I have an Arduino connected to a stepper motor with an Easy Driver as follows: enter image description here

I am controlling the position of the stepper motor using the Serial. This is my code:

#include <AccelStepper.h>
AccelStepper stepper(1, 9, 8);

void setup()

void loop()
  char c;
   int steps = Serial.parseInt();


The code works well but I'm facing a problem, when I set a high position value, it starts turning in the opposite direction, like if there was a limit on the steps. Does anyone know why it starts turning to the opposite direction?

I have tried to solve this problem by using:

if (stepper1.distanceToGo() == 0)        

so I can set lower values to the serial. But the problem goes back again when the value goes up to the power of 6 (like 1000000).

Any idea?


  • 1
    Per a comment from the developer of AccelStepper, the line AccelStepper stepper(1, 9, 8); should be written as AccelStepper stepper(AccelStepper::DRIVER, 9, 8); for clarity
    – dinotom
    Commented Apr 14, 2016 at 20:03

1 Answer 1


Ints on vanilla Arduinos are 16 bits, and signed, which means they hold values from -2^15 to +2^15-1, so of course you cannot assign 10^6 to one of them. Use unsigned long (4 bytes), or, better yet, specify the length explicitly by using uint32_t.

  • could you post me the reference of this?
    – Alvaro
    Commented Apr 14, 2016 at 8:02
  • 1
    This has always been the case for 16-bit processors. Plus, it's in the adruino documentation. Plus, you can verify it for yourself by writing a one-line program.
    – JayEye
    Commented Apr 14, 2016 at 15:44

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