Concept

A keyed, hand-powered musical instrument made from laser-cut plywood. Power is input with a hand wheel, geared up to increase speed, and transferred to a flywheel that stores energy and keeps movement smooth.

Eight “music gears” are attached to the flywheel shaft that create tones when each key is pressed. The number of teeth on each music gear corresponds to the frequency of a note in a C major scale.

When a key is pressed a thin strip of paper comes into contact with a music gear, which creates a tone like a baseball card in bike spokes. The user continues cranking the input wheel as the friction of each key stroke slightly decreases the speed of the flywheel.

Prototype

The prototype was composed of a minimal 3D-printed frame holding the note gears that would be used in the final version and was made to validate the drive system, key action, bearing retainers, and tone accuracy.

Through the use of the prototype it was discovered that the key lever width was too small, which would allow the keys to wobble or strike the wrong note gear. Thickening the key levers near the key shaft made the key motion more stable.

Using the prototype also showed that the mass of the note gears was enough to maintain motion and so the flywheel could be eliminated to simplify the design.

Results

The Flaptone creates a really unique sound and is a lot of fun to play (I just wish I was a musician so I could do it justice). Future versions could replace the manual power input with a DC motor. Implementing a PID speed controller would allow for consistent tones and give the user the ability to choose different scales.