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  • Joe_Fo Level 1 Level 1 (30 points)

    Hey David,

     

    So far it's worked better than I thought possible. I just had a "try again" on the angled tip of my thumb, hit sleep, positioned thumb in the same position as best I could, hit wake and it unlocked instantly. Could very well have moved slightly and touched the home button again, but wanted to convince myself it was not the case where the tip no longer worked. You might be surprised at how well it works. You could always go back to what's been working in less time than it took to write this reply

     

     

    Might want to give it a shot from the writeup as I won't have time to do a video till the weekend. Hopefully my wife doesn't have me doing other work I haven't been informed of yet.

     

    -Joe

  • Joe_Fo Level 1 Level 1 (30 points)

    Okay, this idea needs more work: For the first time ever, I'm getting failures after showering.  More  to follow. Sigh.

  • Joe_Fo Level 1 Level 1 (30 points)

    Quick note: the pressure used when enrolling a finger has a direct effect on overall TID performance. Use light pressure and I can use an angled thumb, but it fails big time after showering for quite a while before working again. This has been reported by others, I now know why. Physiological changes matter. Heavier pressure seem to even out the scanned area which seems to improve the scan.

     

    Heavier pressure, almost but not quite to the point which would actually depress the home button, fingertips and angled thumb fail, but the thicker thumb area as shown in my YouTube video is so far immune to failure, at least for me.

     

    Still looking for a happy medium solution.

  • George Guerrero Level 1 Level 1 (25 points)

    Hi Joe,

    It's been awhile since I've visited the forums on this topic. Thanks for continuing the fight. I have something very interesting to share. There's a technical podcast on the TWIT network called "Security Now" where the hosts touched on (see what I did there?!) a way to "overtrain" TouchID. Here's a link to the show — the relevant part starts at ~11:08

     

    http://twit.tv/show/security-now/440

     

    Essentially, you can continue to train TouchID beyond the initial session within the Settings app. Basically, go into Settings>General>Touch ID & Passcode, put in your passcode as prompted, and tap TouchID.

     

    You should be able to see the registered fingerprints at the bottom of the screen.

     

    Now, touch your finger to the sensor, and you will notice the respective listing for that finger briefly highlight through a shadow-flash. It's essentially registering a new sampling. This is much the same exercise as you described earlier in this thread except in a formal, controlled form. It's like a gym session for TouchID. I plan on giving it a go during edge cases like when it's cold or my fingers are dry in hopes of reducing non-responses.

     

    I really think this is the key. Have a listen to the techie explanation if you are curious, as it does make sense. It's not just registering recognition of the finger — it is signaling new data added to the sampling.

     

    <Edited by Host>

  • mrsnork Level 1 Level 1 (5 points)

    Joe:

     

    You are definitely on to something with the pressure, and it makes perfect sense.  As you note, the physiology of your finger does change the harder or softer you press down on it.  It may explain why not everybody has a problem with TID, and why Apple has been slow to acknowledge a software issue, which may or may not exist (for one finger anyway...having multiple fingers enrolled does seem to cause some sort of failure).

     

    After reading your latest post and suffering a bout of multiple "try again's" using my usual unlock method I experimented with the pressure of my thumb on the sensor.  Waking the phone (by pressing the power button or home button) and then just lightly touching the sensor gives me an unlock every time, at least in the hour or so I've been playing with this approach. 

     

    My usual method was to depress the home button and let my finger rest on the sensor to unlock, which either worked very well or quite poorly depending on the state of my fingers (temperature, dampness, dryness, etc.). It occured to me after reading your post that I wasn't depressing (or nearly depressing) the button on registration. I therefore suspect the light touch works so much better because that is the way I initially registered the print, which seems to corroborate your findings.

     

    Good job!

  • R C-R Level 6 Level 6 (16,755 points)

    George Guerrero wrote:

    Now, touch your finger to the sensor, and you will notice the respective listing for that finger briefly highlight through a shadow-flash. It's essentially registering a new sampling.

    This did not work very well for me -- I only got the shadow-flash once in about every ten tries -- but I eventually noticed something about when it did flash that might help explain why some of us are having problems with the Touch ID & possibly a way to work around it.

     

    What I noticed was that the home button sensor was not recognizing my thumb unless it covered all or almost all of the ring around the button.

     

    From what I have gathered from various sources, the way the Touch ID device works is the ring injects a tiny amount of electrical charge into the flesh of the fingertip, & the sensor in the home button reads the electrical field pattern that creates. Fingerprint ridges & some other variations in the flesh of the fingertip create a more or less unique pattern. When that pattern is a close enough match to the one(s) stored in the phone during training, the phone unlocks.

     

    So, with the realization that the sensor was not reading my thumb at all in "overtraining" mode unless most of it covered the ring, I think the root of the problem may be that just partially contacting the ring doesn't inject enough charge into the fingertips of those of us whose skin isn't very conductive for the sensor to get a good read.

