Innovation is often born from restrictive conditions. For maker and musician Alessandro Voto, this came in the form of a distinct lack of whammy bar options for his bass guitar. So, naturally, he built one using an Arduino. Voto calls his space-age whammy bar a Kinesonic — a theremin-like instrument aid that gives audio feedback based on motion sensors. He tells Make:

“it’s hard for me to use a whammy bar, I was jealous. But I did have a whammy pedal that accepts MIDI, so I used Arduino to create a MIDI device that allows me to do the same motion of a whammy bar, and I can put it on any instrument.”

Here’s Voto demonstrating an earlier version of the Kinesonic (he calls it the Eyecon Beltpack), featuring a wearable cereal box holster:

The Kinesonic shoots out ultrasound waves and has a receiver that operates as a microphone, waiting for that output to come back. It then calculates the time taken for the ultrasound waves to travel. The device doesn’t make sound by itself, but rather takes sensor input and translates that to MIDI CC changes; this can be anything from volume control to pitch or filters. The Kinesonic is essentially a mechanism to influence whatever instrument or computer program you’re using to make music. “You can have different inputs, whatever a musician wants, whatever feels natural,” Voto says, going on to acknowledge the major design flaw, which is that you have to remove your hand from the bass strings in order to operate it.

The process of building it involves hooking up a MIDI circuit (ideally you’d follow the MIDI spec circuitry) to the Arduino TX pin and connecting a PING ultrasound sensor to any digital pin. Next, you plug in a MIDI cord to the MIDI jack, and connect it to your MIDI converter, effect box, synth, or whatever else you’d like to hook it up to. Then as you move your hand closer or farther away from the ultrasound sensor, it will send MIDI CC messages to your MIDI device. Voto’s open source Arduino code can be downloaded from our GitHub, and the schematic can be viewed below.