I have an inexpensive 600 PPR rotary encoder, like these ones found on Amazon. It is powered by a 5V pin of an Arduino Uno.
I was unable to detect any rising edges on the signal pins and they never got high. So I connected them to an Analog Discovery 2 Oscilloscope, and, although I'm getting some signals and their timings make sense, their shape does not look right.

  1. The voltage somehow gets lower instead of getting high.
  2. The steps are not square at all.

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  • 4
    \$\begingroup\$ They have open-collector outputs. Are you using pullup resistors? \$\endgroup\$
    – Dave Tweed
    Dec 4, 2021 at 0:04
  • 3
    \$\begingroup\$ That fixed it. Thanks! I had not used this type of standalone encoder before so did not realize they need pullup resistors. \$\endgroup\$
    – ennam
    Dec 4, 2021 at 0:24


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