Overview
A compact wearable device designed to monitor elderly patients’ vitals and provide a two-way communication channel between patients and care providers. The design prioritised a small form factor without compromising sensor coverage or communication capability.
| Date | September 2025 |
| My role | Hardware Design + Firmware (partial) |
| PCB | 4-Layer, KiCad |
| GitHub | hardware-portfolio/ElderlyHealthTracker |
Features
- Fall Detection — IMU-based detection to alert care providers automatically
- Vitals Monitoring — Pulse oximetry (SpO₂) and body temperature sensors
- Two-Way Audio — Speaker amplifier with speaker, and dual PDM MEMS microphones processed through a DSP chip for clear remote communication
- SOS Button — Dedicated emergency button for immediate alert dispatch
- SD Card Storage — Logging vitals and audio recordings locally
Hardware Highlights
4-layer PCB — Required to meet strict size constraints while routing high-speed PDM lines, analog sensor signals, and power cleanly without interference between domains. Layer stack optimised for signal integrity: signal / ground / power / signal.
Component selection for low-power wearable operation — Every component chosen with continuous current draw in mind. Sensor selection balanced accuracy against current budget for battery life suitable for a pendant form factor.
PDM microphone routing — Dual PDM MEMS mics require careful routing and ground management to avoid crosstalk and noise pickup. Kept PDM clock and data lines short and shielded by adjacent ground pours on the same layer.
Images
