Wearable Health Monitor
Clinical-grade PPG monitors were bulky and uncomfortable for 24/7 wear during sleep studies.
Flexible PCB wearable with optimized sensor placement. BLE streaming to companion app with real-time visualization.
93% participant compliance (up from 61%). Data quality matched clinical benchmarks.
Overview
Sleep study compliance is one of the biggest challenges in clinical research. Participants remove bulky monitors during the night, corrupting data. I designed a wearable thin enough to forget you're wearing it, without compromising signal quality.
Process
User Research
Interviewed sleep researchers and 15 study participants. The #1 complaint was discomfort — rigid housings, thick cables, adhesive irritation. Set constraints: <8mm total thickness, no cables, medical-grade skin contact materials.
Sensor & PCB Design
Flexible 2-layer PCB with MAX86150 PPG/ECG combo sensor and LSM6DSO IMU. Optimized LED placement angle through Monte Carlo simulation of photon paths in skin tissue. Coin cell + boost converter for 72-hour runtime.
Signal Processing
On-device motion artifact rejection using adaptive filtering (accelerometer reference). Heart rate and SpO2 algorithms validated against Masimo reference monitor. Achieved ±2 BPM accuracy during sleep movement.
App & Data Pipeline
BLE 5.0 streaming at 25Hz to companion app. Flutter app with real-time waveform display for researchers. Automatic cloud sync when WiFi available, with local storage buffer for offline use.