MAX30102 heart rate + SpO2 with ESP32

Supply 3.3-5 V Bus I2C I2C address 0x57 Measures heart rate, blood oxygen

Pins and ESP32 wiring

Pin	Role	ESP32 pin	Notes
VIN	Power	3V3
SDA	I2C data (SDA)	D21
SCL	I2C clock (SCL)	D22
INT	Interrupt	D35
IRD	Not wired to the ESP32	—	IR LED output. Leave unconnected
RD	Not wired to the ESP32	—	Red LED output. Leave unconnected
GND	Ground	GND

Suggested wiring for the 30-pin ESP32 DevKit, avoiding flash, input-only and strapping pins. BoardPilot checks it for you as you wire.

Check it is the real chip

Read register 0xFF: a genuine part answers 0x15. BoardPilot does this automatically in “Debug a problem”.

Starter code (Arduino)

#include <Wire.h>

void setup() {
  Serial.begin(115200);
  Wire.begin(21, 22);  // SDA = GPIO 21, SCL = GPIO 22
  Wire.beginTransmission(0x57);
  bool found = Wire.endTransmission() == 0;
  Serial.println(found ? "MAX30102 heart rate + SpO2 found at 0x57" : "Not found: check power, GND and SDA/SCL");
}

void loop() {}

Sources

Maxim MAX30102 datasheet, Register 0xFF Part ID (reads 0x15)
Maxim MAX30102 datasheet, I2C address 0x57 (0xAE write / 0xAF read)

Try it in 3D in BoardPilot

BoardPilot Part data (JSON)

Part data: CC BY 4.0, free to reuse with credit to BoardPilot.