Barometer sensor in iphone6

Discussion in 'iPhone' started by ApplePhy, Nov 13, 2014.

  1. ApplePhy macrumors 6502

    Joined:
    Nov 7, 2013
    #1
    I just realized this week that the iPhone barometer cannot differentiate steps walked up a certain number of floors vs taking an elevator.

    The health app always displays 'floors climbed' to reflect the numbers of floors I ascend in an elevator. This is obviously misleading, since one is not actually walking up a flight of stairs, rather taking a ride in an elevator.

    Does anyone know of any apps that can help differentiate steps taken vs floors ascended on an elevator?

    For example, if I work on the top floor of the John Hancock building in Chicago and take the elevator, I don't want my Health App to say I 'climbed' 100 floors!
     
  2. Tyler23 macrumors 603

    Tyler23

    Joined:
    Dec 2, 2010
    Location:
    Atlanta, GA
    #2
    It does differentiate that, at least for me. I assume it takes in to account when the phone is moving, as if you're walking, and the elevation is increasing to count as steps climbed. I take the elevator at work up and down probably 3-4 times a day, 5 flights each way, and it only reflects flights climbed that I've climbed up to my apartment. It does not show my elevator rides as flights climbed.
     
  3. jim.hickman.777 macrumors regular

    Joined:
    Sep 14, 2014
    #3
    We don't have any 2 story buildings in my town can't verify
     
  4. GoSh4rks macrumors 6502

    Joined:
    Sep 14, 2012
    #4
    Is there any confirmation at all that the health app uses the barometer in this fashion? Altimeters aren't that accurate, especially with no calibrated reference point.
     
  5. Ntombi macrumors 68030

    Ntombi

    Joined:
    Jul 1, 2008
    Location:
    Bostonian exiled in SoCal
    #5
    I never have that problem. Because of mobility issues, I only climb stairs when I have no choice. My phone shows that I have climbed a total of two flights since launch day, which is accurate.

    I even use a stairlift in my home, and the iPhone has never once counted that as a flight of stairs.
     
  6. freeskier93, Nov 13, 2014
    Last edited: Nov 13, 2014

    freeskier93 macrumors 6502

    Joined:
    Jul 13, 2008
    #6
    Do not confuse an analog altimeter used in small planes with the digital barometer used in the iPhone. Digital barometers are extremely accurate at measuring relative altitude changes, which is really all that's needed here. There are various apps you can download that give you the raw pressure and relative altitude data. The iPhone appears to have resolution down to a thousandth of a foot.

    EDIT: Upon further investigation, the iPhone 6/+ uses a Bosch BMP280 which has resolution of 1 Pascal, which is roughly a resolution of 4 inches. This means the app I am using carries to many significant figures for the altitude calculation...

    http://www.bosch-sensortec.com/en/homepage/products_3/environmental_sensors_1/bmp280/bmp280
     
  7. Mr. Buzzcut macrumors 65816

    Mr. Buzzcut

    Joined:
    Jul 25, 2011
    Location:
    Ohio
    #7
    From your link, accuracy is +/- .12 hPa. 1 hPa is equivalent to about 8 meters. This agrees with the stated accuracy of 1 meter. Not bad really but a lot more than 4 inches.
     
  8. freeskier93 macrumors 6502

    Joined:
    Jul 13, 2008
    #8
    I never said anything about accuracy, I'm talking about resolution (not the same things). You have to consider the application here. In context of the thread and measuring flights of stairs the value of the data isn't very important, it's how the data changes.

    Accuracy would be important if you wanted to calculate air density for example, then use it for further calculations.

    Either way though the sensors are still very good.
     
  9. Mr. Buzzcut macrumors 65816

    Mr. Buzzcut

    Joined:
    Jul 25, 2011
    Location:
    Ohio
    #9
    Resolution is meaningless without accuracy. The value I referenced is relative accuracy which is what you want for measuring change in pressure. Absolute accuracy is less.
     

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