Lecture

心跳血氧偵測器

08 Mar 2022 • Zi Ling Wu

實作

系統方塊圖

程式碼

// MAX30102 + 128x32 OLED(I2C) #include //OLED libraries #include #include #include "MAX30105.h" //MAX3010x library #include "heartRate.h" //Heart rate calculating algorithm #include "ESP32Servo.h" MAX30105 particleSensor; int Tonepin = 4; //計算心跳用變數 const byte RATE_SIZE = 10; //多少平均數量 byte rates[RATE_SIZE]; //心跳陣列 byte rateSpot = 0; long lastBeat = 0; //Time at which the last beat occurred float beatsPerMinute; int beatAvg;

//計算血氧用變數 double avered = 0; double aveir = 0; double sumirrms = 0; double sumredrms = 0;

double SpO2 = 0; double ESpO2 = 90.0;//初始值 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 int i = 0; int Num = 30;//取樣100次才計算1次 #define FINGER_ON 7000 //紅外線最小量（判斷手指有沒有上） #define MINIMUM_SPO2 90.0//血氧最小量

//OLED設定 #define SCREEN_WIDTH 128 //OLED寬度 #define SCREEN_HEIGHT 64 //OLED高度 #define OLED_RESET -1 //Reset pin Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET); //Declaring the display name (display)

//心跳小圖 static const unsigned char PROGMEM logo2_bmp[] = { 0x03, 0xC0, 0xF0, 0x06, 0x71, 0x8C, 0x0C, 0x1B, 0x06, 0x18, 0x0E, 0x02, 0x10, 0x0C, 0x03, 0x10, //Logo2 and Logo3 are two bmp pictures that display on the OLED if called 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, }; //心跳大圖 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 }; //氧氣圖示 static const unsigned char PROGMEM O2_bmp[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xf0, 0x00, 0x3f, 0xc3, 0xf8, 0x00, 0xff, 0xf3, 0xfc, 0x03, 0xff, 0xff, 0xfe, 0x07, 0xff, 0xff, 0xfe, 0x0f, 0xff, 0xff, 0xfe, 0x0f, 0xff, 0xff, 0x7e, 0x1f, 0x80, 0xff, 0xfc, 0x1f, 0x00, 0x7f, 0xb8, 0x3e, 0x3e, 0x3f, 0xb0, 0x3e, 0x3f, 0x3f, 0xc0, 0x3e, 0x3f, 0x1f, 0xc0, 0x3e, 0x3f, 0x1f, 0xc0, 0x3e, 0x3f, 0x1f, 0xc0, 0x3e, 0x3e, 0x2f, 0xc0, 0x3e, 0x3f, 0x0f, 0x80, 0x1f, 0x1c, 0x2f, 0x80, 0x1f, 0x80, 0xcf, 0x80, 0x1f, 0xe3, 0x9f, 0x00, 0x0f, 0xff, 0x3f, 0x00, 0x07, 0xfe, 0xfe, 0x00, 0x0b, 0xfe, 0x0c, 0x00, 0x1d, 0xff, 0xf8, 0x00, 0x1e, 0xff, 0xe0, 0x00, 0x1f, 0xff, 0x00, 0x00, 0x1f, 0xf0, 0x00, 0x00, 0x1f, 0xe0, 0x00, 0x00, 0x0f, 0xe0, 0x00, 0x00, 0x07, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };

void setup() { Serial.begin(115200); Serial.println(“System Start”); display.begin(SSD1306_SWITCHCAPVCC, 0x3C); //Start the OLED display display.display(); delay(3000); //檢查 if (!particleSensor.begin(Wire, I2C_SPEED_FAST)) //Use default I2C port, 400kHz speed { Serial.println(“找不到MAX30102”); while (1); } byte ledBrightness = 0x7F; //亮度Options: 0=Off to 255=50mA byte sampleAverage = 4; //Options: 1, 2, 4, 8, 16, 32 byte ledMode = 2; //Options: 1 = Red only(心跳), 2 = Red + IR(血氧) //Options: 1 = IR only, 2 = Red + IR on MH-ET LIVE MAX30102 board int sampleRate = 800; //Options: 50, 100, 200, 400, 800, 1000, 1600, 3200 int pulseWidth = 215; //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();

