I did find an obscure setting in lightburn that could result in this… use the select tool (arrow) to click on the part that is not being cut. Now under the tab “Shape Properties”, verify that “Power Scaling” is set to 100. It looks like this is another way to modify cuts per shape, but I’ve never used it. I checked and if I set it to 0 for a given item, everything else looks fine in lightburn, but the gcode will omit those shapes (or omit the whole layer if all shapes are 0). If you imported svg or similar, I suppose something like that could happen on accident.
I delete the previous configuration of device.
I choose the controller MARLIN (not GRBL!) and the option of PWM control appear !
1 Like
Cool ! does it solved your original issue ?
Not yet… I think I just broke my laser 
(but I don’t know how)
I was looking for a solution because of the last problem I met : the laser didn’t turn off after finishing the cut.
So i try to connect the PWM laser to Fan port (I put a low power in Lightburn because of the risk of 12v compatibility pwm) → after that, no more light…
On the neje board you have a test button. Plug your power supply directly on the board an press the test button to check. It should ligth at 100%
There’s probably a minimum power level below which your laser cannot fire. Might try bumping up the “low power” setting a bit at a time to see if at some point it comes on.
I’d do the test @olijouve suggests first, then try and tune the Lightburn setting.
Follow that post for good wiring/setup:
1 Like
Exactly. When I recept the laser for the first time, I test it with the button (see previous Picture of the top of the laser), and it was lightning.
Now, the same (and only) button doesn’t put on the laser anymore…
I Check the power direct at the diode wires : 0V.
Maybe the diode is ok and the problem should come from the PWM signal ?
When I puss the button, a DEL twist from yellow light to a blue light (two different DEL) → so the button should be ok.
Maybe need to adjust an electronic component level ?? (Two rings with a cross ?)
I am tired, and I will wait first for the manual (I hope to recieve it).
Thanks everybody
I hate to bump an older thread, but I was able to get this exact hardware working (plus Octoprint) pretty well with a Laser Tree 20 W laser (3 wire)
1st, I split the 3 wire to the 2x2 wire setup as in the picture at https://us2.dh-cdn.net/uploads/db5587/original/3X/a/d/adca81742a33684d8eba3f29c8e585f933881dd8.jpeg
Hooked the red and black up to its own 12v Power source, and the white (Ground) and yellow (PC9) to the PC9 and Ground on the SKR Board.
After that I was able to fire the laser without issue using the stock firmware for the SKR using M3 S10
In Lightburn, I manually set up Marlin but I couldn’t initially see the Laser Control Commands so I could set it as inline. I had to EXPAND the settings window in order for that to appear.
After that my biggest issue was with Lightburn generating the inline codes and the laser not turning on, after a bit of trial and error, I found that I needed to send the “M3 I” command to tell Marlin to enter Inline mode
So I added
to the Lightburn gcode settings, and the laser turns off and on as it should
With this setup I am able to generate Gcode using Lightburn, and upload to Octoprint (which I am using to control the CNC) and it works flawlessly now
Hoping this helps someone else save some frustration
1 Like
Thanks, all, for the excellent and helpful replies, and especially to @robertbu, whose consistent help to folks on multiple instances this kind of topic have been awesome.
Also kudos to @ringnutz for his help not only in figuring that bit out, but updating folks reading/following along.
3 Likes
Thanks for the great info Adam! Do you think that this 3 wire laser would be the same procedure?
I was thinking about scavenging the laser of the Sculpfun S9 but I saw this and thought I might give it a try.
Do all of you typically run an separate power supply for the laser power? Is that to try to protect the board?
We usually use a separate power supply for the Laser (as long as you make sure to connect the DC ground from both power supplies).
The main reason for the separate power source is that the laser may need more current than the controller board can safely supply. So, yes, that is to protect the controller board from letting out the smoke.
Mike
LOL, letting out the smoke! Better to keep the smoke in, right?
Thanks for the advice!
So any 3 wire laser with VCC (12-24), GND and PWM should work using the methods above?
I can’t speak for any 3 wire lol, but I expect most work the same way
I wouldn’t set high expectations for this laser. In the Amazon ads, it is listed as a 10W optical. A reviewer indicates that its performance is similar to his 5W optical laser module.
As for hookup, the cables on the right in the list of cables are probably what you want. Two wires go to the power supply, and the second set go to PWM and ground on the control board. As mentioned above, if you have a separate power supply, you need a ground wire to go to both the power supply and the control board. If all you get is a 3-wire connection, you will need to “split” the ground wire so you can connect both the power supply and the control board to ground.
The one thing that may be an issue is the PWM voltage. One of the listings has, " Power Control: PWM/TTL (0-5V signal control)." I don’t know if this laser uses the PWM signal digitally or does analog processing. The potential issue is that I believe the laser pin on the SKR Pro 1.2 is a 3.3V pin. If the laser uses the PWM pin digitally, then everything should work fine. If it is an analog processing, then you will not get full power out of the laser. Most newer lasers are digital.
1 Like
Thanks Robert!!
Maybe I could pick your brain a little more…
So to steal an image from earlier in the forum, is this the correct procedure?:
If I do it this way I won’t need a relay?
And the last thing that’s confusing me is, if I’m taking the power to a separate power supply, why would I need a JST connection on it? Wouldn’t it be better to crimp on some horseshoes and land it directly on the power supply lugs?
Thanks so much for your insight!!!
I’ve never seen someone use a relay with a laser. There was some talk on one of the forum topics about using an SSR with a laser, but I don’t think it was ever used.
Yes, that is the correct procedure. As for the connection, what you describe is better, but this laser module does not require much in the way of a power supply. The specs on this laser say it needs a 4A power supply, and most of those power supplies are either wall warts or bricks, and both of those kinds have a barrel jack for power, not screw terminals (I’m assuming you are using a separate power supply for the laser).
A lot of laser modules (but apparently not this one) come with a companion board like this. The JST connectors plug into the board, and the board provides a female barrel jack connection for the power supply.
1 Like
Hi Robert, one other quick question just occurred to me, if I power the control board with a 24 volt power supply and I power the laser with a separate 12 volt power supply, is that shared ground connection between the 2 units going to cause a problem you think?
A shared ground and two different voltage sources will work just fine. Typically, I’ve seen it the other way around with the laser running at 24V and the control board running at 12V. It is only relatively recently that Ryan started shipping 24V power supplies with his kits. But the voltage difference does not matter either way.
3 Likes
Thanks again!
I created a remix of a router holder to mount the laser to the Z axis. I’ll post pics of it when it’s together and make it available to anyone that wants it.
2 Likes