#define TriggerPin  12
#define EchoPin 11

void setup() {
  Serial.begin(9600);  
  pinMode(TriggerPin,OUTPUT);
  pinMode(EchoPin,INPUT);
}

void loop() {
  long response;
  digitalWrite(TriggerPin,LOW);
  delayMicroseconds(2);
  digitalWrite(TriggerPin,HIGH);
  delayMicroseconds(10);
  digitalWrite(TriggerPin,LOW);

  response = pulseIn(EchoPin,HIGH);
  Serial.println(response/58);

  delay(500);
}