#define trigPin 9
#define echoPin 10

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

}
void loop(){
  long duration;
  float distance;
  //send ultrasonic pulse 
  digitalWrite(trigPin,LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  //read echo time 
  duration=pulseIn(echoPin,HIGH);
  //convert to distance (in cm)
  distance= duration *.034/2;

  Serial.print("Distance :");
  Serial.print(distance);
  Serial.println(" cm");

  delay(1000);
}