#include <Servo.h>

// Create a servo object
Servo myServo;

void setup() {
  // Attach the servo on pin 3 to the servo object
  myServo.attach(3);
}

void loop() {
  // Sweep from 0 to 180 degrees
  for (int pos = 0; pos <= 180; pos += 1) {
    myServo.write(pos);              // Tell servo to go to position in variable 'pos'
    delay(15);                       // Wait 15ms for the servo to reach the position
  }
  
  // Sweep back from 180 to 0 degrees
  for (int pos = 180; pos >= 0; pos -= 1) {
    myServo.write(pos);              // Tell servo to go to position in variable 'pos'
    delay(15);                       // Wait 15ms for the servo to reach the position
  }
}