Well... sort of. I will have more pictures soon, and those will certainly give some clues as to how I did things.
Keep in mind that in addition to 3D printers, I've got a UV printer with a rotary attachment for the clear cylinders. In principle, you can make something that works like it without those things, and I'll give you my thoughts on that below. In the dust port business I get a lot of, "can you just sell me the STL so I can make my own." Then the design gets picked up overseas and soon you have a competitor. Now, in a couple of cases, I have released old designs for either no or modest cost. Probably
not going to do that for this particular thing (at least right away). There's no real protection possible for the concept, which in its base form has been around for probably a thousand years. What you can obscure, to a degree, is how you solved certain design and manufacturing problems.
What I
will do is give you enough insight into those problems such that rolling your own version should be doable with modest materials and equipment. The basic concept isn't really ground breaking.
HERE is something that works on the same principle and might be useful as-is if you have a 3D printer.
The clear cover isn't absolutely necessary. You could draw reference lines on whatever is holding the central pivoting barrel. Not quite as slick looking but functional (calibration is a little different). You could also print on clear sticker material and apply it to a clear cover. Not as permanent as the UV printer, but it should work.
The cover also provides some protection from rain, though it's certainly not completely waterproof.
The pivoting center is also 3D printed in two halves, though I'm still experimenting with different approaches to that. You have to put in a reasonable amount of weight, or mess with your slicer settings to print it so the bottom half is heavier. You could use automotive wheel weights but if you also use a magnet to hold it onto your machine, well, you've introduced a potential problem because they're made of steel. Likewise for small pieces of rebar and lots of other convenient, heavy materials. If you have lead shot, then that and a little epoxy or two-part urethane would solve the problem. If you clamp it or something instead of using a magnet like I do then the weight material is not an issue.
I use a single 40x13.5x5mm potted magnet because I use them on my dust ports, but if you already have some other kind of rare earth magnets, just keep adding them until it sticks to your liking.
I thought about using white PVC pipe for the pivoting center instead of printing it. You could make wooden inserts for it with recesses or holes sized for bearings so it pivots easily. Check out skateboard bearings (608s are what I had laying around) and you can find some reasonably priced options. Once you get it weighted, suspend it, carefully mark, mask off, and paint your level line. If you're careful about how you weight it, this shouldn't be a big problem.
It'd also be fun to do a little machining on aluminum (or other) round stock or tube to make the center. Just machine out a lot of material on the top half if you use round stock.
With no 3D printer, I'd cut the sides out of plywood, and use appropriately sized bolts for your bearings to suspend the center. As noted before, the clear part isn't critical, and you could use some kind of mark on the sides to show the bucket level.
Thus, in the end, the main principle is a weighted cylinder that can move freely with a reference line on it that matches to some mark on the stationary part of the unit (that is then affixed to your bucket/implement). There are a lot of ways to skin that cat. My goal is to make my version cheap enough that you won't want to bother... unless you're into it, which I respect.
Anyway, hope that helps those of you who want to make something of this nature. Post pictures if you do. I should have an orange sample made by tomorrow, print gods willing.