Hi all, made one of these, few notes from my experience in case of use to others:
the first set of idlers I ordered had quite thick flanges and didn’t fit so worth checking. The Bart Dring esp32 electronics I ordered from California - a bit pricey but came very quickly and works perfectly. The start G code I needed to use was
$HY G92 X0 Y0 G0 Y-1.94 F500 G92 X0 Y0 $HX G92 X0 Y0 G0 x-12.1 G92 X0 Y0 G0 X0.1 y0.1 F2000
which I got to after a few painful crashes.
The underneath of my IKEA table (cut out with a drill and hand saw) was quite constrained and I ended up chopping off some of the plastic spacers around the corner pieces to maximise space.
Using a small ball bearing gives a lot more jitter to the lines drawn, a larger one worked much better. My base is thin plywood and makes a bit of a scratchy reverberation noise when in use. Baking soda worked well on top.
A WS2812 LED strip makes it look excellent - lighting low from the sides really helps with the contrast of the sand patterns. Text has been by far the most pleasing pattern to make - found it hard to do anything great with geometric patterns, with the quite rectangular letterbox shape!
Overall a really fun thing to build - thanks so to those who contributed to the design and all the material to help build the thing!