This thing is amazing. It's an Android \ iPhone based camera trigger that uses the audio port to work its magic. It might be the most advanced shutter release I've ever seen. (on balance, I've only ever really used the Nikon one).
I can't remember the rules on linking to pages where products are for sale, but just go to KickStarter and type in "Trigger Happy" in the search field.
I'd be curious to get your opinions on it.