Low-Cost Optical Heartbeat Monitoring System

Co-developed a low-cost heartbeat monitoring device leveraging an infrared LED–phototransistor pair to detect pulse signals through light absorption and reflection. Designed a multi-stage signal conditioning chain with active high-pass and low-pass filters, DC offset removal, and high-gain amplification using LM324N op-amps to isolate and strengthen heartbeat waveforms. Validated performance through oscilloscope-based waveform analysis, converting signal frequency to real-time BPM measurements. The project demonstrated practical applications of analog signal processing, biomedical instrumentation, and electronic circuit design.