Connect to Cohesion3D mini over ethernet

I did not think that the C3D board via ethernet was supported by LightBurn. I always thought that it was just a way to use the C3D board without a PC, by sending the file to the C3D board via ethernet, then running it from the Glcd. I am pretty sure LightBurn does not stream the Gcode via ethernet to the C3D. You could save the gcode then send it to the board, and run it from the Glcd adapter.

Well it definitely has a ethernet option for Cohesion3D smoothie firmware. I had assumed this meant any of the smoothie boards?

LightBurn will have to answer this I guess, I was not aware that it had an option for smoothie via ethernet. Learn something new every day :slight_smile:

It’s there, but the performance wasn’t great when I initially tried it, and it kept getting hung up, so I didn’t bother pursuing it further.

So…is there any work flow here that makes any sense at all?

Seems like the only way I can use lightburn remotely is to generate the gcode, go to the smoothieware web interface, upload the gcode file, then go to the laser, select the gcode from the lcd menu and finally run it? Is there not an option to upload the gcode to the sd from within lightburn?

Also you might want to update your docs to make it clear that you can’t actually use this path if you’re not going to pursue it as a viable option.

Uploading GCode through the serial interface is abysmally slow. Even the Smoothieware docs state this, if I remember right, and since that’s the only connection mechanism supported for the moment, you’d be much better off using the SD card itself or web UI to transfer.

When you say “use LightBurn remotely” how do you mean? I never said I wouldn’t pursue it, just that it wasn’t particularly high priority. Smoothieware is only a good choice for cutting - the GCode performance is too slow for image engraving, and the Ethernet connection does work - It’s used by the Emblaser 2 system actively, so I’m not sure why generic Smoothieware doesn’t work with it, and would have to spend time debugging to figure out why it’s failing. The number of users impacted is low compared to other feature development, which is why it’s not a priority.

You might be able to use OctoPrint or something similar with an RPi to connect to it remotely - I know others have done this with GRBL.

To be honest I’m thoroughly confused with the entire Cohesion3D / Smoothieware / Lightburn ecosystem right now. I feel like I was sold a new controller that in theory was capable of a lot of things, cutting, engraving, web interface, remote control via ethernet etc. But what I’m slowly seeing is that basically none of these things are true.

Let me just get this straight:

Smoothieware (default on Cohesion3D mini) does not work well for engraving, so we’re being advised to use GRBL-LPC to get good engraving support. Ok, fine…

Lightburn looks like it offers Ethernet connection, and Cohesion3D(Smoothie) is listed as a device type that supports Ethernet. But it does not actually work, and since Smoothie isn’t recommended anyway that’s not a good route. So Cohesion3D(GRBL) is the only option that realistically I can use with the mini, but there’s no ethernet interface for that since GRBL-LPC has no web interface.

So basically there’s no way to control my laser cutter from the PC at the other side of the garage.

Is there a controller that is supported and reliably works over ethernet with raster engraving? Or am I just going to have to go and get a new pc, monitor and keyboard to run my laser cutter?

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So I’m guessing the cheapest and best setup I can hope for right now is a Raspberry Pi running Octoprint, connected to GRBL-LPC directly.

Create GCode in Lightburn, then upload via the web interface of Octoprint directly to the SD Card onboard the mini and then run from there? Whats the performance like for Raspberry Pi streaming the GCode via the USB? Is that not recommended?

I haven’t tried running a Raspberry Pi as a streamer, but there’s no reason that wouldn’t work. There’s a script called fast_stream.py that the Smoothieware devs produced to stream as fast as possible to Smoothieware that works well, and should be easy enough to find and use. That’s built for maximum streaming speed and does as well for rasters as Smoothie allows. I’m not sure if Octoprint has the same performance - I haven’t used it.

LightBurn does not document the Ethernet connection for C3D anywhere, and C3D itself cautions that LightBurn does not support the Ethernet adapter on this page: https://cohesion3d.com/shop/peripherals/ethernet-expansion-board/

You can upload GCode directly through the WebUI and start it from the GLCD as you mentioned, but there isn’t a method for direct control from LightBurn via the Ethernet interface at present.

I’ll probably switch to grbl-lpc firmware for now and upload to SD via octoprint interface on an attached raspberry pi, but will be looking into other approaches long term as the number of steps you have to go through with this method is really quite annoying.

Not sure when the Ethernet adapter page was updated but when I read it last year it didn’t have any of these details. Glad it’s been updated for others though.

If you connect with USB, it works just fine.

Were you using a cat 5 cable to connect? If you were you could use something like this:

https://www.primecables.ca/en/p-314332-cab-6042-usb-extender-over-cat5e-or-cat6-connection-up-to-150ft-monoprice?from_pla=google&sku=314332&gclid=Cj0KCQiAwc7jBRD8ARIsAKSUBHJOBfH1ZLeIoTo5978-sqtQXjWSe6ZgtjNBq3To5DAPGrD_IzMrO8AaAiXuEALw_wcB#

to connect via USB over the long distance that you have.

Unpowered USB extenders are literally just long cables. You would be better off with a long USB. I’ve got 5M ones, which is the limit for USB 2.0

To go further requires an active connection which is externally powered and can get you 30M.

To go further than 30M you need USB over Ethernet - not what you linked to, but a protocol-converting piece of hardware.

I’ve got two diffeeent active usb extensions but sadly they don’t work with the cohesion3d mini board it appears. I’ve also tried 5m cables that seem to work sometimes but are flakey and are too short in my new garage setup anyway.

I’m either going to go the raspberry pi route, or get a full fledged pc on that workbench which can then drive the laser, and maybe do the camera integration too.

An ESP32 running as a transparent bridge works. $10.

It would depend on how it was connected. Smoothieware uses a USB connection that appears as a serial port. Connecting an ESP32 to the additional serial port should, in theory, work, but doesn’t. The Smoothieware devs have said that port is not thread safe, nor stable enough for streaming. If you’ve connected an ESP32 to it and successfully used it for streaming I’d be interested in how.

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It appears you have already tried anything I can think of, sorry I could not be of more help to you.

It’s ok. Excuse to buy a new PC!

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Octoprint has been done before - Jim tested it a while ago with C3D. There’s a plugin for it to talk to grbl, and I believe raster streaming performance was decent.

That said, it’s not a Bridge to LightBurn, it’s a separate interface, and you won’t get the benefit of the camera integration.

We have a number of people running C3D + LB off low cost netbook type windows computers (aka cheap/ old laptops) - this seems to be the preferred way.