Heart Beat Sensor

#include <MsTimer2.h>

const int analogInPin = A0;  // Analog input pin that the potentiometer is attached to

unsigned int flag=0,count=0,sec=0;
int sensorValue = 0;        // value read from the pot
int outputValue = 0;

void flash() {
  static boolean output = HIGH;

sec++;
if(sec==30)
{
  count=count*4;
   Serial.println(count);
  sec=0;
  count=0;
}
}

void setup() {
  // initialize serial communications at 9600 bps:
  Serial.begin(9600);
 
   MsTimer2::set(500, flash); // 500ms period
  MsTimer2::start();
 
}

void loop() {
  // read the analog in value:
  sensorValue = analogRead(analogInPin);
  if((sensorValue>800)&&(flag==0))
  {
    count++;
    flag=1;
    delay(100);
  }
  else if((sensorValue<100)&&(flag==1))
  {
    flag=0;
  }
}