BPM_2

#include <stdio.h>
#include <time.h>
#include <stdlib.h>
#include <math.h>

//declare variables
double bpm, ewma, ewma_prev,  average , raw, alpha, stored_bpm, D1, D2, read_pin, ewma_comp;
int t_int;
clock_t time1,time2;

double t_old, t_new;


//////SIMULATED SIGNAL READING DATA/////
double signal_read[] = {1107,1263,1304,1286,2928,2042,1256,1603,1243,1152,1240,1246,1259,2676,2853,1256,1486,1339,1141,1219,1241,1250,2008,2927,1351,1415,1466,1181,1164,1224,1225,2021,2667,1211,1313,1328,1078,1105,1261,1294,2839,2190,1232,1553,1297,1119,1208,1275,1902,2926,1373,1428,1482,1145,1180,1256,1280,2927,1909,1131,1428,1129,985,1162,1233,1778,2669,1355,1362,1500,1181,1192,1295,1860,2925,1345,1421,1531,1163,1216,1298,1330,2927,1998,1246,1514,1190,1077,1221,1266,2223,2925,1293,1412,1357,1035,1096,1187,1204,2929,1701,1096,1501,1216,1124,1326,1355,2913,2004,1084,1563,1321,1139,1225,1286,2753,2790,1159,1504,1307,1068,1189,1295,1739,2939,2934,2944,2938,2938,2938 };


//////SIMULATED TIME READING DATA/////
double time_read[] = {0,100,200,300,400,500,600,700,800,900,1000,1100,1200,1300,1400,1500,1600,1700,1800,1900,2000,2100,2200,2300,2400,2500,2600,2700,2800,2900,3000,3100,3200,3300,3400,3500,3600,3700,3800,3900,4000,4100,4200,4300,4400,4500,4600,4700,4800,4900,5000,5100,5200,5300,5400,5500,5600,5700,5800,5900,6000,6100,6200,6300,6400,6500,6600,6700,6800,6900,7000,7100,7200,7300,7400,7500,7600,7700,7800,7900,8000,8100,8200,8300,8400,8500,8600,8700,8800,8900,9000,9100,9200,9300,9400,9500,9600,9700,9800,9900,10000,10100,10200,10300,10400,10500,10600,10700,10800,10900,11000,11100,11200,11300,11400,11500,11600,11700,11800,11900,12000,12100,12200,12300,12400,12500,12600,12700,12800,12900};

int main()
{
//initialize variables value	
bpm =0;
ewma = 1200;
average = 0;
raw = 0;
alpha=1.5; // X 10% 
D1 = 0;
D2 =0;
t_old =0;
ewma_prev = 1200;
stored_bpm =0;
////////////////
t_int = 0;

while (t_int<= 130)  // loop begins // set how many loops or iterations are desired //                  //POINT OF INTEREST
   { 

ewma_prev = ewma; //store previous EWMA

//read analog pin

//////ANALOG READING SIMULATION 

read_pin = signal_read[t_int];
//////////////////////////////////


raw = read_pin; ///  POINT OF INTEREST

D1 = raw;




///calculate EWMA
ewma = (alpha*D1 + (10-alpha)*ewma)/10;
ewma_comp = ((ewma-1000)/(ewma_prev-1000))*100;
//raw_array[0] = D2;

D2 = D1;

if (ewma_comp>136) /// detect signal peaks, comparing an EWMA with another                              //EWMA in previous iteration (101/100)
      {
          
        t_new = time_read[t_int];//set a timestamp once a peak is detected


    if (ewma>1000 && ewma<2400) // prevent ewma misread or data misread (200,700)
        {
	////get latest running time in ms
         //t_new =  clock(); ////// CAUTION

	 ///calculate bpm
	 //bpm = 1*60000/(t_new-t_old); ///measured time in milliseconds
	//bpm = 1*60000/ (((double) (t_new - t_old)) / CLOCKS_PER_SEC);//measured time in milliseconds
	
	bpm = 1000*60/ (t_new-t_old); ///measured time in seconds(*1) or milliseconds(x1000)
	
    t_old = t_new;///duplicate the t_new once its only use was finished in this iteration


	 if (bpm > 0 && bpm < 5600) ///prevent systematic bpm miscalculation(20,220)
	               {
	                stored_bpm = bpm; /// update bpm
	               }
	 else
	               {
	                bpm = stored_bpm; /// bpm remains the same
	                printf("Measured BPM is outside acceptable range \n");
	               }
	               
	}
	


      } 
      
      	printf("T_peak : %.2f |  signal : %.2f  |ewma = %.0f| ewma comparison =%.2f percent  | BPM = %.2f \n",t_new, D1, ewma,ewma_comp, stored_bpm );
      	t_int++;       

}
return 0;
   }