Using parts from a 3D printer, custom laser-cut components, and LED lighting RCLifeOn created this mechanical table that uses a magnet and a ball bearing to draw complex patterns in sand, only to erase everything it doodles. On the plus side, as soon as it wipes out an image, it gets to work on another.
A while back, maker Ivan Miranda built himself a robot which could write words in the sand. He’s back to build an upgraded version of the machine which can draw much faster than the previous one. It uses 50 mini servos to doodle, two mini tanks to drive, and Arduino Mega controllers for its digital brains.