I will not go into greater detail of the code behind the rotary encoder + arduino experiment, as featured articles and great tutorials are available all over the web. Lab Note: RT & Arduino experiment ...

It is based on some assembler code I wrote for a PIC years ago, and relies on polling the current state of the two input pins from a rotary encoder, and comparing these two binary bits with their ...

I needed a rotary encoder — I pulled a cheap one out of one of those “49 boards for Arduino” kits you see around. Not the finest encoder in the land, I’m sure, but it should do the job.