Robert C. Martin (Uncle Bob) said in a talk:
Imagine you have a button that you can push, it will test your code and if everything is working a green light will come up, but if something is break, a red light will come up [...]He was of course talking about TDD, but I was bored and get inspired to build this little toy.
Hardware schematics, firmware and host software is available in this Github repo. Along with information on how to compile and use.
This is a physical toy traffic light to be used with software development TDD (and testing in general) tools. It will not boost your productivity nor make you a better programmer or TDD practitioner, but it looks cool :)Lets explain how it works, it's very simple: