M4 Waterproof IP67 Smart Watch Wristband Bracelet with Sport Fitness Tracker, Heart Rate Monitor - Black Smart Devices takes up only a few

takes up only a few IO pinsBacklight adjustment via PWMReserved solder pads for control interface

This drive using the drive's current loop subdivision control

anti high interference

Pictures for referenceo only

Can directly connects kinds of SCM for use

M4 Waterproof IP67 Smart Watch Wristband Bracelet with Sport Fitness Tracker, Heart Rate Monitor - Black Smart Devices takes up only a fewDevice Model: intelligent heart rate bracelet Compatible system: Android 4. 4 and above and iOS 8. 4 and above Main functions: real time heart rate measurement, pedometer, calorie burning, distance, sleep monitoring, call reminder, alarm reminder, information push, flip bright screen (WeChat, blood pressure function) Vibration: real time vibration reminder (non Bluetooth connection status) Waterproof and dustproof: IP67 waterproof, bathing swimming