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  1. #21  
    Quote Originally Posted by ananimus View Post
    Also, just to be clear, I thought the magnets were in the TS and that the plugs in the phone were just magnetic (but not magnetized) metal?
    Correct. Magnets are in the Touchstone. All that is in the phone back are small bits of metal that attract to magentas.

    The Pre3 has a compass too, IIRC, so toss that theory.

    You don't really want magnets in the phone. But the TS is fine.
    Did you know:

    webOS ran on a Treo 800 during initial development.
    Rnp likes this.
  2. #22  
    I've put magnets in phones. Not an issue. Compass calibration just subtracts the fixed offset from future readings.

    -- Rod
  3. #23  
    Quote Originally Posted by rwhitby View Post
    I've put magnets in phones. Not an issue. Compass calibration just subtracts the fixed offset from future readings.

    -- Rod

    Not an 'issue' perhaps, until you slide one of these magnet-phones into your pocket next to your wallet and wipe your credit card clean of all it's info! - (Although maybe, that's not necessarily such a bad thing!).


    TP 32Gb 4G. 3.0.5 / CM10. ~ Pre3 16Gb GSM. 2.2.4. ~ TS2 BT Audio-Dock ~ HP iPaq. hx-2790b.
    TP 32Gb Wifi. 3.0.5 / CM10. ~ Veer (Wht.) 8Gb GSM. 2.2.4. ~ HP Omen-15-5206tx. 256Gb SSD. i7-O/C@3.39Ghz. Win10.
  4. #24  
    Quote Originally Posted by Mutoidi View Post
    Not an 'issue' perhaps, until you slide one of these magnet-phones into your pocket next to your wallet and wipe your credit card clean of all it's info! - (Although maybe, that's not necessarily such a bad thing!).

    You may like to watch the Mythbusters episode about that...

    -- Rod
    karstenskov likes this.
  5. #25  
    Quote Originally Posted by rwhitby View Post
    You may like to watch the Mythbusters episode about that...

    -- Rod
    They prove that it's just another 'myth' to they?
    Actually magnets are supposedly good for easing Arthiritis too! (Unless that's also a myth!).

    What about Pacemakers?

    ~*~

    TP 32Gb 4G. 3.0.5 / CM10. ~ Pre3 16Gb GSM. 2.2.4. ~ TS2 BT Audio-Dock ~ HP iPaq. hx-2790b.
    TP 32Gb Wifi. 3.0.5 / CM10. ~ Veer (Wht.) 8Gb GSM. 2.2.4. ~ HP Omen-15-5206tx. 256Gb SSD. i7-O/C@3.39Ghz. Win10.
  6. #26  
    Quote Originally Posted by Mutoidi View Post
    They prove that it's just another 'myth' to they?
    Actually magnets are supposedly good for easing Arthiritis too! (Unless that's also a myth!).

    What about Pacemakers?

    ~*~
    Let's keep this thread on-topic please....
  7. #27  
    Quote Originally Posted by HelloNNNewman View Post
    Let's keep this thread on-topic please....
    OK, apologies - as this General News and Discussion 'topic' appears to be magnetism vs. squidgy stuff - I just ran a compass app with the phone on a (magnetic) Touchstone and it didn't appear to know where to look for 'N'. (And luckily as I don't have Credit, Arthiritis or a Pacemaker - I may well magnetise my phone too!).

    Last edited by Mutoidi; 04/15/2013 at 04:11 PM.

    TP 32Gb 4G. 3.0.5 / CM10. ~ Pre3 16Gb GSM. 2.2.4. ~ TS2 BT Audio-Dock ~ HP iPaq. hx-2790b.
    TP 32Gb Wifi. 3.0.5 / CM10. ~ Veer (Wht.) 8Gb GSM. 2.2.4. ~ HP Omen-15-5206tx. 256Gb SSD. i7-O/C@3.39Ghz. Win10.
    HelloNNNewman likes this.
  8. #28  
    reality hurts

    outstanding article Derek
    32G Touchpad
    iphone 5 on sprint wouldn't leave a good relationship
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       #29  
    Quote Originally Posted by rwhitby View Post
    You may like to watch the Mythbusters episode about that...

