The idea early on was to leverage existing Arduino libraries to connect with a standard USB mouse, specifically, the hardware would take the form of an Arduino Mega 2560 with a USB Host Shield.

The Arduino Mega 2560 R3 is positioned on a suspended platform, with the anodes controlled on the Digital Pins as opposed to the cathodes on remapped AnalogInputs.

It's of course backwards compatible with existing Arduino add-ons, but sets itself apart with a new USB controller with lower latency and driver-free operation on Mac and Linux.