2pcs MAX30102 Heart Rate Sensor Module Heart beat Frequency Tester for Arduino

Here are some useful links on the documentation for this Heart Rate Module:  1. https://www.hackster.io/SurtrTech/measure-heart-rate-and-spo2-with-max30102-c2b4d8; 2. https://pdfserv.maximintegrated.com/en/an/AN6409.pdf; 3. https://drive.google.com/open?id=1CNQe2Z9qPuh5BIPQZTv-oPyTrjssJAXFThe Main Parameters:LED peak wavelength: 660nm/880nmLED power supply voltage: 3.3~5VDetection signal type: light reflection signal (PPG)Output signal interface : I2C interfaceCommunication interface voltage: 1.8~3.3V~5V (optional)Board reserved assembly hole size: 0.5 x 8.5mmPin Description:VIN: main power input terminal 1.8-5V3-bit pad: Select the pull-up level of the bus, depending on the pin master voltage, select 1.8v or 3_3v (this terminal contains 3.3V and above)SCL: the clock connected to the I2C bus;SDA: data connected to the I2C bus;INT: Interrupt pin of the MAX30102 chip;RD: RED LED ground terminal of MAX30102 chip, generally not connected;IRD: The IR LED ground of the MAX30102 chip is gener