I'm working on a project where I need to sense where a modell train goes at 3-4 points on a model train track. I have a bunch of TCRT5000 infrared sensor collecting dust so using them was the obvious choice.
I will get a nice analog signal from them, but I'm not interested in distance data, just that something is over them or not. And definitely don't want to poll them!
A schmitt trigger to the rescue! A quick test video below: