Wearable BLE Health Monitor
A wrist-worn, low-power vital signs monitoring wearable with Bluetooth Low Energy connectivity to a companion mobile app.
The client needed a wearable prototype capable of continuous heart rate and activity monitoring for a multi-day battery life target, in a form factor small enough for comfortable all-day wear — while maintaining the analog signal quality needed for reliable PPG-based heart rate detection.
We designed a compact wearable PCB around a Nordic nRF52-series BLE SoC, with a carefully laid out low-noise analog front end for photoplethysmography (PPG) sensing and a 3-axis accelerometer for activity classification. Power architecture was engineered around aggressive sleep-mode duty cycling between sensor sampling windows.
Firmware implemented BLE GATT services for real-time and buffered historical data sync to a companion app, along with on-device peak detection to reduce the radio-on time required for raw waveform streaming.
The prototype achieved a multi-day battery life target on a small wearable-format battery while maintaining signal quality sufficient for reliable heart-rate detection algorithms, validated against a reference pulse oximeter during bench testing.
“The analog front-end work on our wearable was the difference between a device that "sort of" worked and one that gave us clinically usable signal quality. That's not a skill every hardware shop actually has.”
Have a product idea that needs real hardware?
Tell us what you're building. We'll respond with next steps, not a sales pitch.
autoematio@gmail.com