#include <Servo.h>

#define trigpin 7 
#define echopin 6 
#define led 13 
#define servo 9

int position = 0;
Servo doorservo;
long duration;
float distance;



void setup() {

  // put your setup code here, to run once:
  doorservo.attach(servo);
  pinMode(echopin, INPUT);
  pinMode(trigpin, OUTPUT); 
  pinMode(led, OUTPUT);  
  doorservo.write(position);


}

void loop() {
  // put your main code here, to run repeatedly:

Serial.begin(9600);
  digitalWrite(trigpin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigpin, HIGH);
  delayMicroseconds(10); //output pulse with 1ms width on trig
  digitalWrite(trigpin, LOW);
  
  duration=pulseIn(echopin, HIGH);
  distance = (duration*0.0343/2);
  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(10);
}
 delay(1000);

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

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

}



}