Author Topic: Arduino chilled mirror dew point sensor?  (Read 396 times)

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Online SLOweather

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Arduino chilled mirror dew point sensor?
« 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...

Offline dupreezd

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Re: Arduino chilled mirror dew point sensor?
« Reply #1 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.
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Offline Old Tele man

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Re: Arduino chilled mirror dew point sensor?
« Reply #2 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.
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Online SLOweather

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Re: Arduino chilled mirror dew point sensor?
« Reply #3 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...