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Inexpensive Concentric Rotary Encoders — Parallax Forums

Inexpensive Concentric Rotary Encoders

ke4pjwke4pjw Posts: 1,155
in General Discussion
I am looking into creating a prototype for a ham radio accessory that requires knobs. I would like to use concentric rotary encoders, There will need to be 6 encoders and they would be paired together. A concentric package would be nice and reduce the realestate needed. They appear to be very expensive compared to single encoders. Like a 10x price difference.

Do you guys have any suggestions?

Thanks,
Terry

Comments

  • VonSzarvasVonSzarvas Posts: 3,450
    That's an encoder that works in either dire tion on seperate channels, right?

    What about adding an uC to convert the standard encoder output to concentric?

    One uC could take the 6 inputs and provide 12 outputs.
  • ke4pjwke4pjw Posts: 1,155
    My meaning of concentric is that it has dual encoders and knobs that are concentric (a smaller knob inside a larger knob).

    https://www.amazon.com/Dual-Concentric-Encoder-Switch-Knob/dp/B079SGWVZC
  • VonSzarvasVonSzarvas Posts: 3,450
    OK, I was off target.

    Do both knobs need adjusting simultaneously ? Ie. would having a small selector button beside a single encoder allow dual functionality for reduced cost.

    Probably only practical for occasional adjustments, or may rapidly become annoying!
  • VonSzarvasVonSzarvas Posts: 3,450
    I wonder if you could "roll your own", perhaps with a couple of the Hollow Shaft encoders mounted one behind the other.

    example: ALPS EC10E1220503


    Suppose you'd need to find a suitable shaft-in-shaft and matching knobs. Perhaps they exist.......

  • jmgjmg Posts: 15,173
    ke4pjw wrote: »
    I am looking into creating a prototype for a ham radio accessory that requires knobs. I would like to use concentric rotary encoders, There will need to be 6 encoders and they would be paired together. A concentric package would be nice and reduce the realestate needed. They appear to be very expensive compared to single encoders. Like a 10x price difference.

    Those are always going to be costly, thanks to the
    a) very low volumes and
    b) complex shaft tooling needed + custom knobs

    Even if you could sort the encoder sensor side, you still need the mechanics of 2 custom knobs and 1 hollow shaft.

    What about a single encoder with a push-button on the shaft ? - Maybe that could emulate a concentric part, without the hollow shaft complexity ?

  • TubularTubular Posts: 4,702
    Terry if you get inspired to make something check out this ingenious kiwi single track encoding technique.
    http://www.winzurf.co.nz/Single_Track_Grey_Code_Patent/Single_track_Grey_code_encoder_patent.pdf

    OzProp put me onto this...
  • ke4pjwke4pjw Posts: 1,155
    jmg wrote: »
    What about a single encoder with a push-button on the shaft ? - Maybe that could emulate a concentric part, without the hollow shaft complexity ?

    I like that idea! That may work. I will need to think about how I could utilize it.

    The project is to add the "missing knobs" to my radio. ie. To have knobs to adjust IF width, notch filter, spectrum bandwidth, etc without having to go two and three menus deep to set the single knob that can adjust them.

  • localrogerlocalroger Posts: 3,451
    Like JMG said concentric encoders are going to be hella expensive. If you think about it you can't use both inner and outer knobs at the same time, so why not use a single encoder with a switch or other control to select function. A lot of modern equipment that needs knobs have only one which performs every function, with a display and fairly complex control determining just what the knob is doing at any given time.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    You could put two encoders side-by-side with gear linkage to the outer knob's shaft.

    -Phil
  • kwinnkwinn Posts: 8,697
    Hobby stores sell brass tubing in sizes suited for concentric shafts. Use them with a double sided PCB so the inner shaft connects to the wiper on the bottom of the board and the outer shaft connects to wiper of the top of the board. All three pairs could be on a single PCB. There are rotary switches that work like that.
  • W9GFOW9GFO Posts: 4,010
    Do they need to be encoders? You can get concentric pots (like in the amazon image) for about $4 a piece.
  • ke4pjwke4pjw Posts: 1,155
    Looks like Mouser may have what I am looking for in the correct price range. Been awhile since I perused their catalog.

    https://www.mouser.com/ProductDetail/ALPS/EC11E09244AQ?qs=sGAEpiMZZMsWp46O%2Bq11WbJRzXHpSzpXwpRYQLsQ7q8=

  • ercoerco Posts: 20,256
    I use these a lot, cheap & plentiful on Ebay. They have a nice clicky rotary feel and there is a click push switch. You could either use the push switch to toggle between modes (LED indicator helpful) or simply access the secondary mode while pressed in. Not ideal, but with the right knob/wheel it could be OK if the secondary mode isn't used much.

    https://www.ebay.com/itm/10-pieces-12-mm-key-switch-rotary-encoder-switch-LW/183918656522
  • jmgjmg Posts: 15,173
    ke4pjw wrote: »
    Looks like Mouser may have what I am looking for in the correct price range. Been awhile since I perused their catalog.

    https://www.mouser.com/ProductDetail/ALPS/EC11E09244AQ?qs=sGAEpiMZZMsWp46O%2Bq11WbJRzXHpSzpXwpRYQLsQ7q8=

    I see Alps have other items too...
    These are cute
    https://www.alps.com/prod/info/E/HTML/Encoder/Ring/Ring_list1.html
    the larger ring encoders can fit over a smaller one..

    and these are Potentiometer based Multi Control Devices ThumbPointers

    https://www.alps.com/prod/info/E/HTML/MultiControl/Potentiometer/Potentiometer_list1.html
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