#include <Servo.h>

#define trigPin 8
#define echoPin 10
#define servo 9

Servo doorservo;
int position = 0;

long duration;
float distance;

void setup()
 {
doorservo.attach(servo);
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);
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);
Serial.println(distance);
if (distance <= 35)
  {
    // Sweep from 0 to 180 degrees;
    for (position = 0; position <= 90; position += 1) {
  doorservo.write(position);
  delay(100);
    }
     delay(1000);

for (position = 90; position >= 0; position -=1){
  doorservo.write(position);
  delay(30);
}

  }
  else
  doorservo.write(0);
  delay(30);
 }