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Interfacing MAX30102 Pulse Oximeter Heart Rate Module with Arduino

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MAX30102 Heart Rate Module Features

MAX30102 sensor is used to detect blood oxygen and heart rate. First, infrared radiation is sent and reflected by hitting the finger, and then the amount of oxygen in the blood is determined by measuring the wave amplitude. Heart rate is also obtained by analyzing the time series response of this radiation.
The MAX30102 is an integrated module compatible with the Arduino and STM32. It integrates a red LED with an infrared LED, a photoelectric detector, an optical device, and a low noise electronic circuit for ambient light suppression. Heart rate and blood oxygen data are also transmitted to the Arduino or other microcontrollers via I2C communication.

You can download the datasheet of this module here.  

MAX30102 Heart Rate Module Pinout

This sensor has 8 pins. 4 pins are more useful:

  • VCC: Module power supply – 3 to 5 V
  • GND: Ground
  • SCL: I2C clock bus
  • SDA: I2C data bus

You can see pinout of this module in the image below.

Required Materials

Hardware Components

Arduino UNO R3 × 1
MAX30102 Pulse Heart Rate Module × 1
Male to Female jumper wire × 1

Software Apps

Arduino IDE

Interfacing MAX30102 Sensor with Arduino

Step 1: Circuit

The following circuit shows how you should connect Arduino to MAX30102 module. Connect wires accordingly.

Note

You can use a bread board and pin header to connect module to interface wires, or you can solder pin header to module.

Step 2: Installing Library

Go to Library manager and search Max30, then install SparkFun Max301x.

Tip

If you need more help with installing a library on Arduino, read this tutorial: How to Install an Arduino Library

Step 3: Code for Heart Rate Detection

Upload the following code to your Arduino. This code displays your heart rate graphically in the serial monitor.

    /*
  MAX30102- Heart Rate Pulse Detection-Module
  https://electropeak.com/learn/

  Based on Arduino Library Example
*/
#include <Wire.h>
#include "MAX30105.h"

MAX30105 particleSensor;

void setup()
{
  Serial.begin(115200);
  Serial.println("Initializing...");

  // Initialize sensor
  if (!particleSensor.begin(Wire, I2C_SPEED_FAST)) //Use default I2C port, 400kHz speed
  {
    Serial.println("MAX30105 was not found. Please check wiring/power. ");
    while (1);
  }

  //Setup to sense a nice looking saw tooth on the plotter
  byte ledBrightness = 0x1F; //Options: 0=Off to 255=50mA
  byte sampleAverage = 8; //Options: 1, 2, 4, 8, 16, 32
  byte ledMode = 3; //Options: 1 = Red only, 2 = Red + IR, 3 = Red + IR + Green
  int sampleRate = 100; //Options: 50, 100, 200, 400, 800, 1000, 1600, 3200
  int pulseWidth = 411; //Options: 69, 118, 215, 411
  int adcRange = 4096; //Options: 2048, 4096, 8192, 16384

  particleSensor.setup(ledBrightness, sampleAverage, ledMode, sampleRate, pulseWidth, adcRange); //Configure sensor with these settings

  //Arduino plotter auto-scales annoyingly. To get around this, pre-populate
  //the plotter with 500 of an average reading from the sensor

  //Take an average of IR readings at power up
  const byte avgAmount = 64;
  long baseValue = 0;
  for (byte x = 0 ; x < avgAmount ; x++)
  {
    baseValue += particleSensor.getIR(); //Read the IR value
  }
  baseValue /= avgAmount;

  //Pre-populate the plotter so that the Y scale is close to IR values
  for (int x = 0 ; x < 500 ; x++)
    Serial.println(baseValue);
}

void loop()
{
  Serial.println(particleSensor.getIR()); //Send raw data to plotter
}

In the first part, you have to add related library to program. Next, in the setup loop, the data transfer rate is 115,200. You should set this number in the Serial plotter as well. Sampling is done at a 400 kHz frequency.

Finally, the results appear in the Serial Plotter as follows. As you can see the heart rate fluctuates:

Step 4: Code for Blood Oxygen detection

Upload the following code to your Arduino. This code displays your blood oxygen in the serial monitor.

