Laser ON after project finished auto homing

This started happening after latest update.
Using LB 1.2.01 update on a minigrbl K40:

When a project is finished and machine auto homes the laser turns back on after that auto homing.

The only way I have been able to stop laser is by clicking home in lightburn again.

Please let me know if any other info is needed.


This is almost certainly not going to be related to the update.

Try downgrading or enabling “Show All” in Console to see if there are any codes sent after return to home position.

Question then is what would cause something like this.

Try to isolate the issue to controller or other hardware. If you can check PWM voltage from controller that will tell you if the controller is commanding the laser on or if somehow it’s firing without being commanded. That would be a bad situation if true.

Have you potentially disabled any safety measures on the laser?

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I have included the last couple of lines from “show all”
The controller is a minigerbil v1.1revb

I have not downgraded as of yet. As a side note this pc and in turn Lightburn only get updated sporadically which this time means I hadn’t done an update in about 4 months (wasn’t sure if updates were cumulative with changes)

The minigerbil boards “fire LED”, labeled “Heartbeat LED2” turns on after the auto homing. It turns off after the manual pushing of the home button.
I have include a short video link here:

This K40 did not come with any “safety features” and as of yet I have not added any.

G1 X237.588Y191.864
G1 X237.728Y193.703
G1 X237.958Y195.516
G1 S0
G0 X0 Y0
[MSG:Pgm End
Stream completed in 47:23

I don’t see anything in the G-code that should command the laser to come on.

But try one thing.

Move the laser head to a safe location and then try entering these commands in one at a time in Console. None of these commands should activate the laser but perhaps something else is going on:

G1 S0
G0 X0 Y0

It appeared in the video that the heartbeat LED came on as soon as the cut was complete. Does the laser come on at any point? Make sure you are ready to turn it off. If so, at which command does it come on?

What is the intent of the heartbeat LED? I would have thought it would be on at all times during a burn but apparently that’s not what it’s for?

Here is another video it does appear to have something to do with firing of the laser.
I will reach out to Awesometech and see if they have a solution.
Will update as soon as I can.

The problem seems to have fixed itself.

Came into the shop today and started making some pumpkins for my kids class and no issue with the ghost firing.

Laptop was restarted but that was the only change that was made.
If the problem comes back I will update this thread.

Thanks for the help

That’s not comforting but glad you’re in a working state.

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