iPhone 4S Incorporates Revamped IR Sensor for Siri's 'Raise to Speak' Feature

Apple's new Siri personal assistant feature on the iPhone 4S includes a "raise to speak" feature that allows Siri to be activated whenever an active iPhone is raised to the user's ear. The device is able to sense the raising action using a proximity sensor capable of detecting how close the user's face is to the screen. The iPhone has always incorporated proximity sensors in order to turn off the device's display during phone calls to prevent accidental input, but Siri's raise to speak feature requires that the device be ready to sense proximity to the user's face at all times.


Teardown firm iFixit has gone back to its original teardown of the iPhone 4S to highlight the sensor involved and show how it emits infrared light at all times to support Siri's raise to speak function.

During our iPhone 4S teardown, iFixit buddy Markus noted that the new iPhone had a rather unusual-looking black component next to the ambient light sensor. We didn’t make much of a fuss about it since we were knee-deep in disassembly pictures, but the little black box certainly piqued our curiosity.

Now that the teardown is wrapped up, we’ve re-opened the mystery and made a neat discovery about the 4S: that black component is an infrared LED, and the little bugger almost always wants to know if you’re nearby.

In a video, iFixit demonstrates how the iPhone 4's proximity sensor is only activated while on a phone call, while the sensor on the iPhone 4S is active whenever the device's display is on.

Top Rated Comments

(View all)
Avatar
117 months ago
Does 'Raise to Speak' work for you 100%?

For me, it's hit-and-miss; sometimes the phone registers 'Raise to Speak', sometimes it doesn't. Can be very frustrating. Not sure if something's wrong with my device.
Score: 11 Votes (Like | Disagree)
Avatar
117 months ago

I like the private idea of being able to raise the iPhone to speak with Siri, so it's a shame that you can't get it to reply to you in private too.


I wouldn't mind a private chat with the girl in the video. She's kinda cute! :D
Score: 9 Votes (Like | Disagree)
Avatar
117 months ago
This could potentilaly be why they don't want to support Siri on older devices. :confused:

I am sure Siri would still work, but perhaps they could simply remove the raise to speak feature, or just use the gyroscope and accelerometer to tell the software that the phone is being raised.

Wouldn't an other use for this sensor be for detecting proximity of a person's face? I have seen threads on proximity detector not working well on the iPhone 4 causing spurious inputs for various people. I would be curious if 4s users have less of a problem with this ( my 4 hasn't had issues with the prox sensor, but I may just have a big face :o )
Score: 8 Votes (Like | Disagree)
Avatar
117 months ago

That girl looks funny. Don't really know if I find her very attractive or not attractive at all. Sort of hybrid attractiveness. Very weird.


Cute, but wow, what an irritating & harsh nasally voice :(


You know she's ON this very thread, right? Reading and participating? My god, you folks are socially inept. You two are carved from the same block of people who are like "OMG, A GIRL!!" D.T. is right, some of you need to get out more.
Score: 6 Votes (Like | Disagree)
Avatar
117 months ago
Some of you guys (and gals?) need to get out more often :D
Score: 6 Votes (Like | Disagree)
Avatar
117 months ago

Careful, she lurks here. :D


Cannot believe you just called me out as a lurker. Owned.

As much as "always-on" IR might affect battery life, I'm doubtful that it's responsible for a battery draining at a rate of 10% per hour. My bet's on software.
Score: 5 Votes (Like | Disagree)

Top Stories

Apple References Unreleased 2020 16-Inch MacBook Pro in Boot Camp Update

Monday October 26, 2020 8:42 am PDT by
Last week, Apple released an update for Boot Camp, its utility for running Windows on a Mac. While this update would typically be unremarkable, several of our readers noticed that the release notes reference an unreleased 2020 model of the 16-inch MacBook Pro. While this could easily be a mistake, the 16-inch MacBook Pro is nearly a year old, so it is certainly a worthy candidate for a...

MagSafe Charger Only Charges at Full 15W Speeds With Apple's 20W Power Adapter [Updated]

Monday October 26, 2020 3:38 pm PDT by
Alongside the iPhone 12 and 12 Pro models, Apple introduced a new MagSafe charger that attaches to the magnetic ring in the back of the devices, providing up to 15W of charging power, which is double the speed of the 7.5W Qi-based wireless charging maximum. Apple does not provide a power adapter with the $39 MagSafe charger, requiring users to supply their own USB-C compatible option. Apple...