     

    With that in mind, I have started being careful to cover as much of the ring as possible with my thumb every time I try to unlock the phone. This seems to be working much better than anything else I have tried (which includes every tip mentioned here). So far, the phone unlocks on the first try almost immediately at least 90% of the time. It doesn't matter how hard I press, what the angle between my thumb & the button is, or how many different registration "slots" I have used for my thumb. All that seems to matter is how much of the ring I contact.

     

    I hope this works for some of you as well as has for me.

  • Joe_Fo Level 1 Level 1 (30 points)

    R C-R wrote:

     

    [snip]

    From what I have gathered from various sources, the way the Touch ID device works is the ring injects a tiny amount of electrical charge into the flesh of the fingertip, & the sensor in the home button reads the electrical field pattern that creates.

    [snip]

     

    Sorry, but that's false info. Plastic is an insulator. Cover your finger with a plastic bag, and TID will still unlock. See demo in the video for proof.

     

    What you may be seeing is that by only partially covering the ring, parts of the finger are closer to the button and is not providing as complete a picture to match. Especially true if the finger was in complete contact when enrolled.

  • R C-R Level 6 Level 6 (16,755 points)

    Joe_Fo wrote:

    Sorry, but that's false info. Plastic is an insulator. Cover your finger with a plastic bag, and TID will still unlock. See demo in the video for proof.

    I'm not exactly sure what you mean by this. The ring is metal & does supply a charge to the finger, or at least that is what the patent filing info indicates. It is a capacitive sensing system, relying on the varying dielectric (non-conducting) properties of the finger to keep the charge from dissipating into current flow, just like in any other charged capacitor.

     

    Also, I get a zero success rate unlocking the phone with my thumb covered with even a very thin plastic bag, & I'm now getting about a 90% rate if I am careful to contact all or almost all of the ring with my thumb.

  • Joe_Fo Level 1 Level 1 (30 points)

    R C-R wrote:

     

    Joe_Fo wrote:

    Sorry, but that's false info. Plastic is an insulator. Cover your finger with a plastic bag, and TID will still unlock. See demo in the video for proof.

    I'm not exactly sure what you mean by this. The ring is metal & does supply a charge to the finger, or at least that is what the patent filing info indicates. It is a capacitive sensing system, relying on the varying dielectric (non-conducting) properties of the finger to keep the charge from dissipating into current flow, just like in any other charged capacitor.

     

    Also, I get a zero success rate unlocking the phone with my thumb covered with even a very thin plastic bag, & I'm now getting about a 90% rate if I am careful to contact all or almost all of the ring with my thumb.

    You stated "the ring supplies a charge to the finger".  If a finger is covered by an insulator, IE a clear plastic bag, what charge to the finger is being supplied? Not possible without a very expensive conductive plastic, which a Ziploc bag is not.

     

    I just wrapped a non-enrolled finger in a thin single layer of a Ziploc sandwich bag and enrolled it. It enrolled perfectly fine, and unlocked the phone as well.  Was it possible to provide a charge to my finger through the bag?

     

    I understand what you're saying, and have read the Apple doc which partially speaks to TID functionality, however I have not read the patent filing. Perhaps I should. Okay, I just skimmed over the filings. I stand corrected. My feeling was TID was more of an optical process.  Dead wrong assuming the 5S sensor is what the filings describes.

     

    Thanks for the push into a different direction. I thought my head hurt before. Have to rethink TID from a capacitive perspective rather than optical.

     

    If you watch the Apple video, you'll see incomplete contact with the ring during enrollment, at the 1:10 mark. It's also depicted with incomplete ring coverage in the picture displayed during enrollment in the "Adjust Your Grip" screen example"  I also can not get complete ring coverage using an angled thumb tip as is depicted earlier in that video. Still not clear to me that complete ring coverage is required for the purpose you state, as much as doing so ensures a more complete contact with the lens which would mean drive voltage across the device could remain constant (assuming it is not variable per sensor area) which should yield better results. Think partially out of focus in an optical sense...

  • R C-R Level 6 Level 6 (16,755 points)

    Joe_Fo wrote:

    Still not clear to me that complete ring coverage is required for the purpose you state ...

    Neither am I. All I really know is I am getting much, much better & longer lasting results when I hold my thumb so that it covers as much of the ring as I can manage.

     

    If I don't do that, the recognition rate quickly heads toward zero, even when I am careful to contact the sensor with the same lesser part of my thumb as I did when I first enrolled it, held at the same angle & with the same pressure.

     

    About the only thing I am (relatively) sure of is that the sensor uses capacitive sensing methods to read the biometric signature of the fingertip, & that (as the Apple Doc you provided the link to very briefly mentions) that involves some "subepidermal" characteristics in addition to the fingerprint pattern itself. So despite what Apple says about the sapphire cover acting as a lens, I don't think any optical sensing methods are involved.

