Silly Question: Heat Sensor Gun

Do they work through glass? I would like to find a unit that will allow me to check temperatures in vacant stores through the storefront.

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Like this.

Thanks!

Peter Wieck Melrose Park, PA

Reply to
pfjw
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It's not a silly question.

Regular glass supposedly reflects infrared, does it not? And these devices measure infrared, is not so?

Reply to
William Sommerwerck

s

Actually, glass reflects or absorbs infra-red based on angle and composition and coatings (if any). Were it to reflect (all of) it, a lens would not be very good at starting fires in by concentrating sunlight.

Further, these guns use a laser and some sort of sensing device - so, I am trying to determine how good it would be at sensing say... a wall temperature a few feet inside a building through a window.

Peter Wieck Melrose Park, PA

Reply to
pfjw

"William Sommerwerck" wrote in news:gklog6$qlp$ snipped-for-privacy@news.motzarella.org:

not all IR wavelengths.

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Jim Yanik
jyanik
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Reply to
Jim Yanik

Based on the other answers, I think the best bet would be to get a baseline--normal temp--and from there just look for a rise. IOW, it might not measure actual temperature accurately, but the the consensus seems to be that various types of glass will pass 'some' IR; so it might be good enough to indicate a change. As long as you know what it 'should' read, you can tell if it's above normal.

Of course it will take some experimenting.

jak

Reply to
jakdedert

Actually, glass reflects or absorbs infra-red based on angle and composition and coatings (if any). Were it to reflect (all of) it, a lens would not be very good at starting fires in by concentrating sunlight.

Further, these guns use a laser and some sort of sensing device - so, I am trying to determine how good it would be at sensing say... a wall temperature a few feet inside a building through a window.

Peter Wieck Melrose Park, PA

The laser is purely for aiming and is not involved in the measuement process. Take a cup of coffey and try measuring its temp driectly and from behind some different glass types - some glass may be tempered or laminated which may affect readings (guessing here).

Reply to
K Ludger

PIR detectors don't work through glass

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Reply to
N_Cook

I have a similar looking one in the UK - and that does work through glass (or at least some types). For example it gives the same reading through my glass oven door as with it open (checking the oven thermostat). But things

*may* be different with some types of glass designed to reflect the sun's heat.

I'd also say that looks a high price for these things - perhaps because it's sold for automotive use. Check Radio Shack or Ebay etc for the same thing - in the UK 25 gbp is a guide price.

--
*I used to have an open mind but my brains kept falling out *

    Dave Plowman        dave@davenoise.co.uk           London SW
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Reply to
Dave Plowman (News)

You've got to be kidding. Where did you learn "science"?

Reply to
William Sommerwerck

Yep. I just linked to that as it gave a fair description of the unit. Very similar units may be had at eBay for less than US$30 including shipping. I am going to check in several local supply houses as well. I am willing to pay a premium to find something - MAYBE - made in the USA.

Thanks for the actual answer to the actual question.

Peter Wieck Melrose Park, PA

Reply to
pfjw

From experiance, its not going to work well. You will get some relative indication of a general temperature of the inside comparing different stores.

greg

Reply to
GregS

I just checked with my very similar gun, and it shows the surface temperature of the window glass. The outside temp is currently around

-5°C here, and the gun shows around +22°C on a window above a radiator, and +15°C on a window in a door.

I get the same reading on both coated and uncoated glass. The coated class is very effective at shielding radiowaves.

Thomas

Reply to
Thomas Tornblom

As you can be shot and killed, quite legally with no retribution to them, by the police in the UK just for carying a table leg or just looking Brazilian, then not advisable to do such in the UK.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Reply to
N_Cook

" snipped-for-privacy@aol.com" wrote in news: snipped-for-privacy@40g2000prx.googlegroups.com:

I would guess that the reading will be an AVERAGE of the actual wall temperature and the glass temperature with weighing of those temperature depending on the exact characteristics of the glass.

The only way to 'know' if it will work for YOUR application would be to try it in enough cases. Measure the wall temperature directly (without the glass in the path and then through the glass.

If you need to read the temp through the SAME glass, time after time, you should be able to develop a calibration curve that will allow you to accurately estimate the wall temperature.

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bz    	73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
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bz

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