#include<Servo.h>
const int trigPin = 9;
const int echoPin = 10;
const int motorPin = 3;
void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(motorPin, OUTPUT);

}

void loop() {
  int distance = readDistance();
  if(distance < 20)
  {
    rotateMotor(true);
  }
  else
  {
    rotateMotor(false);
  }
  delay(1000);

}
int readDistance()
{
  digitalWrite(trigPin, LOW);
  delayMicroseconds(1000);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  return pulseIn(echoPin,HIGH)/58;
}
void rotateMotor(bool clockwise)
{
  if(clockwise)
  {
    digitalWrite(motorPin, HIGH);
  }
  else{
    digitalWrite(motorPin, LOW);
  }
}