Which controller for semi-custom laser engraver (Bart Dring controller questions)

I recently added a 5.5w diode laser to my small laser engraver. It works really well, but it has a fixed focal length. The engraver is only a X-Y engraver so it came with a small 2 axis controller that I flashed grbl to.

I’m thinking of adding a Z axis to it and putting a bl-touch on it for setting the Z axis height automatically.

Any idea what small 3 axis controllers are out there these days? I do think I have an old Ramps board lying around doing nothing that I may try to re-purpose for this. I control the machine through cnc.js, so I can use just about anything.

5kw laser?? Like in 5000W??

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Heh… No. Oops. 5.5w :confused:

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A 5kW diode… uh…

I’ll assume that’s 5W…

I use one of Bart Dring’s 2209 laser/pen controllers for my 5.5W diode laser, and I like the interface, so long as I don’t let LightBurn directly control it via USB.

Heh. Yeah… Fixed it.

The 4 axis controller looks pretty slick. Thanks for the recommendation.

if your into that kind of thing, building one using an arduno nano or an ESP32, and a bunch of stepper drives is not to complex (thats how i did mine, cause i am cheap) but if you don’t want to spend days soldering and trouble shooting, then something like the units that Dan mentioned look nice, although I have not used them.

As per your original comment, basically anything will work for this use case i suspect, as long as it has a PWM pin broken out to drive the laser intensity.

I was quite certain that it was a typo, but I had to do a little Google lookup still. There ARE 5kw lasers out there, but I don’t think they’ll fit on a mpcnc/reprap rig…

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There are 5kW lasers… But not diodes. O.o You might be able to put the head on an MPCNC rig, but you’d need a medium sized building worth of cooling…

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CNC Shild and a uno is cheap and used grbl


I ran into your lightroom forum post while searching for more information on the bart dring design.

That’s a pretty weird issue you ran into.

I think I’m going to go with one of his boards. I run my laser off of a CNC.js system, but I’ll try to drive it with lightroom and see if I have a similar issue.

I found this other thread and it caused me to have some questions about the Bart Dring controller.

I was going to post these questions there, but thought I’d leave them here. I’m wondering if I’ll get much answers as my new questions are now off topic from the thread title.

I just picked up one of his 4 axis controllers with the integrated TMC drivers for a semi-diy laser engraver. I’m wanting to add a bltouch to the engraver for setting the height of the laser using a z-axis.

Does anyone know if I have to have the servo add-on or if I can use the regular pins on the board to drive the servo-command part of the bltouch?

Alternative question, does anyone know if I even need to drive the servo portion of the bltouch? I’m assuming I don’t really need to retract the bltouch for a laser, so I’m wondering if I can just set it at a fixed height and leave it there.

I already have the added issue that I need to mount the bltouch low enough to clear the bottom of the air assist nozzle.

The servo basically just needs a PWM pin.

If you are using a BLTouch, you need to deploy the probe, or it can’t sense anything, but really for this application, I don’t see why a simple fixed switch wouldn’t be good enough. Just put a microswitch with a plunger that extends below your air assist, or even let the air assist nozzle move a couple mm and probe using that if it’s stiff enough. The only reason why the BLTouch probe needs to deploy/retract is for 3D printing. For a non-contact application like the laser, having a switch plunger should be perfectly acceptable.

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How are you able to get your hands on those controllers? He seems like he’s always out of stock…

In my memory, any esp32 pin can be a pwm out pin with hardware pwm. I do not know if it is trivial to configure in grbl_esp32 or not.

You can also define a pretty specific homing sequence that gets compiled in. We tried a simple version of that for the ZXY.

I agree that a microswitch would save you a headache. You definitely need to initialize the bltouch with servo commands to get it to work. There is a startup sequence and then each probe sucks the probe up, and you have to deploy it again.

Interesting information about the BLTouch. Honestly, my knowledge on those things was pretty limited when I ordered it. I’ll have to poke around and see if it’s worth trying to get working or not.

The idea of using the air assist nozzle itself is a pretty good one. I might try to run with that somehow.

I’m assuming I just got lucky here. I landed on the purchase page and it said it had 9 in stock. I clicked buy :slight_smile:


I decided to go with a normal roller limit switch to set Z height. Jumped on Amazon to order some and discovered I had bought some in the past. Went out to the shop and looks like I still have a few unused ones… Score!

Now to come up with some type of 3d printed something to hold the switch. I’m thinking I’ll incorporate it into the mount I use to mount the laser to the new Z axis.

I went easy for the Z axis and bought a ready-to-go pre-assembled one:

Reading the reviews, it seems to be a pretty common use for this part. Funny enough, I just noticed I think I bought the 50mm one when I meant to buy the 100mm one. I may not need the full 100mm travel, so I’ll have to hook up the 50mm and see if it will work before deciding to return it or not.

The lowest part of the gantry that this will be mounted to is only 70mm off of the spoilboard. And when I cut through parts (where Z axis is most helpful) I usually have it elevated on a .25" light diffuser panel that you use on florescent lighting.

Well. This is silly. I need to learn to read descriptions better. The stepper on this little linear axis is a 24V NEMA 11.

The Board I bought has the built-in TMC2209 drivers. I need to keep reading, but I believe they only support 12V steppers. :frowning:

Tmc2209s can handle up to 29V (the amazon page says 28V.

The board you are using may have a 12V or 15V limit, but that is probably the power supply for the esp32. I am 95% sure my bart dring board is on my low rider and has a 24V PSU. But I don’t think that has 2209s.