iPhone scale application?

Discussion in 'iOS Apps' started by Crank Lucas, Jan 24, 2009.

  1. Crank Lucas macrumors member

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    Oct 31, 2008
    #1
    no really Im wondering now I mean the touch screen is pressure sensative, so how hard would it take to have a application (lets call it iScale:)) that can measure whatever you put on it in grams?

    you know, just to measure some small materials ;)

    so waddaya think?
     
  2. FunkyMonkey macrumors 6502

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    #2
    Not possible. The touch screen can't sense how much weight or pressure you are applying to the screen. It only knows when you are touching it and where. I have thought of this before and I think it would be awesome if it worked.
     
  3. GetAudiHere macrumors regular

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    #3
    That would be awesome! They do make fake iphone/ipod touch scales.
     
  4. f60 macrumors newbie

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  5. Dr. Cabrera macrumors 65816

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    #5
    the iPhone does not work on pressure, it works on capacitance ( your finger distorts the electrical field on the surface of the iPhone)

    Google it if you don't believe me
     
  6. questrillion macrumors newbie

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    #6
    I have figured out a method

    iScale is possible, without external hardware or a strain gauge.

    I am working on it right now.

    You will be able to weigh objects by placing on your iPhone, from 1/2 ounce to around 1 lb-2 lb.

    ...its not a pendulum...not a balance...not a touch screen.

    Assuming I can get Apple to accept it, look for it soon.
     
  7. chrmjenkins macrumors 603

    chrmjenkins

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    #7
    I'm skeptical as to how this would work. The only thing you have to work with is area of displacement since the capacitive sensors are binary in nature.

    Resistive touch screens are pressure sensitive, however. You would be able to weigh small things with those.
     
  8. questrillion macrumors newbie

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    #8
    There is a way...

    I understand your skepticism.

    I did not know if the method I am using would work or not until I wrote the code and tested.

    I hope to have it finished and fully tested in the next 5-10 days.
     
  9. cellocello macrumors 68000

    cellocello

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    #9
    HA!

    So you're assuming this would work. No code or nothing yet, eh?
     
  10. renewed macrumors 68040

    renewed

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    #10
    That will be a hit in the underground if you get my drift lol :p
     
  11. renewed macrumors 68040

    renewed

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    #11
    I think it could work, just have something on screen, such as a giant touch button, that measures the pressure being applied to the touch portion under the glass. ;)
     
  12. cellocello macrumors 68000

    cellocello

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    #12
    'Cause that is, after all, exactly how the iPhone works ;)

    No wonder I need to press so hard in some apps!
     
  13. CalumC macrumors regular

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    #13
    Are you ok with people guessing at it questrillion? I've got an idea as to how you might be doing it but i'm sure that if its something you're making money with then you'd rather keep it shtum and i'm not out to stop that, even if this is a public forum!
     
  14. chrmjenkins macrumors 603

    chrmjenkins

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    #14
    The iPhone's touch mechanism is not analog. It can only sense the presence of something, not the degree of pressure.
     
  15. cellocello macrumors 68000

    cellocello

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    #15
    Unless he's measuring fingers (and by 'measuring' I mean detecting taps); he's not doing anything.
     
  16. bluenoise macrumors 6502a

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    #16
    Here's how it would work:

    1. Determine how much distributed weight the glass can hold before it shatters.
    2. Run the app and then load the screen with item(s) to be weighed.
    3. If the screen does not collapse, the item being weighed is lighter than the predetermined weight. If it caves in, it weighs more than the predetermined weight.

    Disclaimer: This app may only work once and may void any factory warranties.
     
  17. questrillion macrumors newbie

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    #17
    I works...meaning that changing the weight changes the output in a predictable manner. It is very non-linear, but it can be characterized and calibrated to output the actual weight.

    It is coded, but I have not coded the UI...I have only coded the measurement portion.

    It am still testing out the calibration methods.

    Yes...underground will LOVE it, but it will need to be very accurate for that. Else, it will be good for postal scale, diet scale, but not good for herb scale.

    If it provides decent repeatability, Apple will pass it, else, it will go to the jail break market.
     
  18. renewed macrumors 68040

    renewed

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    #18
    Good to know. I guess its like kicking an appliance to make it work.. sometimes i have to push really hard to make that darn SMS load properly in 3.0 ;)

    Good to know guys, I guess I assumed even though the applications on the iPhone work by touch recognition, not pressure, there would be some way to create an application that can tap in and assume pressure and not just touch. But of course you know what they say about ASS-U-ME.
     
  19. cellocello macrumors 68000

    cellocello

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    #19
    I'm curious how your iPhone detects anything other than fingers. Can you elaborate a bit on that?

    I mean ... Mine won't even detect leather gloves, let alone random objects like envelopes or herbs.
     
  20. bluenoise macrumors 6502a

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    #20
    Given that the screen on my iPhone is completely unresponsive to paper and most dry foods, I doubt it's going to make a decent postal or diet scale.
     
  21. questrillion macrumors newbie

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    #21
    Method

    I'm mum until I run it to ground, win or lose.

    But, if its turns into a dead end, I'll drop my method out here and maybe someone can improve on it.
     
  22. cellocello macrumors 68000

    cellocello

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    #22
    It's not really about that.

    I mean, you get how the iPhone screen works, right? How is detects presses and what not?
     
  23. questrillion macrumors newbie

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    #23
    Yes...I understand touch detection on the iPhone.

    I should have the curve tonight. Then its all about calibration (can it be calibrated to any iphone or is the curve specific to each unit)

    Regardless, it is possible. I am doing it. But, it remains to be seen whether or not it can be distributed.
     
  24. chrmjenkins macrumors 603

    chrmjenkins

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    #24
    Yeah, the touch detection is what makes cap screens good for multi-touch. Just a cap array and each cell reports a touch independently.

    For a resistive screen, you have a resistive gradient behind the screen. That is to say, each touch point will use trigger a specific resistance, which can be extrapolated by means of measuring current. If you want to do multi-touch, you have to consider that there are many ways to get the same answer, so it becomes a challenge. That is why the G1 has been slow to get it, and at the hands of independent developers.

    Based on questrillion's knowledge built into his responses, I'd say he has something going.
     
  25. cellocello macrumors 68000

    cellocello

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    #25
    *shrug*

    Ok homie.
     

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