含氧血液吸收更多的紅外光并通過更多的紅光。但是，脫氧血液會吸收紅光并通過更多的紅外光。

基本上，MAX30100 傳感器讀取兩個光源的吸收水平并將它們存儲在可通過 I2C 引腳讀取的緩沖區(qū)中。

第 3 步：0.96 英寸 I2C OLED 顯示屏。

在顯示模塊中，我們將使用 0.96 英寸藍(lán)色 OLED 顯示模塊。

我們可以輕松地將該模塊與任何使用 SPI/I2C 協(xié)議的微控制器連接。

顯示器的分辨率為 128×64。

I2C OLED 顯示屏

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OLED代表有機(jī)發(fā)光二極管。它是一種自發(fā)光技術(shù)，由放置在陽極和陰極之間的微小多層有機(jī)薄膜組成。

與 LCD 技術(shù)不同，OLED 不需要背光。

OLED對于所有類型的顯示器都具有很高的應(yīng)用潛力。OLED 也被認(rèn)為是下一代平板顯示器的終極技術(shù)

第 4 步：連接 MAX30100 脈搏血氧儀與 ESP32。

電路

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該物聯(lián)網(wǎng)脈搏血氧儀的電路組件非常簡單。

OLED 顯示屏和 MAX30100 血氧計(jì)傳感器均可與 I2C 配合使用。因此，將兩個模塊的 I2C 引腳（SCL 和 SDA）與 ESP32 的 D21 和 D22 引腳連接。

同樣，為 VCC 提供 3.3V 電源并將兩個傳感器的 GND 引腳接地。基本上，您可以按照電路圖進(jìn)行連接。

我不會講太多細(xì)節(jié)，我已經(jīng)在我們的博客上寫了一些信息。

MAX30100 脈搏血氧儀與 ESP32 的接口

5：為物聯(lián)網(wǎng)脈搏血氧儀設(shè)置 Blynk 應(yīng)用程序

現(xiàn)在從適用于 Android 和 iOS 的 Play 商店/應(yīng)用商店下載此 Blink 應(yīng)用程序。

使用您的電子郵件地址和密碼注冊 Blynk IoT 云。

現(xiàn)在，單擊新項(xiàng)目為您的項(xiàng)目命名。我讓“血氧計(jì)”選擇 ESP32 開發(fā)板和連接類型為 Wi-Fi。然后點(diǎn)擊創(chuàng)建。

現(xiàn)在單擊“+”號以添加小部件。

我們需要讀取 BPM 和 SpO2 的值。因此，選擇一對名為 Value Display & Gauge 的小部件。

順便說一句，您訪問我們的網(wǎng)站并從中掃描代碼，您將獲得一個預(yù)制的小部件，這對您來說很容易

單擊此處（為 IoT 脈搏血氧計(jì)設(shè)置 Blynk 應(yīng)用程序）

第 6 步：軟件和庫

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硬件設(shè)置完成，現(xiàn)在我們需要將代碼上傳到 NodeMCU ESP8266-12E Board。但在此之前，您需要安裝一些庫。

庫文件可以從這里下載：

1. Arduino MAX30100 庫

2. OLED庫

3. Adafruit GFX 庫

4.簡單眨眼

第 7 步：編碼

/*
  
  ## Hardware Connections (ESP32 <- OLED <- MAX 30102):

  -VIN = 3.3V
  -GND = GND
  -SDA = 21 (or SDA)
  -SCL = 22 (or SCL)

*/



/*================================================================================================================================== */

char auth[] = "qjZaiBBH26yK40yj29wXwZ8LXOoeQmtR";  
char ssid[] = "nextpcb";      // Your WiFi Name (SSID) (**case sensitive).
char pass[] = "111222444"   // Your WiFi Password.

/*================================================================================================================================== */








//DiY Projects Lab
#define BLYNK_PRINT Serial
#include 
#include 
#include 
#include  //OLED libraries
#include 
#include 
#include "MAX30105.h" //sparkfun MAX3010X library
//#include "heartRate.h"
SimpleTimer timer;
MAX30105 particleSensor;


#define INTERVAL_MESSAGE2 60000
unsigned long time_2 = 0;
int period = 2000;
unsigned long time_now = 0;
double avered = 0;
double aveir = 0;
double sumirrms = 0;
double sumredrms = 0;
int i = 0;
int Num = 100; //calculate SpO2 by this sampling interval

int oxygen;
double ESpO2 = 95.0;    //initial value of estimated SpO2
double FSpO2 = 0.7;     //filter factor for estimated SpO2
double frate = 0.95;    //low pass filter for IR/red LED value to eliminate AC component
#define TIMETOBOOT 3000 // wait for this time(msec) to output SpO2
#define SCALE 88.0      //adjust to display heart beat and SpO2 in the same scale
#define SAMPLING 5      //if you want to see heart beat more precisely , set SAMPLING to 1
#define FINGER_ON 3000  // if red signal is lower than this , it indicates your finger is not on the sensor
#define MINIMUM_SPO2 0.0

