const int trigPin = 3;
const int echoPin = 2;
long duration;
int distance;
void setup()
{
  pinMode(trigPin,OUTPUT);
  pinMode(echoPin,INPUT);
  Serial.begin(9600);
}
void loop()
{
  digitalWrite(trigPin,LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin,HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin,LOW);
  duration = pulseIn(echoPin,HIGH);
  distance = duration *0.034/2;
  Serial.print("Distance: ");
  Serial.println(distance);
}- ]