Hello, will there be a Category for the Gerbil Controller here? Or is Gerbil treated in the Category GRBL?

Gerbil runs GRBL, so unless there are significant differences between them, there’s not much reason to have a distinct category, but I’m open to discussion on it.

Yes, good was just a question. Thank you for your prompt reply

I am using the mini-gerbil (the new ARM based gerbil from, and I am having problems setting up Lightburn. As received it works with the g-code sender CNCjs without any major issues. So I know that the hardware works with my K40 laser.

Looking at the machine settings, I believe that it is using the K40 homing position as the origin. Also, from the max value of each axis in the machine settings, it appears that what LightBurn is calling the X axis, the mini-gerbil is calling the Y axis. With the mini-gerbil, X is downward from the home/origin position.

When I try to run a job or jog in the Y direction, I get one step, then the stepper hits the exhaust housing, making the stepper lose steps (with great noise). I think this is because LightBurn thinks Y is towards the K40’s home position. I think I get one step is because of the homing offset.

Before I go changing all the settings on the mini-gerbil, I would like to see an example of grbl settings that would work on the K40. Would anyone be willing to post their working settings for the K40 from grbl?

I would like to also know if it is possible to pick a coordinate system in LightBurn? It doesn’t seem so, but a work around may be possible using offsets as described for the Shapeoko in the documentation.

Any help would be appreciated.

hello, I still have the old gerbil. Here are my data. If something goes wrong in the home run you can turn the plug to the board.

When you say “pick a coordinate system” I’m not sure what you mean. You can set the origin to any of the four corners, and it is assumed that positive values move you into the work area. X is always left/right, and Y is always up/down.

You might also be thinking in more traditional CNC lines, but if you’ve set your workspace size correctly, you can place art anywhere in the workspace and cut it exactly as it appears, or use the “Current Position” or “User Origin” settings to move the starting location - see here:

Thank you for posting your settings. They have given me some insight into my issue.

When you open the Device Wizard, where do you have the origin set: Rear Left or Front Left?

Did you have to modify the grbl $ settings of your Gerbil board to make your K40 work properly in LightBurn?

After looking at K40JF’s settings, I did the following things:

  1. Changed $2 to 1 from 0. This is the step pulse invert mask (flipped the X axis).
  2. Changed the default jog speed to 30 mm/sec from 100 mm/sec.
  3. Adjusted the max speed of the X ($110) and Y($111) axis to 3000 from 5000 and 8000.
  4. Set the origin of my device to Rear Left from Front Left.
  5. Changed the Start From setting from Absolute Coordinate to Current Position.

With these changes I was able to run a job in LightBurn successfully with my mini-Gerbil.

I am sure people who know more about the mini-Gerbil and LightBurn may have a better solution, and I may also have a belt tension issue. However, this seems to have worked.

Does anyone know if the jog speed default can be permanently changed? I didn’t see it in the settings and it reverts back to its default when a device is changed.

Thanks K40JF and Oz.

I thought the jog speed was captured and saved. I’ll make a note to store / restore that.

hello, yes I had problems with gerbil, but that was due to the miserable mini usb socket which was not soldered properly and is finally broken off the board, here would have the konstukteur a more stable connection to the pc built according to industry standard. With a lot of effort and a good magnifying glass I gerbil gergetet again and soldered directly on the board a new connection. At the back left is my home stop as in the k40 the limit switches are installed. At the moment I play with the gbrl setting something while engraving wood.