HealthGuard #2 - Experimenting with MAXREFDES117# Reference Design Board

taifur 18 hours ago

The received MAXREFDES117# Reference Design Board is small in size, which is good for making a wearable device. To test the module, I soldered 4 jumper wires with 4 male pin headers, to the MAXREFDES117 module as shown in the image below.

Then I used the solderless breadboard to connect the MAXREFDES117 module with the ESP3-C6 Super Mini board.

I used the Arduino IDE to upload code and test the kit. I used SparkFun_MAX3010x_Sensor_Librar library to write the code for the sensor. The following is the code for printing SPO2 and heart rate to the Serial Monitor. I got the sensor value very stable compared with the other MAX3010x sensors I used before.

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

#define SDA_PIN 20
#define SCL_PIN 19

MAX30105 particleSensor;

// MAX30102 data buffers
#define BUFFER_SIZE 100

uint32_t irBuffer[BUFFER_SIZE];
uint32_t redBuffer[BUFFER_SIZE];

int32_t spo2;
int8_t validSPO2;

int32_t heartRate;
int8_t validHeartRate;

void setup()
{
  Serial.begin(115200);
  delay(1000);

  Serial.println();
  Serial.println("=================================");
  Serial.println("ESP32-C6 MAX30102 SpO2 Monitor");
  Serial.println("=================================");

  // Initialize I2C
  Wire.begin(SDA_PIN, SCL_PIN);

  Serial.println("Initializing MAX30102...");

  if (!particleSensor.begin(Wire, I2C_SPEED_FAST))
  {
    Serial.println("MAX30102 was not found.");
    Serial.println("Check:");
    Serial.println("1. Wiring");
    Serial.println("2. Power supply");
    Serial.println("3. SDA/SCL pins");
    Serial.println("4. I2C address");
    while (1);
  }

  Serial.println("MAX30102 detected!");

  // Configure MAX30102
  byte ledBrightness = 60;
  byte sampleAverage = 4;
  byte ledMode = 2;       // Red + IR
  int sampleRate = 100;
  int pulseWidth = 411;
  int adcRange = 4096;

  particleSensor.setup(
    ledBrightness,
    sampleAverage,
    ledMode,
    sampleRate,
    pulseWidth,
    adcRange
  );

  // Set LED amplitudes
  particleSensor.setPulseAmplitudeRed(0x3F);
  particleSensor.setPulseAmplitudeIR(0x3F);

  // Green LED is not needed
  particleSensor.setPulseAmplitudeGreen(0);

  Serial.println("Place your finger on the sensor.");
  Serial.println();
}

void loop()
{
  // --------------------------------------------------
  // Collect 100 samples
  // --------------------------------------------------

  for (int i = 0; i < BUFFER_SIZE; i++)
  {
    while (particleSensor.available() == false)
    {
      particleSensor.check();
    }

    redBuffer[i] = particleSensor.getRed();
    irBuffer[i] = particleSensor.getIR();

    particleSensor.nextSample();
  }

  // --------------------------------------------------
  // Calculate SpO2 and heart rate
  // --------------------------------------------------

  maxim_heart_rate_and_oxygen_saturation(
    irBuffer,
    BUFFER_SIZE,
    redBuffer,
    &spo2,
    &validSPO2,
    &heartRate,
    &validHeartRate
  );

  // --------------------------------------------------
  // Display result
  // --------------------------------------------------

  Serial.println("--------------------------------");

  if (validHeartRate)
  {
    Serial.print("Heart Rate: ");
    Serial.print(heartRate);
    Serial.println(" BPM");
  }
  else
  {
    Serial.println("Heart Rate: Invalid");
  }

  if (validSPO2)
  {
    Serial.print("SpO2: ");
    Serial.print(spo2);
    Serial.println(" %");
  }
  else
  {
    Serial.println("SpO2: Invalid");
  }

  Serial.println("--------------------------------");

  delay(500);
}

The following screenshot shows the sensor output in the Serial Monitor.