const int TriggerPin = 8; 
const int EchoPin = 9;
long Duration = 0;
void setup() {
  pinMode(TriggerPin,OUTPUT);
  pinMode(EchoPin, INPUT);
  Serial.begin(9600);
}
void loop(){
  digitalWrite(TriggerPin, LOW);
  delayMicroseconds(2);
  digitalWrite(TriggerPin,HIGH);
  delayMicroseconds(10);
  digitalWrite(TriggerPin, LOW);
  Duration = pulseIn(EchoPin,HIGH);
  long Distance_mm = Distance(Duration);
  Serial.print("Distance = ");
  Serial.print(Distance_mm);
  Serial.println("mm");
  delay(1000);
}
long Distance(long time) {
  long DistanceCalc;
  DistanceCalc = ((time /2.9) /2);
  return DistanceCalc;
}