Description

Provides the classes BasicDriver, DRV8825, AutoDRV8825, A4988and AutoA4988 to interface with the respective driver chip by means of the python pigpio package.

Intended users: Developers.

This package provides an interface for stepper motor drivers connected to Raspberry Pi GPIO and uses the PIGPIO library to provide accurate PWM pulses to drive the (micro) steps.

It allows for setting microstep size, specifying WAIT_ENABLE time and an appropriate DEFAULT_DUTYCYCLE and defining the allowed microstep sizes.

It provides the step() function which allows for making a step with the size of any multiple of the specified microstep size.

It provides automatic acceleration and deceleration of the motor with the auto_step() function in the AutoDRV8825 and AutoA4988 classes.

It provides the pulse() function to simply output pulses to the configured driver chip.

See testDRV8825.py and testA4988.py for example code.

Requirements

Steppermotor_precise requires both the pigpio daemon and the pigpio package for python to be installed. See here for installation instructions. Armv6 like the early Raspberry Pi and Pi Zero may require compiling from source (git). On some linux distro's a package may be available from the package manager.

Note: Before running steppermotor_precise the pigpio daemon must be started with

sudo pigpiod

Installation

To install this package from github, you need to clone the repository:

git clone https://github.com/jbaans/python-rpi-steppermotor-precise

Then run the setup.py file from the cloned directory:

sudo python setup.py install

Usage

Import the class:

from steppermotor_precise import AutoDRV8825

Make sure you set the GPIO pin numbers using the GPIOS {} dict. Refer to Raspberry Pi and DRV8825/A4988 datasheets for numbering details. For example:

 GPIOS = {
    "enable":23,
    "step":24,
    "direction":25,
    "m0":22,
    "m1":17,
    "m2":4
}

Set PWM frequency (Hz) for stepper driver to run at:

frequency = 1000

Create a motor object:

try:

    motor = AutoDRV8825(GPIOS, frequency)

Enable the motor and run some steps (this will accelerate with microsteps):

    motor.enable()
    
    madesteps = motor.auto_step(steps)

    motor.disable()

Clean up the motor object:

finally:

    if motor:
    
        motor.close()