A software build light indicator using Arduino. For background, see here: https://en.wikipedia.org/wiki/Build_light_indicator
See here for more information: https://youtu.be/M72VJyHf5FY
The circuit is located in the circuit folder, built with KiCAD 5.1.4, but I also included a PDF of it. The code is written in the Arduino IDE, version 1.8.9 as of this writing, and is located in this directory. The interface scripts are written for Python 3, but should work in Python 2 as well.
The parts I used are available on eBay:
Light: https://ebay.to/319dQn9
Case: https://ebay.to/2OJt0x9
Arduino: https://ebay.to/33sAcSa
Shield: https://ebay.to/315kdbi
Boost Converter: https://ebay.to/33wi7mb
Transistors: https://ebay.to/2Mz1AXY
You will also need some 220 ohm resistors and some wire.