Robot Repeatedly Rearranges Remnants In The Round

Sisyphus is an art installation by [Kachi Chan] featuring two scales of robots engaged in endless cyclic interaction. Smaller robots build brick arches while a giant robot pushes them down. As [Kachi Chan] says “this robotic system propels a narrative of construction and deconstruction.” The project was awarded honorary mention at the Ars Electronica’s Prix Ars 2022 in the Digital Communities category. Watch the video after the break to see the final concept.


[Kachi Chan] developed the installation in pre-visualizations and through a series of prototypes shown in a moody process film, the second video after the break. While the film is quite short on details, you’ll see iterations of the robot arm and computer vision system. According to this article on the project [Kachi Chan] used Cinema 4D to simulate the motion, ROS for control, PincherX150 robotic arms modified with Dynamixel XM 430 & XL430 servo motors, and custom 3D prints.

We’ve covered another type of Sisyphus project, sand tables like this and the Sisyphish. Continue reading “Robot Repeatedly Rearranges Remnants In The Round”

Watch A Fast Sand Plotter Plow Patterns At Speed

[Mark]’s sand table wisely has a glass top.
Most of us have probably seen a video of a sand drawing table at work, in which a steel ball — magnetically-coupled to a gantry under a layer of sand — lazily draws geometric patterns with utter precision and zen-like calmness. That’s all well and good, but [Mark Rehorst] thinks it can also be interesting to crank up the speed and watch the ball plow through sand just as physics intended. There’s a deeper reason [Mark] is working at this, however. Faster drawing leads to less crisp results, but by how much, exactly? To answer this, [Mark] simply ran his table (which is named The Spice Must Flow) at both fast and slow speeds and documented the results.

These two images show the difference between running the table at 100 mm/s versus 500 mm/s. The slower speed is noticeably crisper, but on the other hand the faster speed completed the pattern in about a fifth of the time. [Mark] says that as the ball aggressively accelerates to reach target speeds, more sand is thrown around over existing lines, which leads to a loss of detail.

Crisper detail, or a faster draw? Which is “better” depends on many things, but it’s pretty clear that [Mark]’s cat finds the fast version more exciting. You can see [Mark]’s table at high speed and the cat’s reaction in the video, embedded below.

Continue reading “Watch A Fast Sand Plotter Plow Patterns At Speed”