int trigpin=4;
int echopin=5;
long duration;
long distance;

void setup() {
  pinMode(trigpin, OUTPUT);
  pinMode(echopin, INPUT);
  Serial.begin(9600);
}

void loop() {
  digitalWrite(trigpin,LOW);
  delay(2);
  digitalWrite(trigpin,HIGH);
  delay(10);
  digitalWrite(trigpin,LOW);
  duration = pulseIn(echopin,HIGH);
  distance=duration*0.034/2;
  Serial.println(distance);
}