Python library for the Pololu Dual MC33926 Motor Driver for Raspberry Pi
Release Date: 2016-05-04
This library runs on the Raspberry Pi (Model B+, A+, Pi 2, or Pi 3) and provides functions for controlling both channels of the Pololu Dual MC33926 Motor Driver for Raspberry Pi. This library supports both Python 2 and Python 3.
Programs that use this library will need to be run as the root user so they can access the GPIO pins.
A Java port of this library is available at ~vorburger/dual-mc33926-motor-driver-pi4j.
These instructions assume you are using Raspbian, Debian, or some other distribution that provides the
apt-get command for managing packages. If you do not have
apt-get, you will need to use a different method to install the required packages.
These instructions also assume you will use Python 2. If you want to use Python 3, you will need to replace
python3 in the names of the
apt-get packages below, and use the
python3 command instead of
python for running Python scripts, and use the
pip3 command instead of
pip to install pip packages.
First, to download and install WiringPi-Python, run:
sudo apt-get install python-dev python-pip sudo pip install wiringpi
Finally, to download and install the dual_mc33926_rpi library, run:
git clone https://github.com/pololu/dual-mc33926-motor-driver-rpi cd dual-mc33926-motor-driver-rpi sudo python setup.py install
Running the example program
This library comes with an example program that drives each motor in both directions. To run the example, navigate to the dual-mc33926-motor-driver-rpi directory and run:
sudo python example.py
This library uses ultrasonic 20 kHz PWM to drive the motors.
Motor speeds in this library are represented as numbers between -480 and 480 (inclusive). A speed of 0 corresponds to braking. Positive speeds correspond to current flowing from M1A/M2A to M1B/M2B, while negative speeds correspond to current flowing in the other direction.
The library can be imported into a Python program with the following line:
from dual_mc33926_rpi import motors, MAX_SPEED
After importing the library, you can use the commands below to enable the motors and set motor speeds:
motors.enable(): Enable both motor 1 and motor 2.
motors.motor1.enable(): Enable motor 1.
motors.motor2.enable(): Enable motor 2.
motors.disable(): Disable both motor 1 and motor 2.
motors.motor1.disable(): Disable motor 1.
motors.motor2.disable(): Disable motor 2.
motors.setSpeeds(m1_speed, m2_speed): Set speed and direction for both motor 1 and motor 2.
motors.motor1.setSpeed(speed): Set speed and direction for motor 1.
motors.motor2.setSpeed(speed): Set speed and direction for motor 2.
For convenience, a constant called
MAX_SPEED (which is equal to 480) is available on all the objects provided by this library. You can access it directly by just writing
MAX_SPEED if you imported it as shown above, or it can be accessed in the following ways:
If you are controlling multiple motor drivers, you might prefer to import the library using
import dual_mc33926_rpi, which requires the commands listed above to be prefixed with