> >>-          Hot wire? .. Nahhh.
> >>
> >That would work, but you've got the problem that the temperature of the breath isn't predictable
> >
> It's quiet predictable and constant within 0.1 Celcius.

Actually, I just recently worked with a pneumotach that was
calculating flow rate based using the hot wire method.

I don't know much more than that, but it CAN be done.  The air
was actually directed across a fairly elaborate heat sinking fin
array.

Mike H.

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