To keep the electronics as simple as possible, I will be hacking a keyboard (as processing can deal with keyboard input very easily). To activate each of the camera feeds, I will have to press a certain key - so far they are B, G, T.
As I am wanting to take the inputs away from my laptop keyboard I bought a cheap keyboard. However, I did not realise that the connection was not USB & was a PS2, so I am currently waiting for a converter from Amazon. But once I get it, good things will happen!
I took the keyboard apart to find the circuit that I need & discovered how it really works - it's a lot more complicated & prettier than I thought!
To determine what keys I can use for the system, I will be experimenting with this circuit with a simple piece of wire to determine the location of each letter. Watch this space.