# include<servo.h>
servo servo;
int const trigPin = 6;
int const echoPin = 5;
void setup() {
  pinMode (trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  servo.attach(3);

}

void loop()
{ int duration, distance;
  digitalWrite (trigPin, HIGH);
  delay(1);
  digitalWrite(trigPin, LOW);
  //measure the pulse input in echo pin
  duration = pulseIn(echoPin, HIGH);
  //Distance is half the duration devided by 29.1(from datasheet)
  distance = (duration / 2) / 29.1;
  //if distance less than 0.5 meter and more than 0(0or less means over rang)
  if (distance <= 50 && distance >= 0) {
    servo.write(50);
    delay(3000)
  } else {
    servo.write(160);
  }
  //waiting 60 ms won't any one
  delay(60);

}