Clinical Health Wearable

help The problem

A wristband worn by patients in clinical studies continuously captures physiological data and hands it to a data-science team who process it to identify underlying health issues. Because the data drives clinical conclusions, the firmware's job is not just to read sensors — it is to capture data that is time-accurate, integrity-checked and complete, on a device that runs for a month on a charge and survives FCC certification and real production.

build What we built

• Multi-sensor acquisition — IMU, accelerometer, magnetometer, barometer and PPG (for blood pressure / SpO₂) — buffered to 1 Gb NAND flash.
• Timing synchronisation treated as first-class, because misaligned timestamps corrupt the downstream data-science analysis. Getting time right across the system was one of the critical engineering problems.
• Dual-core nRF5340 architecture (Application + Network core) with inter-core communication, distributing peripherals and workload across both cores.
• BLE throughput raised from ~300 kbps to ~1.2 Mbps — roughly 4× — so a month of buffered sensor data offloads in reasonable time. A vendor-specific USB protocol carries the high-rate wired path.
• MCUboot dual-bank bootloader for safe OTA, coredump capture for in-field crash diagnosis, and Direct Test Mode firmware for FCC certification of the radio.
• Full test coverage with a CI/CD pipeline built specifically to keep production bugs out — carried across evaluation kits, development kits and production kits.
• Companion app migrated from Xamarin to .NET MAUI — a full framework migration of a shipping app — with matching BLE throughput work and tested background sync.