Jrk G2 library for Arduino
Jrk G2 library for Arduino

Version: 1.1.0
Release date: 2018-07-24



This is a library for the Arduino IDE that helps interface with a Jrk G2 USB Motor Controller with Feedback using serial or I²C.

Supported platforms

This library is designed to work with the Arduino IDE versions 1.8.x or later; we have not tested it with earlier versions. This library should support any Arduino-compatible board, including the Pololu A-Star controllers.

Getting started


The Jrk G2 USB Motor Controllers with Feedback can be purchased from Pololu's website. Before continuing, careful reading of the Jrk G2 User's Guide is recommended.

I2C connections

To control the Jrk G2 using I2C, you should connect your board's SCL pin to the Jrk's SCL pin, connect your board's SDA pin to the Jrk's SDA pin, and connect one of your board's GND pins to one of the Jrk's GND pins.

Serial connections

To control the Jrk G2 using asynchronous TTL serial, you need to at least connect your board's TX pin (as defined in the table below) to the Jrk's RX pin, and connect your board's GND pin to one of the Jrk's GND pins. If you want to read information from the Jrk, you must also connect your board's RX pin (as defined in the table below) to the Jrk's TX pin.

The example sketches for this library use a hardware serial port on your Arduino if one is available: if you Arduino environment defines SERIAL_PORT_HARDWARE_OPEN, the examples will use that port. The pins for this serial port are different depending on which Arduino you are using.

Microcontroller Board Hardware serial? MCU RX pin MCU TX pin
A-Star 32U4 Yes 0 1
A-Star 328PB Yes 12 11
Arduino Leonardo Yes 0 1
Arduino Micro Yes 0 1
Arduino Mega 2560 Yes 19 18
Arduino Due Yes 19** 18
Arduino Uno No 10 11
Arduino Yun No 10 11

** The Due's serial port is 3.3 V, so it should not be directly connected to the Jrk's 5 V TX line. A voltage divider or level shifter can be used.

Jrk configuration

Before using the example sketches, you should use the Jrk G2 Configuration Utility software to apply these settings:


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 "JrkG2".
  3. Click the JrkG2 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 "jrk-g2-arduino-xxxx" to "JrkG2".
  3. Drag the "JrkG2" 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.


Several example sketches are available that show how to use the library. You can access them from the Arduino IDE by opening the "File" menu, selecting "Examples", and then selecting "JrkG2". If you cannot find these examples, the library was probably installed incorrectly and you should retry the installation instructions above.


The main classes provided by the library are listed below:


For complete documentation of this library, see the jrk-g2-arduino documentation. If you are already on that page, then click the links in the "Classes" section above.

Version history