A long time ago I went to one of those amature radio markets. I bought myself a
wireless keyboard for one euro. It was without the receiver but it's still cheap. A few weeks ago I
figured out the protocol which is used by the keyboard. I hooked up a TSOP IR receiver, with a carrier frequency of 38 kHz, to an
ATMEL (AT90S2313). I also connected a PS/2 connector to the same ATMEL. In GNU C I wrote the software which decodes the
received bit-string into a startbyte, command and scancode. To be able to transmit the key to the computer, it looks
up the key in a translation table, using the commonly used scancode set (scancode set 2).
Download the software here
The keyboard we're talking about. It's one of those keyboards 'primafoon' sold to use with the NetBox
The schematic to interface an IR receiver, ATMEL and PS/2 port.