K8055 USB board

I picked up one of these in the trove at Makespace, thinking it was a cheap board, and it turns out to be a nifty bit of kit I can use for testing. If it were both expensive and useless to me, I’d return it, but I have plans for it in testing Itchy. I’d like to be able to see a slowed-down schem of the Gcode, f’rex. Outputting directly from my computer to an external board is a goal, and this is a step along the way.

Making it work on Arch was not a problem. Making it work as described on Arch was pretty horrible. In fact, I failed at just about every point.

The only available package is moribund, which at least means I don’t have to keep it updated. Make Install was not my friend but I stripped out the default install path and put in the correct one, then kicked a few things around. I wish I could remember what.

Then I entirely failed to make udev play happily. USB Device. Udev. I have a USB device. Is it devicing? Is it hell. I don’t know if it is because I run k8055 and that tries to take the device – Arch does not have the usual installation paths for everything, so there could be something seriously funky going on. I think it’s just malconfigured, though. I am just as likely to have fucked up small as big.

It had the same error message when I had the wrong group name as when I detypoed, so something is finding the rules and failing to pass them. Currently I can work with sudo or sticky bit. Neither is ideal.

Itchy – now we’re committed

I bought a single piece of V slot in the right shape for the gantry I want. It’ll work for lightweight stuff. I also bought the things I think I need for the gantry build, except for what I can make. I’d like to try making oldham connectors at some point, for interest’s sake. The flexible shaft to shaft connection was much cheaper than any I could find on eBay, though.

I used ooznest, which was the cheapest V rail supplier in the UK – just about the only one I could find, in fact – and padded out a lot of the build with items from eBay. I’m going to machine my own head including mountings, but I know why it needs to be what shape it needs to be, so I can live with that.

I modelled it up in Onshape, as the very basic blocks of what I wanted to make, using cuboids instead of profile sketches, so I knew what had to go where. That-one-engineer-with-the-beard showed me how he had handled the box that held his couplings, and I’ll probably go with square section stuff to hold other stuff together.

Technical terms, there.

Project: Itchy

I have just been given a lot of aluminium profile. I want to make a cnc router to allow me to engrave acrylic sheets and cut lino. The lino cutting will be the easiest problem, as it just needs a 2d movement and some human setting of the x axis. Plus a lot of glue.

So, the first thing I need to know is how the heck to build it. I don’t want to move a plate under a fixed head, if I can help it, as that makes the entire base way too big, and I don’t want to take up too much space. If I wanted to engrave an area a x b I’d need twice the run, 2a x 2b, to go from left to right. Given I might create big stuff, it’s too large for storage, and too clumsy, and I don’t want to move the platen. I think it’s called a platten. I don’t know how to spell that, so I’ve tried both ways.

So, I’m going to have to move the head, which means linear bearings and stepper motors. And stepper drivers. There should be plenty of explanations out on the internet, and I just need to find an explanation that isn’t geared to solutions I’m not using.

On the internet.

Fuck.