Recommended · for beginners
How to use linear encoders with Arduino. hardware, code, and demo.
Why people recommend it
Recommended as a clear explanation of how salvaged printer optical encoder strips produce quadrature signals you can read for position and direction.
Watch for: Salvaged sensors fail above their low rated voltage
In their words
I advise you watch this video to see the output signal and understand how to use it:
Gerge on electronics.stackexchange.com, Apr 2022. CC BY-SA.