#include <Servo.h>

Servo myServo;

int pos = 0;

void setup() {
  myServo.attach(3);

}

void loop() {
  for (pos = 0; pos <= 180; pos += 1) {
    myServo.write(pos);
    delay(5);
  }
  for (pos = 180; pos >= 0; pos -= 1){
    myServo.write(pos);
    delay(5);
  }

}