Arrakis Sand Table

A table that draws patterns in sand.

Similar projects worth following
I'd call this a 2nd generation table, but the first one, The Spice Must Flow, went through about 5 major design changes, so maybe this is better called 6th generation. The table uses a redesigned and 3D-printed corexy mechanism with sliding PTFE bearings to move a neodymium magnet that pulls a steel ball through a thin layer of sand, leaving behind interesting patterns. The patterns are lit from low angles by red and blue LED strips, lighting ridges red on one side and blue on the other, with dark shadows in the valleys between ridges.

This is a project that's got a lot of off-the-shelf electronics and open source software to control the mechanism. Unlike most other sand tables you may have seen around the web, this one is powered by servomotors that allow insane speed and acceleration, operating at very low to low noise level, even at high speeds.

I'll be posting a lot of details to my blog, and post a link to it soon. In the meantime, here is some basic information about the table.


I put a lot of effort into making the mechanism and electronics reliable and quiet., and largely succeeded. It is also capable of extraordinary speed and acceleration (for a sand table, anyway).  My sand table running in real time looks like other sand table time-lapse videos.  I routinely draw patterns at 500-1000 mm/sec but the table is capable of almost 2000 mm/sec.  Acceleration can go up to 2gs before it throws the ball, though I normally run it at 5k-10k mm/sec^2.

The Mechanism

Arrakis uses a belt driven corexy mechanism powered by servomotors with 20 tooth pulleys. The frame is made of 45 mm square t-slot aluminum and all the mechanical parts fit inside the rectangular frame. The slots in the long rails serve as guides for the Y axis with sliding PTFE bearings. The X axis guide is a square aluminum tube and it too, uses sliding PTFE bearings to keep noise down. Pulleys are made from stacked F625 bearings. All bearing, pulley, motor mounts, and the magnet carriage are 3D printed. The table uses a 1" cube, N52 neodymium magnet. Patterns are drawn using an 11mm steel ball. 


Each motor has its own power supply, as does the Duet 2 WiFi controller board. There are two LED strips, red and blue, that are each powered by buck converters connected to one of the motor power supplies.  The motors are iHSV 78W (there's no kill like overkill!) Nema-17 integrated servomotors. They are driven by step/direction/enable signals from an expansion board plugged into the Duet controller. The Controller has a web server that can be accessed to control the table via phone or laptop computer.

The Sandbox

is made with 1/2" walls and a 1/4" bottom from Baltic birch plywood. There's a layer EPDM rubber on the bottom of the box to minimize noise from the ball rolling. The sides of the box are finished with 1/2" high density upholstery foam covered with red and blue striped fur cloth.  The box is mounted so that there's an air gap between the bottom of the box and the magnet to minimize noise. The top cover consists of an oak frame that has been stained and finished with oil based polyurethane which holds a tempered glass cover. The cover was put at coffee table height and the bottom of the sandbox placed close to the floor to keep sand from sticking to the glass. The sides of the box come down almost to the floor to keep Ms. Kitty from getting under it and chewing on wires or belts.


Patterns are generated using Sandify. I wrote a post processor to take advantage of the high speeds that the servomotors can provide. The post-processor allows two speeds to be set in the pattern files- a low speed for drawing the pattern and preserving detail, and a high speed for travel around the edges of the table. Now, for example, I can specify that  the drawing should occur at 100 mm/sec and the edge motion at  1000 mm/sec. In some patterns with a lot of edge motion the result is a significant reduction in pattern completion time and reduced boredom if you're watching the table draw the pattern.

  • More video uploaded to youtube

    Mark Rehorst12/16/2021 at 02:42 0 comments

    A recent short drawing:

  • A few updates and more video

    Mark Rehorst12/09/2021 at 16:40 0 comments

    I did some experiments with different size steel balls and have settled on a 6.3 mm diameter ball. The smaller ball can produce more detailed patterns, even when run at high speeds because it throws a lot less sand than the larger balls, and its lower mass makes it wobble less at high speeds. I continue to use the dual speed post processor as it seems to be working perfectly. 

    I put the bottom of the sandbox well below the top of the table to prevent thrown sand from sticking to the glass. Unfortunately, it's not the best position for viewing the drawing when seated. With the smaller ball size I find that even at high speeds, there's much less sand being thrown by the ball, so I think I can move the bottom of the sandbox closer to the top cover. I'll be working on that soon.

    The downside of using a smaller ball is that erase patterns require closer line spacing so take longer to run. I'm looking into different ways to erase the patterns that won't require moving the ball over the entire surface of the table., hopefully powered by the same motors that drive the ball.

    I finally invested in a better tripod than the awful one I've been using, so I shot a few more pictures and will soon be shooting more video of the table drawing a pattern. I like using a macro lens on my camera and shooting from an angle that almost puts the camera down on the sand. The new tripod allows me to place the camera directly over the center of the table to shoot video that captures the whole drawing.

    In addition to a couple "normal" Samsung lenses, I have Canon 50 and 200 mm macro lenses that fit on my camera with adapters. They allow for some very nice photos/video.

    Shooting still images
    That's a Canon FD 200mm Macro lens on my Samsung NX500 camera

    The video below was shot using the new tripod and Samsung 16-50 mm lens.

  • Dual speed drawing on Arrakis

    Mark Rehorst10/31/2021 at 12:50 0 comments

    I wrote a blog post on the dual speed post processor here. There's a link to download the program in the blog post.

    Here's video of Arrakis drawing a pattern at 200 mm/sec with edge speed at 500 mm/sec. This particular pattern doesn't have a lot of edge motion, so the dual speed operation doesn't really speed things up a lot, but it makes a big difference in other patterns. Yes, it's pretty quiet...

    I'll be shooting more video, so as they say on the interwebs, "smash that LIKE, and hit SUBSCRIBE"!

  • Blog post is done...

    Mark Rehorst10/28/2021 at 19:14 0 comments

    I have written a blog post on Arrakis that includes a link to the CAD STEP file.  See:

View all 4 project logs

Enjoy this project?



Ossum wrote 09/20/2021 at 08:09 point

Beautiful pictures, the two colours really look great. Do you have a video of it in action?

  Are you sure? yes | no

Mark Rehorst wrote 09/20/2021 at 19:12 point

I'll shoot some video in the dark tonight and post it. In the meantime, there's this video demonstrating the dual speed post processing:

  Are you sure? yes | no

Mark Rehorst wrote 09/21/2021 at 04:38 point

Here's a video shot in a dark room. The table is drawing at 200 mm/sec. It can go much faster- I'll post a high speed video tomorrow.

  Are you sure? yes | no

Ossum wrote 09/21/2021 at 08:53 point

Really really awesome, great work, thanks for sharing! It is incredible how quiet you managed to make it.

  Are you sure? yes | no

Similar Projects

Does this project spark your interest?

Become a member to follow this project and never miss any updates