BPW34 Photodiode Pulse Detector

Shine an IR LED through your fingertip onto a photodiode and watch your heartbeat appear on the scope.

Difficulty: Through-hole. Estimated build time: about 60 minutes. Estimated parts cost: about US$4.00. 5-part bill of materials with live supplier pricing. A photoplethysmogram (PPG) front end built from a BPW34 silicon photodiode, an LM358 transimpedance amplifier, and an infrared LED.