Nam Tran's Kurt Cobot3000 Is a Stepper Motor Synth Tuned Specifically for Nirvana Classics

Maker Nam Tran has put a stepper motor synth to work as "Kurt Cobot3000," playing a recognizable version of Nirvana's Smells Like Teen Spirit using nothing but the motion of four salvaged stepper motors.

"Parts used: 4× NEMA17 stepper motors, salvaged from [an] old 3D printer," Tran writes of the hardware which went into the project. "4× A4988 stepper motor drivers. 1× Teensy-LC microcontroller. 2× googly eyes," the latter being entirely necessary for the visual portion of the ensuing show.

The "synth" itself has no parts designed specifically for audio generation. Instead, the microcontroller simply starts and stops the stepper motors — turning them differing amounts and at different speeds to turn what is normally undesired operating noise into music, which if not exactly CD-quality is at least immediately recognizable as a Nirvana hit.

Tran's not the only one to have turned to stepper motors for their musical capabilities: Two years ago David Scholten built a very similar four-channel synth, though without the all-important googly eyes; four years before that Josh Sheldon used 49 stepper motors to drive a wooden organ — back-driving the motors using spinning disks, rather than powering them directly, and amplifying the resulting pseudo-sinusoidal alternating current they produce.

The full video is available on Tran's YouTube channel; source code has not yet been released.