How to Use MAX30100: Examples, Pinouts, and Specs

The MAX30100 is a pulse oximeter and heart-rate monitor sensor that uses photoplethysmography (PPG) to measure blood oxygen levels (SpO2) and heart rate. It integrates two LEDs (red and infrared) and a photodetector in a compact package, along with an analog-to-digital converter (ADC) and a digital signal processor (DSP) for accurate measurements. The MAX30100 is designed for low-power operation, making it ideal for wearable health monitoring devices such as fitness trackers, smartwatches, and medical equipment.

• Wearable fitness trackers and smartwatches
• Medical devices for SpO2 and heart rate monitoring
• Health monitoring systems for athletes
• Research and development in biomedical engineering
• IoT-based health monitoring solutions

The MAX30100 is a highly integrated sensor with the following key specifications:

The MAX30100 has 14 pins, but only a subset is typically used in most applications. Below is the pin configuration:

1. Power Supply: Connect the VIN pin to a 3.3V power source and the GND pin to ground.
2. I2C Communication: Connect the SDA and SCL pins to the corresponding I2C pins on your microcontroller (e.g., Arduino UNO). Use pull-up resistors (typically 4.7kΩ) on both SDA and SCL lines.
3. Interrupt Pin: Optionally, connect the INT pin to a GPIO pin on your microcontroller to handle interrupts.
4. Bypass Capacitor: Place a 0.1µF capacitor between VIN and GND for power supply decoupling.

• Ensure proper alignment of the sensor with the skin for accurate readings.
• Avoid ambient light interference by enclosing the sensor in a dark housing.
• Use a low-noise power supply to minimize measurement errors.
• Calibrate the sensor for your specific application to improve accuracy.

Below is an example of how to interface the MAX30100 with an Arduino UNO using the MAX30100 library:

#include <Wire.h>
#include "MAX30100_PulseOximeter.h"

// Create an instance of the PulseOximeter class
PulseOximeter pox;

// Timer variables for periodic updates
uint32_t lastUpdate = 0;

// Callback function for new heart rate and SpO2 readings
void onBeatDetected() {
  Serial.println("Beat detected!");
}

void setup() {
  Serial.begin(9600); // Initialize serial communication
  Serial.println("Initializing MAX30100...");

  // Initialize the MAX30100 sensor
  if (!pox.begin()) {
    Serial.println("Failed to initialize MAX30100. Check connections!");
    while (1);
  }

  // Set the callback function for beat detection
  pox.setOnBeatDetectedCallback(onBeatDetected);

  Serial.println("MAX30100 initialized successfully.");
}

void loop() {
  // Update the sensor readings
  pox.update();

  // Print heart rate and SpO2 every second
  if (millis() - lastUpdate > 1000) {
    lastUpdate = millis();
    Serial.print("Heart Rate: ");
    Serial.print(pox.getHeartRate());
    Serial.print(" bpm, SpO2: ");
    Serial.print(pox.getSpO2());
    Serial.println(" %");
  }
}

• Install the MAX30100_PulseOximeter library from the Arduino Library Manager before running the code.
• Ensure the I2C address (0x57) matches the default address of the MAX30100.

1. No Response from the Sensor

   • Cause: Incorrect wiring or power supply.
   • Solution: Double-check the connections and ensure the VIN pin is connected to 3.3V.

2. Inaccurate Readings

   • Cause: Ambient light interference or poor skin contact.
   • Solution: Shield the sensor from ambient light and ensure proper alignment with the skin.

3. I2C Communication Failure

   • Cause: Missing pull-up resistors or incorrect I2C address.
   • Solution: Add 4.7kΩ pull-up resistors to SDA and SCL lines and verify the I2C address.

4. Sensor Overheating

   • Cause: Continuous operation of LEDs at high current.
   • Solution: Use the lowest LED current settings that provide reliable readings.

Q1: Can the MAX30100 measure SpO2 and heart rate simultaneously?
A1: Yes, the MAX30100 is designed to measure both SpO2 and heart rate simultaneously using its dual LED and photodetector setup.

Q2: What is the maximum distance between the sensor and the microcontroller?
A2: The maximum distance depends on the I2C bus capacitance. For reliable communication, keep the distance under 1 meter and use proper pull-up resistors.

Q3: Can the MAX30100 be used with a 5V microcontroller?
A3: Yes, but you must use a level shifter for the I2C lines, as the MAX30100 operates at 3.3V logic levels.

Q4: How do I improve measurement accuracy?
A4: Minimize ambient light interference, ensure good skin contact, and calibrate the sensor for your specific application.

This concludes the documentation for the MAX30100.