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Thread: Manual scanner

  1. #31
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    mixedgas is offline Creaky Old Award Winning Bastard Technologist
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    LET ME REPHRASE THAT. ALL SINGLE WOMEN ARE A PAIN IN THE NECK.

    I KNOW MANY STABLE MARRIED FEMALES THAT HAVE THEIR ACT TOGETHER THAT ARE A PLEASURE TO WORK WITH AND BE AROUND. There IS just something about kicking out a Kid or two that gets rid of the :Gee, I am unsure of myself and dont know who I want to be thing."

    Steve

  2. #32
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    Steve, the circuit you made will not give full +-5V swing
    The TL082 is not a rail-to-rail opamp and you seem to have used 5V voltage regulators

  3. #33
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    That was just a quickie. Done late at night.

    I tend to keep some things simple when getting some one started with a idea.

    In the TL082's defense, I usually have no problems driving them close to the rails.

    mea culpa if it causes any problems.

    Steve

  4. #34
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    [quote=mixedgas;89664]That was just a quickie. Done late at night.

    I tend to keep some things simple when getting some one started with a idea.

    In the TL082's defense, I usually have no problems driving them close to the positive rails, but they usually glitch at the negative. . But in this case, hes not going there.

    Unless I'm missing something, The PP3s are 9V each , the 7809 and 7805 should just provide references for the pots. If he power's the tl082s off the PP3s and not the regulator he should get 5-0-5 with the follower and the inverter and be at least 3V from the rails.

    Steve

  5. #35
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    As I mentioned in my previous post, I have exactly the same need here. I want to drive the galvos with a joystick, to check the range and alignment when building projectors. I promised I would post the circuit for the "ildastick", so here it is...

    All of the other circuits presented so far should work well if you can use the whole range of the pots, and if you only need single-ended outputs (or if you are happy to use double-gang pots). However, typical joysticks only use single-gang pots, and only a small range in the middle of the pots is used, so an op amp circuit is really necessary.

    This circuit produces differential outputs from single-gang pots, and the gain is adjustable to match the range of the pots which is used in the joystick. Using 7805/7905 regulators and a rail-to-rail op amp is a smart idea, because it means your signals can never exceed +/- 5V regardless of the gain settings, no voltage clamps or other protection is required. Another advantage of using an op amp is that the outputs are buffered, so it is happy to drive long cables.

    I should add, when R1 and R2 are equal, the maximum gain is 2X, which works if more than half of the pot is used. If less than half of the pot is used, you have to increase the value of R1 (or decrease the value of R2) to increase the maximum gain. The same applies to the Y-axis. In my joystick, only about 1/6 of the pots is used, so I increased the value of R1 and R5 to 25k to get the maximum gain of 6X.









    If you have any questions I am pleased to answer them. Best regards, weartronics
    Last edited by weartronics; 04-06-2009 at 20:52.

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