Seattle-based designer Mark Wheeler embedded contact microphones on ping pong paddles, hid an Arduino in a retro radio, and designed an app, all to get a ping pong table to play music to the rhythm of a game. The idea of Ping Pong FM, as Wheeler and his team call it, is to play fast enough that the song’s true tempo is maintained. It’s high stakes. If a player misses the ball, the music stops completely. That's no fun.
The microphone in the paddles picks up on the reverberation of the ball making contact, which then is processed by the Arduino in the retro radio. If it registers that hit, a custom app on a computer then controls the music playing and adjusts the tempo to how fast players are volleying. The real beauty of the project is the accompanying video, which you must watch.