    -- Rod
    Rod, I love the work you're doing and I especially enjoyed the post you had on Android Central the other day. You might remember, I called that one guy out who was mocking you and he then got destroyed by everyone. Keep up the great work, I've enjoyed following you all these years and will continue to do so on Android. (I split my time 50/50 now, but when I upgrade to a new Android device who knows what will happen.)
    Proud owner of a 16GB HP Touchpad since 10/26/2011!
    Proud PALM user since the Palm III in 2002
  10. #30  
    Quote Originally Posted by rwhitby View Post
    You may like to watch the Mythbusters episode about that...

    -- Rod
    I didn't watch, but found a 'report' that Derek also seems to mention below, on what is presumably the same episode you refer to?

    "..The first thing that comes to mind is credit cards and access/ID cards. Every credit card and most state/federal/corporate ID’s have a magnetic strip across the back that can be disrupted by magnetism. Thankfully, since these cards’ magnetic strips only need to be written once, they are what’s called high-coercivity strips and are thus not very coercive to magnetic interference (as tested by Mythbusters). But hotel room key cards are a different story; they use low-coercivity strips to allow easy and quick rewriting for new customers, and are thus prone to failure in the face of magnetism. You or somebody you know has had a hotel key card stop working and the only explanation you (and the front desk) could conjure was that your cell phone had killed it. Most cell phones don’t even have magnets and yet are capable of causing wanton key card destruction, let alone the low-but-powerful-enough magnets in the Touchstone back."

    PSA: Your Touchstone Battery Door Has Magnets in it. | webOS Nation

    (Actually, it appears that the standard Pre3 Touchstone Battery door at least, does not seem to hold 'magnets' as such at all, but magnetically attractive discs that sit between the + & - poles of each of the actual high power magnets in the Touchstone itself?).

    ~~~

    Here is the Mythbusters 'test' mentioned above:

    "..Then try and determine how much magnestism it would require to wipe a card. Using an electromagnet, they determine it would take at least 1000 gauss to wipe a card. The Earth's magnetic field is one gauss. They look at a number of household objects and they only get as high as 70 gauss which is no where near the needed 1000. To finally prove the myth busted, they put a credit card in a tank of electric eels and again nothing happens.."

    MythBusters/Barrel of Bricks, Pissing on the Third Rail, Eel Skin Wallet - The TV IV

    (EELS? I thought we were talking rare earth magnets here?

    ~~~

    Also here is brief extract on the 'Gauss' rating of various magnets:

    "..Ferrite (also known as ceramic) magnetic assemblies typically have a gauss rating of 1500-2000 gauss.."
    "..Rare Earth magnets can achieve strengths of up to 12000 gauss and therefore give a far superior performance.."

    Magnet Strength (Gauss) Testing

    However:
    "..the peak field areas on the outside of the (neodyium) magnet will only be a couple of millimetres away from the middle of the field. Now moving just another couple of millimetres away gives you 1/8th field strength.."

    Rare earth magnets for fun and profit

    (So field strength is exponentially related to distance).

    ~~~

    Regardless, I have since fitted x 8 rare earth magnets to a Pre3, which locks it to a Palm Touchstone like glue!
    The original discs now barely adhere to the back of the phone however.

    make your classic touchstone hold your pre 3 better
    @ #102.

    But on running the 'Quick Compass' App with it's 'N' oriented towards magnetic North, there appears to be a wild variation in readings with the back cover (and magnets) fitted and after a reset, with the back cover removed. (Screenshots).
    It therefore appears that the magnets are distinctly influencing the phone's magnetic compass readings - or at least limiting it's ability to compensate?

    ~*~

    Attached Images Attached Images
    Last edited by Mutoidi; 04/20/2013 at 01:20 PM.

