This system uses 4 controllers which send signals to a central hub which holds an Arduino.
It was designed for use with a game called Fraction Smash that my group was developing for a class. Students would enter a fraction using the keypad to re-size their character and then hit the smash button to break through the door if they are the right size.
More info here:
Ethernet Keystones (1.24)
Step 1: Cut out pieces
The .DXF files are attached for automated processes.
All of the CAD files and assemblies can be found here: