"Wheel" Music with Stepper Motor and Homemade Pickup

In the middle of the 20th century, Hammond organs used gear-shaped tone wheels to create a changing electromagnetic force on a pickup. While electronic sound is now generated mostly by integrated circuits, it’s an interesting bit of technology that YouTuber “The Mixed Signal” decided to replicate using 3D printing, a stepper motor, and an Arduino Uno/CNC shield for control.

In this rig, a ferromagnetic tone wheel with a series of lobes is spun past a pickup to produce a tone. Interestingly, the tone wheel isn’t made out of steel or some other traditional ferromagnetic material, but is instead printed using a special type of Proto-pasta PLA filament with iron embedded into it.

The pickup itself was made out of 40AWG wire, wrapped using the same stepper setup that plays the notes. As this involved around 12,000 turns of wire, being able to control this with a stepper and not do things manually was certainly extremely helpful. Notably, this type of pickup works in a similar manner to how an electric guitar functions, and using that type of pickup was the backup plan if the homemade winding assembly didn’t work out.

Be sure to check out the video below to see the build process. As seen on Twitter, since then he’s been able to use this device with a MIDI keyboard, so hopefully even more interesting musical hacking with this project is in the works!