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;

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
#define OLED_RESET -1    // Reset pin # (or -1 if sharing Arduino reset pin)

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET); //Declaring the display name (display)

//Logo2 and Logo3 are two bmp pictures that display on the OLED if called
static const unsigned char PROGMEM logo2_bmp[] =
{ 0x03, 0xC0, 0xF0, 0x06, 0x71, 0x8C, 0x0C, 0x1B, 0x06, 0x18, 0x0E, 0x02, 0x10, 0x0C, 0x03, 0x10,
  0x04, 0x01, 0x10, 0x04, 0x01, 0x10, 0x40, 0x01, 0x10, 0x40, 0x01, 0x10, 0xC0, 0x03, 0x08, 0x88,
  0x02, 0x08, 0xB8, 0x04, 0xFF, 0x37, 0x08, 0x01, 0x30, 0x18, 0x01, 0x90, 0x30, 0x00, 0xC0, 0x60,
  0x00, 0x60, 0xC0, 0x00, 0x31, 0x80, 0x00, 0x1B, 0x00, 0x00, 0x0E, 0x00, 0x00, 0x04, 0x00,
};

static const unsigned char PROGMEM logo3_bmp[] =
    {0x01, 0xF0, 0x0F, 0x80, 0x06, 0x1C, 0x38, 0x60, 0x18, 0x06, 0x60, 0x18, 0x10, 0x01, 0x80, 0x08,
     0x20, 0x01, 0x80, 0x04, 0x40, 0x00, 0x00, 0x02, 0x40, 0x00, 0x00, 0x02, 0xC0, 0x00, 0x08, 0x03,
     0x80, 0x00, 0x08, 0x01, 0x80, 0x00, 0x18, 0x01, 0x80, 0x00, 0x1C, 0x01, 0x80, 0x00, 0x14, 0x00,
     0x80, 0x00, 0x14, 0x00, 0x80, 0x00, 0x14, 0x00, 0x40, 0x10, 0x12, 0x00, 0x40, 0x10, 0x12, 0x00,
     0x7E, 0x1F, 0x23, 0xFE, 0x03, 0x31, 0xA0, 0x04, 0x01, 0xA0, 0xA0, 0x0C, 0x00, 0xA0, 0xA0, 0x08,
     0x00, 0x60, 0xE0, 0x10, 0x00, 0x20, 0x60, 0x20, 0x06, 0x00, 0x40, 0x60, 0x03, 0x00, 0x40, 0xC0,
     0x01, 0x80, 0x01, 0x80, 0x00, 0xC0, 0x03, 0x00, 0x00, 0x60, 0x06, 0x00, 0x00, 0x30, 0x0C, 0x00,
     0x00, 0x08, 0x10, 0x00, 0x00, 0x06, 0x60, 0x00, 0x00, 0x03, 0xC0, 0x00, 0x00, 0x01, 0x80, 0x00};

#define USEFIFO

void setup()
{
  Serial.begin(115200);
  Serial.println("Initializing...");
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C); //Start the OLED display
  display.display();
  display.clearDisplay();
  Blynk.begin(auth, ssid, pass);

  // Initialize sensor
  while (!particleSensor.begin(Wire, I2C_SPEED_FAST)) //Use default I2C port, 400kHz speed
  {
    Serial.println("MAX30102 was not found. Please check wiring/power/solder jumper at MH-ET LIVE MAX30102 board. ");
    //while (1);
  }
  Serial.println("Place your index finger on the sensor with steady pressure.");

  //Setup to sense a nice looking saw tooth on the plotter
  byte ledBrightness = 255; // 0x7F 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
  int sampleRate = 400;     //1000 is best but needs processing power//Options: 50, 100, 200, 400, 800, 1000, 1600, 3200
  int pulseWidth = 411;     //Options: 69, 118, 215, 411
  int adcRange = 16384;     //Options: 2048, 4096, 8192, 16384
  // Set up the wanted parameters
  particleSensor.setup(ledBrightness, sampleAverage, ledMode, sampleRate, pulseWidth, adcRange); //Configure sensor with these settings
  particleSensor.enableDIETEMPRDY();
  timer.setInterval(500, sendUptime);
}

void sendUptime()
{
  Blynk.virtualWrite(V4, oxygen);
  //Blynk.virtualWrite(V5, beatAvg);
}

void loop()
{
  Blynk.run();
  timer.run(); // Initiates SimpleTimer

  uint32_t ir, red, green;
  double fred, fir;
  double SpO2 = 0; //raw SpO2 before low pass filtered

#ifdef USEFIFO
  particleSensor.check(); //Check the sensor, read up to 3 samples

  while (particleSensor.available())

