SerialStepper Library for Arduino and compatibles

This is a driver for unipolar stepper motors driven by ULN2003/ULN2004 darlington arrays.

Introduction

Why another stepper library

This stepper motor library is alternative to the Arduino Stepper Library. One problem with this library is that the step() function to move the stepper, is blocking.
That is, everyting else will have to wait until the motor reaches its
target. This also means that only one stapper can run at the time.

Another problem with multiple steppers, is that each stepper requires
four output pins on the microcontroller.

This library should overcome these problems.

Overview

The library consists of 2 parts:

1. The Stepper, that represents the status of the stepper

2. The StepperControl, that requests update of the stepper status
   and generate the output to the Darlington arrays

In addition, there is the loopClock, that takes care of the time, and the Steppers can check if they should move anoter step.

No delay

The library requires that all steps in the loop are fast. The total time spent in one loop iteration needs to be less than about 2 millisconds, if the steppers should be able to run at full speed.

A typical loop function with steppers may look like:

void loop() {
  loopclock::tick();
  
  if (some_condition) {
    stepper.turn(0.5);
  }

  if (some_other_codition) {
    do_other_stuff();
  }

  stepper_ctl.run();
}

some_condition and some_other_condition are typically functions of time or external events.