OS X Mavericks Taps Into Ambient Light Sensor to Help in Determining if User is Away
Generally, when a user steps away from their Mac for a long period of time without letting the machine know that they’re close by using the keyboard or mouse, the Mac will fall asleep to save power, and in some cases where a password is set, increase security. This, of course, depends on the user's personal computer settings.
It has been discovered by a third-party Mac software developer named Moshen Chen that Apple’s new OS X Mavericks operating system now adds a third item to the list of tools that a Mac can use to determine if a user is nearby or away. The ambient light sensor located to the left of the iSight camera is now used by the operating system to not only adjust the screen brightness, but also to determine if there is movement from the user.
As The Verge
notes, if the ambient light sensor detects rapid light changes, the operating system can reset the sleep timer so that the machine stays awake longer. This way, the user doesn't have to constantly touch the multi-touch trackpad, mouse, or keyboard to keep their machine awake in front of them.
All of Apple’s latest MacBook Pros, MacBook Airs, and iMacs use this ambient light sensor right above the display. OS X Mavericks can take advantage of the sensor on all of these machines, where hardware and software is applicable.
Sources: The Verge