[HH] low-cost alternative to a thermal imaging camera

[Drew Van Zandt]

I suggested that last idea at a previous company I worked for, doing
temperature monitoring.  The owner loved it, and thought it would make a
ton of money for us.

And then did nothing with it.

*
Drew Van Zandt
Artisan's Asylum Craft Lead, Electronics & Robotics
Cam # US2010035593 (M:Liam Hopkins R: Bastian Rotgeld)
Domain Coordinator, MA-003-D.  Masquerade aVST
*



On Tue, Mar 13, 2012 at 2:32 AM, Tom Metro <tmetro+hhacking at gmail.com>wrote:

> Thermal flashlight 'paints' cold rooms with colour
> http://www.newscientist.com/article/mg21328546.200
>
>  The device comes from the Public Laboratory for Open Technology and
>  Science, a non-profit group based in Cambridge, Massachusetts, that
>  develops open-source tools to allow ordinary people to investigate
>  environmental issues.
>  ...
>  Standard thermal cameras are prohibitively expensive for ordinary
>  people.
>
> Right, a Fluke Thermal Imager, for example, will set you back $2000 ~
> $3000.
>
>
>  In contrast, the thermal flashlight prototype costs about $40. What's
>  more, it can easily be assembled by someone with no electronics
>  expertise.
>  ...
>  The thermal flashlight is built around a single infrared thermometer.
>  This scans an area of wall and picks up varying levels of radiation
>  emanating from it. This temperature information is fed into a
>  microprocessor, which controls a multicoloured LED light. Shine the
>  flashlight against a surface and the colour shows you a real-time
>  temperature reading. Areas of the wall with a cooler temperature show
>  up blue, while red light shines on patches that register as warmer.
>
> Even easier, you can buy one for $24:
> http://www.amazon.com/Black-Decker-TLD100-Thermal-Detector/dp/B001LMTW2S/
>
> I bought one of these a couple of years ago when they cost $50. It's
> essentially a run-of-the-mill non-contact IR thermometer, with a slight
> twist. They stick a multi-color LED on it that lights up the target area
> with green, red, or blue light depending on whether the current spot you
> are pointing at is warmer or colder than your starting point. (I forget
> some of the details, like whether the color change is relative (I think)
> or tied to a fixed absolute temperature. And whether it is continuously
> variable (intensity) from red to green to blue, or if flips from one
> color to the next when a threshold is tripped (product description and
> my vague recollection supports the latter).)
>
> My first thought when getting this device was how one might hack it to
> emulate an expensive thermal imager. The initial thought was that you'd
> stick it on a tripod, mounted to a computer controlled pan/tilt security
> camera mount. Then a computer could make it raster scan a wall. How
> you'd capture the color information eluded me.
>
>
>  An image of the light-painted room showing exactly where heat is
>  leaking can then be captured using a webcam with an online app called
>  Glowdoodle or just standard time-lapse photography.
>
> Ah! Glowdoodle (http://scripts.mit.edu/~eric_r/glowdoodle/) is the
> missing piece. Looks like you need to use it in a fairly darkened room,
> which also would work for an old-school solution using a 35mm analog
> camera with the shutter held open.
>
> To really emulate an IR imager the Black and Decker thermometer wouldn't
> cut it. The wall would appear in only 3 color, and no varying shades.
> This is perhaps where the D-I-Y thermometer is superior.
>
> I think the B&D thermometer also has a laser pointer to help you aim (as
> is common for IR thermometers), and I don't recall if you can turn the
> laser off. That bright red dot would mess up your captured heat map.
>
> One of the sales claims for the B&D was "Helps homeowners track down
> power-draining drafts." Before buying I was skeptical how it could do
> that. After buying it became apparent that they were stretching the
> truth and not directly detecting drafts, but just temperature variations
> that are often affiliated with drafts. There are tools that can actually
> detect drafts, but this isn't it.
>
> In any case, after playing around with it for a while, I lost enthusiasm
> for the tool and never did really make use of it. (I was really far more
> interested in detecting actual drafts than measuring insulation quality;
> on a first pass for weatherization, you have a far higher impact by
> stopping  air leaks than by improving insulation.) I should dust it off
> and do something with it.
>
> The real question is why hasn't some manufacturer created a low-end
> thermal imager that employs this technique. There are no recent
> developments that have just made it possible. All the tech involved was
> pretty much available a decade ago.
>
> For example, you create a tool a bit larger than an IR thermometer,
> stick a cheap CCD camera into it, and a motorized mirror assembly in
> front of the IR sensor so it can scan the field of view. Stick in a
> micro to drive the scanner and composite the thermal data over the
> video. Add on an LCD for aiming and image preview, plus an SD card and
> USB port to get the images out of it. Presto, thermal imager for under
> $300. It'd be slow. You'd have to stick it on a tripod. Pros wouldn't
> want it, but you might sell enough to non-profit energy conservation
> groups and early adopters to get the price under $200, at which point
> you'd interest homeowners.
>
>  -Tom
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