Hackaday

A $20 Colmi R02 smart ring was converted into a MIDI controller by reprogramming its firmware. The device lacks code signing or encryption, making it easy to upload custom firmware. The ring's accelerometer data is transmitted via Bluetooth to a web app that converts it into MIDI CC commands, enabling control of synthesizer parameters like filter cutoff frequencies. The project demonstrates how affordable consumer hardware can be repurposed for musical expression without requiring custom hardware builds.

Cheap Smart Ring Becomes MIDI Controller