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RatRig V-Core 3 EVA wiring over RJ45

A toolboard that mounts on a 3D printer hotend assembly to enable wiring over RJ45.

PCB top view

Buy a kit OSHW_mark_JP000011 Hackaday Logo
Buy on Tindie OSHW Certification Project


See the detailed documentation in the docs/ directory:

  • EXPLAIN: learn the story behind this PCB, safety information, and OSHW
  • HOWTO: more detailed information on testing and wiring patterns
  • REFERENCE: learn about the pinouts, trace widths, and other technical information
  • TUTORIALS: a quick guide to get started using this module

Updated PCB v.2 now supports hotend heater cartridge, thermistor, and PWM fan.

These instructions are for the PCB v.2. Please click here to read instructions for PCB v.1.

Note: PCB v.1 is not compatible with PCB v.2 due to the rerouted traces/wiring.


  • Form factor 80mm x 41mm
  • Lead-free, RoHS compliant
  • PCB traces are 0.5mm and can support at most 1A of current
  • High-current PCB traces are 3.0mm and can support at most 3.9A of current (2A tested)
  • Grounded M3 mounting holes connected to GND pins
  • Easy to source off-the-shelf through-hole components
  • Simple passive design draws 0mA current when no devices are connected

Getting started

Click here to read the tutorials quick guide to get started.

DISCLAIMER: We are not responsible for accidents or problems caused by your use or misuse of these modules.


Usage of the logos and marks below are in no way an endorsement by their copyright and trademark owners.

  • The Tindie and Hackaday logos are Copyright © 2013, Supply Frame, Inc. All rights reserved.
  • The OSHWA certification mark is Trademark ™ 2018, the Open Source Hardware Association.


μ3D: RatRig V-Core 3 EVA wiring over RJ45 and documentation © 2021 by Alexander Williams is licensed under CC BY-SA 4.0 (Attribution-ShareAlike 4.0 International).