This looks amazing... and seems quite understandable in how one would go about implementing it. In fact, it seems to me that it would be reasonable to create and deploy a fully software only solution for this right now... and let the specialized hardware follow later... give me a desktop app that acted as the clock or a web page that only my 'circle' had access to.

I hope the folks in research feel the same and ship a working set of software to us in the near future... even if the UI for setting your location(s) is rudimentary and even if it is limited to certain subset of phones... I'd be interested in a heartbeat!