updated 04:18 pm EDT, Wed September 11, 2013
Real-world implementation might prove difficult
Apple has won the rights to a US patent on an accelerometer-based security system for mobile devices. The accelerometer would, in theory, be able to detect if someone is stealing an iPhone or iPad, instead of just picking it up as its rightful owner. In the case of theft, an alarm would go off to alert bystanders.
Since it could be hard to discern the difference between theft and regular motion, Apple suggest the possibility of tweaking a number of parameters. People could adjust the sensitivity of the accelerometer, for instance, or the time for the alarm to hit maximum volume, if it's enabled at all. Apple also proposes combining motion detection with audio and visual cues.
The patent was originally submitted a year ago. Apple appears to have since taken a different tack for security. iOS 7 includes a feature called Activation Lock, which prevents thieves from wiping and restoring a device. The iPhone 5s incorporates Touch ID, a fingerprint recognition system which won't unlock a device until the owner's thumb is detected.