Can you confirm that you have a variable power laser? This would have 3 pins (V, G, PWM). Are you able to modulate power in the other software?
Try setting up a simple design like a square. Set your cut settings to 100% power and 500 mm/min (make note of the units). Run the job.
Report back results please.
This one is not a variable power laser (only 2 wires for a 12V source).
I’ve created a 20mm diameter circle, speed 500mm/min, power 100%. When I run it it does the circular motion but the laser stays at minumum power.
I’m not really familiar with non TTL/PWM laser modules.
Is the weak laser light on all the time? As soon as the laser is turned on or only when a job is run?
What is the behavior of the laser in GRBL Controller?
Do you know how the laser is wired to the Arduino? From the photo I’m guessing that one of the connectors on the left with the red and black wires is carrying 12V and Ground to the laser module. The board between the ports and the Nano looks like it has a MOSFET and I assume is providing the 12V to the laser port.
Do you know what pin is being used to trigger laser on?
A manual or schematic for your controller would be useful.
Is it possible to save g-code from an example file in GRBL Controller or Master Engraver? That could help narrow things down.
Also, can you confirm that you can still control the laser with that other software?
The more I look at that middle board I’m wondering if that’s actually the laser interface and is meant to handle TTL/PWM. I’m used to seeing this on the laser module itself but seems it’s external here. Then it just provides raw 12V to the laser module itself at PWM duty cycle.
Is the weak laser light on all the time? As soon as the laser is turned on or only when a job is run?
As soon as I plug the power supply it turns weakly on.
What is the behavior of the laser in GRBL Controller?
Not sure what you mean. Before I started fiddling with everything it was dim like now but was turning to full power when engraving, then back to dim once done.
Do you know how the laser is wired to the Arduino?
Laser is wired to the yellow board. Like you my guess is the little additional board acts like a relay and powers the laser.
Do you know what pin is being used to trigger laser on?
No clue.
A manual or schematic for your controller would be useful.
I think that’s a big part of my issues. This machine is quite old and from a chinese website so I can’t find any documentation or downloadables…
Also, can you confirm that you can still control the laser with that other software?
Not anymore unfortunately. Now I have the same issue in all the software. Basically everything works fine except laser doesn’t turn full power. I’ll look tonight if I have an old gcode, before my modifications…
I think what might be happening is that when PWM was introduced in version 0.9 Arduino pin 11 was repurposed for PWM when it was previously Z-axis limit. Z-axis limit went to pin 12.
Pin 12 had previously been used for Spindle Enable which I assume is what your laser interface board is wired to.
Are you able to see how the “laser interface board” (the one between the port and Arduino) is wired? I assume it’s 3 pins (G, V, Signal). If so, can you follow the Signal trace back to the Arduino? Is it going to pin 12?
I’m debating if you could safely just short pins 11 and 12 (D11 and D12 on board) on the Arduino to make this work. I assume you don’t have a Z-axis limit switch. I think this might work but I’m a little hesitant to suggest it. If you’re daring maybe give it a shot if you can jump those pins.
If not, then I suggest rolling back to an older firmware and seeing if you can use GRBL-M3 as a device type in LightBurn to connect (possibly with a lower baud rate). Or upgrading to a newer control board although I’ve not seen other shield like boards with built-in laser interface modules so might require a new laser module.
Thanks a lot for your time. I’ve been trying to follow the wires and find the pins but I was scared to mess some hardware…
So I’ve ultimately decided to downgrade to the 0.8c firmware and changed the baud rate to 9600 with few other settings and now everything works !
here is a 20x20mm square Gcode if that helps someone in the future:
"; Bounds: X0 Y0 to X20 Y20
G00 G17 G40 G21 G54
G91
; Cut @ 500 mm/min, 100% power
M8
M5
G0 X0Y0
; Layer C00
M3
G1 Y20S1000F500
G1 X20
G1 Y-20
G1 X-20
M5
M9
G1 S0
; return to starting pos
G0 X0Y0
M2
"
That’s good news.
Are you configured to GRBL device type? Or GRBL-M3?
If you ever want to try to go back to testing this you could do a continuity test with a meter on the connections if a visual inspection wasn’t working.
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