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(); //Reading the IR value it will permit us to know if there’s a finger on the sensor or not //是否有放手指 if (irValue > FINGER_ON ) { display.clearDisplay();//清除螢幕 display.drawBitmap(5, 5, logo2_bmp, 24, 21, WHITE);//顯示小的心跳圖示 display.setTextSize(2);//設定文字大小 display.setTextColor(WHITE);//文字顏色 display.setCursor(42, 10);//設定游標位置 display.print(beatAvg); display.println(“ BPM”);//顯示心跳數值 display.drawBitmap(0, 35, O2_bmp, 32, 32, WHITE);//顯示氧氣圖示 display.setCursor(42, 40);//設定游標位置 //顯示血氧數值 if (beatAvg > 30) display.print(String(ESpO2) + “%”); else display.print(“—- %” ); display.display();//顯示螢幕 //是否有心跳 if (checkForBeat(irValue) == true) { display.clearDisplay();//清除螢幕 display.drawBitmap(0, 0, logo3_bmp, 32, 32, WHITE);//顯示大的心跳圖示 display.setTextSize(2);//設定文字大小 display.setTextColor(WHITE);//文字顏色 display.setCursor(42, 10);//設定游標位置 display.print(beatAvg); display.println(“ BPM”);//顯示心跳數值 display.drawBitmap(0, 35, O2_bmp, 32, 32, WHITE);//顯示氧氣圖示 display.setCursor(42, 40);//設定游標位置 //顯示血氧數值 if (beatAvg > 30) display.print(String(ESpO2) + “%”); else display.print(“—- %” ); display.display();//顯示螢幕 tone(Tonepin, 1000);//發出聲音 delay(10); noTone(Tonepin);//停止聲音 Serial.print(“beatAvg=”); Serial.println(beatAvg);//將心跳顯示到序列 long delta = millis() - lastBeat;//計算心跳差 lastBeat = millis(); beatsPerMinute = 60 / (delta / 1000.0);//計算平均心跳 if (beatsPerMinute < 255 && beatsPerMinute > 20) { //心跳必須再20-255之間 rates[rateSpot++] = (byte)beatsPerMinute; //儲存心跳數值陣列 rateSpot %= RATE_SIZE; beatAvg = 0;//計算平均值 for (byte x = 0 ; x < RATE_SIZE ; x++) beatAvg += rates[x]; beatAvg /= RATE_SIZE; } }

//計算血氧
uint32_t ir, red ;
double fred, fir;
particleSensor.check(); //Check the sensor, read up to 3 samples
if (particleSensor.available()) {
  i++;
  red = particleSensor.getFIFOIR(); //讀取紅光
  ir = particleSensor.getFIFORed(); //讀取紅外線
  //Serial.println("red=" + String(red) + ",IR=" + String(ir) + ",i=" + String(i));
  fred = (double)red;//轉double
  fir = (double)ir;//轉double
  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 % Num) == 0) {
    double R = (sqrt(sumredrms) / avered) / (sqrt(sumirrms) / aveir);
    SpO2 = -23.3 * (R - 0.4) + 100;
    ESpO2 = FSpO2 * ESpO2 + (1.0 - FSpO2) * SpO2;//low pass filter
    if (ESpO2 <= MINIMUM_SPO2) ESpO2 = MINIMUM_SPO2; //indicator for finger detached
    if (ESpO2 > 100) ESpO2 = 99.9;
    Serial.print("Oxygen % = "); Serial.println(ESpO2);
    sumredrms = 0.0; sumirrms = 0.0; SpO2 = 0;
    i = 0;
  }
  particleSensor.nextSample(); //We're finished with this sample so move to next sample
}

} else { //清除心跳數據 for (byte rx = 0 ; rx < RATE_SIZE ; rx++) rates[rx] = 0; beatAvg = 0; rateSpot = 0; lastBeat = 0; //清除血氧數據 avered = 0; aveir = 0; sumirrms = 0; sumredrms = 0; SpO2 = 0; ESpO2 = 90.0; //顯示Finger Please display.clearDisplay(); display.setTextSize(2); display.setTextColor(WHITE); display.setCursor(30, 5); display.println(“Finger”); display.setCursor(30, 35); display.println(“Please”); display.display(); noTone(Tonepin); } }

This site was last updated June 01, 2023.