How to Use MAX30102 HR + SpO2 sensor: Examples, Pinouts, and Specs

The MAX30102 is an integrated pulse oximetry and heart-rate monitor sensor module. It combines two LEDs, a photodetector, optimized optics, and low-noise analog signal processing to detect pulse oximetry and heart-rate signals. The MAX30102 is widely used in wearable health devices, fitness trackers, and medical monitoring devices due to its small form factor and low power consumption.

• Wearable devices for heart rate monitoring
• Fitness trackers that measure blood oxygen levels
• Portable medical monitoring devices
• Sleep tracking devices

• Power Supply Voltage (VCC): 1.8V to 3.3V
• Operating Current: 0.6mA (typical) during Heart Rate and SpO2 measurement
• Peak LED Output Current: 50mA (maximum)
• Operating Temperature Range: -40°C to +85°C
• Communication Interface: I2C (up to 400kHz)

1. Power Supply: Connect the VIN pin to a 1.8V to 3.3V power source and the GND pin to the ground.
2. I2C Communication: Connect the SDA and SCL pins to the corresponding I2C data and clock lines on your microcontroller.
3. Interrupts (Optional): The INT pin can be connected to an interrupt-capable GPIO pin on your microcontroller to handle events like data-ready.

• Ensure that the power supply is stable and within the specified voltage range.
• Place the sensor close to the skin to get accurate readings.
• Avoid direct sunlight on the sensor as it may interfere with the readings.
• Use pull-up resistors on the I2C lines if they are not already present on the microcontroller board.

#include <Wire.h>
#include "MAX30105.h" // Include the MAX30105 library

MAX30105 particleSensor;

void setup() {
  Serial.begin(115200); // Initialize serial communication at 115200 baud rate
  Wire.begin(); // Initialize I2C

  if (!particleSensor.begin(Wire, I2C_SPEED_FAST)) { // Initialize sensor
    Serial.println("MAX30102 was not found. Please check wiring/power.");
    while (1);
  }

  particleSensor.setup(); // Configure sensor with default settings
  particleSensor.setPulseAmplitudeRed(0x0A); // Set Red LED amplitude
  particleSensor.setPulseAmplitudeIR(0x0A); // Set IR LED amplitude
}

void loop() {
  long irValue = particleSensor.getIR(); // Read IR value

  if (irValue > 50000) { // Check if the sensor is covered
    // Read the heart rate and SpO2 levels
    float heartRate, spO2;
    if (particleSensor.checkForBeat(irValue) == true) {
      if (particleSensor.getSpO2(&spO2, &heartRate)) {
        Serial.print("Heart Rate: ");
        Serial.print(heartRate);
        Serial.print(" bpm - SpO2: ");
        Serial.print(spO2);
        Serial.println("%");
      }
    }
  } else {
    Serial.println("No finger?");
  }

  delay(1000); // Wait for 1 second before next reading
}

• Inaccurate Readings: Ensure the sensor is properly placed on the skin and not affected by external light sources.
• No Data: Check the I2C connections and ensure the correct I2C address is used in the code.
• Sensor Not Detected: Verify the power supply and connections to the sensor.

• If you encounter inaccurate readings, try adjusting the LED pulse amplitude settings in the code.
• For connectivity issues, use a multimeter to check the continuity of the I2C lines and the power supply.
• Ensure that the sensor is not exposed to strong electromagnetic interference.

Q: Can the MAX30102 be used on a 5V system? A: The MAX30102 operates at 1.8V to 3.3V. A logic level converter is required for 5V systems.

Q: How can I improve the accuracy of the readings? A: Ensure a snug fit against the skin, minimize motion, and avoid direct sunlight on the sensor.

Q: What is the I2C address of the MAX30102? A: The default I2C address is 0x57 (7-bit).

Q: Can the MAX30102 measure heart rate through clothes? A: No, the sensor needs to be in direct contact with the skin for accurate measurements.