1. Overview

Pololu jrk 21v3 USB motor controller with dimensions.

Bottom of the jrk 12v12 USB motor controller with feedback with dimensions.

The jrk family of versatile, general-purpose motor controllers supports a variety of interfaces, including USB. Analog voltage and tachometer (frequency) feedback options allow quick implementation of closed-loop servo systems, and a free configuration utility (for Windows 7, Vista or Windows XP) allows easy calibration and configuration through the USB port.

There are two different jrk motor controllers:

The jrk 21v3 has a broad operating range from 5 V to 28 V. The continuous output current of 3 A (5 A peak) allow this board to control most small DC brushed motors.

The jrk 12v12 has an operating range from 6 V to 16 V. The high continuous output current of 12 A (30 A peak) allow this board to control many medium-sized DC brushed motors

Main Features of the Jrk 21v3

• 5 V to 28 V operating supply range.
• 3 A maximum continuous current output (5 A peak).
• Automatic motor driver shutdown on under-voltage, over-current, and over-temperature conditions.

Main Features of the Jrk 12v12

• 6 V to 16 V operating supply range.
• 12 A maximum continuous current output (30 A peak).

Main Features of all Jrk Motor Controllers

• Simple bidirectional control of one DC brush motor.
• Four communication or control options:
  • USB interface for direct connection to a PC.
  • Full-duplex, TTL-level asynchronous serial interface for direct connection to microcontrollers or other embedded controllers.
  • Hobby radio control (RC) pulse width (PWM) interface for direct connection to an RC receiver or RC servo controller.
  • 0–5 V analog voltage interface for direct connection to potentiometers and analog joysticks.
• Two closed-loop feedback options:
  • 0–5 V analog voltage.
  • Frequency/tachometer digital input up to 2 MHz with 1 ms PID period.
  • (Open-loop control with no feedback also available.)
• Simple configuration and calibration over USB with free configuration program (Windows 7, Vista, Windows XP compatible).
• Configurable parameters include:
  • PID period and PID constants (feedback tuning parameters).
  • Maximum current.
  • Maximum duty cycle.
  • Maximum acceleration.
  • Error response.
  • Input calibration (learning) for analog and RC control.
• Optional CRC error detection eliminates communication errors caused by noise or software faults.
• Reversed power protection.
• Field-upgradeable firmware.
• Optional feedback potentiometer disconnect detection.

Specifications

Included Hardware

The jrk 21v3 ships with a 14×1 straight 0.100" male header strip and two 3.5mm, 2-pin terminal blocks. The jrk 12v12 ships with a 14×1 straight 0.100" male header strip and two 5mm, 2-pin terminal blocks. To provide maximum flexibility, none of these parts are soldered to the board.

For the most compact installation, you can solder wires directly to the jrk pads themselves and skip using the included hardware. The included hardware allows you to make less permanent connections. You can break the 14×1 header strip into an 8×1 piece and two 3×1 pieces and solder these strips into the jrk’s I/O pads.

The three mounting holes are intended for use with #2 screws (not included).

Note: A USB A to mini-B cable (not included) is required to connect this device to a computer.