Rishabh Jain's AirMIDI Is a Simple, Four-Component MIDI Theremin-Style Contactless Instrument

Maker Rishabh Jain, also known as "Mr_Electronaut," has designed a MIDI controller with a difference: inspired by the classic theremin, it doesn't require you to touch it in order to play music.

"As a long-time music lover, I've always been fascinated by how performers connect with their instruments," Jain explains. "Whether it's a guitarist bending strings, a pianist flowing across keys, or a DJ shaping sound with nothing but hand movements over a mixer, there's something powerful about expressing music through motion. I kept thinking about DJs and live performers who move their hands in the air, controlling sound almost instinctively. What if those gestures could actually become music?What if motion itself could trigger beats, samples, and effects? That question became the spark for AirMIDI."

The AirMIDI is powered by an Espressif ESP32-WROOM-32 microcontroller module, which provides both on-board sensor processing and Bluetooth Low Energy (BLE) connectivity to send the MIDI messages to a nearby smartphone or tablet. The cardboard enclosure houses three STMicroelectronics VL53L0X single-photon avalanche diode (SPAD) array-based time-of-flight (ToF) distance sensors — the components actually responsible for detecting the player's motion, and a quantity that Jain notes could be increased to provide increased precision.

"The three VL53L0X sensors are placed horizontally with equal spacing, creating three interaction zones: left, center, right," Jain explains. "Each sensor continuously measures the distance to the user's hand." Data from these sensors are then processed to detect four distinct gestures: a quick tap, to play notes; a hold gesture to "arm" other gestures; swipe, which can be used for navigation or control changes; and push-pull, for continuous MIDI control. "All gestures are time-based and debounced," Jain notes, "to avoid false triggering."

The detected gestures are turned into MIDI messages and sent to a nearby device over Bluetooth Low Energy. Visual feedback, meanwhile, is provided by an addressable RGB LED strip at the top of the case. "AirMIDI started as a simple idea inspired by motion, music, and curiosity, and evolved into a fully functional, touchless MIDI controller built entirely from components found in a junk drawer," Jain muses. "Through this project, it became clear that meaningful and expressive musical instruments do not always require complex hardware or expensive parts—sometimes, creativity and thoughtful design are enough."

The project is documented in full, including source code, on Instructables.