Bill Harris wrote:
>
> I'd like to borrow an old ACE Thermal Sniffler and reverse-engineer one for personal
>use.
I've seen a few different implementations of varios ...
Use heated wires in a bridge, with half of the bridge inside the flask.
The resistence of the heating wires change with temperature, and
unbalance the bridge, causing a measurable output.
Similar to above, but use warmed thermisistors. I think this is what
the sniffler used, and the flask was only plastic. [Been ages since
I looked at a sniffler.]
Use a solid-state differential pressure transducer to measure the
flow in and out of the flask. Very little power required (no heating).
This is the simplest to design a vario around.
Use a solid-state absolute pressure transducer to measure the rate
of change of pressure. Doesn't require a flask, but needs additional
smarts to output the rate of change.
--
Andrew E. Mileski
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