Arduino CNC Shield – 100% GRBL Compatable

Do it yourself CNC projects are popping up everywhere and we decided that we wanted to contribute to the growth.

Here are a few of our design goals:

  • Modular Design – We wanted to do more than just keep cost down. We wanted things to be reusable and up-gradable. (Arduino , Individual Stepper Motor Drivers and more…)
  • Compact Design – Squeezing a 4 axis design into a board the same size and Arduino Uno.
  • Opensource Software – 100% GRBL compatible (G-Code Interpreter)
  • Evolving Development – We are keen to improve on the design and welcome all feedback.

Arduino CNC Shield – 100% GRBL Compatable

Extra pins:

  • Limit switch pins have been doubled up so that each axis has a “Top/+” and “Bottom/-“. This makes it easier to install two limit switches for each axis. (For use with a normally open switch)
  • EStop – These pins can be connected  to an emergency stop switch. This does the same as the RESET button on the Arduino board. (We do advice that an extra emergency button also be installed that cuts power to all machinery. A REAL EMERGENCY BUTTON)
  • Spindle  and coolant control has their own pins.
  • External GRBL Command Pins have been broken out allowing you to add buttons for Pause/Hold , Resume  and Abort.
  • Serial Pins (D0-1) and I2C Pins (A4-5) have their own break out pins for future extensions. I2C can later be implemented by software to control things like spindle speed or heat control.
  • Version 3.00 of the board added a jumpers to configure the 4th axis(Clone the other axis’s or run from Pin D12-13), Comms Header(RX+TX , I2C) and a Stepper Control Header(All Pins needed to run 4 steppers)

GRBL Software/Firmware

GRBL is opensource software that runs on an Arduino Uno that takes G-Code commands via Serial and turns the commands into motor signals.

The GRBL source Code is located here.

I have also written a few turorials on uploading the firmware onto an Arduino Board:

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