Curiosity about laptop trackpads

Discussion in 'Macintosh Computers' started by Erendiox, Jul 24, 2005.

  1. Erendiox macrumors 6502a


    Oct 15, 2004
    Brooklyn NY
    Sorry if this is common knowledge, but I just noticed that if you drag anything other than your finger across the trackpad, the mouse does not move. Also, if you breath hot air onto the trackpad, the mouse freaks out for a few seconds until it cools down. Are trackpads heat sensitive? I always thought they were only pressure sensitive. :confused:
  2. ChrisBrightwell macrumors 68020


    Apr 5, 2004
    Huntsville, AL
  3. katie ta achoo macrumors G3

    May 2, 2005
    I may be wrong, but aren't trackpads thousands of unfinished circuits? When you drag your finger across, you complete the circuits and it looks at which way they are going and that translates into mouse moving.

    Same stuff that makes iPods do junk. :)

    (again, I could be TOTALLY wrong. hehe. )

    try objects that conduct electricity. Metal, wetted Q-tip. Then try non-conducive materials- pencil erasers, most kinds of plastic
  4. mkrishnan Moderator emeritus


    Jan 9, 2004
    Grand Rapids, MI, USA
    No, they're neither heat nor pressure sensitive. They're capacitance devices. They work with your fingers because they are partially electrically conductive.

    This Wiki article explains more.

    FWIW, the buttons and dial on the 3rd gen iPod are the same way.

    I think the breathing is problematic because you get water on the trackpad, but I am not sure -- my breath doesn't seem to do that. If you try using one with wet fingers, though, you will see that the trackpad will not operate properly at all when it is wet. Which somehow still hasn't stopped me from trying to check e-mail after showering when my hair is still wet.... :rolleyes:

    PS. when you said the mouse wouldn't move, I assume you mean the pointer on the screen, and not an additional, external mouse. If you mean the latter, there are settings in the trackpad preferences that determines whether the computer ignores trackpad input during typing and/or external mouse usage, to prevent accidentally bumping the pointer. So that might be your issue, if that's what you meant. You can try turning these off and seeing if it helps.

    Cheers! :)

    EDIT: we were all typing at the same time, and two out of three calls for the Wiki. Go Wiki, yeah Wiki! :D
  5. katie ta achoo macrumors G3

    May 2, 2005

    I like making stuff up more than I like looking stuff up. :)

    Some of it is real, some of it is made up, I keep ya guessing!

    for instance:
    did you know that there was a great German oat battle? It happened in the 1800s during the great oat drought.

    Also, veggie/fruit peelers were invented by Steve Jobs in 1983. They were billed as "insanely great". They were user-friendly because you didn't cut your thumb when you tried to peel your apple. they were all white, cost $39.99 and they sold millions of them.

    Also, the pot bellied pig was invented when a pig was eating out of a pot, they were both struck by lightning, and the DNA switched.

    Guess which one is real!! :D

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