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

iPhone Pocket Short

iPhone Pocket is Now Completely Sold Out Worldwide

Tuesday November 25, 2025 7:16 am PST by
Apple recently teamed up with Japanese fashion brand ISSEY MIYAKE to create the iPhone Pocket, a limited-edition knitted accessory designed to carry an iPhone. However, it is now completely sold out in all countries where it was released. iPhone Pocket became available to order on Apple's online store starting Friday, November 14, in the United States, France, China, Italy, Japan, Singapore, ...
Cyber Week Deals 2025

Best Cyber Week Apple Deals Include Big Discounts on AirPods, Apple Watch, and More

Sunday November 30, 2025 7:33 am PST by
Cyber Week is here, and you can find popular Apple products like AirPods, iPad, Apple Watch, and more at all-time low prices. In this article, the majority of the discounts will be found on Amazon. Note: MacRumors is an affiliate partner with some of these vendors. When you click a link and make a purchase, we may receive a small payment, which helps us keep the site running. Specifically,...
Netflix Smaller 4

Netflix Kills Casting From Its Mobile App to Most Modern TVs

Monday December 1, 2025 4:36 am PST by
Netflix has quietly removed the ability to cast content from its mobile apps to most modern TVs and streaming devices, including newer Chromecast models and the Google TV Streamer. The change was first spotted by users on Reddit and confirmed in an updated Netflix support page (via Android Authority), which now states that the streaming service no longer supports casting from mobile devices...
studio display purple february

M5 iPad Pro Could Hint at New Studio Display Feature

Sunday November 30, 2025 10:30 am PST by
The updated specs of the M5 iPad Pro may point toward a major new feature for Apple's next-generation Studio Display expected in early 2026. Apple's latest iPad Pro debuted last month and contains one display-related change that stands out: it can now drive external monitors at up to 120Hz with Adaptive Sync. The feature should deliver lower latency, smoother motion, and fewer visual...
New Intel Logo

Apple and Intel Rumored to Partner on Mac Chips Again in a New Way

Friday November 28, 2025 7:33 am PST by
While all Macs are now powered by Apple's custom-designed chips, a new rumor claims that Apple may rekindle its partnership with Intel, albeit in a new and limited way. Apple supply chain analyst Ming-Chi Kuo today said Intel is expected to begin shipping Apple's lowest-end M-series chip as early as mid-2027. Kuo said Apple plans to utilize Intel's 18A process, which is the "earliest...
iphone black friday gold

The Best Black Friday iPhone Deals Still Available

Friday November 28, 2025 6:24 am PST by
Cellular carriers have always offered big savings on the newest iPhone models during the holidays, and Black Friday 2025 sales have kicked off at AT&T, Verizon, T-Mobile, and more. Right now we're tracking notable offers on the iPhone 17, iPhone 17 Pro, iPhone 17 Pro Max, and iPhone Air. For even more savings, keep an eye on older models during the holiday shopping season. Note: MacRumors is...
Sad Siri Feature

Apple AI Chief John Giannandrea Retiring After Siri Delays

Monday December 1, 2025 2:16 pm PST by
Apple AI chief John Giannandrea is stepping down from his position and retiring in spring 2026, Apple announced today. Giannandrea will serve as an advisor between now and 2026, with former Microsoft AI researcher Amar Subramanya set to take over as vice president of AI. Subramanya will report to Apple engineering chief Craig Federighi, and will lead Apple Foundation Models, ML research, and ...
maxresdefault

The MacRumors Show: Apple's Big Plans for iPad Mini 8

Friday November 28, 2025 8:39 am PST by
On this week's episode of The MacRumors Show, we talk through the latest rumors about Apple's upcoming iPad mini 8. Subscribe to The MacRumors Show YouTube channel for more videos The next-generation version of the iPad mini is expected to feature an OLED display, as part of Apple's plan to expand the display technology across many more of its devices. Apple's first OLED device was the Apple...
maxresdefault

iPhone Fold: Launch, Pricing, and What to Expect From Apple's Foldable

Monday December 1, 2025 3:00 am PST by
Apple is expected to launch a new foldable iPhone next year, based on multiple rumors and credible sources. The long-awaited device has been rumored for years now, but signs increasingly suggest that 2026 could indeed be the year that Apple releases its first foldable device. Subscribe to the MacRumors YouTube channel for more videos. Below, we've collated an updated set of key details that ...

Top Rated Comments

MrX8503 Avatar
158 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
158 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
158 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
158 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
158 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
158 months ago
this doesn't help?

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