#define echo 8
#define trig 9

long Duration;
int Distence;

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

}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(trig, LOW);
  delayMicroseconds(2);

  digitalWrite(trig, HIGH);
  delayMicroseconds(10);
  digitalWrite(trig, LOW);

  Duration=pulseIn(echo, HIGH);

  Distence = Duration * 0.0344 / 2;

  Serial.print("Distence : ");
  Serial.print(Duration);
  Serial.println(" cm");
}