How to measure whether air is flowing through a pipe? I'm looking for a way to check the air-flow from an aquarium air pump. I need something that can test whether air is flowing or not and I'm not bothered about measuring flow speed. The air will be flowing through a pipe but if required I can have the sensor on the end of an additional pipe just used for measuring.
Did you consider a barometric sensor deployed inside the pipe?
The pressure should be higher when the pump is active.