Did you know that you can use Arduino to turn on an LED when you press a button? Well, it is true, you can do this! Leaving the joke aside, let me show how you can achieve this. You will need the ...

Off the shelf RGB colour pickers allowing you to extract and objects RGB values can range from a few hundred dollars to thousands depending on your needs.

But if you can push your button while your yellow LED is lit, the light speeds up tremendously until the next button press in the green. Our only wish is that subsequent yellow-light button ...

You can throw a Raspberry Pi camera and OpenCV at the problem and approach it through software, or you can buy an off-the-shelf RGB sensor and wire it up to an Arduino.