#include <Servo.h>

Servo myservo; // object servo

int pos = 0; // position of servo
int servoPin = 9; // pin for servo

void setup() {
  // put your setup code here, to run once:
  myservo.attach(servoPin); // attaches servo on servoPin to servo object
}

void loop() {
  // put your main code here, to run repeatedly:
  for(pos = 0; pos <= 180; pos++){ // 0 - 180
    // rotating in steps of one degree
    myservo.write(pos); // tell servo to go to position in variable "pos"
    delay(15); // delay of 15 ms
  }
  for(pos = 180; pos >= 0; pos--){ // 180 - 0
    myservo.write(pos); // tell servo to go to position in variable "pos"
    delay(15); // delay of 15 ms
  }
}