iPad Pro According to John Gruber Apple Pencil doesn't need any extra hardware/sensor on the iPad Pro display

Discussion in 'iPad' started by mdridwan47, Nov 24, 2015.

  1. mdridwan47 macrumors 6502

    mdridwan47

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    Jan 20, 2014
    #1
    Apparently the display is still the same as other iOS devices. The Apple pencil emits radio waves on the display to register drawings.

    I didn't know that. He isn't 100% certain either. Is it true?

    Listen from the 7:20 mark.
    http://daringfireball.net/thetalkshow/2015/11/21/ep-136
     
  2. Fuchal macrumors 68020

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    #2
    If it's true then it would work on an iPad Air as long as the Pencil is on, since the iPad doesn't care it's a Pencil. Does it?
     
  3. mdridwan47 thread starter macrumors 6502

    mdridwan47

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    #3
    That's what I'm thinking.. It should work on iPhone 6 too..
     
  4. KPOM macrumors G5

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    #4
    It doesn't work on any other iOS device. The iPad Pro scans at 240hz when it detects the Pencil, which reduces the latency and improves the accuracy.
     
  5. drz macrumors newbie

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    #5
    Does that mean the display's refresh rate is 240hz? I find that hard to believe, but would be cool if it was true.
     
  6. bcaslis macrumors 68020

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    #6
    He's speculating. In Apple's own iPad Pro video they talk about making the display different to have a more accurate digitizer. There is no way it's the same as other iPads.
     
  7. Phonzoxd macrumors 6502

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    #7
    So hes wrong? I dont understand, why dont he just test it on any other ios device?
     
  8. bcaslis macrumors 68020

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    #8
    It's already been tested by many on other iPads. It only works on the iPad Pro. Just like Apple says.

    And to be fair to Gruber, the OP is misinterpreting. Gruber in his podcast speculates that the Pencil uses radio. But he never says it works with other iPads.
     
  9. modernaccord macrumors 6502a

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    #9
    I believe he's trying to say that the Apple Pencil would theoretically work on other iOS devices, but the iPad Pro has a more advanced display so that the pencil can be accurate and interface with it. An iFixit teardown of iPad pro did reveal an extra chipset for Pencil input, so obviously there's something going on.

    I'm sure getting the Pencil to work on other iOS devices isn't too hard, but it would require additional hardware to be built into the device.
     
  10. mdridwan47, Nov 24, 2015
    Last edited: Nov 24, 2015

    mdridwan47 thread starter macrumors 6502

    mdridwan47

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    #10
    I said verbatim,

    "I didn't know that. He isn't 100% certain either. Is it true?"

    I didn't say that he said it.
     
  11. aevan macrumors 68000

    aevan

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    #11
    John Gruber is a smart guy and his podcasts are great but he is not, in fact, that tech savvy and he's most likely wrong about this. The Pencil is not capacitive so there must be a different tech inside the iPad itself that detects position.
     
  12. KALLT macrumors 601

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    Sep 23, 2008
    #12
    Obviously the touch screen must have the capacity to register/receive the input of the Pencil. There is not anything in other iOS devices that would be capable of doing this and we also know that the touch screens of these devices are not nearly as precise to make this work. The Pencil alone is not doing anything on these devices that could not be replicated by an ordinary stylus.

    Because you cannot rule out that way that it is technically impossible to make it work. Apple is known to artificially restrict features with software. It seems that nobody outside Apple knows the secret yet.
     
  13. AceFernalld macrumors 65816

    AceFernalld

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    #13
    If there wasn't additional tech in the display, why are Pencil touches registered before contact is made?
     
  14. mdridwan47 thread starter macrumors 6502

    mdridwan47

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    #14
    According to Gruber, Apple pencil emits radio waves on the display to register contact.
     
  15. AceFernalld macrumors 65816

    AceFernalld

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    #15
    Hmmmm... Interesting. I want a full technical breakdown of how this all works, some really fascinating technology and 'insanely great' execution if I do say so myself.
     
  16. Rogifan macrumors P6

    Rogifan

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    #16
    Gruber doesn't know he's just guessing.
     
  17. LunaC macrumors member

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    #17
    A regular old Samsung S5 can have the sensitivity turned up so that a regular #2 pencil will work great, nothing special needed as it is in the settings. I wanted to see if I could discover how via BT to initiate the other mode on the iPP but now someone else will have to.
    Ive wondered if a regular iPad could be done the same way for a long time.
     
