Who doesn't love music? These Piano Stairs are an interactive, relatively portable, musical installation that can be applied to basically any stairwell. I built them for HackPrinceton and won 2nd place in the hardware track. I've had requests to share my code and diagrams, so I decided to make an Instructable! These piano stairs use a light-based “tripwire” for each stair. The light sources should be on one ...