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Return-to-center potentiometer

  1. Feb 13, 2010 #1

    Ivan Seeking

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    Does anyone happen to know a good supplier for an inexpensive, single-axis, return-to-center potentiometer, in the 5-10K range? Maybe I just keep missing it, but I am finding surpringly few options. What I am finding is surprisingly expensive. For example, Allied carries a rocker pot made by ETI.
    http://www.alliedelec.com/search/productdetail.aspx?SKU=5229600

    But, wow, $148 a piece? It needs to be industrial grade, but even for an industrial grade pot, that seems pretty expensive. Ideally it would have a petcock-style actuator rather than a rocker.

    In a pinch I could probably live with a five position r-t-c switch, but I really wanted to do this with analog.
     
  2. jcsd
  3. Feb 13, 2010 #2

    dlgoff

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    I don't know how much these cost but here you go.
    http://www.p3america.com/pp/scb50,fp50.htm" [Broken]
    scb50pp.jpg
    http://www.p3america.com/pp/scx.htm" [Broken]
    scx50pp.jpg
     
    Last edited by a moderator: May 4, 2017
  4. Feb 13, 2010 #3

    Ivan Seeking

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    I don't see anything indicating a return-to-center function?
     
    Last edited by a moderator: May 4, 2017
  5. Feb 13, 2010 #4

    dlgoff

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    Well they claim to be 360 degree.

    edit: Maybe I don't understand what you mean by return to center. I was thinking 0 ohm to Max ohm then 0 ohm after 360 degree turn. i.e. back to where you started.
     
    Last edited: Feb 13, 2010
  6. Feb 13, 2010 #5

    Ivan Seeking

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    Ah, I think we have slight misunderstanding. I need a pot that has a spring-driven return to the center position. Note that the rocker pot always returns to a predefined null state when not manually actuated. It would be same way a joystick operates but only in one axis... and industrial grade.
     
  7. Feb 13, 2010 #6

    dlgoff

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    Oh I see. Never heard of such a thing. Maybe you could design one yourself?

    edit: seems like a spring around the shaft of a single turn pot might work?
     
    Last edited: Feb 13, 2010
  8. Feb 13, 2010 #7

    Ivan Seeking

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    Yuck! But I am starting to wonder. It wouldn't take much and I can easily allow for a wide predefined deadband in the signal to allow for offsets, but I would by far prefer to buy something off the shelf.

    I wouldn't even mind the price of the rocker pot so much if it was the desired petcock design... but, still, that is spendy for a pot. I really expected to find something for well under $100.
     
    Last edited: Feb 13, 2010
  9. Feb 13, 2010 #8

    dlgoff

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    I added an edit to my above post while you were posting I think. Could you get a cheap pot and put a spring around the shaft to bring it back to center?
     
  10. Feb 13, 2010 #9

    Ivan Seeking

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    Yuck! I may have to but am open to other options. I have a few days before I have to decide. I would almost prefer to go with the rocker rather than something I have to rig. Ultimately someone else buys the pot, but if I make it, I assume additional liability unnecessarily.

    Thanks dlgoff. That may be the best option but still hoping for a better one...
     
    Last edited: Feb 13, 2010
  11. Feb 13, 2010 #10

    sophiecentaur

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    Have you considered doing it all digitally? It could cost a lot less and would be much more sexy!
     
  12. Feb 13, 2010 #11

    Ivan Seeking

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    Thanks. Good idea, but not appropriate for this application. We had one analog port left open after many months of design, and I realized that we could use that to add a valuable feature. I'm limited to one analog input having 12 bit resolution over 0-10 vdc.
     
    Last edited: Feb 13, 2010
  13. Feb 13, 2010 #12

    dlgoff

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    Look what I've found.
    http://www.precisionsales.com/joysticks/images/saj2515g.gif [Broken]
    "[URL [Broken] SAJ2515G- Spring return to center with round G knob
    [/URL]
     
    Last edited by a moderator: May 4, 2017
  14. Feb 14, 2010 #13

    Ivan Seeking

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    BINGO! Don't know how I missed it, but thank you. I was sure someone must make this.

    It comes in exactly the right style. Wunderbar!!!
     
    Last edited by a moderator: May 4, 2017
  15. Feb 15, 2010 #14

    Ivan Seeking

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    Yikes! $300. I guess my expectations were way out of line. Apparently the reason for the high price is the precision spring return function. This is what worried me about making our own; repeatability on the return is probably an issue.
     
  16. Feb 15, 2010 #15

    dlgoff

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    Dang. So what's the verdict? Going to use it? I would guess not?
     
  17. Feb 15, 2010 #16

    Ivan Seeking

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    I think I will simulate the function on the prototype and let the customer make the call on the final product. If they want the added function, which I'm sure they will, the price won't matter. I just don't want to pocket the cost indefinitely. There is no time for a budget adder approval.

    What matters is that I have the component identified with price in hand. No problem. Thanks again.

    PS. Even if I chose to pocket the cost, the pot wouldn't be delivered before the product handoff occurs next Monday, for evaluation. There is about a one-week lead time. They probably only make them on demand.
     
    Last edited: Feb 15, 2010
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