IC_Continuous.ino

/*************************************************** 
IAS - Instituto Superior Técnico
MSc in Biomedical Engineering

Rita Silva 86805
Vicente Garção 86810

This code uses MPC9808 IC contact temperature sensor and 
NodeMCU ESP32 
 ****************************************************/

#include <Wire.h>
#include "Adafruit_MCP9808.h"

// Create the MCP9808 temperature sensor object
Adafruit_MCP9808 tempsensor = Adafruit_MCP9808();

  //variables for kalman 1st pass
  double Q=0.00001;
  double R=1.000;
  double xhat=36.000; 
  double P=1.000;
  double xhatminus=0.000;
  double Pminus=0.000;
  double K=0.000;
  double M=36.00;
  double vm[]={xhat,P,xhatminus,Pminus,K,M,Q,R};

  //variables for kalman 2nd pass
  double QCPost=0.00001;
  double RCPost=1.000;
  double xhatCPost=36.000; 
  double PCPost=1.000;
  double xhatminusCPost=0.000;
  double PminusCPost=0.000;
  double KCPost=0.000;
  double MCPost=34.00;
  double vmCPost[]={xhatCPost,PCPost,xhatminusCPost,PminusCPost,KCPost,MCPost,QCPost,RCPost};

  //variables for when the sensor outputs nan
  float d=0.0;
  int nanI=0;

  //variables for initial stabilization
  int counter=0;
  int counter1=0;
  int counter2=1;
  double rr=0.0;
  double counteraux=1.0;
  double result=36.00;
  
void setup() {
  Serial.begin(115200);
  
  while (!Serial); //waits for serial terminal to be open, necessary in newer arduino boards.
  Serial.println("MCP9808 demo");
  
  // Make sure the sensor is found, you can also pass in a different i2c
  // address with tempsensor.begin(0x19) for example, also can be left in blank for default address use
  // Also there is a table with all addres possible for this sensor, you can connect multiple sensors
  // to the same i2c bus, just configure each sensor with a different address and define multiple objects for that
  //  A2 A1 A0 address
  //  0  0  0   0x18  this is the default address
  //  0  0  1   0x19
  //  0  1  0   0x1A
  //  0  1  1   0x1B
  //  1  0  0   0x1C
  //  1  0  1   0x1D
  //  1  1  0   0x1E
  //  1  1  1   0x1F
  if (!tempsensor.begin(0x18)) {
    Serial.println("Couldn't find MCP9808! Check your connections and verify the address is correct.");
    while (1);
  }

   Serial.println("Found MCP9808!");

  tempsensor.setResolution(3); // sets the resolution mode of reading, the modes are defined in the table bellow:
  // Mode Resolution SampleTime
  //  0    0.5°C       30 ms
  //  1    0.25°C      65 ms
  //  2    0.125°C     130 ms
  //  3    0.0625°C    250 ms
}

static void kalman(double v[]) {
  v[2]=v[0];
  v[3]=v[1]+v[6];
  v[4]=(v[3])/(v[3]+v[7]);
  v[0]=v[2]+v[4]*(v[5]-v[0]);
  v[1]=(1-v[4])*v[3];
}

void loop() {

      float c = tempsensor.readTempC();

      //checking for very low or very high values or nan
      if(c>44.0 || isnan(c) || c<15.0){
        if(isnan(c)){
          Serial.println("nan");
        }
        c=d;
        nanI+=1;
        if(nanI==20) {
          Serial.println("ERROR: Please check the connection.");
          nanI=0;
          }
       }
       d=c;

       //filtering
       
       //kalman 1st pass
       vm[5]=c;
       kalman(vm);
       
       //kalman 2nd pass
       vmCPost[5]=vm[0];
       kalman(vmCPost);

       //code for initial stabilization
       if(counter1<30) {
         counter1+=1;
       }
       else {
         if (counter2<=10){
           rr+=vmCPost[0]/10;
           counter2+=1;
         }
         else {
          counteraux=(120-counter)/120;
          result=counteraux*rr+(1-counteraux)*vm[0];
          if (counter<120){
              counter+=1;
          }

          //fever alert message
          if(result>37.5) {
              Serial.println("ALERT: POSSIBLE FEVER DETECTED");
          } 
          else {
             if(result>37.2) {
               Serial.println("ALERT: POSSIBLE PRE-FEBRILE STATE DETECTED");
             }
          } 
          //raw temp
          //Serial.print(c, 3);
          //Serial.print(","); 
          //result:
          Serial.println(result, 3);
          }
        }
  delay(1000);
}