One thing that pops into our minds is write protection. The machine uses a big PCB to which the three Arduinos mount. That can be produced anywhere without threat of having the source code leak as ...

The Arduino replaces the hand controller, receiving the commands from the PC (HC procotol) and controlling the mount (AUX protocol).

Once printing is complete, drill holes into the outer 4 mounting points on the arduino case. Drill the holes in the arduino ...

The ‘under’ in Undershield comes from this shield being mounted underneath the Arduino, unlike every other shield on the planet. Doing so allows use of a standard 0.100″-spaced prototype PCB ...