Ever heard of Arduino? It’s an awesome programmable microprocessor (mini computer) that you can make do almost anything! Its main purpose is to make sensors react to actuators (lights, motors, and more). This primer will help you get started with Arduino and a little bit of coding.
The Arduino Leonardo is the main model of the Arduino, with just enough features for you to get started. It is also one of the most inexpensive and easy to use micro-controller platforms ($25).