For this module, I executed the full lifecycle design—build, program, and test—of a photoelectric heart rate monitor.
Operational Principle#
The device functioned as a photoplethysmogram (PPG) sensor. It utilized a non-invasive photo transmitter/receiver pair clipped to a finger.
- Sensing: The sensor detected minute variations in light absorption caused by the volumetric change of blood flow with each heartbeat.
- Signal Processing: The raw analog data was filtered and amplified to isolate the heartbeat signal from noise.
- Calculation: A microcontroller algorithm measured the period between peaks to calculate the beats-per-minute (BPM) in real-time.
