Front pockets and purses are being emptied of one of civilisation's most basic and enduring tools: the key. It's being swallowed by the cellphone.
New technology lets smartphones unlock hotel, office and house doors, open garages and even car doors.
It's a not-too-distant cousin of the technology that allows key fobs to remotely unlock automobiles or key cards to be waved beside electronic pads at office entrances. What's new is that it is on the device more people are using as the Swiss Army knife of electronics, the cellphone.
The phone simply sends a signal through the Internet and a converter box to a deadbolt or door knob. Other systems use internal company networks, like General Motors' OnStar system, to unlock car doors.
Because nearly everyone has a cellphone, a number of start-ups, lock companies and carmakers are betting on broad acceptance of the technology.
Schlage, a major lock maker, markets a system that lets homeowners use their mobile phones to unlock their doors from miles away, and manage their home heating and air-conditioning, lights and security cameras.
Recently, Dwight Gibson, vice president for connected home solutions at Ingersoll Rand, Schlage's parent, said he used the system to let a friend into his house while he was at work. "She thought it was magic," he said.
In October, General Motors introduced an app that lets owners of most 2011 GM models lock and unlock the doors and start the engine remotely. It allows car owners to warm up the engine on a frigid day or fire up the air-conditioning on a hot one from the comfort of their office cubicle, said Timothy Nixon, who oversees "infotainment" products for the automaker. "In the winter, when my wife and I went to dinner and the check came, I pulled out my phone and started the car," he said. "By the time we got to it, it was toasty and warm."
But having a phone double for entry or ignition does not yet feel fail-safe. "You don't want a dead phone battery and discover you can't go anywhere," Nixon said.
It's unlikely you'd hide a spare phone under a rock or in the bushes — though a homeowner may want to stash a physical house key outside in case the Internet connection goes down or the cellphone simply dies.