Update: CNC Pen Plotter
3D printed housing for the Arduino and CNC shield/stepper drivers. I remixed this design from https://www.thingiverse.com/thing:2379541/files .
I minimized some vents, while adding others, and put in an acrylic window to better show the machine's innards. Invariably, folks ask what drives my bots and gadgets; this way, they have visual access but fingers don't get shocked.