#include <Servo.h>
Servo myservo;
int pos = 0;

void setup() {
myservo.attach(9); 
}

void loop() {
for (pos = 0; pos <= 180; pos += 1) {
myservo.write(pos);
delay(15);
}
for (pos = 180; pos >= 0; pos -= 1) {
myservo.write(pos);
delay(15);
}
}