/diy/ - Do It Yourself

I am building an anemometer as part of a small home weather station, just trying to work around what would be the path of least resistance without losing accuracy for determining the number of rotations, and then working that back to speed.

Considering a small AC motor, where I work around the waves produced, but also looked at using reed switches and hall sensors as a possibility. Any ideas here? This seems to be a general problem about counting rotations.