A simple radio-based start system using traffic lights for rowing competitions.
Devices control traffic lights (red and green) conforming to the regulations for rowing competitions. The starting umpire (starter) switches the lights from neutral (all off) to an active red light when competitors are called to be "ready". When the race is started, the red light switches off and the green one turns on ("go"). At the same time an acoustic signal is emitted. If a false start was detected (by whichever mechanism), the lights alternately turn on and off with along an acoustic signal which indicates the false start to the crews.
There is a device (starter unit) that is under the control of the starter and manages all traffic lights. The starter unit uses the same hard- and software as the traffic light units on the individual lanes (lane units). They only differ in configuration (starter vs lane unit). The lane units can be configured with their lane number.
When the starter unit receives a ready signal, it broadcasts an according command via radio. If the starter unit receives a ready signal again, the lights are turned off (neutral position). When lights are red (ready) and the start command is received, again a command is broadcast to turn the red light off, the green one on, and start the audio. The lane unit reset themselves into neutral state again after a certain timeout. A separate false start signal can trigger an according message from the starter unit to the lane units.
For each lane a timeout value can be configured via radio in order to have individual lanes switch to the green lights when that timeout is expired.
A LoRA gateway-like device can forward the commands from the starter unit to the timing system.
All radio messages are encrypted using AES and should be protected against replay attacks.
Microship ATtinyX1Y (1-series). Currently, the ATtiny816 is targeted.
In order to build the package, you need the current libc/m for the ATtiny
1-series. You can download them from Microchip website:
[https://www.microchip.com/mplab/avr-support/avr-and-arm-toolchains-c-compilers].
Extract libm.a and libc.a from
avr8-gnu-toolchain-linux_x86_64/avr/lib/avrxmega3/short-calls/.
In addition, you need the libattiny816.a and crtattiny816.o files from the
Microchip ATtiny Series Device Support pack
([https://packs.download.microchip.com/])
Place those files under build/dev/attiny816/avrxmega3/short-calls/
Not tested with actual hardware, just software implementation for proof of concept and resource usage exploration.