🚀 go-pugleaf

Henry Spencer (henry@zoo.toronto.edu) wrote:
: In article <CnEBL0.5Gx@cryton.demon.co.uk> pcats@cryton.demon.co.uk (Patrick Arnold) writes:
: >: If they're silicon CCDs, which I believe all of them are, forget it.
: >: Thermal-IR photons simply are not energetic enough to register on them.
: >
: >Sure they are. The only problem is that you need fairly high temperatures. I have
: >a small monochrome CCD camera that will easily produce a picture of a hot 
: >soldering iron, etc...

: Picky, picky, picky...

Afraid so...

: >As an aside, I have played with using the PIR detectors intended for intruder
: >alarms as sensors in a slow-scan imaging system, with fair results. The main
: >drawback is quite short range, ie a few meters or less.

: Hmm, yes, I hadn't thought of those.  Those *are* honest-to-God thermal IR
: sensors.  Unfortunately, at room temperature their S/N ratio is very poor;
: this is why the thermal-IR imagers are cooled.

So use a peltier heatpump module and cool the thing to about -60 C. The only
problem then is stopping frost forming on it and blocking the IR ;-)

Patrick.

-- 
The shortest distance between two points has not yet been built.

email pcats@cryton.demon.co.uk
voice +44 (373) 464957 or +44 (749) 670058 fax +44 (749) 670809