Jumping Cursor In Tiger

Discussion in 'Mac Basics and Help' started by SaintSteven, Dec 28, 2008.

  1. SaintSteven macrumors newbie

    Dec 28, 2008
    I recently picked up an old eMac for cheap running Tiger, and when I got it home discovered the mouse was an optical one, and that I must need an optically reflective mousepad of some sort. Years ago I had a Mac Se that I eventually bought an optical mouse for when the mouse that came with the computer wore out. As I recall, that mouse pad had a slick plastic shiny surface ... optimized for reflectivity I guess. Anyway, I was frustrated that the guy that sold me the computer had forgotton to send me the mousepad along with the other hardware. But I thought, heck, I'll just try to run it on the bare surface of my wooden desk and it seemed to work fine. A couple weeks later I found a common mousepad at a thrift store, and thought I'd pick it up to use with my optical mouse as I didn't want to scratch the surface of my desk sliding my new/old eMac optical mouse around on it. It had a nice smooth surface and I thought it would be better than using my bare desk. But I immediately I began to have cursor jumping problems. So I thought, hmmm, maybe I'll try a six inch square piece of thin plywood for a mousepad. And I haven't had a single cursor jump since.:)
  2. BlueRevolution macrumors 603


    Jul 26, 2004
    Montreal, QC
    Uh, was there a question somewhere in there?

    Optical mice aren't designed for mouse pads, although they won't work well on glass desks and may need one then. If you do have a glass desk or just want a mousepad, look for a cheap foam-like mousepad rather than something shiny. Optical mice work by taking a series of "pictures" of the desk under the sensor and calculating the motion of the mouse by determining how the surface underneath is moving. When the surface is reflective, all the sensor can see is its own reflection and as a result may have trouble determining the mouse's position.

    Since this will likely come up as a search result for people wondering about optical mice behaving oddly, I'd like to add that if a mouse is acting up, there are two likely causes. First, there could be a buildup of dust in the sensor. Blow vigorously into the little sensor cavity. If that doesn't get you sorted out, you could try using a Q-tip and some rubbing alcohol to clean the sensor lens.

    If you have a cordless mouse, the issue may also be a result of wireless interference. There's not a lot you can do about that besides moving the mouse or looking for the device that is causing the problems.
  3. catachip macrumors regular


    Jun 7, 2007
    Vancouver, British Columbia
    I'll also add that optical mice tend to work best on surfaces that have complex, different patterns on them, rather than a single, solid colour. As the person above me commented, optical mice work by taking a series of pictures (very quickly obviously) and comparing them to calculate movement and translate that into the movement of the cursor on your screen. If the mouse pad is a solid, unchanging colour, then it can effectively get mixed up and you'll get hops and jumps.

    This is why your desk, which probably has a complex, unique wood grain worked better than your presumably solid-coloured mouse pad. I would recommend cleaning out the mouse optical area on the underside, as suggested above, and switching back to the desk or to a new mousepad with the aforementioned complex patterning. These solutions will give you an optimal mousing surface. Also, always avoid any time of plastic or shiny mousepad - they spell bad news for optical mice.

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