int trigpin = 4;
int echopin = 5;
float duration, distance;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(trigpin, OUTPUT);
  pinMode(echopin, INPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  // this speeds up the simulation
  digitalWrite(trigpin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigpin, LOW);
  duration = pulseIn(echopin, HIGH);
  distance = 0.017 * duration;

  Serial.print("Distance =  ");
  Serial.print(distance);
  Serial.println("cm");
  delay(1000);
}