The onboard microcontroller does the decoding, optionally some more processing, and sends byte-sized data to the main project board. The byte contains information about direction, push-button status and maybe even about average rotation speed (encoded in the higher bits). I think I will like it – if it works
Quick and dirty application: Volume control knob for Amarok or kmix. All you need is a 5V USB-serial adapter and a little perl script that listens for data. Oh, and linux of course. Amarok’s volume is controlled using dbus calls. Very simple to do, actually. Part of the demo code for this little project!