I managed to program a 18F2455 using the same serial programming schematics as project alpha's (but another program, WinPic800. I connected an old keyboard and I finally managed to decode the input. Since it was a long time ago, I can't go into details now (I know, I should have kept up with posting, but if I remember correctly the project-section on my website was less updatable back then).

The advantage of the 18F2455 is that it has a built in oscilator. Once the pic is programmed I think you don't need much more than a pic and connectors between keyboard and computer (I already have those), PS2 provides +5V as well!

The major obstacle as I see it now is this: the current set-up is a keyboard host for the keyboard. For debugging purposes it reports back through the serial port. But in a sniffer, the keyboard has to be connected to the PC as well...and all data must come through transparantly.

Now, I think I have two options: 1 is to simulate a keyboard inside the PIC. So, it acts as a host for the keyboard, takes the input (saves it for later use) and creates a new signal for the PC. But I don't know if this will work and how many exceptions and protocol stuff one has to implement to satisfy the PC.

Another option is to let the keyboard communicate with the pc just as it would normally do, but also tap the signals going back and forth. I don't know however if one can tap the signals without disturbing them. It will be a electronical challange maybe. Perhaps someone else already tackled it. It might as well be very straight-forward, I don't know. Future will tell :)

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