A hot wire (hot bead) anenometer is often used to measure breath eg in respiration masks. They're a wire or thermistor slightly heated by the cuirrent passing through them. When air is passed over them, they're cooled and the resistance change gives a measure of air speed. Need correcting for temperature if accuracy is required.
@alowhum nano bootloaders have changed recently. They now use the same one as Uno, used to be an older version. I too struggled with this at first but now realise that, if you use a recent ARduino IDE (eg 1.8.8) and select 'nano' as the device, you can then further select 'processor' and have a choice of ATmega 168 and two ATmega368, one of which is 'old bootloader'. Earlier versions of the IDE will always be 'old bootloader'. So I don't know if these boards are to the new standard (and you're trying to use them as the old ones) or the old standard (and you haven't selected that in the IDE) but you'll find the same thing with some ordinary nanos too.