Monday, December 24, 2018

Sand Table Updates

I built the sand table as a quick project for the Milwaukee MakerFaire, and it showed.  The electronics and cabling were thrown together and everything was held together with zip-ties.  Now that the table is at my house, I wanted to dress it up a little before the final-final upgrades that are being planned.

The electronics enclosure for the sand table was butt-ugly, just as it was when it was on my 3D printer, so I decided to do something about it.  I found a wonderful piece of junk on the hack-rack at the makerspace- an aluminum enclosure, anodized black, that contained two MeanWell 12V 10A power supplies.  I tested them and both worked fine (of course, they're MeanWells).  The box had a line cord jack, fuse holder and power switch ready to go, and there were a lot of ventilation holes in the box.

The first thing I did was test the sand table running from 12V.  There were no problems at all, even running at 500 mm/sec.  Switching the sand table from 24V to 12V operation meant I could get rid of the DC-DC converters that were powering the LED strips, so wiring was simplified and made more reliable.

I pulled one of the power supplies from the box and installed the SmoothieBoard controller in its place, then got to work on wire management.  When I bought the t-slot material used for the frame at the scrap yard, it came with the plastic slot covers, so I routed the wires in the slots and placed the covers over them. The result is much nicer looking, even though it is under the table and mostly hidden from view:

The new electronics enclosure.  No wires hanging all over to temp the cats to chew on them!

New electronics enclosure- all the cables enter the box through a hole near the top.  It's still pretty inconvenient to reach under the table to select a file to run.  The next version will probably have a wifi capable controller.

"A" motor and Y axis limit switch.

"B" motor and X axis limit switch (behind the motor).  Cables are routed in the slots in the table's frame and covered with the plastic strips that are made for the task.

The wires to the LED strips really need to be reworked so they don't exit along the back edge of the table, and I should add a connector so that they can be disconnected easily if the table has to be taken apart to be moved.

Since my original post on the sand table, Jeff Eberl and others have been making huge upgrades to Sandify and it now produces even more interesting patterns than before, and has many added convenience features such as allowing the gcode files to be saved under names you specify.  That makes it a lot easier to combine gcode pattern files into one big file.  It also stores the parameters in each gcode file so you can recreate it if needed.  You can also grab pattern files from several locations on the web, too.

Ms. Kitty enjoying one of the new patterns produced using Sandify.

Final upgrades being planned:

1) Switch to NEMA-17 motors for lower vibration, quieter operation.
2) Install a controller with 256:1 microstepping drivers to reduce noise.
3) Replace the big, ugly limit switches with something smaller and quieter (reed switches, maybe...)
4) Finally, get a nice looking glass-topped table and rebuild the whole mechanism into it so it looks a lot nicer and is more presentable and usable as a piece of furniture.  I'm watching Craig's list for a good deal on either a whole table or a nice glass top.

When I update anything else I'll make another post about it.  When I get NEMA-17 motors installed I'll post some video comparing the noise levels of the NEMA-23 and NEMA-17 motors, and then do it again when I install a higher microstepping controller board.


  1. Love your projects. Just discovered your work while looking at coreXY resources. The sand table is brilliant and looks like a ton of fun. Watched most all of your Vimeo videos. Do you have a Youtube channel? (I couldn't find one using just your name.)

    1. Thanks! No YouTube channel. I don't produce content fast enough, interesting enough, or well enough for that.

  2. I always enjoy reading your posts. That is a beautiful sand pattern.


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