Moniteur d'Oxygène Sanguin et Température Corporelle Arduino – Système Bi-Capteur

Composants et Fournitures

À Propos du Projet

Ce projet mesure simultanément le taux d'oxygène dans le sang (SpO2) et la température corporelle. Toute valeur inférieure aux seuils définis allume une LED rouge d'alerte.

Important : Pour le capteur SpO2, posez naturellement le doigt dessus sans appuyer fort, sinon la mesure sera faussée.

Lien GitHub (schéma et code) : https://github.com/DKARDU/bloodoxygen

Code Arduino (Blood_Oximeter.ino)

#include <LiquidCrystal_I2C.h>
#include <Wire.h>
#include <Adafruit_MLX90614.h>
#include <EEPROM.h>
#include "MAX30105.h" // Bibliothèque SparkFun MAX3010x

MAX30105 particleSensor;
LiquidCrystal_I2C lcd(0x27, 20, 4);
Adafruit_MLX90614 mlx = Adafruit_MLX90614();

double avered = 0, aveir = 0;
double sumirrms = 0, sumredrms = 0;
int i = 0, Num = 100;
int Temperature, temp;
float ESpO2, ESpO2_ROM;
double FSpO2 = 0.7;    // Filtre passe-bas pour SpO2 estimé
double frate = 0.95;   // Filtre pour composante DC IR/Rouge

#define TIMETOBOOT 3000
#define SCALE 88.0
#define SAMPLING 5
#define FINGER_ON 30000
#define USEFIFO
#define Greenled 8
#define Redled 9

void setup() {
  Serial.begin(115200);
  lcd.init(); lcd.backlight();
  lcd.setCursor(3,1); lcd.print("Running......"); delay(3000); lcd.clear();
  
  ESpO2 = readEEPROM();
  Temperature = EEPROM.read(6);
  pinMode(Greenled, OUTPUT); pinMode(Redled, OUTPUT);
  digitalWrite(Greenled, LOW); digitalWrite(Redled, LOW);

  // Initialisation MAX30102
  while (!particleSensor.begin(Wire, I2C_SPEED_FAST)) {
    Serial.println("MAX30102 non trouvé. Vérifiez câblage/alimentation/soudure jumper MH-ET LIVE.");
  }
  
  byte ledBrightness = 0x7F;
  byte sampleAverage = 4;
  byte ledMode = 2;
  int sampleRate = 200;
  int pulseWidth = 411;
  int adcRange = 16384;
  particleSensor.setup(ledBrightness, sampleAverage, ledMode, sampleRate, pulseWidth, adcRange);
  particleSensor.enableDIETEMPRDY();
  mlx.begin();
}

void loop() {
  uint32_t ir, red, green;
  double fred, fir, SpO2 = 0;
  
#ifdef USEFIFO
  particleSensor.check();
  while (particleSensor.available()) {
#ifdef MAX30105
    red = particleSensor.getFIFORed();
    ir = particleSensor.getFIFOIR();
#else
    red = particleSensor.getFIFOIR();   // Inversion sur carte MH-ET LIVE
    ir = particleSensor.getFIFORed();
#endif
    
    i++;
    fred = (double)red; fir = (double)ir;
    avered = avered * frate + (double)red * (1.0 - frate);
    aveir = aveir * frate + (double)ir * (1.0 - frate);
    sumredrms += (fred - avered) * (fred - avered);
    sumirrms += (fir - aveir) * (fir - aveir);
    
    if ((i % SAMPLING) == 0) {
      if (millis() > TIMETOBOOT) {
        // Affichage graphique Serial Plotter
        float ir_forGraph = (2.0 * fir - aveir) / aveir * SCALE;
        float red_forGraph = (2.0 * fred - avered) / avered * SCALE;
        // ... (tronquage pour autoscaling)
        
        float temperature = particleSensor.readTemperatureF();
        
        if (ir < FINGER_ON) { // Doigt non détecté
          temp = Temperature;
          EEPROM.write(6, temp);
          ESpO2_ROM = ESpO2;
          writeEEPROM(&ESpO2_ROM);
          lcd.setCursor(0,2); lcd.print("Last test: "); lcd.setCursor(11,2); lcd.print(ESpO2_ROM); lcd.print(" %");
          lcd.setCursor(0,3); lcd.print("Last temp: "); lcd.setCursor(11,3); lcd.print(temp); lcd.print(" *C");
          break;
        }
        
        if (ir > FINGER_ON) { // Doigt détecté
          Temperature = mlx.readObjectTempC();
          lcd.setCursor(0,0); lcd.print("Oxygen % = "); lcd.setCursor(11,0); lcd.print(ESpO2); lcd.print(" %");
          lcd.setCursor(0,1); lcd.print("Temperature: "); lcd.print(Temperature); lcd.print(" *C");
          
          // Seuils alerte : SpO2 < 90% OU Temp > 37°C → LED rouge
          if ((ESpO2 >= 90) && (Temperature < 38)) {
            digitalWrite(Redled, LOW); digitalWrite(Greenled, HIGH);
          }
          if ((ESpO2 < 90) || (Temperature > 37)) {
            digitalWrite(Greenled, LOW); digitalWrite(Redled, HIGH);
          }
        }
      }
    }
    
    if ((i % Num) == 0) {
      double R = (sqrt(sumredrms) / avered) / (sqrt(sumirrms) / aveir);
      SpO2 = -23.3 * (R - 0.4) + 100; // Formule Microchip AN1525B
      ESpO2 = FSpO2 * ESpO2 + (1.0 - FSpO2) * SpO2; // Filtrage passe-bas
      sumredrms = 0.0; sumirrms = 0.0; i = 0;
      break;
    }
    particleSensor.nextSample();
  }
#endif
}

void writeEEPROM(float *data) { ... }
float readEEPROM() { ... }

Schéma de Câblage