#include<Servo.h>
Servo s1;

void setup() {
  // put your setup code here, to run once:
s1.attach(9);
}

void loop() {
  // put your main code here, to run repeatedly:
for (int i=0; i <= 180; i+= 1) 
{
    s1.write(i);
    delay (15);
}
for (int i=180;i>=0; i -= 1)
{
    s1.write(i);
    delay(15);

}

}