Thanks to Bluetooth Low Energy, we are going to be seeing a lot more of these kinds of proximity beacons (Previous example: StickNFind). One interesting application of the $29 SpotLoss keychain fob is that you can create a computer log that shows when your son or daughter comes home at night.
The range of the device is 50 meters (164 feet) and works through walls and other solidsSpotloss
-- Runs for a year on replaceable watch battery without recharging
-- Uses a free app that allows users to easily customize settings
-- Get texts or emails about proximity events
-- Works with iPhone 4s, iPhone 5, iPad 3, iPad 4, and iPad Mini
-- Will work with Android Bluetooth 4.0 devices shortly
-- Uses Bluetooth Low Energy (a.k.a. BlueSmart) protocol so the battery use is minimal
-- 5.6 x 3.0 x 1.5 cm carabiner style easily attaches to almost anything
-- Connect up to ten devices to one phone or computer at the same time
-- Connects with cell phones and computers in a many-to-many relationship
-- Fob supports vibrating and variable pitch alerts
-- Printed circuit boards and their enclosures will be assembled in Upstate New York
Mark Frauenfelder is the founder of Boing Boing and the editor-in-chief of MAKE and Cool Tools. Twitter: @frauenfelder. Come and hear Mark speak at the ALA conference in Chicago on July 1.
MORE: Bluetooth Low Energy