Floyd Steinberg spotted a bargain in the Colmi R02, a smart ring that discreetly tracks your everyday health data. That’s just the tip of the iceberg, as this little device also features a motion-sensing accelerometer, Bluetooth connectivity, a small battery, and a slew of sensors that track your daily steps, sleep, as well as heart rate via a companion app.
Steinberg, however, saw beyond that. He decided to get creative and completely repurpose the ring, transforming its motion-sensing capabilities into a tool for composing music, yes, really. The Colmi R02 stands out because, in a welcome departure from the standard for wearables, the maker avoided code signing and encryption. Anyone can create and upload new firmware without having to overcome security obstacles that are typically in place. That groundwork was built by a previous developer, Aaron Christophel (@atc1441), who was able to squeeze out a faster firmware that allows for quicker data transmission while keeping the ring fully compatible with the original application. Steinberg then expanded upon that base.
- [Purchase a Sizing Kit] Before purchasing the COLMI R02 smart ring, we strongly recommend that you purchase the COLMI sizing kit or measure your...
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- [Portable Charging Case] Includes a compact charging case for charging anytime, anywhere, without worrying about running out of power.
First, let’s talk about the ring itself. The Colmi R02 comes in plain packaging, with a magnetic charging wire, and fits nicely on your finger. It has an accelerometer that detects movement in all three axes, which are X, Y, and Z. However, out of the box, the firmware is sluggish and only delivers data once per second, which feels slow for real-time music control. When properly configured, the modified firmware significantly improves the speed with which the motion sensor provides updates.
Next, Steinberg connects the ring to a computer via Bluetooth and creates a custom web application in Javascript to handle the connection using the Web Bluetooth and WebMIDI APIs. The software then requests permission and begins listening for incoming accelerometer readings, which arrive as raw X, Y, and Z data. These are then normalized to the appropriate and conventional MIDI range of 0 to 127. This allows users to select which axis to map to which MIDI Control Change message, so tilting the hand on the Y-axis may modify the filter cutoff on a synth, whereas the X axis controls modulation depth or expression.
Then there’s the MIDI data, which flows from the browser into a digital music workstation, such as Reaper, where Steinberg routes the output via a virtual MIDI connection like LoopMIDI. In the DAW, a plugin such as Jura receives control change commands and applies them to the parameters. What do you know, the consequence appears to be immediate: a subtle palm tilt opens or closes a filter, providing a level of expressiveness that feels completely natural on the finger.
The setup is kept to a minimum because there is no extra hardware between the ring and the PC. The ring then works on its internal battery for hours as you get creative, and charging occurs via the magnetic cord, with the device being water resistant enough to be used on a regular basis. Steinberg even shocases this system being used to control an external synthesizer such as a Yamaha Montage via the computer bridge, with hand gestures substituting typical knobs or mod wheels, allowing the performer to move freely while performing. If you want to get involved with this project, the whole files, including the web app code and references to the custom firmware, are available on GitHub.
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