StepperULN2003.h

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/**
 * @file StepperULN2003.h
 * @brief Control 28BYJ-48 stepper motor via ULN2003 driver.
 *
 * Supports full-step (8) and half-step (4) modes. Default is half-step.
 * Typical full rotation: 4096 steps (adjust for gear ratio).
 *
 * @include StepperMotorSimple/StepperMotorSimple.ino
 *
 * See README for wiring and step sequence details.
 * @author Philippe Gabriel
 */
 
#ifndef StepperULN2003_h
#define StepperULN2003_h
 
#define FULL Stepper::FULL8
#define HALF Stepper::HALF4
 
/**
 * @class Stepper
 * @brief Controls a 28BYJ-48 stepper motor via ULN2003 driver IC.
 *
 * This class provides an interface to control a unipolar stepper motor
 * using the ULN2003 driver in either half-step (4) or full-step (8) mode.
 * Step timing is managed internally based on the set speed.
 */
class Stepper {
public:
    /**
     * @enum StepMode
     * @brief Step resolution modes supported by the driver.
     */
    enum StepMode {
        HALF4 = 4, ///< Half-step mode (4 steps per cycle)
        FULL8 = 8  ///< Full-step mode (8 steps per cycle)
    };
 
    /**
     * @brief Constructor for the Stepper class.
     * @param steps Number of steps required for a full rotation (e.g., 4096).
     * @param in1 Pin connected to IN1 of ULN2003.
     * @param in2 Pin connected to IN2 of ULN2003.
     * @param in3 Pin connected to IN3 of ULN2003.
     * @param in4 Pin connected to IN4 of ULN2003.
     */
    Stepper(int steps, int in1, int in2, int in3, int in4);
 
    /**
     * @brief Set the motor speed in revolutions per minute (RPM).
     * @param speed Desired speed in RPM (positive values only).
     */
    void setSpeed(unsigned long speed);
 
    /**
     * @brief Set the stepping mode (half-step or full-step).
     * @param mode StepMode::HALF4 or StepMode::FULL8.
     */
    void setStepMode(StepMode mode);
 
    /**
     * @brief Move the motor a specified number of steps.
     * @param steps Number of steps to move. Positive = clockwise, negative =
     *     counterclockwise.
     */
    void step(int steps);
 
private:
    /// Bit pattern for full-step sequence
    static const unsigned int STEP_SEQUENCE[8][4];
 
    unsigned long speed;             ///< Current speed in RPM
    unsigned long stepDelay;         ///< Delay between steps in microseconds
    unsigned int steps;              ///< Total steps per revolution
    StepMode mode;                   ///< Current step mode
    unsigned int in1, in2, in3, in4; ///< Control pins
    unsigned long lastStepTime;      ///< Micros timestamp of last step
 
    /**
     * @brief Activate motor coils according to step index.
     * @param stepIndex Index into the step sequence (0–7).
     */
    void stepMotor(int stepIndex);
 
    /**
     * @brief Update step delay based on current speed and step mode.
     * @details Adjusts delay to maintain correct RPM, accounting for step mode.
     */
    void updateStepDelay();
};
 
#endif