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Miscellaneous Debris => Tech Corner => Topic started by: SLOweather on January 30, 2018, 02:59:43 PM

Title: Arduino chilled mirror dew point sensor?
Post by: SLOweather on January 30, 2018, 02:59:43 PM

My Dew Point Depression got me to thinking about chilled mirrors.

It seems like it wouldn't be too hard to build an Arduino based chilled mirror dew point sensor, with a Peltier device and mirror, a temperature sensor, and an LED and photodetector.

Generally, my ideas turn out to be not so original when I do a search, but I couldn't locate such a device.

Maybe it's harder than I think...

Title: Re: Arduino chilled mirror dew point sensor?
Post by: dupreezd on January 30, 2018, 03:57:04 PM

Good idea,I think this is do-able.

My 2 cents.
In stead of using a glass mirror as it transfer heat/cold rather slowly, use a highly reflective piece of stainless steel.
Angle the led and photo detector so that together with less light reaching the detector, the refraction of light in the water molecules aid in the detection.

The Arduino code should be fairly easy.

Title: Re: Arduino chilled mirror dew point sensor?
Post by: Old Tele man on January 30, 2018, 05:53:47 PM

Modify an old PC "mouse," it contains all the necessary electronic components already...except the "mirror" surface.

Title: Re: Arduino chilled mirror dew point sensor?
Post by: SLOweather on January 30, 2018, 06:33:42 PM

I was thinking of a stainless steel camping mirror. Also, Peltier devices are reversible in polarity and thereby hot/cold side, so it should be possible to chill it to dew point, reverse the current, warm it up to dry it off, and repeat. Maybe even include a fan to hasten drying and blow dust off the mirror.

Hmmm... I wonder if a Davis leaf wetness sensor could be substituted for the mirror...