Re: [ATM] Cloud detector

[David Nicholls <dcn@dcnicholls.com>]

Many years ago when Barnes Instruments were the only ones selling
triglycine sulphate pyroelectric detectors, I made one by crystallizing
a 1:3 acqueous mixture of glycine and sulphuric acid (doped with a
small quantity of alanine), chopping up the crystal into 1mm square
0.1mm thick slices, and then using a mechanical chopper and chopper
amplifier to detect mid IR (2-10 microns), using simple 741 op amps, and
no cooling.  It was extremely good at detecting clouds of any sort when
pointed at the night sky.

I'd not recommend following the same path, but I wonder if the
pyroelectric sensors in IR motion detectors could be useful.  I think
they are packaged in a can behind a thin germanium window (by the look
of them) so should be impervious to visible light.  Might be a fun
project for a long wintery rainy night.

DN

Robin Chassagne wrote:

> Hello,
> 
> I am a french astronomer , and i search the plans , schemas of a cloud
> detector ; i have seen in the archives , the links on Scientific
> American but there is error page
> 
> 
> Thanks for help
> 
> Best Regards
> Robin
> 
> _______________________________________________
> ATM mailing list http://www.atmlist.net/
> 
> 

-- 
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David Nicholls
Nicholls Communications
http://www.dcnicholls.com/
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