I was inspired by videos of people using 3D printers and stepper motors to make music. I wanted to make an instrument that could be played on a keyboard while also taking advantage of this unique sound. The main focus of this build was to express the movement of the motors through a dynamic movement that feels interactive.
I used a laser cutter to create the majority of the pieces and used a 3D printer for the decorative elements. The motor "speaker" runs off an Arduino nano hooked up to three stepper motor controllers. The user input is being read by keys made of conductive tape. I originally tried to use conductive paint and touch-capacitive sensing but it became too finicky with this many inputs. The glove I wear grounds the pressed key which is read by an Arduino mega.
A supplimental feature I added was the ability for the instrument to play compositions via MIDI input (see video above). I flashed the Arduino mega with custom firmware to have it be recognizeable by computers as a MIDI device. I used the AccelStepper Arduino library to regulate the frequencies that the stepper motors were supposed to produce. The note produced by a motor is determined by how many steps is makes per second. One step (or micro-step) is equal to one square wave. So one step per second equals one hertz. I set my stepper motors to run with eight steps which was a perfect balance between vibration and musical clarity.