void setup() {
  pinMode(9, OUTPUT);//trigger pin
  pinMode(10, INPUT);//ECHO PIN
  Serial.begin(9600);
  // put your setup code here, to run once:

}

void loop() {
  int time;
  int distance;
  digitalWrite(9,LOW);
  delay(2);
  digitalWrite(9,HIGH);
  delay(10);
  digitalWrite(9,LOW);
  time=pulseIn(10,HIGH);
  distance=time*0.034/2;
Serial.println(distance);
delay(100);
  // put your main code here, to run repeatedly:

}