void loop() {
  // read the value from the sensor:

starttime = millis();
while (millis()<starttime+10000)                          // so i'm reading the pulse for 10 seconds
{
  sensorValue = analogRead(sensorPin);
  if (sensorValue >550 && counted == false)         // counting the pulse, and making sure I dont count
  {                                                                // each peak more than once
    count++;
    counted = true;
  }
  else if (sensorValue < 500)
  {
    counted = false;
  }
}

    heartrate = count*6;                                    // multiplying by six to get pulse per minute
 Serial.println(heartrate);                                   // printing to serial screen

  heartrate=0;
  count =0;
}