const int trigPin = 9;
const int echoPin = 10;
long duration;
int distanceCm;
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);
distanceCm= duration*0.034/2;

      Serial.println(distanceCm);// if distance less than 0.5 meter and more than 0 (0 or less means over range)

delay(100);

}