
iBeacon
I am very excited by the capabilities (admittedly non-audio) that Bluetooth 4.0 Low Energy offers and some of the interesting product ideas that are popping up.
I just pledged to the Gecko indiegogo project (after Steve Wozniak mentioned it) that wants to build smart-tags with sensors that notify your BT4 equipped phone (or other device) if they have been moved or removed from the 100′ range.
The iBeacon from startup estimate offers ‘micro-location based notifications’ to both help map software work when indoors (no line of sight to GPS satelites) and provocatively, conversely to map user’s time and paths in a space. Impressively the iBeacon’s ARM Cortex M0 can run off a lithium cell while sending and receiving BT LE messages for up to two years (techie details & API).