Four Stepper Motors Can Make Beautiful Sand Art

There are challenges to making art in any medium, and with sand the issue is clearly accuracy. How do you keep everything in place while you're working? David Bynoe, a kinetic sculptor in Calgary, Alberta, created this drawing machine for the Telus Spark Science Centre to solve that problem.

Bynoe attached four strings to a weight and then connected each string to a pulley and stepper motor at the four corners of a box so the weight could be controlled by tightening and slackening the ropes. When the box is filled with sand, the weight can draw precisely on the sand in a 590 x 590 x 220mm area.

Bynoe used LinuxCNC and got his friend Kevin Loney to write a custom kinematics module and python script to control the fine movements. The spatial accuracy is within about 0.1mm though that starts to break down around the outer edges. The machine may be kind of complicated for a trip to the beach, but it's mesmerizing to watch it work in the studio. [David Bynoe via Hack A Day]