How could an iPhone tell it's being stolen?

While an accelerometer-based theft deterrent is not yet available to consumers, Apple has filed a patent application for the technology. See more iPhone Pictures.

Thefts of hand-held devices are on the rise; robberies involving portable Apple devices increased by 40 percent in New York City alone from 2011 to 2012, and there were 11,447 reported thefts of Apple devices in between Jan. 1-Sept. 23, 2012 -- that means more than 14 percent of all the major crimes committed in the city during that time frame were iCrimes [source: Cambell]. Of course, it's not just a problem in New York City.

One of the best ways to secure your device from being stolen is to lock it down, and for many years, that meant physically tethering that device to a fixed object with a lock and cable. But while that may be OK for a computer, it's just not practical for a smartphone. Today, iPhone users might be familiar with Find My iPhone, a free lost-and-found service Apple provides through, allowing owners to locate their device on a map, lock it down and even wipe it clean if needed. But times are again changing, and in November 2012, Apple filed a U.S. patent application for an accelerometer-based theft detection system for portable electronic devices -- think of this as a car alarm for your iPhone.

Accelerometers measure motion, the increase in the rate or speed something is moving. You use accelerometers all the time, although you probably haven't thought about it. In Nintendo's Wii Remote controllers, accelerometers detect the motion of, say, your golf swing; they detect the increase in speed when your laptop gets knocked off the desk (that's the free-fall sensor); and they're also used to detect if your car has crashed and the airbag system should deploy.

iPhones, iPads and other iDevices have built-in accelerometers, too, and here they're used to detect things such as when you're turning or moving your device -- smartphones, tablets, e-readers and your digital camera all rely on acceleration sensors to adjust the screen orientation between landscape and portrait as needed, and many games make use of accelerometers as part of the play experience.

But that acceleration sensor in the iPhone could get additional job duties. Let's talk about how the iPhone's accelerometer could clue a smartphone in to its own theft.