K40 Controller Options


I ordered a K40 setup, and I want to swap the controller out to use LightBurn with it. I was leaning towards the Mini Gerbil 3, but those are back ordered, and the Cohesion3D looks like it has some nice extra features.

Does anybody use the C3D with the LCD on a K40? Any photos/examples of what that looks like? Is the LCD useful?

Is smoothieware really superior to grbl as they claim?

With either of these drop-ins, does the control panel on the front of the K40 still work?


eBay also has some ads now for variations of “OMTech K40+ Mainboard for LightBurn Rotary Axis Control” - is this a scam, or did OMT really make a K40+ board? If so, is it on any of the newer K40 machines?

Just looked this up again and remembered seeing this pop-up last year. I don’t think it’s a scam and is sold by OMTech Direct on Amazon.

I don’t think I’ve seen this sold pre-installed on any of their K40s although it would be a differentiator for them if they did. I suspect cost is what deters them from doing so.

I kind of doubt they would design a brand new board for this. I was trying to see if it looked like a clone of another common design but while it looked familiar I didn’t recognize it.

I tried to find reviews of any kind on it but found nothing which I was surprised about, not even on Amazon. Looks like it runs Smoothieware for what it’s worth.

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Very interesting. I would love to hear if somebody has actually used this board. I’m curious if there’s any benefit to the K40+ vs. C3D, besides being $50 cheaper.

Another question, does either support, and has anybody setup ethernet with it?

Neither of the controllers have an ethernet port. And either way, as of now at least LB doesn’t support ethernet connections with any g-code controllers as far as I know.

The C3D has an ethernet expansion header on it. Though I don’t know if anybody has done anything with it. I snow Smoothieware supports it.

Oh cool. Wasn’t aware of that. Looks like it provides a Smoothware Web UI for 3d printing but not supported on GRBL-LPC.

Would there be any way to get it to work with the more expensive license of lightburn? Or maybe it’s a future ready feature. :wink:

Not as of now. If you were very keen on getting Ethernet to work you could put in a Ruida controller but not sure if have the stomach for that after all this.

One of the challenge for any IP based control interface or for any of the Bluetooth or WiFi based laser controls is that as far as I know they’re all proprietary and work differently. Don’t think there’s any standard in place today for this. So this would mean that every single one of these would need to be reverse engineered and implemented uniquely.

Smoothie is different at least since it’s open. But even here the interface is a web based UI. Not clear if there’s a Web API that you can use to dynamically control the device remotely with g-code.

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Yeah, I wouldn’t go the ruida route just because of the cost. I’d already be at least half way to a bigger machine that comes with ruida at that point.

I can be patient for now, I suppose. Somebody will eventually want smoothie cutting stuff over the network.


I wound up getting the OMTech K40+ controller. It was super simple to setup, runs smoothie including clustering, and I haven’t had any issues. It has support for motorized Z, so I’m going to get something for that too. It turns out my stock bed was 17mm too low, so it’s useless on its own anyway.

The only oddity is that the Origin and Home are both Rear Left, so other peoples files often need to get flipped horizontally in LightBurn.


Any initial observations in comparison to Smoothieboard?

Well, it’s running Smoothieware, and I’ve never run anything besides this and the m2 nano. The m2 nano was trash IMO. This K40+ runs great, no issues so far.

I had a goofy job I ran where running 17 different / separately grouped items didn’t engrave one of the items, but I dunno if that was the random material I was using, or a communication error. I know a lot of people prefer to send to device using the Ruida stuff, but this isn’t that, so I don’t think it works the same way?

I like it. I’m looking forward to seeing how well it works with a motorized Z table.


Nice. I thought I had remembered you mentioning using Smoothieboard in another Topic but must have misunderstood.

So I guess I should put OMTech K40+ in the list of viable options.

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Definitely! It’s good stuff. Hopefully my opinion of it doesn’t change. :wink: