#include <Stepper.h>
#define STEPS 64
#define IN1 11
#define IN2 10
#define IN3  9
#define IN4  8
Stepper stepper(STEPS, IN4, IN3, IN2, IN1);
#define joystick A0

void setup() {
  Serial.begin(9600);
}

void loop() {
  int val = analogRead(joystick);
  if ( (val > 500) && (val < 523) ) {
    digitalWrite(IN1, LOW);
    digitalWrite(IN2, LOW);
    digitalWrite(IN3, LOW);
    digitalWrite(IN4, LOW);
  }
  else {
    while (val >= 523) {
      int speed_ = map (val, 523, 1023, 5, 500);
      stepper.setSpeed (speed_);
      stepper.step(1);
      val = analogRead (joystick);
    }
    while (val <= 500) {
      int speed_ = map (val, 500, 0, 5, 500);
      stepper.setSpeed (speed_);
      stepper.step(-1);
      val = analogRead (joystick);
    }
  }
}