    TP 32Gb 4G. 3.0.5 / CM10. ~ Pre3 16Gb GSM. 2.2.4. ~ TS2 BT Audio-Dock ~ HP iPaq. hx-2790b.
    TP 32Gb Wifi. 3.0.5 / CM10. ~ Veer (Wht.) 8Gb GSM. 2.2.4. ~ HP Omen-15-5206tx. 256Gb SSD. i7-O/C@3.39Ghz. Win10.
    ananimus likes this.
  11. #31  
    Nice, Mutoidi! This last part is what I was worried about. Naively believing that a digital compass bears any resemblance to an actual compass (small magnetic moment that aligns to external fields), I would be concerned that very strong, local, permanent magnetization would make it impossible to calibrate away at some point.

    It's the magnetic equivalent to signal-to-noise ratio, if you consider the magnets' field as the noise and the earth's the signal. If the field of the magnets at the digital compass start to equal to or larger than the earth's field, it will effectively pin the compass in place, confusing the hell out of the thing. It's a bit like putting a weak FM transmitter directly on top of a radio that's trying to receive the signal from a distant radio station. At some point, if the little transmitter is just strong enough, it wins by proximity and screws up the fuzzy signal from afar.

    Now then, fields drop off quickly. So as long as the distance from the magnets to the compass are sufficient that the local field at the detector is less than 1 milli-Tesla, then maybe it is some constant background offset that can be subtracted away.

    This would very likely be true using magnetic, but not magnetized discs. It's rather unlikely, given the size of the phone, when using strong rare earth magnets. (My two cents.)
  12. #32  
    Although, to be fair, magnetic field sensing is also directional. So you win a bit if all of them are roughly in the same plane. The compass is most effiective parallel to ground, and the field from the magnets would be perpendicular to that. So you're going to be less sensitive by some decent geometric factor, but still.
  13. #33  
    I think you may be correct.. and that compensation is not effectively occurring.
    Certainly the needle in 'Quick Compass' is both locking and also twitching strangely - perhaps as an internal battle to register the relevant/dominant field rages!
    In fact even 'Marine Compass' which is GPS driven, tips on its side when this (rare earth magnet containing) phone is placed (either way up) upon it's Touchstone now.. so perhaps even the 'Gyro' is also being affected somehow?

    Also, just because the 'screen' may be paralell to the Earth's surface whilst making a compass reading - does that necessarily mean that the field of the internal compass 'magnet' is also in that plane.. thereby perhaps not effectively running at 90* to the field of the rare earth magnets now in the battery door - or for that matter, those of Earth's field lines?

    We don't know!

    We don't even really understand 'how' Gravity works yet either (or do we?).
    - Least of all 'Anti-Gravity'!
    Electro-Gravetic Fields are a major key to our future-tech I believe - but first webOS-tech!

    Last edited by Mutoidi; 04/20/2013 at 04:58 PM.

    TP 32Gb 4G. 3.0.5 / CM10. ~ Pre3 16Gb GSM. 2.2.4. ~ TS2 BT Audio-Dock ~ HP iPaq. hx-2790b.
    TP 32Gb Wifi. 3.0.5 / CM10. ~ Veer (Wht.) 8Gb GSM. 2.2.4. ~ HP Omen-15-5206tx. 256Gb SSD. i7-O/C@3.39Ghz. Win10.
  14. #34  
    Alright, had to check some dirty calculations. Assuming:
    1) Magnet has 1 T surface field, pointed to the sky
    2) Sensor detects field parallel to ground and
    3) 25 mm distant from axis of magnet and
    4) The magnet is not exactly in the same plane as the sensor (5-deg off)

    I estimate about a 10 uT in-plane permanent background, ballpark. Best guess of course, but that puts it right on par with the earth's field (tens of uT, depending on latitude).

    If instead it were a hard ferromagnetic slug, it would retain maybe half of the field it sees. In that case the pellets in the back plate would hold a remnant field big enough to see with a simple paper clip test, and still big enough to possibly interfere when off the TS.

    A soft ferromagnet would lose at least an order of magnitude more, and is what I think is in the Pre 2 and 3 backplates.

