I'm an industrial design student in Umea, Sweden, and this is a working prototype of my degree project. I've been working on this for a while. It's basically a Spotify box. I can link different RFID tags to Spotify links or searches, so you can have your own physical collection of playlists and music.
The two small buttons skip to the previos/next track, the big knob controls the volume and the RFID tags are placed on it. There's a small magnet in the knob and a metallic part in the RFID tags, so they stick to it without falling.
The sketch uses AppleScript to control Spotify: it opens a Spotify link or performs a search and uses the keyboard shortcuts to control what's playing. It's still a work in progress, the three led matrix will be used to display battery status, track info, maybe it will display the time when it's not in use? There're still a few things to decide.
I'm planning on working on the UI for tagging music too, so the RFID id's and the spotify links can be stored in a xml file locally, this way the processing side of the prototype can access the xml to play whatever is assigned to each tag. Right now, I've to assign music manually within the Processing sketch.
I'll upload all the code once I'm done with it, I'll be presenting everything in one month and I still have a lot of stuff to finish, so by then I'll hopefully be able to share some drawings of how it's build to let others build their own.
So far, this is what I've got:
I'm keeping a project log here: http://blog.zenona.com and a flickr set: http://www.flickr.com/photos/parrita/sets/72157625436664189/
Enjoy! Merry christmas!!