You can program a PIC that intercepts the signal from the second keyboard, and then manipulate that signal and send it to the PC. E.g., the PIC adds 26 to every ASCII number, and thus your A when pressed on the second keyboard turns into an a (iirc), and a B turns into a b. It would be more practical to decrease the number with 26, so that the a becomes an A.
a) Learn the PS/2 specification b) Cut a keyboard-cable in the middle, connect the wires from both ends to the PIC, so the PIC is like "in the middle" between the keyboard and the PC c) Program software for the PIC that reads the incoming PS/2 packets (from the keyboard), manipulates if necessary, and sends them through to the PC. Also make sure it can easily pass on packets sent from the PC to the keyboard. There. Extensive knowledge of PIC's is required though.
You could try moving the key switches in the second keyboard, or rewireing them, so that when you hit the key marked W on the 2nd keyboard, it actually presses the key that's wired up to I or whatever (ie a key you won't be pressing on the first keyboard, then assign I to rocket etc. Course, the second keyboard would be useless for typing, but it would look normal. I think having the same effect as using a PIC as above? Or, some how rewier the second keyboard so that every keypress, also engages the shift key, thereby making the whole keyboard uppercase when you type on it. Only problem will be if you press a key on the 1st keyboard at the same time, it would probably 'Shift' that letter as well.
