There's a few devices like this out there, usually with a limited range and audio-only alerts though: http://www.amazon.com/EZ-FIND-Item-Design-Electronic-Locat

There's a few devices like this out there, usually with a limited range and audio-only alerts though: http://www.amazon.com/EZ-FIND-Item-Design-Electronic-Locator/dp/B004FVFGMW/ref=pd_sim_e6 http://www.amazon.com/EZ-FIND-Item-Design-Electronic-Locator... Full geolocation would be quite a bit harder, what would be the use case where you'd need to, say, plot the location of your keys on a map?