This is a work in progress because I have yet to successfully program the ATMega 168.This is the RepRap/MakerBot Extruder Controller, but without all the extruder-controlling bits. I would love to have a dedicated Unicorn Plotter controller board, but don't want to shell out $45 for one. The schematic just contains all the necessary parts for an Arduino to be controlled and powered over RS485 with two digital I/O ports.The board file is experimental! It should work, but there's no guarantee.By the way, this board costs around $20 (including components) to make, but only if it's priced in groups of 10.