  18. Atomic Walrus macrumors 6502a

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    #18
    Tech journalists don't understand tech, shocking.

    What you have is an active capacitive system. The digitizer itself is still a traditional capacitive touch digitizer (like N-trig), but the pen emits a distinct signature the digitizer will detect.

    The digitizer itself polls at 240hz, this has nothing to do with LCD panel refresh rate. This is likely a hardware improvement over the older capacitive digitizers and probably wouldn't work on older hardware.

    The capacitive digitizer grid also has greatly improved linearity and accurayc, most likely due to an increase in density. This is also a hardware change.

    Now to address the issue: Yes, the existing digitizers could likely be adjusted to read the active capacitive signal of the Pencil, but they would have a lower polling rate AND significantly worse linearity/accuracy than what we see now. Performance would be quite a bit worse, which would make the whole system look bad (like N-trig) and of course eat into Pro sales.
     
  19. ozthegweat macrumors regular

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    Switzerland
    #19
    No, the display scans for Pencil input at 240Hz. Normal touch input is scanned at 120Hz. Screen refresh rate however is most likely 60Hz, as a higher refresh rate is usually not noticeable.
     
  20. DarwinOSX macrumors 65816

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    #20
    Gruber is wrong. Kind of surprised he didn't know this already.

     
  21. NT1440 macrumors G4

    NT1440

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    #21
    The rate varies, and Apple has that timer coalescing chip which was first made for the 5K iMac, now in the iPad Pro.

    So this isn't simply a case of the screen being the same, there is much more to it that makes the pencil work.
     
  22. dyt1983, Nov 25, 2015
    Last edited: Nov 25, 2015

    dyt1983 macrumors 65816

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    #22
    Some empirical data points from my personal testing:

    - The rubber tip of the Pencil does not seem to be conductive enough to activate any capacitive touch screens. I thought it might be, but I measured it and the material seems to not have much dielectric polarization. I couldn't get any displays to register the tip as touch.

    - I have a Sony Xperia Z Ultra with a very sensitive touch display. I could use a #2 pencil as a stylus, and it writes well enough for the handwriting input. It was not quite as good as an iPad Pro but if it's a result of only 120Hz scanning, I think it's certainly usable. The sensitivity has been lessened by the application of protective tempered glass, so the writing with the pencil isn't as smooth now, where before I could use the pencil almost as well as an iPad Pro.

    - I tried just the tip of the  Pencil on the Sony and it didn't register. I tried the tip on the iPad Pro with a tempered glass protector and it also did not register.

    - I tried the whole  Pencil on the Xperia and it works, about as well as a #2 pencil. So something in the Pencil is making it work with the Xperia. I'll have to try it when the Pencil has a dead battery to know if it is something electrical causing it to function with the Sony, but since it is not paired by Bluetooth, I'm not sure if the Pencil is always active electrically or why it would activate when near the Xperia, or maybe pressing on the tip is registered to activate the rest of the electronics.

    - Although the pressure sensitivity of the Pencil is transmitted to the iPP by BT, I haven't seen an explanation on how the angle sensing works (I may just not have read enough or listened to any podcasts). However, to me it seems there's something in the iPP that lets the angle sensing operate, although I guess technically it could work by calculating the difference of orientation in space of the iPP and the Pencil. This seems like it would take a lot continual computation.

    I won't speculate further on its operation, but will leave that as an exercise for the reader.
     
  23. Atomic Walrus macrumors 6502a

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    Sep 24, 2012
    #23
    A higher refresh rate is extremely noticeable with moving content, but there are currently very few IPS panels capable of 120hz refresh. Getting anything out of it also requires hardware that can put out 120 frames/sec

    The old claim that humans can't tell the difference between 60fps and higher was based on a study with very poor methods and is clearly absurd to anyone who's seen higher frame rate content.
     
  24. Atomic Walrus macrumors 6502a

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    Sep 24, 2012
    #24
    **Sorry about the double post, meant to combine this into the post above

    The version I've heard is that the tilt detection works by having two emitters in the pencil. One is in the very end of the tip (in the little "ball" at the end of the cone) which is how it can actually detect the position of contact without offset at any angle (this is also why the tip is a bit larger than the SP4 pen, which has the emitter in the pen itself).

    The second emitter is farther up I the pen. The digitizer compares the two signals to determine tilt. This is why you can mess up tilt detection by having your finger too close to the tip on screen.
     
  25. haruhiko macrumors 68040

    haruhiko

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    #25
    John Gruber does not know any better. It's just his guess.
     

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