This is a picture of my iPhone 4 that I just took with an infrared-capable camera. As you can see, there is a light on top, around the middle. You can only see it with with an infrared-enabled camera, and it usually blinks whenever the screen is lit up and turns off when the screen gets turned off.

enter image description here

I find it super creepy, and would LOVE to turn this thing off. Whether I'm in my right mind to freak out about something that is a) concealed (not visible by human eyes) and b) whose purpose is super shady is really mostly my problem, but I'd love to know if it can be done. Besides from the freaky part, I used to be able to use my iPhone 3gs all day long with the same charge and the battery on this sort of newer iPhone 4 has a much lower duration, maybe because this little light-thing blinks so much all the time?

The information I've found online mentioned Siri being the cause of this, so I turned off Siri. Before I took the picture.


Well, that is the proximity sensor which should detect when you hold the phone to your ear and turn off the touch screen, etc. On my iPhone 5 it is only active when I make a phone call or use a App that uses it (e.g. SmartSleep). It is also visible to the eye when you are in a dark room.

These (rather old) articles (1, 2) has more info and states that this is a known problem on the iPhone 4. They suggests to try the following:

  • Hard reboot (hold power and home button until the Apple logo appears again)
  • Reset your settings (Settings > General > Reset > All Settings)
  • Reset Network setting (Settings > General > Reset > Reset Network Settings)

After resetting you should also reboot the device.

  • Hi! Thanks. What informations can possibly be lost during a hard reboot / reset? Jul 23 '15 at 9:57
  • It is a safe procedure. I do it regularly. Maybe make sure that you close open apps: Press home button twice and slide the app upwards.
    – n1000
    Jul 23 '15 at 9:59
  • it is unclear in your answer, whether this infrared light is supposed to be blinking like that all the time, what type of information it records (constant calculation and recording of user proximity top device? why, to avoid lawsuit in case of health problem?) and whether or not disabling it will make the screen go dark when i place the device on my ear. Aug 16 '15 at 23:47
  • @fabriced The sensor normally only turns on when you make a phone call or an App requests it. It simply measures if an object is close to the device. If so the screen is turned off. What health problem? Read about infrared. It is actually a light naturally occurring at the lower end of the visual spectrum and also known as heat emissions. You cannot disable it in iOS.
    – n1000
    Aug 17 '15 at 5:24
  • Thank you! I know what infrared is (I took the picture in the original question using ... an infrared sensitive camera I own). I was talking about EMR related health problems. But it was off topic! So everything is okay now. Aug 17 '15 at 14:15

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .