File content as of revision 13:5d3b478ea9c7:

/** ECG ADS1291 Test program.
ADS1291 is a single channel ECG chip
with a 24 bit Sigma-Delta ADC
 */
 
#include "mbed.h"
#include <string.h>
#include <stdio.h>
#include "ds3231.h"
#include "SDFileSystem.h"
#include "ecg_dec.h"
#include "rtc.h"
#include "sdcard.h"
#include "ec_bp.h"
Serial pc(USBTX,USBRX);  



float ecg(int pid) 
 {

    int concatenate_value2 = 0;
 //   int32_t sample_sum; // static int32_t avg[1500];
    int32_t count = 0; int32_t fs = 500; 
    uint32_t ecg_buf[N_ECG];
    Timer t;
    
    //------------------ Declaration for Peak value detection ------------------------------------
 
 uint32_t hi_val;uint32_t pk_val[20];unsigned int pk_pos[20]={0};unsigned int a; //uint32_t pk=0;
 int hi_dif = 0;int j=0; // int count1 = N_ECG/fs, a_dif=0, fs1 = fs ,h=0;
    // ------------------------- Declaration for Heart Rate calculation --------------------------
 int n=0;    //int n=10; 
 float pos_dif, HR[2], HR1,t_pos_dif;int t_sec = 60; float HR_sum = 0,HR_avg;
    // -------------------------------------------------------------------------------------------
    
  //  unsigned char chk = 1;
    pc.baud(baud_rate);
    freqset();               // setting the frequency
    setupfunc();              
    ecgsetupfunc();
 //   chk = 1;
   sd_open_ECGfile(pid);        // opening the ecg file
  pc.printf( "Raw data is = \n"); 
 for(int i=0; i<N_ECG; i++)
   {
     concatenate_value2= readvalue();
     sd_write(concatenate_value2);               // writing into the sd card
     ecg_buf[i] = concatenate_value2;
     pc.printf( "%d\n", concatenate_value2);
   } 
   
   sd_close();          // closing the file
/*   
 // ---------- reading back SD data for processing --------------------
 sd_read_file(15);
 printf("Reading back SD data\n");
 for(int i=10;i<N_ECG;i++)
 {
 ecg_buf= sd_read();
 //printf("%d\n",ecg_buf[i]);
 }
 
  sd_close();    */
 
 //----------------------------- PEAK DETECTION AND HEART RATE CALCULATION ---------------------------------------------------
 // -------------------------------------- PEAK DETECTION -------------------------------------------------------------
 
  // ------------------ Main loop ---------------------------------
 
for(int i=0;i<N_ECG-10;i++){
if(ecg_buf[i]>ecg_buf[i+1])
{
hi_val = ecg_buf[i]; //To find the high value
//printf("high value= %d\n",hi_val);
a = i;
//printf("a= %d\n",a);
hi_dif = hi_val-ecg_buf[a+10];

//a_dif = ecg_buf[a+2] - ecg_buf[a+1]; 
//printf("The difference between high and low value is = %d\n",hi_dif);

   // ---------------------------- If hi_val is greater than next ten input values, then compare the hi_val with the tenth input value. 
    //     If the diff is greater than 10000, then it is a valid peak (pls chk the below condition)--------------------------------------------------
 //   if((hi_dif > 10000) && ((a+10) < N_ECG))
    if(hi_dif > 10000)
    {
   //  if(a_dif <= 0) ------------------------ add this condition if needed ----------------------
   //  {
     pk_val[j] = hi_val; //if condition satisfied, put the "pk" value into "pk_val" buffer
     pc.printf("peak value= %d\n",pk_val[j]);
     pk_pos[j]=a; // also save the peak's position
     pc.printf("peak position is = %d\n",pk_pos[j]);
     i = a+120;  // once confirmed that this is the necessary peak, skip the next 120 input values
     n = j; // where n is the number of peaks detected
     j = j+1;
     
  //   printf("j after peak detection is= %d\n",j);
  //   }
     }
    else
    {
    //h = a+1;
    i = a+1;
  //  printf("i if peak not found is= %d\n",i);
    }
     // store the peak value position in "pk_pos" 
     
}
}
 // ----------------- HEART RATE LOGIC --------------------------- 
 
 for(int i = 0;i < n-1;i++)
 {
  pos_dif = pk_pos[i+1] - pk_pos[i];                 // difference between two consequtive peaks
  pc.printf("peak position diff is = %f\n",pos_dif);
  //printf("peak position i value is = %d\n",i);
  t_pos_dif = pos_dif/fs;                           // sample difference between peak positions divided by sampling frequency gives the difference value in terms of actual time
  pc.printf("time in seconds is = %f\n",t_pos_dif);
  HR[i] = t_sec/t_pos_dif;                          //HR calculation
  pc.printf("Heart Rate is = %f\n",HR[i]);
 // n = i;
  HR1 = HR[0];
 
 }
 // ---------------------- To average individual HRs for higher number of samples -----------------------
 /* for(int i = 0;i < 5;i++)
 {
 HR_sum = HR[i]+HR_sum; 
 }
 HR_avg = HR_sum/5; // To find average of all the individual HRs calculated
 printf("Heart Rate sum is = %f\n",HR_sum);
 printf("Denominator = %d\n",n);
 printf("Heart Rate = %f\n",HR_avg);
 */
  return HR1;
  // return HR_avg; 
  
}          // End of main function