Anyone elses compass not work while in a car?

Discussion in 'iPhone' started by Senn, Jun 19, 2009.

  1. macrumors member

    Jun 10, 2009
    So the compass app and the compass feature in google maps does not work while Im in my car. It says there is interference and it cant calibrate. If I get out of my car it works fine.

    If the metal in a car does indeed interfere with the compass..then this is completely useless. I was only happy because I thought it could tell which direction Im heading while driving..and so far that doesnt work.
  2. macrumors regular

    Mar 8, 2008
  3. Guest


    May 26, 2004
    Randy's House
    Your car is a big hunk of metal, that's what is interfering.

    The compass is intended for foot use.
  4. macrumors 6502a


    Jul 3, 2007
    The Lone Star State
    Sorry...but just metal should not interfere.... Now maybe there are some electronics or an in-car compass that is interfering....but not the frame of the car.
  5. macrumors 68000


    Jul 27, 2003
    From Apple:

  6. macrumors regular

    Dec 22, 2008
    How come my google maps isn't showing the direction I am pointed? I thought that was a feature

    edit: NVM tap the location button twice
  7. macrumors 65816


    Oct 4, 2003
    Just stick your arm out the window to use the compass. :p
  8. macrumors regular

    Jul 6, 2007
    New Jersey
    How to RE-calibrate?

    I've read a few threads here about the compass being inaccurate. I, too, have been having issues. In maps, my location is accurate, my the direction I'm facing is like 45 degrees off.

    After the initial calibration I have not been able to get the option to calibrate again. Does anyone know how to re-calibrate?

    It's very minor, I know. But it's just frustrating.
  9. macrumors 65816

    Oct 18, 2007

    Apparently you don't know anything about magnetism, magnetometers or compasses. Do some research into magnetic deviation related to a compass. All boats that rely on a magnetic compass for navigation have a deviation table plotted for all points around the compass. The amount of error will be different in any particular direction. The table allows you to correct for the deviation.

    A car not only has a shell of metal and a frame of metal but also a huge hunk of metal called an engine. That engine also has an alternator attached that creates it's own magnetic field. ALL of these things will interfere with the proper use of a compass. Turn off the car and you'll still have problems (electronics eliminated). Get out of and step well away from the car and the problem disappears.

    The calibration will help within the car but once outside of the car it will no longer be calibrated because the same forces affecting it for the calibration are not involved.
  10. macrumors 6502a


    Jul 30, 2007
    Austin, TX
    I don't even get the figure 8 motion...what is going on with that?

    I still don't know how to get it to work in the car. I tried waiting and it does it sort of in the background but not as great as it could be (and is very wobbly)
  11. macrumors member

    Jan 25, 2009
    i too am really curious on what we are exactly doing when we move it in the figure 8 motion. being an electrical engineer i admit i am very nerdy with these types of electronics, but i can't come to a conclusion on what we are actually doing when we do that. i was thinking that a gyro-type device is used in conjunction with the magnetometer, but i don't see any way how moving it in a figure 8 motion is tied to a magnetic-only device. :confused:
  12. macrumors demi-god


    Jun 9, 2007
    Device engineer 30+ yrs, touchscreens 24+.
    My Grand Cherokee required that I drive in a circle three times to calibrate its onboard compass.

    From what I can tell, magnetometer makers have proprietary algorithms for self-calibration that you can license and use in your OS code.

    My guess is the figure-8 is used to average out any magnetic anomalies around you.
  13. macrumors 68020

    Jul 11, 2008
  14. macrumors 601


    Jul 24, 2008
    Pacific Northwest, US
    Yes, for Apple trying to sell iPhones. :p

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