SEN0203 Heart Rate Sensor Schematic

Hi everyone,
Can someone help me by explaining to me what exactly is the function of the four SON3130 in this schematic?
Any help would be much appreciated.
https://github.com/DFRobot/DFRobot_Hear ... ematic.pdf
Hi everyone,
Can someone help me by explaining to me what exactly is the function of the four SON3130 in this schematic?
Any help would be much appreciated.
https://github.com/DFRobot/DFRobot_Hear ... ematic.pdf