Adrian C wrote:

Marnok.com wrote:

These are Pro-Luxe IR-650ST.

They were pretty cheap, and they make me look a bit like a cyberman

I tried shutting the curtains, turning the lights out and switching my
monitor off in case any of that was an IR source, none of it seemed to make
any difference.

You need to pipe cold liquid nitrogen into the IR receiver modules to
reduce the noise floor. Looking like a cyberman does help ;-)

You just reminded me of something.

When I was at (St Albans) School there was an almost 'spare' lab in the Science
Block. It rarely got used for lectures, so enthusiasts like the Radio Society had
use of it. At that time they downloading weather maps ! Together with 2 friends I
was working on an organic dye laser but were knackered by the impossibility of
getting optically flat mirrors. We still did some 'interesting stuff' there some
of which is utterly hilarious but since you mention LN2, we went and bought some.
Or at least 2 of us did. They went to the local 'British Oxygen' depot with a
crate full of thermos flasks and were asked on admittance if they wanted oxygen
or nitrogen !

So they went to the nitrogen section which they described as being like a petrol
pump and filled up all the thermos flasks. It wasn't even that expensive.

So we had fun trying the effects of extreme cold on many things like ICs for
example.

Then my friend Nick and I had a mischievious idea. Our next lesson was Computing,
and the teacher was well known to be rather poor with discipline, so each of us
took a boiler tube of LN2 in our jacket pockets (well insulated with several
layers of simple paper), made sure we were last into class, and before entering
poured the LN2 over our suits !

So the 2 of us entered looking like something from Dr Who, white fumes smoking
all over us and totally straight faced.. One of the guys knew we we were up to
something and unfortunately for him, was leaning back in his chair. He was so
surprised that the chair slid from under him and he got put on report.

Not a word to Nick or myself, as the 'smoke' gradually dissipated. I'm glad you
reminded me of that.

Graham