Hardware / The band
A dry-electrode front end, a small neural decoder, and a radio, packed into a band thin enough to forget you're wearing. Everything that touches your signal runs locally.
Muscle activity carries the words. The other two channels carry the context that makes those words unambiguous.
A dry electrode array over the speech muscles. Subvocalised speech still produces a myoelectric signature; the array samples it at 1 kHz across eight differential channels, which is enough to separate phoneme groups before any decoding runs.
An optical channel reads heart rhythm and skin perfusion. It contributes almost nothing to the words themselves; its job is to tell the decoder whether you are speaking, resting, or stressed, so the same muscle pattern isn't misread three different ways.
Orientation and motion, so the runtime knows whether you are at a desk or walking. Combined with a capacitive presence pad, it answers the question that makes hands-free systems tolerable: is this person actually using me right now?
Architecture
The band does not stream raw data to a phone. Everything between the electrode and the Bluetooth packet happens inside the enclosure.
On-device decoder · generation 1
Eight differential channels, 1 kHz sampling, 110 dB common-mode rejection. Dry electrodes need a high input impedance: that single number decides whether the band feels like nothing or like a science project.
A quantised recurrent model, sized to run continuously inside a low-single-digit watt envelope. Beamforming, phoneme scoring, and language correction are fused here rather than split across devices.
Bluetooth Low Energy to the host, plus a sub-GHz transceiver for direct device control. The second radio is why Lumina can turn a lamp on without a hub, a cloud, or your phone.
A day of continuous decoding, or roughly a week idle. Charging is inductive, so there is no port to break and no gasket to fail.
Target mass. Above roughly twenty grams a band starts to be felt, and anything you can feel while concentrating is a distraction.
End-to-end latency from muscle onset to host action. Above this, speaking to the machine stops feeling like an extension of thinking and starts feeling like a wait.
Continuous EMG sample rate per channel. A hard floor, not a preference: subsampling here destroys the high-frequency structure the decoder depends on.
Wet electrodes are the easy answer and the wrong one: gel dries, hair interferes, and nobody puts on a headset to check a notification. We use dry, compliant contact with enough input impedance to keep signal quality through a loose fit.
A decoder that needs a week of labelled data is a research instrument. The onboarding flow asks you to read a short set of phrases, adapts its prior to your electrode geometry, and hands over control in the same sitting.
Skin-safe materials, no pressure points on the ulnar nerve, and thermal headroom measured against the 41 °C contact limit rather than the comfortable average. Wearing duration is the only specification users actually experience.
Most "control anything" claims route through a cloud service and collapse without a phone nearby. A sub-GHz transmitter places common receivers (lights, sockets, blinds, garage doors) inside the product rather than inside someone else's infrastructure.
Everything on this page describes the prototype generation in development. Values will move; the constraints above are the ones we hold.
The hardware collects intent. The runtime is where it becomes an action on your machine.