  • Joe_Fo Level 1 Level 1 (30 points)

    R C-R wrote:

     

    Neither am I. All I really know is I am getting much, much better & longer lasting results when I hold my thumb so that it covers as much of the ring as I can manage.

     

    If I don't do that, the recognition rate quickly heads toward zero, even when I am careful to contact the sensor with the same lesser part of my thumb as I did when I first enrolled it, held at the same angle & with the same pressure.

     

    [snip]

    If you watched the video I posted, you'll see that's how I've been enrolling since Oct, only not much if any angles.  The only time I've had failures is when I've enrolled more than one finger for testing purposes, the exception being areas off center which rarely are exposed to the sensor fade away as (I believe) part of the learning process.

     

    I'm repeating myself here, but it's in a new light. The other day I wrote here about how using a much lighter amount of pressure seemed to work much better, and for the first time I was able to use the tip of my thumb in the same angled manner Apple shows. Sadly, for the first time too it failed for an hour or two after showering, something that someone in the erratic thread (paulfromnere I believe) mentioned happened routinely.  That baffled me as I've never had water related problems using my method.  Now I have to factor in the effects of a damp finger and capacitive effects and the increased noise levels due to the increased gain levels.

     

    I think I'd rather just use my method, firmer pressure, flat finger in full contact, and go on with life. Oh, and it also works with cold fingers and a cold phone. Works for me

  • R C-R Level 6 Level 6 (16,755 points)

    Joe_Fo wrote:

    The only time I've had failures is when I've enrolled more than one finger for testing purposes ...

    I have seen the same thing mentioned by a few others, but for me the number of fingers enrolled (including enrolling the same finger more than once) had made no noticeable difference. In every case, unless I'm careful to keep making sure I touch the sensor with as much of my finger as possible, the success rate gets progressively poorer with each Touch ID unlock attempt until eventually it doesn't work at all.

     

    That's what makes this so frustrating -- what works great for some users doesn't make any difference for others.

     

    BTW, I didn't mention it before, but both my wife & I have iPhone 5S models, both bought about three weeks ago at the same time from our local Apple Store, & set up with the help of store employees at that time. They are different colors but otherwise identical 16 GB models; however, their serial numbers are different enough that it seems likely they are from different production runs.

     

    Both began having the same kind of fingerprint recognition problems around 24 hours after we got them home. For our two phones, it doesn't matter whose finger(s) are enrolled with either one.

  • Joe_Fo Level 1 Level 1 (30 points)

    Thanks. Somehow I missed your post from yesterday. After reading through the patent filings today, I have a slightly better understanding of how TID works.  While a lighter pressure worked better at first, the post shower problem is a problem I'd rather not have. I've gone back to my normal one finger firm pressure when enrolled and in use. Problem after showering instantly resolved.

     

    Not done beating up on TID. I love a challenge, but it takes time to do properly, especially when only changing one variable at a time and then have to wait a few days to see if it holds up.

  • Joe_Fo Level 1 Level 1 (30 points)

    I think you're missing the point. If you're having failures as you've described you need to both watch my YouTube video (link on first page) only enrolling one finger or thumb, and now I can add use firmer pressure during the enrollment procedure.

     

    Try that before anything else.

  • R C-R Level 6 Level 6 (16,755 points)

    Joe_Fo wrote:

    I think you're missing the point. If you're having failures as you've described you need to both watch my YouTube video (link on first page) only enrolling one finger or thumb, and now I can add use firmer pressure during the enrollment procedure.

     

    Try that before anything else.

    Please believe me, I have tried everything you have suggested here, everything in your video (which I did watch carefully), the "overtraining" approach mentioned by George Guerrero (& watched the referenced TWIT video carefully too), & every other suggestion I could find.

     

    That includes but is not limited to enrolling only one finger, enrolling one finger multiple times, using light or heavy pressure; plus restarting, resetting, or even restoring the iPhone for each new test.

     

    But no matter what I try, if I am not careful to cover as much of the sensor as possible every time I try to unlock the phone, my success rate begins to decline & eventually goes to zero. Moreover, this is true for both our phones, using any combination of one of our phones & one (or more) of our fingers.

     

    For our phones, it does not matter in the least if we enroll just one finger or several. Unless we are careful to cover the sensor during unlock attempts, each finger has its own limited lifespan, so to speak. IOW, if a thumb & say an index finger are enrolled, each of them works for a while & then does not, independently of the other digit.

     

    That's what I meant about what works for some doesn't for others. If you wade through all the stuff on the web about this issue, that becomes evident -- just about every suggested method or technique has its share of successes, but there are also too many reported failures to dismiss them all as the result of not following the instructions carefully enough.