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Can anyone explain to me what is the purpose of the proximity sensor, on my phone. What if my phone's proximity sensor stops working or gets damaged. What problems will I face?

PS: I am just curious to know.

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9 Answers 9

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The proximity sensor on most smart-phones with touchscreen exists to disable accidental touch events. The most common scenario is the ear coming in contact with the screen and generating touch events, while on a call.

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mobile phones use IR-based proximity sensors to detect the presence of a human ear. This sensing is done for two purposes: Reduce display power consumption by turning off the LCD backlight and to disable the touch screen to avoid inadvertent touches by the cheek. IR sensors have a number of disadvantages, including high power consumption, high cost, blind zones, and accumulation of dirt, as well as unreliable performance over temperature, hair, and skin color variations.

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    There are also capacitive proximity sensors. By the way, an interesting application for the IR LED in the proximity sensor is also eye tracking when taking photographs (using the sensors IR light reflected from the cornea which is visible for digital cameras to learn the eyes location). It's also sometimes used to automatically switch to the loudspeaker.
    – ce4
    Dec 5, 2014 at 14:39
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    I guess a proximity sensor that uses IR when combined can also be used to prevent taking a picture of a person when their eyes are closed. IR sensors are also called light sensors and are a kind of optical sensors.
    – John Sonderson
    Dec 8, 2014 at 17:20
  • "high power consumption" comparing to what alternatives on the topic?
    – Marian Paździoch
    Jan 9, 2020 at 10:51
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It prevents that your ear is doing input actions on the touchscreen when you are making a call. :)

Most proximity sensors are simply light sensors that will detect "proximity" when they are covered.

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Developers can get access to the sensor and use it for other things. At a users suggestion I use it in my biking app IpBike to wake up the screen. The user just has to wave there hand over the sensor and the screen switches back on. Very handy when cycling with gloves on.

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Another usage for the proximity sensor is to detect while it's in pocket and disable accidental touch or power button press.

Keep screen off when proximity sensor is covered (in pocket)

In Moto Gx series (and I believe in Moto Z and Moto X also) if you pick the phone out from pocket or move the phone while it's laying on the table it'll show up the screen for fast unlock and a quick glance at notification. If you cover the proximity sensor while it's in static state for a while and uncover it you'll see the same effect

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When you get a call in a touch screen smart phone, when your phone get closer to ear or any body part the phone screen get off. That is done by the proximity sensor. Proximity sensor is responsible to heat and when a body part get close to sensor the screen gets off and it prevents accidental touches in the screen. In some smart phones proximity is used to keep the screen off when the mobile phone is in the pocket(pocket mode). If you loose functioning of proximity sensor, your phone will make accidental touches when your phone is in the pocket or when you gets a call.

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Proximity detector is non contact type displacement sensor i.e proximity sensor used to are sense and indicate target presence of object to without physical contact.

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In simple proximity sensors are light sensors. It turns the screen off while you are making an call.

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  • Welcome to the site! This answer doesn't add a lot to the existing answers. Try to find a question that needs more information.
    – Dan Hulme
    Jul 6, 2013 at 10:49
  • Your answer is only partially correct. As this site points out, while light sensors are among the cheapest kinds of proximity sensors and are the way proximity sensors are implemented on most mobile phones, there are also other kinds of proximity sensors such as electrical, magnetic, and sonar based.
    – John Sonderson
    Dec 8, 2014 at 17:23
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The following explanation appears in the instruction manual for most LG phones:

The proximity sensor automatically turns the backlight off and locks the touch screen by sensing when the phone is near your ear. This extends battery life and prevents you from unintentionally activating the touch screen during calls.

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