Quote:
Originally Posted by
Face

I think most switch boxes use a small micro-controller to convert GPIO signals to a serial keyboard protocol.
An easy ready-to-use option is the
I-PAC. I once used it to quickly make a hardware keyboard for a DSYK project.
Quote:
Originally Posted by
Face

The link you posted yourself in the previous thread about your project contains detailed information about how to do it with an Arduino

.
If you like a bit more control (or fanciness) I would vote for an micro-controller based approach. You could make one box receive lots of keys/switches and also drive -for example- an analog meter or lights (LEDs). Daisy-chaining those, your number of switches / indicators becomes practically infinite.
Arduino like boards also have the advantage that you don't have to think about extra power supply (as long as you only need switches and LEDs or drive only low power outputs like low current draining meters).
The downside is of course that you have to program that micro-controller too (not
that hard when you've got a little C experience)