Arduino library for 28BYJ48 Stepper motor and ULN2003 driver.

Here is the source code for our 28BYJ48 stepper motor, ULN2003 driver library, as well as an implementation. Check out the diagram for the wiring.

The header file:
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#ifndef Stepper_h
#define Stepper_h

class StepperMotor {
public:
    StepperMotor(int In1, int In2, int In3, int In4);    // Constructor that will set the inputs
    void setStepDuration(int duration);    // Function used to set the step duration in ms
    void step(int noOfSteps);    // Step a certain number of steps. + for one way and - for the other

    int duration;    // Step duration in ms
    int inputPins[4];    // The input pin numbers
};

#endif


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The cpp file:
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#include <Arduino.h>
#include <StepperMotor.h>

StepperMotor::StepperMotor(int In1, int In2, int In3, int In4){
    // Record pin numbers in the inputPins array
    this->inputPins[0] = In1;
    this->inputPins[1] = In2;
    this->inputPins[2] = In3;
    this->inputPins[3] = In4;

    // Iterate through the inputPins array, setting each one to output mode
    for(int inputCount = 0; inputCount < 4; inputCount++){
        pinMode(this->inputPins[inputCount], OUTPUT);
    }
    duration = 50;
}

void StepperMotor::setStepDuration(int duration){
    this->duration = duration;
}

void StepperMotor::step(int noOfSteps){
    /*
        The following 2D array represents the sequence that must be
        used to acheive rotation. The rows correspond to each step, and
        the columns correspond to each input. L
    */
    bool sequence[][4] = {{LOW, LOW, LOW, HIGH },
                          {LOW, LOW, HIGH, HIGH},
                          {LOW, LOW, HIGH, LOW },
                          {LOW, HIGH, HIGH, LOW},
                          {LOW, HIGH, LOW, LOW },
                          {HIGH, HIGH, LOW, LOW},
                          {HIGH, LOW, LOW, LOW },
                          {HIGH, LOW, LOW, HIGH}};
                     
    int factor = abs(noOfSteps) / noOfSteps;    // If noOfSteps is +, factor = 1. If noOfSteps is -, factor = -1
    noOfSteps = abs(noOfSteps);    // If noOfSteps was in fact negative, make positive for future operations

    /*
        The following algorithm runs through the sequence the specified number
        of times
    */
    for(int sequenceNum = 0;  sequenceNum <= noOfSteps/8; sequenceNum++){
        for(int position = 0; ( position < 8 ) && ( position < ( noOfSteps - sequenceNum*8 )); position++){
            delay(duration);
            for(int inputCount = 0; inputCount < 4; inputCount++){
                digitalWrite(this->inputPins[inputCount], sequence[(int)(3.5 - (3.5*factor) + (factor*position))][inputCount]);
            }
        }
    }
}

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An implementation:
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#include <StepperMotor.h>

StepperMotor motor(8,9,10,11);

void setup(){
  Serial.begin(9600);
  motor.setStepDuration(1);
}

void loop(){
  motor.step(1000);
  delay(2000);
  motor.step(-1000);
  delay(2000);
}

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Wiring diagram: