模組有兩個發光二極體，一個光檢測器，優化光學和低噪聲的模擬訊號處理，以檢測脈搏血氧飽和度和心臟速率訊號。

• 只需要將手指頭緊貼在感測器上，就能估計 脈搏血氧飽和度(SpO2)及脈搏(相當於心跳)。
• 攜帶氧氣的紅血球能吸收較多紅外光(850-1000nm)，未攜帶氧氣的紅血球則是吸收較多的紅光(600-750nm)。
• 因此pulse oximeter就是一個迷你的分光計，利用不同紅血球之吸收光譜的原理，來分析血氧飽和度。

/*

1、安裝庫：IDE-工具-管理庫-搜尋“MAX30105”-安裝
2、專案：串列埠讀取測量資料
3、連線(I2C)：
VIN  → 3.3V
GND  →  GND
SDA  接 A4 
SCL  接 A5 
 
*/

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

MAX30105 particleSensor;

const byte RATE_SIZE = 4; //Increase this for more averaging. 4 is good.
byte rates[RATE_SIZE]; //Array of heart rates
byte rateSpot = 0;
long lastBeat = 0; //Time at which the last beat occurred

float beatsPerMinute;
 
int beatAvg;

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);
  }
  
  Serial.println(
 
"Place your index finger on the sensor with steady pressure.");

  particleSensor.setup(); //Configure sensor with default settings
  particleSensor.setPulseAmplitudeRed(0x0A); //Turn Red LED to low to indicate sensor is running
  particleSensor.setPulseAmplitudeGreen(0); //Turn off Green LED
}

void loop()
{
  long irValue = particleSensor.getIR();

  if (checkForBeat(irValue) == true)
  {
    //We sensed a beat!
    long delta = millis() - lastBeat;
    lastBeat = millis();

    beatsPerMinute = 60 / (delta / 1000.0);

    if (beatsPerMinute < 255 && beatsPerMinute > 20)
    {
      rates[rateSpot++] = (byte)beatsPerMinute; //Store this reading in the array
      rateSpot %= RATE_SIZE; //Wrap variable

      //Take average of readings
      beatAvg = 0;
      for (byte x = 0 ; x < RATE_SIZE ; x++)
        beatAvg += rates[x];
      beatAvg /= RATE_SIZE;
    }
  }

  Serial.print("IR=");
  Serial.print(irValue);
  Serial.print(", BPM=");
  Serial.print(beatsPerMinute);
  Serial.print(", Avg BPM=");
  Serial.print(beatAvg);
  Serial.println();
  delay(1000);
}