Project 1 – Playable MIDI stepper motor instrument

A stepper motor is a type of electrical motor that moves a very small distance (angular) every time it receives a pulse. They are notoriously loud when driven at audible frequencies. For this reason, manufacturers that use these motors for precision movement go to great length to avoid this.

I wanted to turn this very inconvenience into a musical instrument. Every stepper motor can play a single note (probably more with some convolution magic), so with three motors we can play many melodies as long as we don’t exceed this limit (more on this during my presentation). This is the setup:

The motors are attached to an acrylic plate to amplify the vibrations. Contact microphones are used pick up the sound and feed it into the speaker array and Max for visualization. The steppers are driven by two Arduino microcontrollers.

Max is used for formatting the MIDI/Serial packets and playing sequences but also for sound visualization. Using jit.mo and pfft I made a series of dodecahedron that change sizes according to the amplitude of the buckets. The color of these figures also changes pseudo-randomly every time a MIDI note is played:

For some reason there is some delay in the video. This doesn’t happen live….

Link to Drive