MAX30102 with NUCLEO-F401RE

Wiring for the MAX30102 heart rate + SpO2 on the NUCLEO-F401RE (STM32F401RE, 3.3 V logic), chosen with the same pin rules BoardPilot uses: default buses first, and no pins that are used for flash, USB, the debugger or booting.

Wiring

MAX30102 pin	Role	NUCLEO-F401RE pin	Notes
VIN	Power	3V3
SDA	I2C data (SDA)	SDA/D14 (PB9)
SCL	I2C clock (SCL)	SCL/D15 (PB8)
INT	Interrupt	D2 (PA10)
IRD	Not wired to the board	not connected	IR LED output. Leave unconnected
RD	Not wired to the board	not connected	Red LED output. Leave unconnected
GND	Ground	GND

Check before you power it on

Supply: 3.3 V from the 3V3 pin.
I2C uses the board’s default pins SDA/D14 (SDA) and SCL/D15 (SCL). Most modules include pull-up resistors; if the part is not found, check them and swap-test SDA/SCL.
To make sure it is the real chip, read register 0xFF: a genuine part answers 0x15.

Test code (Arduino)

#include <Wire.h>

void setup() {
  Serial.begin(115200);
  Wire.begin();  // SDA = SDA/D14, SCL = SCL/D15 (the board's default I2C pins)
  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() {}

Arduino board: STMicroelectronics:stm32:Nucleo_64:pnum=NUCLEO_F401RE. Plug the USB cable into the mini-USB port on the ST-LINK end. No button press is needed.

Questions

Which NUCLEO-F401RE pins do I use for the MAX30102?

VIN → 3V3, SDA → SDA/D14 (PB9), SCL → SCL/D15 (PB8), INT → D2 (PA10), GND → GND.

Does the MAX30102 work with the NUCLEO-F401RE at 3.3 V?

Yes: the MAX30102 runs at 3.3-5 V and the NUCLEO-F401RE uses 3.3 V signals, so no level shifting is needed.

What is the I2C address of the MAX30102?

0x57. An I2C scan (BoardPilot does it for you) shows which one your module uses.

BoardPilot checks this wiring in 3D as you build it, and finds crossed or missing wires on the real board.

Download BoardPilot

Full NUCLEO-F401RE pinout · MAX30102 heart rate + SpO2: all pins and data

The MAX30102 on other boards

ESP32 DevKit Arduino Mega 2560 R3 Arduino Nano Arduino Uno R3 WeAct Black Pill STM32F411CE ESP32-C3-DevKitM-1 ESP32-S3-DevKitC-1 Nordic nRF52840 DK Raspberry Pi Pico 2 Raspberry Pi Pico W Raspberry Pi Pico Teensy 4.1

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