[frankus]

You could do this with multiple devices at known locations. E.g. if you always keep your (latest-generation) Mac mini in the office, and your MacBook Air in the kitchen, and have programmed them as such, they could communicate with the app and give you a rough location for any tag.

Which would actually be a pretty cool project for someone: create a system for triangulating the approximate location of stuff in your house with strategically-placed fixed Bluetooth LE devices ("stuff" in the degenerate case meaning powered-up BLE hardware like an iPhone, or with these sorts of tags, things like keys and pets). Sort of like this project but wit less of the "getting warmer…getting colder" hide-and-seek aspect.