Sand Table
By Ron Marianetti
This table draws designs in the sand by moving a steel ball through the sand via a magnet mounted on a software controlled platform underneath.
Type: Artistic
Website: https://youtu.be/Onn9rp-YEog
About them: I'm a software engineer by day and love to tinker with all manner of things by night. I love to dabble in woodworking, some metal-working, 3D design, 3D printing, CNC machining, electronics design, motor control, robotics, etc. For my wood-working projects lately, I've really enjoyed making kinetic sculptures and have built a number of designs published by Derek Hugger (https://www.derekhugger.com). One of my earliest and proudest wood projects (made about 20 years ago) is a clock made entirely from wooden gears, from plans found in Fine Woodworking magazine. I've also designed and built a number of homemade robots as a way to learn about the technologies and sensors available and as another excuse to buy more gadgets and tools. :)
Social:
What inspired you or what is the idea that got you started?
I was inspired by seeing the Sisyphus table by Bruce Shapiro (https://sisyphus-industries.com). I thought it was so cool and wanted to make one of my own.
What is your project about and how does it work?
Underneath the table is a mechanism that moves a magnet. The magnet in turn pulls a steel ball through the sand, making designs. The mechanism has two motors on it - one to move the ball radially in and out from the center using a rack and pinion gear, and another to rotate the arm around 360 degrees. It is essentially a 2D polar plotter.
For the motors, I use two DC motors with shaft encoders on them. The motors are controlled by an Arduino with a motor shield mounted on it. The Arduino accepts simple motor movement commands through its serial port - "move to this specific angle and radius" for example. The Arduino in turn is controlled by a Raspberry Pi which has the set of available designs and breaks them down into the simple motor movement commands that it sends to the Arduino. The Raspberry pi also implements a web server implemented in python and javascript that allows you to talk to the table over WiFI using a web browser in order to select which design(s) you want.
What did you learn by doing this project?
* How to control motors using the Arduino
* How to decipher and use the feedback signals provided by a motor encoder
* How to design and prepare parts for cutting on a CNC router using Fusion 360
* How to design and prepare parts for 3D printing using Fusion 360
* How to design and send out a PCB for manufacture using Eagle CAD.
* How to write a web page GUI using React (Javascript)
What impact does your project have on others as well as yourself?
It's relaxing and fascinating to watch. I think it also inspires others on how science and engineering can meld with art and meditative experiences.