  { //do we have new data
#ifdef MAX30105
    red = particleSensor.getFIFORed(); //Sparkfun's MAX30105
    ir = particleSensor.getFIFOIR();   //Sparkfun's MAX30105
#else
    red = particleSensor.getFIFOIR(); //why getFOFOIR output Red data by MAX30102 on MH-ET LIVE breakout board
    ir = particleSensor.getFIFORed(); //why getFIFORed output IR data by MAX30102 on MH-ET LIVE breakout board
#endif

    i++;
    fred = (double)red;
    fir = (double)ir;
    avered = avered * frate + (double)red * (1.0 - frate); //average red level by low pass filter
    aveir = aveir * frate + (double)ir * (1.0 - frate);    //average IR level by low pass filter
    sumredrms += (fred - avered) * (fred - avered);        //square sum of alternate component of red level
    sumirrms += (fir - aveir) * (fir - aveir);             //square sum of alternate component of IR level
    if ((i % SAMPLING) == 0)
    { //slow down graph plotting speed for arduino Serial plotter by thin out
      if (millis() > TIMETOBOOT)
      {
        if (ir < FINGER_ON)
          ESpO2 = MINIMUM_SPO2; //indicator for finger detached
        //float temperature = particleSensor.readTemperatureF();
        if (ESpO2 <= -1)
        {
          ESpO2 = 0;
        }

        if (ESpO2 > 100)
        {
          ESpO2 = 100;
        }

        oxygen = ESpO2;

        Serial.print(" Oxygen % = ");
        Serial.println(oxygen);
      }
    }
    if ((i % Num) == 0)
    {
      double R = (sqrt(sumredrms) / avered) / (sqrt(sumirrms) / aveir);
      // Serial.println(R);
      SpO2 = -23.3 * (R - 0.4) + 100;               //http://ww1.microchip.com/downloads/jp/AppNotes/00001525B_JP.pdf
      ESpO2 = FSpO2 * ESpO2 + (1.0 - FSpO2) * SpO2; //low pass filter
      //Serial.print(SpO2); Serial.print(","); Serial.println(ESpO2);
      sumredrms = 0.0;
      sumirrms = 0.0;
      i = 0;
      break;
    }
    particleSensor.nextSample(); //We're finished with this sample so move to next sample
    //Serial.println(SpO2);
  }

  long irValue = particleSensor.getIR();
  //Serial.println(irValue);

  if (irValue > 7000)
  {                                                     //If a finger is detected
    display.clearDisplay();                             //Clear the display
    display.drawBitmap(5, 5, logo2_bmp, 24, 21, WHITE); //Draw the first bmp picture (little heart)
    display.setTextSize(2);                             //Near it display the average BPM you can display the BPM if you want
    display.setTextColor(WHITE);
    display.setCursor(50, 15);
    display.println("SpO2");
    display.setCursor(50, 50);
    //display.println(beatAvg);
    display.print(oxygen);
    display.println("%");

    display.display();
  }

  if (irValue == true)
  {

    display.clearDisplay();                             //Clear the display
    display.drawBitmap(0, 0, logo3_bmp, 32, 32, WHITE); //Draw the second picture (bigger heart)
    display.setTextSize(2);                             //And still displays the average BPM
    display.setTextColor(WHITE);
    display.setCursor(50, 15);
    display.println("SpO2");
    display.setCursor(50, 50);
    //display.println(beatAvg);
    display.print(oxygen);
    display.println("%");
    display.display();

   
  }

  if (irValue < 7000)
  { //If no finger is detected it inform the user and put the average BPM to 0 or it will be stored for the next measure
    //beatAvg=0;
    display.clearDisplay();
    display.setTextSize(1);
    display.setTextColor(WHITE);
    display.setCursor(30, 10);
    display.println("WiFi Connected ");
    display.setCursor(30, 25);
    display.println("Please Place ");
    display.setCursor(30, 4
    0);
    display.println("your Finger ");

    
    display.display();
  }

  if (millis() > time_2 + INTERVAL_MESSAGE2 && oxygen < 93)

  {
    time_2 = millis();

    Blynk.notify("Alert! Oxygen Saturation below 93% Detected");
    Serial.print("Alert called");
  }

#endif
}

第 8 步：從 MAX30100 ESP32 輸出 Blynk 上的觀察值和讀取值

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在 Android 應(yīng)用程序上，BPM 和 SpO2 值會在一秒鐘后上傳，您可以看到儀表和顯示參數(shù)的變化。

訪問我的網(wǎng)站DiY Projects Lab擁有超過 25 個很棒的詳細(xì)項(xiàng)目

第 9 步：DIY 和購買

我將我的血氧儀與專業(yè)血氧儀進(jìn)行了比較，它顯示出幾乎 99% 的準(zhǔn)確度。

謝謝 NextPCB：這個項(xiàng)目之所以順利完成，是因?yàn)橛?NextPCB 的幫助和支持。

伙計(jì)們，如果您有 PCB 項(xiàng)目，請?jiān)L問他們的網(wǎng)站并獲得令人興奮的折扣和優(yōu)惠券。

這是仲夏銷售的 NextPCB

1. PCB 訂單最高可享受 30% 的折扣

2. PCBA 訂單最高 20% 折扣

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