#include <Servo.h> 

Servo doorServo; 
const int trigPin = 10; 
const int echoPin = 11; 
const int openDistance = 15; 

void setup() {
  doorServo.attach(9); 
  pinMode(trigPin, OUTPUT); 
  pinMode(echoPin, INPUT); 
  doorServo.write(0); 
}

void loop() {
  long duration, distance;

  
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  
  duration = pulseIn(echoPin, HIGH);

  
  distance = duration * 0.034 / 6; 

  if (distance > openDistance) { 
    doorServo.write(90); 
  } else {
    doorServo.write(0);
  }

  delay(100); 
}