moteur pas a pas avec joystick

#include <Stepper.h>

const int stepsPerRevolution = 48;

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

unsigned long lastTime = 0;
unsigned long thisTime = 0;
int led = 12;

void setup() {

  myStepper.setSpeed(350);
  pinMode(led, OUTPUT);
}

void loop() {

  int sensorReading = analogRead(A0);
  int motorSpeed = map(sensorReading, 0, 1023, -500, 500);

  thisTime = millis();

  if (abs(motorSpeed) > 0){

    if ((thisTime - lastTime) > abs(abs(motorSpeed)-500)){

      if (motorSpeed > 0){
        myStepper.step(1);
      }
      else
      {
        myStepper.step(-1);
      }
      lastTime = thisTime;
    }
  }
}