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.

NOW AVAILABLE at our Ebay store…
… or in assembled from from

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GRBL – How to clear EEPROM settings

I have lately been flashing a bunch of Arduino micro-controllers with GRBL and I had a small issue where an older version of GRBL’s settings were stuck in the Arduino’s EEPROM.

To get around this I used a quick script from the Arduino website to clear it. I thought it would be useful for people who want to clear GRBL’s setting or make it reset to its defaults.


Raspberry Pi CNC Board / Hat


We are happy to announce the next generation of our CNC boards.


By combining a real-time CNC system (good old GRBL) and offloading less timely processes to a more powerful processor + operating system we have created a much more flexible but capable solution.

To show some of the possibilities we have created a Web / Browser app to allow users to remotely control their CNC machines. (Welcome to the Internet-Of-Things)


The app code also includes a working example on how to expand your ecosystem by taking advantage of what we call the “Command Router” and “Single Command Mode” system. It allows us to add custom commands that can execute a shell command, one command at a time without getting buffered / queued in GRBL.

Custom command examples:

  • Simple – Send Email Notifications / Flash a warning light / Play a warning sound / Switch on a relay.
  • Moderate – Wait for external inputs like temperature, safety switches to clear before moving to the next command.
  • Complex – CNC Clustering, combining CNC machines to form a pipeline of operations like in a moving assembly line.

Extra Links:

Raspberry Pi CNC Board – Gallery:


Arduino CNC – GRBL Shields / Boards

The following are a few of the shield / boards that are compatible with GRBL. GRBL is G-Code interpreter that is able to run on small Atmel Micro-controllers like the controllers used on Arduino Boards.

Using GRBL (software) and these micro-controllers(Hardware) makes it very easy and affordable to build your own Computer Numerated Controlled Machines(CNC) .

Arduino CNC Shield – 100% GRBL compatible (USD25+ Exluding Arduino, Pololu Drivers , Shipping Included)

Arduino CNC Shield V3

  • Up to 4 Axis’s. (4th Axis can clone the X, Y, Z axis’s or run of the D12-D13 pins)
  • Compatable with Pololu A4988 type drivers including the latest DRV8825 drivers.
  • 12-36V Input Voltage. (Only the DRV8825 can run at 36V)
  • Jumper to adjust micro stepping. Up to 1/16 micro stepper with A4988 and 1/32 with the DRV8825 drivers )
  • Breakout pins for :
    • End stops , 2 per axis.
    • Spindle and Coolant control.
    • Abort / Hold / Resume
    • E-Stop

Arduino CNC Shield V3 - Top View

The Arduino CNC Shield is now available from our Ebay Store –




GRBL Shield – (USD70+ excluding Arduino,Shipping)


  • 2.5 Amps per winding
  • 12-30V Input Voltage
  • 8x Microstepping
  • 3x Axis (x,y,z)
  • TI DRV8818 Stepper Drivers Stepper Shield – (USD90+ excluding Arduino,Shipping

) Stepper Shield

TinyG CNC controller – (USD130+ Excluding Shipping)


  • On-board Micro-controller – Atmel ATxmega192
  • 4-Axis
  • TI DRV8818 Stepper Drivers
  • 8x Microstepping

Arduino to Raspberry Pi Bridge Shield – PCB’s finally Arrived.

In the first part of this project I described the technical details of the shield

After a few weeks of waiting, I have finally receive the first batch of PCB’s I designed and they look fantastic.

Here are a few photo’s:

So what are the advantages/benefits/pro’s of this little shield?

  • Firstly this shield will protect your Raspberry from getting damaged by the high voltages the Arduino’s are running. It also adds a layer of protection where the Arduino might get damaged by external input.
  • I picked UART / serial communication because it’s simple to set up. No extra drivers or libraries.
  • It uses the standard Arduino footprint allowing you to re-use your old Arduino’s.(Arduino Mega’s are also supported)
  • It’s easy to assemble with only 12 parts. All parts have through hole footprints making it easy to solder.
  • Using the Arduino’s on-board 3.3 voltage regulator, it reduces the number of bridging wires. (3 in total).
  • Right Angled headers ensures that the connection wires exits at the back of the shield.

Preparing the environment

Lets start with the Arduino. Upload the following serial echo sketch to your Arduino.

By default the Raspberry Pi is set up to write debug/status messages to the on-board serial port.

To disable this we need to make some changes. Run the following command to start…

Change: T0:23:respawn:/sbin/getty -L ttyAMA0 115200 vt100
To: #T0:23:respawn:/sbin/getty -L ttyAMA0 115200 vt100

Change: dwc_otg.lpm_enable=0 console=ttyAMA0,115200 kgdboc=ttyAMA0,115200 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait

Removing all references to ttyAMA0 (which is the name of the serial port).

To: dwc_otg.lpm_enable=0 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait

Restart the Raspberry Pi to apply the changes.


To test if it’s working you can start-up Putty or if you want test it in the shell by installing minicom.


If all went well it should echo back all the characters you entered.

Next step for me is to write a little application that talks to my CNC software (GRBL) via this shield.

Below is the Schematics and board layout.


Just a small update on how I wired the cables up…

  • rPi Bridge Shield Gnd Pin -> Raspberry Pi Gnd
  • rPi Bridge Shield TX Pin -> Raspberry Pi Pin 14 (Red Cable)
  • rPi Bridge Shield RX Pin -> Raspberry Pi Pin 15 (White Cable)

For more help on locating the correct Raspberry Pi Pin have a look at the Raspberry Pi Pin-layout page.



To round it off, I have some spare PCB’s if anyone is interested in trying it out.