[tomek_ycomb]

It's a fun exercise in which I think you'll find polling to be fine for many Arduino cases. Not as much for raspi and higher level in my limited experience for various hardware reasons and overhead. And quickly when you do other stuff, especially blocking high level communication, polling does suffer. But interrupts exist and are a reasonable level 2 for people to learn.

https://www.mikrocontroller.net/articles/Drehgeber is an excellent article (in German, Google translate is fine afaik. Check the interrupt section