Makers Stephanie McCarty and Andrew Siu built this fun interactive audio device using a couple of Arduino and miscellaneous parts.

A stand-alone Interactive Musical Device that produces tones and loops. Made using Arduino Boards, Wave Shields, IR Sensors and Servo Motors, sound can be manipulated by physically moving and controlling certain elements of the device.
IR sensors detect the distances of propeller blades triggering a corresponding tone to emit from the device.
Rotations of the propellers are controlled by 2 potentiometers (silver knobs) at the front of the device which alter the tempo of the resulting tones.