The Letter Logger can be programmed to check its position every few minutes, over longer intervals, or only when a built-in motion detector senses movement, says Jude Daggett, of TrackingTheWorld.
The 675-square-foot model apartment, with its beige carpets, white walls and galley kitchen, looks like your standard new-build condo, but for the emergency pull cords and the motion detector over the entryway.