    /*
  MAX30102- Blood Oxyge -Module
  https://electropeak.com/learn/

  Based on Arduino Library Example
*/


#include <Wire.h>
#include "MAX30105.h"
#include "spo2_algorithm.h"

MAX30105 particleSensor;

#define MAX_BRIGHTNESS 255

#if defined(__AVR_ATmega328P__) || defined(__AVR_ATmega168__)
//Arduino Uno doesn't have enough SRAM to store 100 samples of IR led data and red led data in 32-bit format
//To solve this problem, 16-bit MSB of the sampled data will be truncated. Samples become 16-bit data.
uint16_t irBuffer[100]; //infrared LED sensor data
uint16_t redBuffer[100];  //red LED sensor data
#else
uint32_t irBuffer[100]; //infrared LED sensor data
uint32_t redBuffer[100];  //red LED sensor data
#endif

int32_t bufferLength; //data length
int32_t spo2; //SPO2 value
int8_t validSPO2; //indicator to show if the SPO2 calculation is valid
int32_t heartRate; //heart rate value
int8_t validHeartRate; //indicator to show if the heart rate calculation is valid

byte pulseLED = 11; //Must be on PWM pin
byte readLED = 13; //Blinks with each data read

void setup()
{
  Serial.begin(115200); // initialize serial communication at 115200 bits per second:

  pinMode(pulseLED, OUTPUT);
  pinMode(readLED, OUTPUT);

  // Initialize sensor
  if (!particleSensor.begin(Wire, I2C_SPEED_FAST)) //Use default I2C port, 400kHz speed
  {
    Serial.println(F("MAX30105 was not found. Please check wiring/power."));
    while (1);
  }

  Serial.println(F("Attach sensor to finger with rubber band. Press any key to start conversion"));
  while (Serial.available() == 0) ; //wait until user presses a key
  Serial.read();

  byte ledBrightness = 60; //Options: 0=Off to 255=50mA
  byte sampleAverage = 4; //Options: 1, 2, 4, 8, 16, 32
  byte ledMode = 2; //Options: 1 = Red only, 2 = Red + IR, 3 = Red + IR + Green
  byte sampleRate = 100; //Options: 50, 100, 200, 400, 800, 1000, 1600, 3200
  int pulseWidth = 411; //Options: 69, 118, 215, 411
  int adcRange = 4096; //Options: 2048, 4096, 8192, 16384

  particleSensor.setup(ledBrightness, sampleAverage, ledMode, sampleRate, pulseWidth, adcRange); //Configure sensor with these settings
}

void loop()
{
  bufferLength = 100; //buffer length of 100 stores 4 seconds of samples running at 25sps

  //read the first 100 samples, and determine the signal range
  for (byte i = 0 ; i < bufferLength ; i++)
  {
    while (particleSensor.available() == false) //do we have new data?
      particleSensor.check(); //Check the sensor for new data

    redBuffer[i] = particleSensor.getRed();
    irBuffer[i] = particleSensor.getIR();
    particleSensor.nextSample(); //We're finished with this sample so move to next sample

    Serial.print(F("red="));
    Serial.print(redBuffer[i], DEC);
    Serial.print(F(", ir="));
    Serial.println(irBuffer[i], DEC);
  }

  //calculate heart rate and SpO2 after first 100 samples (first 4 seconds of samples)
  maxim_heart_rate_and_oxygen_saturation(irBuffer, bufferLength, redBuffer, &spo2, &validSPO2, &heartRate, &validHeartRate);

  //Continuously taking samples from MAX30102.  Heart rate and SpO2 are calculated every 1 second
  while (1)
  {
    //dumping the first 25 sets of samples in the memory and shift the last 75 sets of samples to the top
    for (byte i = 25; i < 100; i++)
    {
      redBuffer[i - 25] = redBuffer[i];
      irBuffer[i - 25] = irBuffer[i];
    }

    //take 25 sets of samples before calculating the heart rate.
    for (byte i = 75; i < 100; i++)
    {
      while (particleSensor.available() == false) //do we have new data?
        particleSensor.check(); //Check the sensor for new data

      digitalWrite(readLED, !digitalRead(readLED)); //Blink onboard LED with every data read

      redBuffer[i] = particleSensor.getRed();
      irBuffer[i] = particleSensor.getIR();
      particleSensor.nextSample(); //We're finished with this sample so move to next sample

      //send samples and calculation result to terminal program through UART
      Serial.print(F("red="));
      Serial.print(redBuffer[i], DEC);
      Serial.print(F(", ir="));
      Serial.print(irBuffer[i], DEC);

      Serial.print(F(", HR="));
      Serial.print(heartRate, DEC);

      Serial.print(F(", HRvalid="));
      Serial.print(validHeartRate, DEC);

      Serial.print(F(", SPO2="));
      Serial.print(spo2, DEC);

      Serial.print(F(", SPO2Valid="));
      Serial.println(validSPO2, DEC);
    }

    //After gathering 25 new samples recalculate HR and SP02
    maxim_heart_rate_and_oxygen_saturation(irBuffer, bufferLength, redBuffer, &spo2, &validSPO2, &heartRate, &validHeartRate);
  }
}

In this code, adding the library as well as adjusting the speed and data transfer rate is done. Notice that the calculation of blood oxygen begins after pressing a desired button.

The results are as follows. As you can see blood oxygen has measured 96.

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