Arduino library for the Pololu Dual VNH5019 Motor Driver Shield
C++
Latest commit 2640f1b Aug 24, 2016 @DavidEGrayson DavidEGrayson README.md: Added notes about how the PWM frequency
can make the current readings unreliable.  Fixes issue #14.

README.md

Arduino library for the Pololu Dual VNH5019 Motor Driver Shield

Version: 2.0.0
Release Date: 2016-08-16
Build Status
www.pololu.com

Summary

This is a library for the Arduino IDE that interfaces with the Pololu Dual VNH5019 Motor Driver Shield. It makes it simple to drive two brushed, DC motors.

Supported platforms

This library is designed to work with the Arduino IDE versions 1.6.x or later; we have not tested it with earlier versions. This library should support any Arduino-compatible board, including the Pololu A-Star 32U4 controllers.

Getting started

Hardware

The Dual VNH5019 Motor Driver Shield can be purchased from Pololu's website. Before continuing, careful reading of the product page as well as the product user's guide is recommended.

Software

If you are using version 1.6.2 or later of the Arduino software (IDE), you can use the Library Manager to install this library:

  1. In the Arduino IDE, open the "Sketch" menu, select "Include Library", then "Manage Libraries...".
  2. Search for "DualVNH5019MotorShield".
  3. Click the DualVNH5019MotorShield entry in the list.
  4. Click "Install".

If this does not work, you can manually install the library:

  1. Download the latest release archive from GitHub and decompress it.
  2. Rename the folder "dual-vnh5019-motor-shield-xxxx" to "DualVNH5019MotorShield".
  3. Drag the "DualVNH5019MotorShield" folder into the "libraries" directory inside your Arduino sketchbook directory. You can view your sketchbook location by opening the "File" menu and selecting "Preferences" in the Arduino IDE. If there is not already a "libraries" folder in that location, you should make the folder yourself.
  4. After installing the library, restart the Arduino IDE.

Example

An example sketch is available that shows how to use the library. You can access it from the Arduino IDE by opening the "File" menu, selecting "Examples", and then selecting "DualVNH5019MotorShield". If you cannot find these examples, the library was probably installed incorrectly and you should retry the installation instructions above.

Demo

The demo ramps motor 1 from stopped to full speed forward, ramps down to full speed reverse, and back to stopped. Then, it does the same with the other motor. Current readings for each motor are sent over serial and can be seen with the serial monitor. If a fault is detected, a message is sent over serial.

Documentation

  • DualVNH5019MotorShield()
    Default constructor, selects the default pins as connected by the motor shield.
  • DualVNH5019MotorShield(unsigned char INA1, unsigned char INB1, unsigned char EN1DIAG1, unsigned char CS1, unsigned char INA2, unsigned char INB2, unsigned char EN2DIAG2, unsigned char CS2)
    Alternate constructor for shield connections remapped by user. PWM1 and PWM2 cannot be remapped because the library assumes PWM is on timer1.
  • void init()
    Initialize pinModes and timer1.
  • void setM1Speed(int speed)
    Set speed and direction for motor 1. Speed should be between -400 and 400. 400 corresponds to motor current flowing from M1A to M1B. -400 corresponds to motor current flowing from M1B to M1A. 0 corresponds to full coast.
  • void setM2Speed(int speed)
    Set speed and direction for motor 2. Speed should be between -400 and 400. 400 corresponds to motor current flowing from M2A to M2B. -400 corresponds to motor current flowing from M2B to M2A. 0 corresponds to full coast.
  • void setSpeeds(int m1Speed, int m2Speed)
    Set speed and direction for motor 1 and 2.
  • void setM1Brake(int brake)
    Set brake for motor 1. Brake should be between 0 and 400. 0 corresponds to full coast, and 400 corresponds to full brake.
  • void setM2Brake(int brake)
    Set brake for motor 2. Brake should be between 0 and 400. 0 corresponds to full coast, and 400 corresponds to full brake.
  • void setBrakes(int m1Brake, int m2Brake)
    Set brake for motor 1 and 2.
  • unsigned int getM1CurrentMilliamps()
    Returns current reading from motor 1 in milliamps. See the notes in the "Current readings" section below.
  • unsigned int getM2CurrentMilliamps()
    Returns current reading from motor 2 in milliamps. See the notes in the "Current readings" section below.
  • unsigned char getM1Fault()
    Returns 1 if there is a fault on motor driver 1, 0 if no fault.
  • unsigned char getM2Fault()
    Returns 1 if there is a fault on motor driver 2, 0 if no fault.

Current readings

The current readings returned by getM1CurrentMilliamps and getM2CurrentMilliamps will be noisy and unreliable if you are using a PWM frequency below about 5 kHz. We expect these readings to work fine if you are using a board based on the ATmega168, ATmega328P, or ATmega32U4, since this library uses 20 kHz hardware PWM on those boards.

On other boards, this library uses analogWrite to generate PWM signals, which usually means that the PWM frequency will be too low to get reliable current measurements. If analogWrite uses a frequency of 490 Hz or more on your board, you can add a 1 µF (or larger) capacitor between each current sense line you are using and GND. To make getM1CurrentMilliamps work well, you would add the capacitor between M1CS and GND. To make getM2CurrentMilliamps work well, you would add the capacitor between M2CS and GND.

Version history

  • 2.0.0 (2016-08-16): Updated library to work with the Arduino Library Manager.
  • 1.2.4 (2016-08-10): Added continuous integration testing. Thanks photodude.
  • 1.2.3 (2014-03-24): Added 20 kHz PWM support for ATmega32U4. Thanks blacksound.
  • 1.2.2 (2014-03-18): Add keywords.txt file. Thanks eatonphil.
  • 1.2.1 (2013-01-06): Fixed a bug in setM2Speed that was introduced in 1.2.0.
  • 1.2.0 (2012-12-26): Changes the behavior of the library at speed 0 so that it makes the motor coast regardless of which direction the motor is spinning.
  • 1.1.0 (2011-12-15): Arduino 1.0 compatibility.
  • 1.0.1 (2011-11-07): Adds support for Arduinos not based on ATmega168/328.
  • 1.0.0 (2011-10-28): Original release.