It is a bit cobbled together, but the prototype is working. Very much a minimum viable but it is working and doing what it needs to do.
I used the USB keyboard emulation code from my ZX Keyboad project that uses the VUSB for Arduino library. This currently limits it to the Arduino 1.0.x IDEs but I intend to update this library in time and this is another good reason to do so.
Next I need to miniaturise it so it is portable. The final version will be a low cost custom board, but I really need to try it in the field first, and this means a some what smaller hardware prototype.
Also I have a lot of features I want to add to the device, including making the setup easy for the "man in the street", but one step at a time.