Ideas on table control

Hi all,

I have been using 3D printers for a long time now. So all in all i am used to the controls used in that area of making. I wondered if anyone had ever used an Octoprint instance on a raspberry pi to control a Lowrider? Right now i am hoping to use endstops and a capacitive sensor to auto bed level the Lowrider. I am not 100% certain thus will all work out. If it does not my last different idea would be to use an xbox 360 controller. This would let me wirelessly jog the Lowrider and set macros for the buttons on the controller. If anyone has tried this with success i would love to get some pointers and maybe save a bit of time.

I guess if nothing else let me know what you think of these ideas. Or if you have better suggestions i am always willing to listen.

Octoprint will work with it fine. Afaik, there isn’t a usb controller interface to octoprint, but if I’m wrong please tell me!

There is a ps3 control for cnc.js, which basically supports Marlin. It’s not easy to set up either.

I’m not sure about the auto level, but I’m interested to hear about it. The levelling I do for my printer wouldn’t work for CNC, because you really want to find level across the surface of your work, not the whole spoil board. There are some manual probe choices though.

Have you followed the basic CAM tutorials first? It’ll go better if you’ve already got the basics down.

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I have worked a little bit in a CAM enviroment (fusion 360). By no means am i an expert. If i can get octoprint to work i should be able to control the jog with any internet browser, an old phone or one of my tablets. If i cannot get octoprint to work i would be using a very cheap laptop or raspbian maybe with repetier and the xbox controller. I know if using a Pi3 you can pair an xbox one controller to the Pi without adapters of any sort. It might take some experimentation to get a Pi to jog this with a self contained program but on a laptop it would be a sinch.

As for the auto bed level. I have been going over this one a bit in my head. If i use endstops no matter what it will want to level check the entire surface. If i set a absolute position for leveling you could level to the material surface. That does lead to a few other problems though. The material surface in question would constantly change sizes dependant on the project. You might be able to set a mesh up that covers the max size you may use. Once zeroed even if the ABL ran off the edge of the material it might not matter. For it not to matter the code would have to be set up NOT to extrapolate a plane and just used the raw map from G29. Running a G29 might take a little time due to running over unused portions of material or bed, that would just be a waste of time. I might just need to build a little MPCNC or Lowerider to experiment with jogging and controls. If nothing else i am now interested in what can be accomplished.

Lots of stuff crammed in my brain. This is what happens when you mentally check out while watching barbie with your 3yr old daughter all night.

Octoprint is definitely doable. If you haven’t seen my v1pi, it is based on octopi and adds cnc.js. if you just want octoprint and you don’t need auto hotspot, then just use octopi.

I don’t want to damper your creativity, but levelling to the spoil board doesn’t make a whole lot of sense to me. If you’re doing through cuts, then who cares if it’s not level (it will be close enough, just cut deeper). If you’re doing anything else, then you really care only about the top surface of the work material. Probing the top of the work piece makes a ton of sense though. If it were me, I would make a script to output the gcode to probe just the area of a specific gcode file, and then find a way for Marlin to save that as it’s mesh. I think unified bed levelling lets you do something like that.

The controller will connect to the pi fine, but convincing octoprint to read the inputs from /dev/inputs/js0 is the trick. Octoprint supports a lot of plugins, maybe one of them already jogs from a controller? Otherwise, there’s some software to be written.

Either way, any web browser will also work.

If you haven’t checked out estlcam, I highly recommend it. It’s way easier than fusion 360. You could learn it and probably learn fusion faster after having known estlcam.

Are you sure about using an X-Box One controller with a Pi3 without adapters. I looked into it a while back and the consensus seemed to be you needed a specific blue tooth dongle, you couldn’t use the Pi3 bluetooth. Or maybe RF, I forget which protocol. But everyone was adamant you needed a dongle.

I have a retropi with alot of games on it right now. As long as you buy a new controller for the project it already has bluetooth built in. Xbox started that 2 years ago. The pi3 has bluetooth on board. All you have to do is pair it in raspbian. Been using the xbox one controller for over a year now with retropi and no adapter. The xbox 360 controller needs a wireless adapter to work through usb.


I am not used to being able to cut through the bed to finish a project. Still wpuld like to setup a little test rig for this but you are probably correct. It might not be worth the time invested.

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That’s why we install a spoil board on top of our tables, it’s a replaceable consumable. I don’t understand probing either the table or the workpiece. For the most part, a cnc router is used to make useable stuff. If the things have a wave cut into them because the bed isn’t flat, they’re not going to fit into whatever they’re supposed to fit into. It’s not like a 3d printer where the point touching the work is usually less than a millimeter in diameter. Even if you autoprobed a 4X8 sheet of whatever, and then used, say a quarter inch flat end mill to cut in some pockets, you’re still going to see some cut lines because of the geometry of the face of the mill. If you install a spoil board, then face it flat to the plane of movement, then it doesn’t matter. You might still need to face off the top of your work piece, because wood is almost never perfectly flat from the manufacturer, but at least you’re starting out with a known good surface to work from.

I see two good reasons:

  1. Your using a v-bit (especially a shorter one) to carve fine details. With a 90 degree bit, a difference in depth of 2mm can make a difference in width of 4mm. I use a sharper v-bit (from Ryan’s store) but still, if I wanted to carve something big, or at least long, it would help. You’d want to either have perfectly flat stock or probe the work surface. Surfacing the spoil board would give you similar results with very flat stock.

  2. Your work piece is very irregular and you can’t resurface it. Like the project I made where I cut into an already painted cabinet door. There wasn’t enough material for resurfacing. If I could have an accurate probe (of the surface) then I could have cut shallower. In the estlCAM video on surface probing, he carved a logo onto the back of a computer mouse.

Another thing that would just be interesting is just to probe the spoil board for a sense of the accuracy of the table. I didn’t use a probe for this, but it was interesting.

Also, w.r.t. the probe, the standard CNC solution is to connect an alligator clip to the bit and connect another to something like a spatula. When you probe, you put the spatula under the bit, on the work surface. The wires are connected to ground and Z Min and act like an endstop when they connect, then you subtract the thickness of the spatula from your measurements.

Okay, I kinda get that. Never thought of routing on something that curved.