I want to tell you how to make incremental encoder from stepper motor. When we turning shaft of stepper motor it works like generator. It generates certain impulses on its coils. After some signal processing, we get same impulses as incremental encoder.
This encoder has one problem, it can drop steps if you turning very slowly. But for many applications, it doesn't matter.
Impulses from stepper motor turn on/off this triggers and on output we get signal like rotary encoder.
In this video shown how encoder works with arduino. In this example, I used stepper motors from old printer but you can use any stepper motors.
Code of these examples you can find here:
Circuit diagram with stepper motor and driver a4988:
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