Solder: Attiny 85 / 45 + switch using 1-key-keyboard schematic
Fabricate: headphone hook w/ switch holder
Software: Use Quicksilver* to trigger Applescript/Python script to do some thinking about pressing play, pause, or do nothing.
*: Anything that can monitor for a couple keyboard strokes should be good enough. I like Quicksilver, what do you like?
Enjoy this project?