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Rotary Switch

Discussion in 'General Electronics Discussion' started by Sadlercomfort, Oct 11, 2016.

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  1. Sadlercomfort

    Sadlercomfort Ash

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    Feb 9, 2013
    Hi Guys,

    I'm looking for a Rotary Switch on [email protected] to use for a project.. I've never used one before so the terminology is confusing me slightly.

    [​IMG]

    I understand the concept, but dont understand things like n.o of poles, switch positions and angle of throw.

    I need one that clicks in aswell. This will be used to control an LCD Menu Interface so dont need anything complicated. Just something like the above graph.
     
  2. Minder

    Minder

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    Apr 24, 2015
    That is known as a quadrature encoder, the pulses are 90deg apart, it is used for speed and direction and is rated in pulses/rev, this number applies to either chA or chB, not both additively.
    That may not be the type you are looking for?
    M.
     
  3. dorke

    dorke

    2,342
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    Jun 20, 2015
    Here are some links that may help you:
    Poles and Throws
    In rotary switches Angles

    BTW,
    you can use a simple momentary SPST push button for controlling menus.
    They are much smaller and cheaper.
     
  4. Sadlercomfort

    Sadlercomfort Ash

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    Feb 9, 2013
    Thanks :) I've used push buttons before.. now want to try a rotary encoder. A little bigger but only need one so use much lets space.

    I'm not sure what type I need
     
  5. Sadlercomfort

    Sadlercomfort Ash

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    Feb 9, 2013
    I believe the quadrature encoder was what I was after :)
     
  6. dorke

    dorke

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    Jun 20, 2015
    Yes,
    you do need to define your requirements before you can select a switch.
    Will this switch be the only one used?
    In what manner? etc.
     
  7. Minder

    Minder

    3,015
    640
    Apr 24, 2015
    Why do you need a quad encoder, it could be done either with a simple single wafer multi position switch, there is also coded versions such as BCD etc if needed .
    M.
     
  8. Sadlercomfort

    Sadlercomfort Ash

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    Feb 9, 2013
    This will just be used to cycle through different menus, a default menu will be display with some information. Once the encoder button is pressed it will enter the menu.. then when I rotate the encoder it will cycle through until i press the button. I will also use a keypad if I need to type in any numerical information.

    Isn't the single wafer multi position switch the same?
     
  9. Minder

    Minder

    3,015
    640
    Apr 24, 2015
    Are you operating this switch manually or is there another means used?
    How many menu's does it cycle through?
    M.
     
  10. Sadlercomfort

    Sadlercomfort Ash

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    Feb 9, 2013
    Its manually operated.. 8 menus or less
     
  11. dorke

    dorke

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    Jun 20, 2015
    What you need is called "Incremental Encoder".
    You can actually build an optical one yourself just for the fun of it,
    Opto Transmit/Receive and a slotted rotating disc( slots can be less than shown ) .
    Incremental encoder-phases.png
     
    Arouse1973 likes this.
  12. Minder

    Minder

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    640
    Apr 24, 2015
    So I still really don't know why you need a quadrature/incremental encoder for this function, it is not standard practice for the application you seem to need,
    And a little over-complicated method.
    A 8 position wafer selector switch is the customary way, there are many manuf. of these, Grayhill for one.
    M.
     
  13. Sadlercomfort

    Sadlercomfort Ash

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    Feb 9, 2013
    I'm not looking a simple method here, it's supposed to be an advanced project. Its a university project
     
  14. hevans1944

    hevans1944 Hop - AC8NS

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    Jun 21, 2012
    You don't need two optical "tracks" to build a rotary optical control. One track of alternating opaque and reflecting (or transparent) segments and two appropriately angular spaced optical sensors (reflective or transmissive) will suffice. One sensor should be adjustable with respect to the other one to adjust for a quadrature relationship in their signals. You can add a second track if you need an "index" mark, but that sounds unnecessary for your application.

    It would be easier to just spend the three bux plus some change to purchase this one off of eBay. Twenty positions per revolution with detents at each position, plus a push-switch built into the shaft that you can use to enable and disable menu selection. What's not to like?

    Back in the day, Centralab sold wafer switch components that you stacked up and assembled to make just about anything you can imagine, with or without a detent mechanism. Two wafers, each single pole with multiple positions and continuous rotation could be wired to produce the wave forms you show. So, twelve positions over 360 degrees would give you three cycles if appropriately wired. I'll leave that wiring as an exercise for the student. Don't forget to "condition" the switch transitions for bounce-free performance in whatever logic you add to the switches.
     
    Last edited: Oct 12, 2016
  15. Minder

    Minder

    3,015
    640
    Apr 24, 2015
    There is also a thing know as 'Over Engineering'
    M.
     
  16. hevans1944

    hevans1944 Hop - AC8NS

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    Jun 21, 2012
    Yep. Bet he's gonna construct a furnace and zone refine and dope his own silicon transistors too. Or maybe build a particle accelerator and implant ions for a planar structure. Lots of ways to over-engineer this project.:cool:
     
  17. dorke

    dorke

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    Jun 20, 2015
    Hop,yes he can.
    But looks like @Sadlercomfort wants to be flamboyant in his project.
    Or maybe,It may be a project requirement to use a rotary switch.

    I still think a momentary push button is the way to go, total software controlled,simplest and cheapest .
    Say like:
    Short push/release to toggle menus and a long push(say 2 seconds or more) to activate the selected menu .
     
  18. hevans1944

    hevans1944 Hop - AC8NS

    4,543
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    Jun 21, 2012
    @dorke I really like rotary incremental encoder controls. Hardly anything to wear out, silent, good resolution... yada, yada, yada. However, buttons are appropriate for some functions too. My KX3 transceiver is a mixture of both and I wouldn't want to have it any other way. Tuning and menu selection is with optical encoders, while selecting a menu option requires a button press. All feedback is via the backlit LCD screen, or really tiny LEDs here and there. It takes two simultaneous button presses to turn it off or on. Way cool. I love it! Oh, and you can download macros to program the buttons to do things besides their factory programmed functions.

    Hop - AC8NS
     
  19. dorke

    dorke

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    Jun 20, 2015
    Hop,
    Agree with you tuning of transceivers is the easiest with an optical encoder.
    Long long ago I worked with some WJ receivers and later on with iCOM receivers which had great rotary encoders for tuning + a button to select the "digit of tuning"and a number pad for direct frequency entry.
     
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