Ultrasonic Range Finder

Ultrasonic Range Finder

int trigPin = 12;
int echoPin = 13;

void setup() 
  {
  Serial.begin (9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  }

void loop() 
  {
  int duration, distance;

  digitalWrite(trigPin, HIGH);
  delayMicroseconds(1000);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = (duration/2) / 29.1;

  if (distance >= 500 || distance <= 0)
  {
    Serial.println("Out of range");
  }
  else 
  {
    Serial.print(distance);
    Serial.println(" cm");
  }
  delay(500);
}