Using motion detectors and an Arduino you can trigger lights, ... Here is the Arduino code for the Parallax sensor. int motion_1 = 2; int light_1 ... flash the on-board LED in front of digital pin ...

If you have an Arduino that can act as a keyboard for a PC, the code almost writes itself. [Rootsaid] uses a specific library for the PAJ7620 and another — Nicohood — for sending media keys.