In this tutorial, you will learn how to make two simple projects that use LEDs and push-button switches that are controlled by a Python program running on your Raspberry Pi. The first project uses an RGB (red, green, blue) LED to interface to the popular Cheerlights project. Cheerlights (cheerlights.com) allows users all over the internet to set each other’s LEDs to different colours just by tweeting. The second project is a reaction timer using LEDs and push-buttons to test the speed of your reactions.