i'm going to lose my neo....

[Robin Paulson]

i know i will, it's a certainty. i lost a phone 2 weeks ago and another in June

i know it's got a gps and can e-mail/text us where it is, but that
will only work if someone doesn't re-flash it and has other caveats on
it working. Besides, I'd rather it not get that far away from me, i
want to know as soon as i get off my seat on the train, that I've left
it behind

what i would like is a (v. small) device that i can carry in my
wallet, or somewhere, that sounds a reminder (on the phone, or
external device) when it moves out of range. it doesn't have to be any
fancy bluetooth or wi-fi or GPS thing, some simple technology for
measuring proximity and triggering a signal would suffice

ideas? any other absent-minded daydreamers out there? is RFID the way
to go? are there any unlicensed parts of the radio spectrum that are
free for use by anyone using low-powered radio transmitters?

of course, this tech could be applied to any object that a person could lose