    But back to the practical test: you see it wreaking havoc. Mind you, there's some recalibration that needs to be done to know for sure. Also, Rod had mentioned "not using it," but I wonder that some apps that are compass aware might try to use it when you're standing still to figure out a bearing, particularly on Android. I imagine standing still and having the map flicking back and forth unless the compass were recalibrated or altogether disabled.
  15. #35  
    im guessing that with the magnets typically being in the touchstone and not phone that even if the phone compass does go banannas with extra/different magnets that it only applies to when its sat on the touchstone?

    seems fair enough given that i probably dont want/case about a compass going insane while its charging so long as nothing breaks afterwards when you need to use it afterwards.
    Touchpad Keyboard Themes - >> Click Me <<
  16. #36  
    Quote Originally Posted by HelloNNNewman View Post
    The Touchstone2 dock was going to retail around $50 and was 2 weeks into beta testing when HP killed everything off. It did fit the Pre3 perfectly and was nice looking when used.
    Another case where we need a 'webOS Rage' button beside 'Thanks' and 'Like' ....
    White Z10, Touchpad 16GB [Retired: Pre 3, Pre 2, Pixi Plus, Pre Plus]
    Back on a BlackBerry after 2 1/2 years with WebOS.

    One-step Picasa batch image upload: http://forums.webosnation.com/hp-tou...ecl-webos.html
    geekpeter and ananimus like this.
  17. #37  
    Quote Originally Posted by ananimus View Post
    Alright, had to check some dirty calculations. Assuming:
    1) Magnet has 1 T surface field, pointed to the sky
    2) Sensor detects field parallel to ground and
    3) 25 mm distant from axis of magnet and
    4) The magnet is not exactly in the same plane as the sensor (5-deg off)

    I estimate about a 10 uT in-plane permanent background, ballpark. Best guess of course, but that puts it right on par with the earth's field (tens of uT, depending on latitude).

    If instead it were a hard ferromagnetic slug, it would retain maybe half of the field it sees. In that case the pellets in the back plate would hold a remnant field big enough to see with a simple paper clip test, and still big enough to possibly interfere when off the TS.

    A soft ferromagnet would lose at least an order of magnitude more, and is what I think is in the Pre 2 and 3 backplates.

    But back to the practical test: you see it wreaking havoc. Mind you, there's some recalibration that needs to be done to know for sure. Also, Rod had mentioned "not using it," but I wonder that some apps that are compass aware might try to use it when you're standing still to figure out a bearing, particularly on Android. I imagine standing still and having the map flicking back and forth unless the compass were recalibrated or altogether disabled.
    Thanks for doing the Maths!
    So, there is a very fair chance that the Pre3's magnetic compass is being 'influenced' by the rare earth magnets fitted into it's back cover ~ (@ geekpeter - whether it is on the dock or not!).

    But I also made the assumption from what Rod was saying, that the compass *automatically* re-calibrates and makes compensations for itself ~ but perhaps this is not the case? Is there a 'manual over-ride'?

    Certainly after some more tests I have found the needle in 'Quick Compass' to still lock and twitch, apparently randomly - and when reorienting the phone, often the needle just follows the phone! This indicates to me that it is listening, not to the Earth's field, but to over-riding influence the fields of the (rare Earth!) magnets in it's own back door ~ yes!

    I have not encountered any spinning maps yet ~ but a Patch to disable compass may be a good safeguard?

    Hey ~ the Sun always (so far) sets in the West anyway!

    Last edited by Mutoidi; 04/24/2013 at 03:44 PM.

    TP 32Gb 4G. 3.0.5 / CM10. ~ Pre3 16Gb GSM. 2.2.4. ~ TS2 BT Audio-Dock ~ HP iPaq. hx-2790b.
    TP 32Gb Wifi. 3.0.5 / CM10. ~ Veer (Wht.) 8Gb GSM. 2.2.4. ~ HP Omen-15-5206tx. 256Gb SSD. i7-O/C@3.39Ghz. Win10.
  18. #38  
    Ha... Well, the maths may be overkill. Practically speaking, adding a 1 T magnet next to a compass hunting uT fields isn't savvy. Interesting to me though the relevant field is that *small* at the compass, though I was being aggressive (it's likely higher). Does show that a soft slug should be plenty okay though.

    And yeah, it's not clear to me when/how the calibration is done on webOS or Android. As I understand it, calibrations involve moving the phone around in a figure 8 or something.
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