or 1, and the two bits from the microswitches represent the machine’s “state”.

When a machine is called, the stepper motor rotates 1/240th of a revolution, and then the microswitches read the machine’s current state. Based on this state and the Markov Chain algorithm coded into the machines, a machine with the corresponding state is then called, which in turn moves, continuing the chain.

The piece is intended to reflect the idea of a deterministic universe, one in which the current state can be used to predict all future states. As an art piece, it combines its message with a visually attractive presentation of understated black metal and neatly finished wood.

We love a good art installation here at Hackaday – like this amazing snowflake install from a couple years back. Video after the break.

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Keyboard Composes Its Own Music

May 1, 2012 by 5 Comments

Summer is right around the corner and all the final projects from electronic design classes are rolling into the tip line. This time, we’ve got [Chaorong] and [Siyu]’s auto-composing keyboard from their time in ECE4760 at Cornell.

The keyboard has two modes: a ‘happy’ mode and a ‘tender’ mode, the difference being the tender mode is slower and sounds a little like a lullaby. After two keys are pressed, the ATMega644 figures out what key it should play in and starts generating a random-ish sounding song using a Markov probability matrix.

There’s a third option for the keyboard as well: play a short melody and the software will loop through a few permutations of the melody. After the break, you can see [Siyu] play Ode to Joy and have the autocomposer improvise around the tune. Very, very nice work and we can’t wait to see more senior design projects hit the tip line.

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