AccelStepper Arduino Library

AccelStepper is an object-oriented Arduino library designed for controlling 2, 3, or 4-pin stepper motors and motor drivers. It is a more advanced alternative to the standard Arduino Stepper library, specifically designed for applications requiring complex motion profiles or multiple motors.

Key capabilities include:

• Acceleration and Deceleration: Smoothly ramps motor speed up and down.
• Non-blocking API: Functions never call delay(), allowing for concurrent execution of other code.
• Multi-motor Support: Enables independent, simultaneous stepping for multiple steppers.
• Hardware Versatility: Supports 2, 3, and 4-wire steppers, including 3 and 4-wire half-stepping, and drivers like the Sparkfun EasyDriver (3967 chip).
• Compatibility: Includes support for AFMotor (Adafruit Motor Shield) stepping functions.

The MultiStepper class manages multiple AccelStepper instances (up to a maximum of 10, defined by MULTISTEPPER_MAX_STEPPERS) to ensure they all arrive at their target positions at the same time. This is ideal for achieving linear motion in multi-axis systems like X-Y plotters or 3D printers.

Important Limitations:

• Constant Speed Only: MultiStepper does not support acceleration or deceleration. All managed steppers will move at a constant speed calculated to synchronize their arrival times.
• Array Length: When using moveTo(), the provided array must be at least as long as the number of steppers added via addStepper() to avoid undefined behavior.

The moveTo(long absolute[]) method sets the target absolute positions for all managed steppers. The class automatically computes new constant speeds for each stepper so they all arrive at their respective targets at approximately the same time.

Parameters:

• absolute[]: An array of desired absolute positions. absolute[0] corresponds to the first stepper added via addStepper(), absolute[1] to the second, and so on.

long positions[2] = {1000, 500};
multi.moveTo(positions);

Use addStepper(AccelStepper& stepper) to include a stepper in the managed set. The class supports a maximum of MULTISTEPPER_MAX_STEPPERS (10) steppers.

Returns:

• true if the stepper was successfully added.
• false if adding the stepper would exceed the maximum limit.

MultiStepper multi;
// ... setup stepper ...
if (!multi.addStepper(stepper)) {
    // Handle error: too many steppers added
}

The run() method calls runSpeed() on all managed steppers that have not yet reached their target position. This should be called frequently in your main loop to allow motion to progress.

Returns:

• true if any stepper is still moving toward its target.
• false if all steppers have reached their targets.

// In your main loop
if (multi.run()) {
    // Steppers are still moving
} else {
    // All steppers have arrived
}

The runSpeedToPosition() method blocks execution of your program until all managed steppers have reached their target positions. Use this if you do not need to perform other tasks while the motors are moving.

long positions[2] = {1000, 500};
multi.moveTo(positions);
multi.runSpeedToPosition(); // Execution stops here until motion is complete