> > MOISTURE
> >
>
> > 10-90% Humidity Sensor BC1333-ND $11.94
> > www.digikey.com
> >
> > Hey, that sounds like just the ticket! A cheap,
> > small sensor
> > that can detect "humidity"! Never used one
> before,
> > but there
> > it is, waiting to be played with.
>
> I am not a PhD and this topic is a bit far from my
> "core know-how". Nevertheless, by coincidence, I
> spent
> those 2 last weeks playing with RH and thermocouples
> for technologic validation in a pharma application.
> Those people are very stringent about instruments,
> calibration, methodologies, tracking and so on. My
> little experince with RH sensor lead me to be very
> very reluctant to trust the above sensor. I checked
> briefly the data sheet and I would just use it at
> home, nothing more. I recently bought several RH
> probe
> from 200$ to 700$. Even at those prices, accuracy
> guaranteed is only 2% RH. I even required special
> calibration (not standard factory calibration)
> according to known calibration protocol but found
> deviation when using probes on-field. Drift has to
> be
> checked frequently. All this in an extremly clean
> and
> controled environment, with controled flow, not in
> waxed, propolised and turbulent flow environment.
> Quality RH probe seem to me quite big and invasive
> in
> the hive. But once again, I am not an expert in this
> field and I may ignore adapted instruments.
>
> Even for thermocouples, I would check closely raw
> data, type of thermocouples used, drift, calibration
> and so on before being confident with data although
> the 8 or 16 bits data logger will give you 5 or
> maybe
> 10 numbers after the point. Especially in a study
> spread on several years in such environment as a
> hive.
> For example, 0.4C offset drift is not uncommon, even
> with a T-type thermocouple. And I do not speak about
> "electronic noise", shielded wire, and data logger
> sampling... Shortly, everyone can put a button
> temperature sensor in the hive and obtain results.
> But
> validated results obtained according to the
> state-of-the-art allowing flow interpretation is
> someting else. Forget cheap and quick
> (unfortunately)!
>
>
>
> Hervé
>
>
>
>
>
>
> Yahoo! Mail : votre e-mail personnel et gratuit qui
> vous suit partout !
> Créez votre Yahoo! Mail sur
> http://fr.benefits.yahoo.com/
>
Yahoo! Mail : votre e-mail personnel et gratuit qui vous suit partout !
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