So your 4 year old drew on the wall. You’re less shocked that it’s permanent marker and more shocked that he managed to outfit your raspberry pi with two motors and a pen to cover the living room wall in a perfect remake of Van Gogh’s Blossoming Almond Tree. Could happen. And, he would have done it with the gocupi. The gocupi is a Polargraph, aka vertical plotter, drawing machine or drawbot, that piggybacks a Raspberry Pi running two motors which controls the location of a pen or other drawing instrument. Brandon Dunson (on hardware) and Brandon Green (on software), with the community at Dallas Makerspace, have create the small drawbot device and just hit their goal on Kickstarter to bring it all to you this side of 2014.
The gocupi main board (with power supply and switch to power both Raspberry Pi and gocupi)
That beauty you see above is top shelf PCB with everything needed (and then some) to set up your very own vertical navigating drawing machine. It comes in two versions. The gocupi base board gets you started cheap with some self-assembly soldering knowledge required and the gocupi main board comes completely assembled with a little power supply and switch to power both Raspberry Pi and gocupi, ready to connect and draw. On the software side, you have open code written in Go+ that reads X/Y coordinates from an svg, gcode, mouse input or from an algorithm and interpolates the points to move the pen across the surface.
All software and hardware is completely open source with all files on Github.
Through the gocupi Kickstarter project, you can get the unassembled base board, the fully assembled main board, or the complete gocupi kit ready to do your bidding. While the latter comes with everything you need, The Brandons also have the gondala and motor mount 3d models available here. Video below show the gocupi in action.