I don't remember the exact wavelength, but there is a large peak in the IR
band for H2O, not far from the CO2 peak.  If you optically bandpass on the
H2O nm you may obtain the desired detection result.

Check out the IR band.
Good luck
Richard

----- Original Message -----
From: "Jinx" <joecolquitt@CLEAR.NET.NZ>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Sunday, November 03, 2002 6:53 AM
Subject: Re: [EE]:Infra-red Opto help


> > I'm looking for suggestions for making a rain sensor using Infra-
> > Red techniques.
>
> Is this outside or inside looking out (glass ?)
>
> a heated element like a thermistor - maybe for big drops
>
> fine parallel lines on a PCB (gold-plated if outside) that short
>
> a dew sensor from a VCR
>
> frosted/etched glass that gets more transparent when wet
>
> --
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>

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