The sensor fabric
Certified wearables running BioFlow firmware. Signal conditioning, feature extraction and a small classifier all execute on the microcontroller, so raw waveform never leaves the device unless a rule asks for it.
| Layer | Responsibility | Flash budget |
|---|---|---|
| Application | Rule subset, alert thresholds, haptic and on-device prompts | ~40 KB |
| Inference | Quantised classifiers for rhythm, fall, stress and fatigue | ~180 KB |
| Signal processing | Filtering, R-peak detection, artefact rejection, feature windows | ~90 KB |
| RTOS | Deterministic scheduling, power states, radio duty cycling | ~120 KB |
| Drivers and silicon | Analogue front end, IMU, thermistor, secure element, radio | - |
Privacy by construction
Rules run on features, not waveforms. If the raw signal never leaves the body, there is nothing to leak from the wire.
Latency you can promise
A fall does not wait for a round trip. On-device classification puts the first decision within four milliseconds of the sample window.
Battery arithmetic
Transmitting is the expensive part. Sending an event instead of a stream is what turns three days of endurance into ten.
Attested before it is trusted
A device proves its firmware measurement to the gateway before any of its signal is allowed to influence a rule. Builds that do not match a signed manifest are quarantined; they keep recording, but nothing they say can move an action.
Keys live in the secure element and never leave it. Firmware is signed with a chain that has a published post-quantum migration path, because a device deployed today may still be in service when that matters.
Graceful degradation
Losing a channel narrows what rules can fire; it does not take the wearer off monitoring. Proposals raised on partial signal are labelled as reduced-confidence at the gate, so the person answering knows what they are working with.
Start with one ward, one shift, or one squad
A pilot runs four to sixteen weeks depending on deployment model. You bring the population and the responders. We bring devices, gateways and the first set of rules, and we measure override rate and time-to-answer from day one.