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Thread: Manual scanner

  1. #11
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    I'm sure it wouldn't be difficult to rig a joystick with dual gang pots, then as DrLava suggested; you would have a simple silicone free, resistance based voltage divider.
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  2. #12
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    Andy - DrLava is correct. Do you need differential?

  3. #13
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    I need to feed pretty much the same analog as a standard laser show controller such as pangolin. Cant remember what the output levels are. To have + 0 and -

  4. #14
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    A standard controller should have a range of +5V to -5V relative to ground on two differential outputs: + and -. This gives a total differential of 10V max. To do this with a single pot per axis and an op-amp is easy, just use an inverting op amp with a gain of one and there you go. While you're using op-amps, you might as well use a chip with a quad package so the outputs are all buffered. I'm sure someone will draw it up.

  5. #15
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    similar discussion here
    http://www.physicsforums.com/showthread.php?t=120734
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  6. #16
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    DrLava - wouldn't my original design work if I placed another pot in parallel with the first, only wired opposite? So when one is +5, the other is -5?

  7. #17
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    Quote Originally Posted by drlava View Post
    A standard controller should have a range of +5V to -5V relative to ground on two differential outputs: + and -. This gives a total differential of 10V max. To do this with a single pot per axis and an op-amp is easy, just use an inverting op amp with a gain of one and there you go. While you're using op-amps, you might as well use a chip with a quad package so the outputs are all buffered. I'm sure someone will draw it up.

    I love it when somebody says "is easy".

  8. #18
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    Quote Originally Posted by trwalters001 View Post
    DrLava - wouldn't my original design work if I placed another pot in parallel with the first, only wired opposite? So when one is +5, the other is -5?
    Yes that is a description of my first posted circuit.

  9. #19
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    In that case, if it were me, I'd use DrLava's circuit.

  10. #20
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    I guess this is an opp amp circuit right, usualy they have a description, anyone now what this style has?


    I was just wondering something:

    The problem seams to be differencial right?

    If the output from the op amp can go - and + in respect to ground and we take that output to the + of the scanner amp + input and the op amp ground to the scanner amp - do we have full scale movement or still only half?

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