Hi all,

The IR emitted by IR LEDs in remote controls, etc., is just slightly
longer than visible light (shorter than 1 micron wavelength). The IR
emitted by hot objects in the 100 deg C range is going to peak around
several microns in wavelength, way too long for a regular CCD to see.
The problem is not that the emission is weak but that it is the wrong
wavelength.

Vitaliy, I don't know what your friend was able to see on the PCB with
a regular camera in "night mode" (which is usually just removing the
IR filter and illuminating with IR LEDs).

IR thermal imaging cameras use exotic focal plane array detectors
(made not from Silicon or GaAs, etc. but from InCdTe, InSb, PbS, or
similar materials, or microbolometers which are arrays of sensitive
temperature sensors which absorb the incident IR and measure the
resulting tiny temperature increase). I don't think you are going to
find them for anything less than several thousand dollars new. You
might possibly find something used on eBay for much less. A quick eBay
search turned up a few hits in the low thousands of USD. The
technology is the same as used in newer generation heat seeking
missiles.

Sean






On 5/18/07, Vitaliy <spam@maksimov.org> wrote:
> Alan B. Pearce wrote:
> >> Color would be ideal, but I'd like to stay in the <$1k range so b/w may
> >> be
> >> acceptable too. Personal testimonies and tips for using such camera are
> >> of
> >> course welcome.
> >
> > The biggest problem with thermal imaging is that it seems to need special
> > sensors as the thermal heat temperature range is too low for normal
> > visible
> > light sensors to be sensitive to.
>
> A fellow engineer mentioned that he used a regular camcorder in "night" mode
> to troubleshoot PCBs. I thought maybe I could use an IR security cam with an
> IR filter for the same purpose? Do you think it's not going to be sensitive
> enough?
>
> > I believe the colour ones post process a gray scale image to give false
> > colour to make the differences easier to see, but I could be wrong here.
>
> If that's the case, I'm sure there must be PC software out there, that can
> do the same thing.
>
> Vitaliy
>
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