Heart Rate Estimation Using Arduino DUE

Project tutorial

Components and supplies

About this project

The electrocardiogram or ECG signal is the principal record used for anomalies detection of the human heart. The ECG is an electrical signal with low amplitude and is composed for different waves form. ECG signal is acquired from human body surface using amplifier and filter analog circuits. But, some noise components not allows the detection or the waves form. Whereby, a filtering strategies and wave form detection algorithms are required in the ECG treatment. The detection of R wave from ECG signal is the most important reference for heart rate estimation and is the principal object in this paper.

This work the design and implementation of a digital system based on open hardware development board (Arduino) applied to heart rate estimation. Positive results are presented about digital filtering oriented to R wave detection and thresholding based on histogram calculation from ECG signal. Results from test using patient simulator with different heart rate values are shown and its error percentage.

Code

Complete ProgramC/C++

This is the program for heart rate estimation.

#include <SPI.h>
#include <SD.h>
const int chipSelect = 4;
int N=3000;
int n=0;
int muestra;
int x[3000]={0};
int x1[3000]={0};
int h[1100]={0};
int d[1100]={0};
int xr[10];
int M0;
int M1;
int i;
int c;
int L;
int a=0;
int u=0;
int s=0;
int ini=0;
int m=0; 
int temp;
int z=0;
int r=0;
int p=0;


void setup() 
   {
      L=32;
     Serial.begin(9600);
     analogReadResolution(12);
     Serial.print("Initializing SD card...");
    // see if the card is present and can be initialized:
     if (!SD.begin(chipSelect))
           {
           Serial.println("Card failed, or not present");
           return;
           }
  Serial.println("card initialized.");

//////////////////
///  Filtrado

  for(n=0;n<N;n++)
 {
  x[n] = analogRead(0);
  delay(1);
 }


for (n=L;n<N;n++)
{
c=0;
  for (i=0;i<L;i++)
   {
    c=c+x[n-i];
   }
   x1[n]=c >> 4;
}


x[0]=0;

for (n=1;n<N;n++)
{
c=x1[n]-x1[n-1];
if (c < 0) c=0;
if (c > 1024) c=0;
x[n]=c;
}




/////////////

for(n=0;n<N;n++)
{
   File dataFile = SD.open("ELECTRO.txt", FILE_WRITE);
   String dataString = "";
   muestra = x[n];
   h[muestra]=h[muestra]+1;
   dataString += String(muestra);
   dataFile.println(dataString);
   dataFile.close();
}

Serial.println("ECG Guardado");

for(n=0;n<1100;n++)
{
   File dataFile = SD.open("HISTO.txt", FILE_WRITE);
   String dataString = "";
   muestra = h[n];
   dataString += String(muestra);
   dataFile.println(dataString);
   dataFile.close();
}


Serial.println("Histograma Guardado");



d[0]=0;
for (n=1;n<1100;n++)

{
  File dataFile = SD.open("DERIV.txt", FILE_WRITE);
  String dataString = "";
  d[n]=h[n]-h[n-1];
  dataString = String(d[n]);
  dataFile.println(dataString);
  dataFile.close();
}

  c=0;
  p=0;
  for (n=1;n<1100;n++)
   { 
     if (h[n]>c)
       {
        c= h[n];
        p=n;
       }
    } 


for (n=p;n<1100;n++)
   { 
     if (h[n]==0)
       {
        c= n;
        break;
       }
    } 




Serial.println("Valor Umbral");
Serial.println(c);

 for (n=0;n<N;n++)
    {  
       File dataFile = SD.open("UMBRAL.txt", FILE_WRITE);
       String dataString = "";
       if (x[n]>c)
         {
        x[n]=1;
          }
            else
          {
        x[n]=0;
          }
        dataString = String(x[n]);
        dataFile.println(dataString);
        dataFile.close();
    } 

  
 

for (n=0;n<N;n++)
   {  
     
   
     if (x[n]==1)
       {
        ini=n;
        break;
       }

   }

Serial.println(ini);

     for (m=ini;m<N;m++)
     {
          if (x[m]==0)
            {
              temp=temp+1;
               z=0;
            }
            else 
           {
              z=z+1;
              if (z<=1)
                  {
               r=r+1;
               xr[r]=temp;
               temp=0;
               z=z+1;
                  }
                else 
                  {
                  z=z+1;
                  temp=temp+1;
                  }
            }       
    }
     



Serial.println(r);



for (n=0;n<10;n++)
   {

    File dataFile = SD.open("FREC.txt", FILE_WRITE);
    String dataString = "";
    dataString = String(xr[n]);
    dataFile.println(dataString);
    dataFile.close();
   }


Serial.println("Archivo cerrado");






  
}










void loop() {



}