Proximity sensor iphone how does it work

The "high technology" sensors as Apple calls them in the iPhone are some of the more exciting features this new device brings to the table. These sensors won't result in the iPhone doing anything other phones aren't capable of, but it will let the iPhone do it without instruction from you. This sensor detects how close the screen of the phone is to your body. This allows the iPhone to sense when you have brought the phone up to your ear. At that point, the iPhone turns off the display in order to save battery.

It also stops detecting touches, as to avoid unwanted input, until you take the phone away from your ear. This sensor detects how you are holding the iPhone. Specifically, the orientation sensor is able to determine whether you are holding the iPhone vertically or horizontally. When you raise your iPhone to your ear, its screen will automatically go dark due to the feature, saving battery and making sure you don't press any buttons.

If you don't want this feature, you're out of luck: proximity sensors are featured in every generation of iPhone going back to the year of release in , and you can't turn off an iPhone proximity sensor.

But if your proximity sensor is annoying you, you can at least make sure it's working properly. If your iPhone proximity sensor is having issues and causing frustration, here are the best ways to try to get it working properly again.

Force-restarting your iPhone can often jog the system, freeing up memory and making the hardware work properly again. Don't bother swiping to power down if that option comes up, just keep holding those buttons and the phone will soon display the Apple logo, after which it will restart itself.

And likely with sensor issues fixed. For more info, check out our article, " How to restart and force-restart any iPhone model.

Physical matter may well be the issue with your malfunctioning iPhone sensor. Remove its case and its screen cover, and set them aside. Carefully clean the front of the phone with a dry, lint-free cloth, noting that the proximity sensor is that little dot just above the speaker on the face of the phone. Raise to Wake lets you see your lock screen display wakes up when you raise your iPhone up.

If you are having this because of a hardware problem, e. Your device could be covered under warranty. You may want to make a Genius appointment. Serhat Kurt worked as a Senior Technology Director. Here is his LinkedIn profile. The iPhone has both. The Touch does not have a proximity sensor, making it a poor choice for user input.

It would be a bad idea anyway since Apple isn't obligated to locate it in the same place in future devices; you aren't supposed to know or care where it is. The proximity sensor works by pulsing an infrared LED and measuring the amount of reflectance.

You can see this using your iSight camera most digital cameras are sensitive to IR. Just launch Photo Booth, initiate a call or play a voicemail on the phone and point it at your iSight camera. Note the flashing light next to the earpiece; cover it with your finger and the screen will go black. In iPhone 3. This seems like a bug. I've encoutered this problem too. It took me a long time to figure out the real reason of why the proximity sensor is not working.

Those proximity sensors are basically a matrix of conductors. The vertical "wires" are tracks on one side of a thin sheet of insulator, the horizontal ones are on the other side. The intersections function as capacitors. Your finger carries an electrostatic charge, so capacitance of each junction varies with proximity. FETs amplify the signal and biasing sets a threshold.

In practice the circuit is more complex than that because it has to detect a relative change and reject noise. But anyway, what the sensor grid tells you is that a field effect has been sensed, and that field effect is characteristic of object about the size of a fingertip and resting on the surface of the display.

The centroid of the capacitive disturbance is computed probably by hardware and the coordinates are presumably reported as numbers on a port most likely brought to the attention of the device OS by an interrupt. In something as sexy as an iPhone there's probably a buffer of the last dozen or so positions so it can work out direction and speed.

Probably these are also computed by hardware and presented as numbers on the same port. To turn the screen off it's conceivable that more than one sensors is used to figure out if the screen should be turned off or not. The IR proximity sensor described by Cryptognome in conjunction with the Touch screen sensor described by Peter Wone could work out if the iphone is being held close to your face or something else with a slight electric charge or if its just very close to something in-animate.

Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams?

Collectives on Stack Overflow. Learn more.