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Encoder signals — Parallax Forums

Encoder signals

jdoleckijdolecki Posts: 726
edited 2023-11-24 08:41 in Robotics

My scorbot has encoders on each axis.

They are described as phototransistors.
I have no info on them

They are powered by 5v with a 39 ohm resistor to limit current.

My signal is not a clean square wave as the manual says.

What could be the issue?

Comments

  • Pictures

  • evanhevanh Posts: 15,405

    On the scope traces, where is zero volts? The photo was too close up.

    The pulse rate is also very stable in that photo - At a little under 10 kHz. Disc is 20 lines per rev. So that's 500 revs per second or 30000 RPM. Sounds a tad too fast. :D I'm guessing what you're seeing on the scope is just noise.

  • jmgjmg Posts: 15,155

    @jdolecki said:
    They are described as phototransistors.
    I have no info on them

    As #4 says, you may be miss-measuring these.
    They are open collector photointerrupters, so need pullups to 5V. You should then see slow square waves of HLHL on the outputs as the disk spins manually.
    They also may not like too much light intrusion.

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