Google Reportedly Pays Apple $8-12 Billion Per Year to be Default iOS Search Engine

Sunday October 25, 2020 2:59 pm PDT by
The United States Justice Department is targeting a lucrative deal between Apple and Google as part of one of the U.S. government's largest antitrust cases, reports The New York Times. On Tuesday, the Justice Department filed an antitrust lawsuit against Google, claiming the Mountain View-based company used anticompetitive and exclusionary practices in the search and advertising markets to ...

After Mocking Apple, Samsung May Remove Power Adapter From Galaxy S21 Box

Tuesday October 27, 2020 4:29 pm PDT by
Samsung's Galaxy S21, coming in 2021, may not include a power adapter or headphones in the box, according to reports from Korean media sites highlighted by SamMobile. Rumors earlier this year also said that Samsung was considering removing these accessories from future smartphone models, but that didn't stop Samsung from mocking Apple for selling the iPhone 12 models without a power adapter...

Report: Apple Silicon iMac Featuring Desktop Class 'A14T' Chip Coming First Half of 2021

Tuesday October 27, 2020 4:14 am PDT by
The first iMac powered by Apple Silicon is set to arrive in the first half of next year and will feature a desktop class "A14T" chip, according to Chinese-language newspaper The China Times. Codenamed "Mt. Jade," Apple's first custom-made desktop processor will be twinned with its first self-developed GPU, codenamed "Lifuka," both of which are being produced using TSMC's 5-nanometer process, ...

iPhone 12 Six-Foot Drop Test Results: Ceramic Shield More Durable But Not Damage Proof

Monday October 26, 2020 5:00 am PDT by
Apple's new iPhone 12 and iPhone 12 Pro feature a new Ceramic Shield screen that Apple says offers 4x better drop performance. To test that claim, Allstate Protection Plans put the two models through a range of breakability tests and recorded the results. In a face down sidewalk drop test at six feet, the iPhone 12 suffered small cracks and scuffed corners and edges, leaving sharp grooves in ...

Bloomberg: New AirPods and AirPods Pro Coming in 2021, AirPods Studio Delayed, Third HomePod Model Also Possible

Monday October 26, 2020 3:34 am PDT by
Apple plans to update its AirPods line next year with two new models including third-generation AirPods and second-generation AirPods Pro, according to a new report from Bloomberg. The Cupertino, California-based technology giant is working on two new models: third-generation entry-level AirPods and the second version of the AirPods Pro earbuds, according to people familiar with the plans. ...

2020 iPad Air vs. iPad Pro: Hands-On Comparison

Tuesday October 27, 2020 3:03 pm PDT by
Apple announced the new 2020 fourth-generation iPad Air in September, but the new tablets just started shipping out to customers last Friday. We picked one up and thought we'd do a hands-on comparison with the iPad Pro, which was last updated in March, because both tablets are about as powerful and share many similarities. Subscribe to the MacRumors YouTube channel for more videos. Design and ...

iPhone 12 Ceramic Shield Still 'Scratches at Level 6 With Deeper Grooves at Level 7' in Mohs Hardness Test

Wednesday October 28, 2020 7:10 am PDT by
iPhone 12 and iPhone 12 Pro models feature a new Ceramic Shield front cover that is "tougher than any smartphone glass," according to Apple, but the displays on the devices still have similar scratch resistance as previous iPhones based on a new test. Zack Nelson today shared his much-anticipated iPhone 12 Pro durability test on his YouTube channel JerryRigEverything, and based on the Mohs...

Apple Files Mystery 'Personal Computer' With Placeholder 'B2002' Name in Bluetooth Product Database

Tuesday October 27, 2020 12:36 pm PDT by
Last week, a listing appeared in the Bluetooth product database for an Apple product with a placeholder name "B2002" and a model number of "TBD." MacRumors was alerted to the listing by health and fitness tech website MyHealthyApple. The product is filed under the "personal computer" category, which Apple has used for previous Mac and iPad listings in the database, so it is hard to pinpoint...