Grove - Finger-clip Heart Rate Sensor with shell 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 Rate Detection (HRD) sensor. This module 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. This module also provide tow bandages and 3D printing shell for finger test and arm test.