#include <Servo.h>

#define trigPin  7
#define echoPin  6
#define led 13
#define servo 9

Servo doorservo;
int position = 0;

long duration;
float distance;

void setup()
{
doorservo.attach(servo);
pinMode(trigPin, OUTPUT);
pinMode(echoPin,INPUT);
pinMode(led,OUTPUT);
doorservo.write(position);
}

void loop()
{
  Serial.begin(9600);
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

duration = pulseIn(echoPin, HIGH);
distance = 0.034* (duration/2);
Serial.println(distance);
if (distance <35)

{
  digitalWrite(led, HIGH);
  //sweep from 0 to 180 degrees:
  for (position =0; position <=180; position+=1){ 
  
  doorservo.write(position);
  delay(30);
}
delay(1000);

for (position = 180; position >=0; position -=1){
  doorservo.write (position);
  delay(30);
}
 }

else
digitalWrite(led, LOW);
delay(300);
}