#include <Servo.h>

Servo servo;  // create servo object to control a servo

#define PAUSE 5000 // duration of time servo will be at 180 degrees

int buttonPin = 12; // declare a button pin
int servoPin = 13; // declare the servo pin
int ledPin = 11; // add an LED on pin 11

void setup() {
  pinMode(buttonPin, INPUT_PULLUP);
  servo.attach(servoPin); // attach the servo instance to the servo PWM pin
  servo.write(90); // rotate the servo to 90 degrees.
}

void loop() {
  if (!digitalRead(buttonPin)) { // is the button pressed?
    delay(150); // debounce the button ringing noise
    for (int pos = 90; pos <= 180; pos++){
    servo.write(pos);
    delay(30); // waits 15ms for the servo to reach the position
    }
    digitalWrite(ledPin, HIGH); // turn LED ON
    delay(PAUSE); // pausing at 180 degrees
    for (int pos = 180; pos >= 90; pos --){
    servo.write(pos);
    delay(30); // waits 15ms for the servo to reach the position
    }
    digitalWrite(ledPin, LOW); // turn LED OFF
    }
  }