// include Arduino stepper motor library
#include <Stepper.h>
 
// change this to the number of steps on your motor
#define STEPS 32
 
// create an instance of the stepper class, specifying
// the number of steps of the motor and the pins it's
// attached to
Stepper stepper(STEPS, 8, 10, 9, 11);
 
void setup()
{
  Serial.begin(9600);
  while (! Serial);
  Serial.println("Enter a speed from 2 to 500");
}
 
int direction_ = 1, speed_ = 400, val=0;
 
void loop()
{
  
 if (Serial.available())
  {
    val = Serial.parseInt();
    Serial.print("VAL = ");
    Serial.println(val);
    if (val > 1 && val <= 500)
    {
      speed_=val;
      Serial.print("SPEED = ");
      Serial.println(speed_);
    }
 
  }

  stepper.setSpeed(speed_);
  // move the stepper motor
  stepper.step(direction_);
 
}