#include <Servo.h>

int potpin = 0;
int val = 0;

Servo servo_9;

void setup()
{
  servo_9.attach(9, 500, 2500);
}

void loop()
{
  // reads the value of the potentiometer (value
  // between 0 and 1023)
  val = analogRead (potpin);
  // scale it to use it with the servo (value
  // between 0 and 180)
  val = map(val, 0, 1023, 0, 179);
  // sets the servo position according to the
  // scaled value
  servo_9.write(val);
  // waits for the servo to get there
  delay(15);
}