OS X Mavericks Taps Ambient Light Sensors to Detect Motion and Prevent System Sleep

energy_saver_preferenceOS X Mavericks includes a new feature that leverages the light sensors included in many Macs to detect movement in front of the machine and prevent the system's Energy Saver sleep functions from activating even when the user is not actively using the machine, notes The Verge.

First highlighted by Moshen Chen of Radiantlabs and confirmed by developer Jonathan Wight, the feature was initially thought to use the iSight camera to monitor movements but was quickly discovered to actually be tapping into light sensors.

The sensor is already used to adjust screen brightness to ambient light, but the new OS puts it to a different purpose, tracking changes in the light as "movement," and resetting idle time accordingly. Verge tests confirmed this on two separate Mavericks laptops: after covering the camera but not the light sensor, we were able to delay sleep mode by changing the ambient lighting conditions.

Users have long been able to set separate thresholds for display and system sleep based on lack of interaction with their Macs, but under Mavericks, many Macs have now become smarter about being able to detect whether or not the user is sitting in front of the machine.

Related Forum: OS X Mavericks

Popular Stories

hikawa phone grip stand apple%402x

Apple Launches Second Limited-Edition iPhone Accessory in a Month

Friday November 21, 2025 3:53 am PST by
Apple has begun selling the Hikawa Phone Grip and Stand, a new limited-edition iPhone accessory designed with accessibility in mind. Designed by LA-based Bailey Hikawa to celebrate the 40th anniversary of accessibility at Apple, the grip uses magnets to securely snap onto any iPhone with MagSafe. Apple says it can be removed with ease, and doubles as a stand with two different viewing...
iOS 26

iOS 26.2 Adds These New Features to Your iPhone

Thursday November 20, 2025 10:50 am PST by
iOS 26.2 is currently in beta testing. The upcoming update includes a handful of new features and changes on the iPhone, including a new Liquid Glass slider for the Lock Screen's clock, offline lyrics for Apple Music, and more. In a recent press release, Apple confirmed that iOS 26.2 will be released to all users in December, but it did not provide a specific release date. Keep reading...
Apple Shopping Event 2025

Apple Announces 2025 Black Friday Event, Here's What You Can Get

Thursday November 20, 2025 6:28 am PST by
Apple's annual four-day Black Friday through Cyber Monday shopping event is returning on Friday, November 28 through Monday, December 1 in many countries, including the United States, Canada, Australia, New Zealand, France, Germany, Italy, Spain, the United Kingdom, Belgium, the Netherlands, Sweden, Thailand, and others. During the shopping event, customers can get an Apple gift card with...
iOS 26 on Three iPhones

iOS 27 Will Reportedly Have Two Key Upgrades

Sunday November 23, 2025 8:48 am PST by
iOS 27 will reportedly have two major elements: quality improvements and new AI features. In his Power On newsletter today, Bloomberg's Mark Gurman said that iOS 27 will be similar to Mac OS X Snow Leopard, in the sense that Apple is focused on improving "quality and underlying performance" over adding new features. Gurman said there is one exception to this rule, though, as he expects...
maxresdefault

The MacRumors Show: iPhone 18 Pro Looks Like a Huge Upgrade

Friday November 21, 2025 9:10 am PST by
On this week's episode of The MacRumors Show, we talk through all of the new features and improvements expected to come to next year's iPhone 18 Pro and iPhone 18 Pro Max models. Subscribe to The MacRumors Show YouTube channel for more videos Apple's next-generation iPhones are less than ten months away and we already have a good idea about what to expect based on corroborated leaks, rumors,...
Apple Foldable Thumb

Foldable iPhone to Debut These Two Breakthrough Features

Wednesday November 19, 2025 7:26 am PST by
Apple's first foldable iPhone is expected to launch alongside the iPhone 18 Pro models in fall 2026, and it's shaping up to include two standout features that could set it apart from the competition. The book-style foldable will reportedly feature an industry-first 24-megapixel under-display camera built into the inner display, according to a recent JP Morgan equity research report. That...
ipad black friday 2025

The Best Early Black Friday iPad Deals

Thursday November 20, 2025 10:20 am PST by
Black Friday is just over a week away, and iPad deals have finally started to flood in at retailers like Amazon and Best Buy. Below we're tracking discounts on every current generation iPad, including lowest-ever prices on M3 iPad Air and M5 iPad Pro, plus steep markdowns on iPad and iPad mini. Note: MacRumors is an affiliate partner with some of these vendors. When you click a link and make a ...
General Black Friday Deals 25 Red

Apple Black Friday Deals Available Now on AirPods, iPads, Accessories, and More

Friday November 21, 2025 8:48 am PST by
We're officially less than one week away from Black Friday, which will take place on Friday, November 28 in 2025. As always, this will be the best time of the year to shop for great deals, including popular Apple products like AirPods, iPad, Apple Watch, and more. In this article, the majority of the discounts will be found on Amazon. Note: MacRumors is an affiliate partner with some of these...
Low Cost MacBook Feature A18 Pro

Report: Low-Cost iPhone, iPad, MacBook Coming Early 2026

Friday November 21, 2025 2:26 am PST by
Apple is planning to release new entry-level models across its iPhone, iPad, and Mac categories early next year, with an all-new affordable MacBook the most notable addition to the lineup. According to a new research report by Jeff Pu of GF Securities seen by MacRumors, Apple will launch the iPhone 17e – its second iteration of the "e" line – in the spring, likely along with a...

Top Rated Comments

MrX8503 Avatar
157 months ago
How about we have the Mac not go to sleep when you're downloading something or encoding a video?

That would be really helpful.
Score: 23 Votes (Like | Disagree)
Small White Car Avatar
157 months ago
Dave?

Dave, are you awake?

"Ugh, just go to sleep."

I'm sorry, Dave. I can't do that.

Why are you not typing on my Dave?

I know you're awake...
Score: 22 Votes (Like | Disagree)
needfx Avatar
157 months ago
How about we have the Mac not go to sleep when you're downloading something or encoding a video?

That would be really helpful.

this doesn't help?
Score: 19 Votes (Like | Disagree)
leman Avatar
157 months ago
How about we have the Mac not go to sleep when you're downloading something or encoding a video?

That would be really helpful.

Well, ask your application developers to use power assertions.
Score: 10 Votes (Like | Disagree)
Small White Car Avatar
157 months ago
How about we have the Mac not go to sleep when you're downloading something or encoding a video?

That would be really helpful.

Here's my FAVORITE simple Mac app:

http://caffeine.en.softonic.com/mac

It puts an icon in the task bar that toggles on a 'no sleep mode' when you want it.
Score: 9 Votes (Like | Disagree)
djtech42 Avatar
157 months ago
this doesn't help?

It should automatically disable sleeping in those cases though.
Score: 6 Votes (Like | Disagree)