OK, in perusing Craigslist last night I found a plethora of tables to buy. Lots and lots of sizes though, as well as differing materials (wrought iron coffee table with beveled glass top for $15?). What’s liable to look best? What’s liable to really screw things up? What should I use for the lower layer panels? Window glass, tempered glass, Plexiglass, plywood, MDF? It’s under the sand it shouldn’t need to be transparent like the top. Should I plan on some sort of sealing caulk between the lower panel and the area between panels to keep sand/soda from leaking after a few months of movemsnt? Can all the fiddly bits of electronics and hardware be directly mounted to the lower panel, or should it also be attached to the table itself?
Is there going to be a standard way to connect multicolored LED strings to mount between the two panels? How about software to drive them? What about WiFi or Bluetooth connectivity so I don’t need to deal with an SD card each time I want to change designs?
I’m sure I’ll come up with more questions, but these seemed like they’d be early on most peoples lists…
I made my first table using a nice end table made of oak or walnut - something heavy, anyway. I think it helped cut down some on the noise. The panel that forms the bottom of the sand tray I made with a piece of whiteboard from Home Depot. It is caulked all the way around to keep the “sand” - baking soda in my case - in.
i designed mine so that everything is mounted in a frame - mine is mdf - that can be completely removed from the table.
I don’t think there is a standard way to do the lights yet. Mine are addressable and controlled by a separate arduino. Mine have a number preset patterns to choose from, using a button to cycle through them. There are several videos on youtube about controlling leds with phones and other things, I just chose a simpler setup for now. The lights are programmed using the fastled library.
I suggest attaching your electronics to the frame - the one I mentioned, that’s separate from the table - or to the lower cover, if you have one. There probably won’t be room to mount anything on the underside of the sand tray.
The ZXY will attach to the bottom of the surface your sand is on, or very near there anyway. I plan on using 1/8" hardboard. White board is a good idea, but I need about 26"x26", so that would be more than a quarter sheet. There is enough room for at least some of the electronics in between the two motors. The gantry can’t come that far. It’s sort of like an ‘H’.
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I was at HD today, and they sell glass in several sizes for pretty cheap, if you want to make your own table.
Yes, to be clear, I meant to mount the electronics to the frame, between the motors, then mount the frame to the tray (where the sand is). I read Bill's question as asking whether the electronics should be mounted to the bottom of the tray itself.
I’ve thought about that, but can’t figure out how to hide a rectangular or polar gantry under an elliptical table and still cover the whole ellipse. I’m sure there’s a way to make an elliptical gantry, but it wouldn’t be as simple as what we’re using, I don’t think.
So I did some mock-up assembly today. Do we have a figure yet on how much space the sides take up? My sand base that the ZenXY screws onto is something like 17"x21" and there’s a pretty small lip inside that to hold the glass. How much of my rectangle won’t be accessible to the ball? I can fabricate some filler, and the LED strips will take up some room, but I’m going to bet there will be a border around the designs. Maybe 2-3 inches on each edge? Width of the rail plus width of the side rollers plus half the width of the center?
I’ll hopefully be able to work with a local wood crafter to design a table specifically for this, but it’ll have to have a wider border to allow for the mechanism…
Sorry for laggin Bill. I have my CAD issues resolved, so no I think I can make a decent size calculator. The down side to this I have to reference the outer edge of the assembly. It is going to be the easiest. Let me get some lunch in me , ship the days orders and I will get to it.
Here you go, approximate because of the end stops, and bolt head thickness. I will get a more official one later. I do think it works better if the ball touches the edge as that keeps it from piling the sand out of the work area.
So with the nuts on the bearing bolts, I’m thinking of allowing about 100mm clearance from the edge of the gantry to the drawing area. Not bad! The bezel on my new donor dining table is 2.5 inches, but I expected that I’d need to deal with a border area. The travertine tiles you see in my first table are there to provide an interesting border, because that gantry also took up more space than the bezel provided. I was lucky that my local Lowes had those travertines on sale eight for $3.50. I bought ten packages - I know I’m going to wish I had bought more, eventually.
So these end tables will be pretty small when fully assembled. Looks like 11" x 15" or so. Still be good for demonstrations and custom tables designed to fit will allow more reasonable sizes. I’ve got the first one mostly assembled, still haven’t mounted the limit switches or run the belt. Do you have a good diagram for mounting the belt ready yet? I can puzzle it out if need be…
BOM seems to be missing the M3 x 10mm screws to hold the steppers in place. M3 x 15 don’t seem to be available, but M3 x 16 are easy to find.
How are people planning on mounting the electronics? I’m thinking the display needs to be accessible but the rest doesn’t. I’m thinking of mounting a couple of short drawer slides and putting a display case between them, possibly with a mega/RAMPS case adjacent. That way it can be slid in under the table for normal operation but pulled out for access. I’m also thinking of ditching the RAMPS since we only need two drivers, that might allow for a WiFi/Bluetooth shield, which would greatly improve the possibilities for the software side. Control it from your smart phone or your computer.
If I cost it all out, short the table, using $20/hr for print time, I get around $500… Good thing I don’t charge myself for print time.
I plan on mounting my lcd on a fold out hinge. Hope it works the way I envision it. Bluetooth would be cool but I don’t have time to work on that yet…started a really cool software project I have been putting off for a longggg time.
