Build Your Own Gorgeous Sand Drawing Robot

Aug 22, 2023

Those little desktop Japanese zen gardens are pretty neat and it is always relaxing to rake the sand smooth. But modern life is all about the hustle and most of us don't have time for relaxation, which is why we need to build robots to relax for us. A few years ago, Aiden Vigue built a small desktop sand drawing robot to help him relax after high school classes. But now he's heading off to college, so he decided to redesign the sand drawing robot to bring the relaxation to the dorms.

We've seen a handful of similar contraptions, both available as consumer products and DIY builds. They come in various sizes, from big units that double as coffee tables to more reasonable affairs like this one. They all follow similar principles to draw lines in the sand, resulting in pleasing patterns or even recognizable images. Vigue's design, like most of them, accomplishes that by dragging a steel ball bearing around across a tray of sand. Underneath that tray is a kinematic system with a powerful magnet that pulls the ball with enough force to move through the sand.

Vigue's kinematic system is somewhat unique, in that it is a radial design. A bit turntable rotates an arm that can extend in towards the center of the circle or out towards its edge. That arm uses a rack-and-pinion drive, so it moves at a consistent rate and can pull the magnet all the way to the center point of the circle. The pinion gear attaches to a shaft that pokes through the turntable, which enables continuous rotation. The turntable has gear teeth along its outer edge.

All of those mechanical parts were 3D-printed. Stepper motors turn the gears to rotate the turntable and extend the magnet arm. An ESP32 development board controls those through a custom PCB designed by Vigue for the stepper drivers. The ESP32 also controls a strip of SK6812 RGBW individually addressable RGB LEDs for interior lighting. A TSL2561 light sensor lets it adjust the brightness to suit the ambient lighting. An SD card slot provides storage for designs.

Vigue even created a web interface for setting up patterns, images, lighting effects, and so on. This is nice and polished, so it makes interaction smooth and pleasant. All of the files are in the tutorial, so you can build your own sand drawing robot for all your relaxation needs.