MAX30100 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
SCL	I2C clock (SCL)	D22	Many purple boards pull SCL up to 1.8 V only: the ESP32 may not read it
SDA	I2C data (SDA)	D21	Many purple boards pull SDA up to 1.8 V only: the ESP32 may not read it
INT	Interrupt	D35	Interrupt output, optional
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 0x11. 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 ? "MAX30100 heart rate + SpO2 found at 0x57" : "Not found: check power, GND and SDA/SCL");
}

void loop() {}

Sources

Maxim MAX30100 datasheet, Register 0xFF Part ID (reads 0x11); I2C address 0x57
Maxim MAX30100 datasheet, Chip supply 1.8 V plus 3.3 V for the LEDs; boards regulate both

Try it in 3D in BoardPilot

BoardPilot Part data (JSON)

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