Do some research on the common IR protocols to get a grounding on how its usually done. There's plenty of info on the web.

There two major ways of doing IR control - either you can record the bits and replay this (you record the on and off periods) or crack the protocol and write specific code to generate the protocol. The first method needs a few 'k of storage and tends to be a generic solution. It can record any protocol. The second solution is more specific and required much less storage as knowing the protocol, each button press probably generates 32bits of data.

How do you 'crack' the protocol? - again research and using a IR receiver (there's plenty from various vendors like Sharp, Vishay etc - there's been discussion on this site regarding which is best) and a digital 'scope or use CoolEdit2000 software and your PC sound card to sample the data. Once you've got a picture of the data you can compare it with the various IR formats to see if they use a standard one. You can then look at figuring out what each keypress code is.


It's a bit labourious, but is quite fun.