Alessio Sangalli has been maintaining a guide for a few years that shows you how to create a serial port IR receiver from scratch and use it in both Windows and Linux. Her design is pretty slick since, as you can see from her photo above, the whole package fits neatly inside a standard 9 pin serial connector. There are still plenty of machines that don’t have built-in IR support, so this could be handy if you’re thinking of turning an old box into a media player or DVR.

How To Build A Simple But Cool IR (Infra Red) Receiver