Grove - Finger-clip Heart Rate Sensor is based on PAH8001EI-2G, a high performance and low power CMOS-process optical sensor with Green LED and DSP integrated serving as a Heart Reate Detection(HRD) sensor.This modual is based on optical technology which measures the variation human blood movement in the vessel. Low power consumption and flexible power saving mode make it suitable for wearable device. Cause the heart rate sensor chip need high processing speed for the algorithm of heart rate data, this module integrate a STM32, reserved SWD interface allow users to reprogram the STM32.