#include <Stepper.h>

const int stepsPerRevolution = 500;  // change this to fit the number of steps per revolution
const int speed = 100;

Stepper myStepper(stepsPerRevolution, 8, 9, 10, 11);

void setup() {
  myStepper.setSpeed(speed);
}

void loop() {
  myStepper.step(stepsPerRevolution);
  delay(500);

  myStepper.step(-stepsPerRevolution);
  delay(500);
}