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Encoder causing "ghosting" in button matrix

Discussion in 'General Electronics Discussion' started by Braeden Hamson, Mar 21, 2017.

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  1. Braeden Hamson

    Braeden Hamson

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    Feb 18, 2016
    Hopefully I can explain this in a clear enough manner. I'm making an human interface device that has 6 encoders, as well as some switches but the switches aren't important. It consists of a 7 x 4 matrix with a column of of the 6 encoders next to that matrix. The C terminal (middle pin, ground pin?) of each encoder is connected to the rows of the 7 x 4 matrix. and the A & B Signal pins of the encoders (first and last pin) are connected in their own column. Each of these rows and column is wired to an arduino promicro (if the exact model matters, genuine article too)

    The real issue is that one of the encoders I'm using causes ghosting where buttons that the encoder is not wired to appear to be pressed when the encoder turns. The circuits that are being closed are a few within the column of encoders, not all just a few. As well as one circuit in a different row and column that's not even related. Which I find very very strange. I'm fairly certain that this issue comes from the encoder itself which is this encoder:

    http://industrial.panasonic.com/cdbs/www-data/pdf/ATC0000/ATC0000CE15.pdf

    https://www.digikey.com/product-det...nic-components/EVE-VCGJL016B/P12418-ND/637155

    EVE-VCGJL016B

    (all links to the same product)

    I'm using the EVEV model but that doesn't matter AFAIK.

    The reason I think the encoder is the issue is because if I swap where this encoder is plugged in to where another encoder is plugged, this other encoder functioned normally, I'll get the same issue but this time with new circuits. And where the other encoder is plugged in it will work fine. I tested the continuity on the pins of the offending encoder and I get a constant continuity on pins 2 & 3 while the encoder is rotating, and the expected intermittent continuity on 1 & 2. I have another encoder of the offending type and its the same story for that one.

    Hopefully that can be understood. Thanks for any help
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    It sounds to me that one of your rotary encoders is faulty. Afaik you shouldn't get unbroken continuity between 2 pins of an encoder while it is being rotated.
     
  3. Braeden Hamson

    Braeden Hamson

    224
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    Feb 18, 2016
    I also think it may be broken, but what are the odds I got two encoders with the same issue?
     
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,500
    2,840
    Jan 21, 2010
    Oh, sorry, I misread that as one encoder with the odd behavior and that the side effects followed it.

    But if you have encoders of the same type that don't operate the same it's hard to escape that there is a fault with more than just your understanding.
     
  5. Braeden Hamson

    Braeden Hamson

    224
    13
    Feb 18, 2016
    So I think I got it to work. And I now have proof that electronics don't run on electrons. They run on malevolent black magic. So I have the encoder that isn't working and causing ghosting in other circuits. I also had a header pin that didn't work. It seemed to be wired wrong or something and didn't work even if I shorted it with metal tweezers. But, if I plug the bad encoder into the bad header, it works.

    That's it, I'm done. I think I'll go do something that makes sense. Maybe brain surgery, politics, unicorn hunting I don't know.
     
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