What are the best practices for detecting non-UI trigger events? (Polling seems not)

[billko]

Polling, interrupts, and your doorbell.

Polling your doorbell: You are waiting for a package and you keep checking your doorbell app to see if anyone is coming to your door with a package.  You can't do much else because checking your app all the time takes a lot of concentration.

Doorbell Interrupt: You are watching TV, you hear the doorbell, you answer it and get your package.  You are not actively polling the doorbell.  True that there is a little program inside your brain that tells you to respond to the doorbell, but you can easily watch TV while waiting for your package.

It all comes down to semantics, and I guess that's your answer.