#include <Servo.h>

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


void setup() {
  myservo.attach(2);  // attaches the servo on GPIO D4 to the servo object
}

void loop() {
    myservo.write(0);              // tell servo to go to position in variable 'pos'
    delay(500);
    myservo.write(180);
    delay(500);
}