#include <Servo.h>
Servo myservo;
int out_val;
int out_pin = 13;

void setup() {
  // put your setup code here, to run once:
  myservo.attach(out_pin);
}

void loop() {
  // put your main code here, to run repeatedly:
  for(out_val = 0; out_val <= 360; out_val ++){
    myservo.write(out_val);
    delay(20);
  }
  for(out_val = 360; out_val >= 0; out_val --){
    myservo.write(out_val);
    delay(20);
  }
}