How does iPhone4s activate Siri when you put it to your ear?

Discussion in 'iOS 5 and earlier' started by nini1026, Dec 14, 2011.

  1. nini1026 macrumors newbie

    Oct 29, 2011
    Hi, guys.
    Does somebody know how iphone-4s activate Siri when you put it to your ear?
    Which sensor that it has really make it work?

    I was trying to figure out that, but get frustrated..
    Proximity sensor, magnetometer,illuminance sensor,gyroscope ...

    Can somebody simply explain which sensor it use and how it works in S/W aspect?
  2. Slix macrumors 6502a


    Mar 24, 2010
    It's most likely the combination of proximity sensor and accelerometer.
  3. WordMasterRice macrumors 6502a

    Aug 3, 2010
    Upstate NY
    Do you know what an interrupt is in hardware/software?
  4. Julien macrumors G4


    Jun 30, 2007
    The same way the iPhone (from the original) knows how to cut off the screen when you rase it to your ear.;)
  5. BaldiMac macrumors 604


    Jan 24, 2008
  6. nini1026 thread starter macrumors newbie

    Oct 29, 2011
    I guess so.
    I did learn it.
    Let me take a proximity case as an example,
    if you put your ear over the proximity sensor when you get a call,
    the sensor an H/W interrupt to iPhone's AP chip(A5).
    Then iOS would call ISR(interrupt service routine) that it maps with that H/W interrupt, which would be turning off the screen.

    Now am I ready to hear your lesson???


    It should only happen when you get a call.
    Normally(for Smartphone) mobile only wake up a proximity sensor when you get a call to find out right timing to switch off the screen.

    But I'm not really sure how the Smart iPhone really use the the sensor.....


    Thank you so much.
    I've just go through it.
    But still not really get it.
    If IR sensor is the core part, siri also has to be activated if you put your parm
    on the device.

    Plz, somebody let me know this puzzle..:confused:
  7. Jimbo47 macrumors 6502a

    Jun 21, 2010
    It has to use the accelerometer too. You're right, when you cover the sensor it doesn't activate. It takes the phone being pulled up (forcefully for it to work for me) then covering the sensor for it to activate.
  8. thelatinist macrumors 603


    Aug 15, 2009
    Connecticut, USA
    When it was first announced it was explained as a combination of IR proximity sensor and accelerometer data. When you swing your phone up to your ear, it moves in a characteristic arc in three dimensions. Combine that arc with sudden proximity to an IR-opaque object and the software interprets it as raising the phone to your ear.

    I can duplicate it against my palm, but it takes effort.

Share This Page