Pulse Sensor is an analog pulse sensor designed specifically for use with Arduino and other microcontrollers that measures heart rate (BPM) by fixing it to the fingertip or earlobe. The round and compact sensor consists of a green LED light and a photodetector; the LED sends green light through the skin while the photodetector detects the difference in reflection caused by the change in blood volume in the capillaries with each heartbeat (photoplethysmography / PPG principle). It can be powered by 3V or 5V, making it directly compatible with both Arduino and ESP series boards. BPM can be calculated in software by reading the analog output with Arduino's ADC pin; integration is very easy thanks to the ready-made libraries developed by the Pulse Sensor community. It is the most popular pulse sensor used for wearable health trackers, smart fitness bands and biometric project trials.
