I wish to be able to read wireless traffic sent from my wireless keyboard. At first I thought I could just buy some board like Arduino, plug in a module like nRF24L01+ and use this combo. Since I'm not good at all with electronics, I'd rather find another solution and, eventually, I thought that I already have a transceiver for wireless comunication: my laptop's WiFi adapter. As I said I don't know much about electronics so I wonder if it's actually possible to write, let's say, a linux device driver for my adapter in order to make it able to capture and process wireless communication other than WiFi. Is there some electronic impediment? Is this just a software problem or maybe my WiFi adaptare firmware won't allow me to read anything except from WiFi traffic?
If it does use the same frequenzy as a wifi card it should be possible depending on your card, skills, and willingness to invest time ;). It might be easier and quicker to go with something else though, look at the path Tim took to make his diy-spy for instance.
Using a device like a wifi spy should answer if it is there or not, Tim made his own diy-spy based on a cheeper device and has published the source code he used. Basing this device on a wifi card should be possible if it supports digital RSSI reporting or not. Starting of at this code it should be possible to find the signal you are intereseted in and working with that.
Another "simple" way to find out what frequency your keyboard uses would be to check it using a Frequency Counter (either borrow from a hackerspace, a friend, a ham or buy one [there are cheap options on for instance ebay]). The reason I say this is that some [I have seen] uses 2.4 GHz, and some 27MHz; and I would be highly impressed if you are able to read 27MHz using a hacked wifi driver ;)
You might wish to check out KeyKerki
This opensource hardware and software project enables every person to verify the security level of their own keyboard transmissions, and/or demonstrate the sniffing attacks (for educational purpose only).