2009/4/1 Marco Genovesi <carroz53@gmail.com>:
>
> Maybe simple but I haven't any experience of this..
> Is it possible to use a common PIR surveillance sensor to detect a warm->=
cold->warm temperature transition?
> I know taht the "normal" use in surveillance is to detect an "hot" body c=
rossing the sensor area.
> Instead, I would to detect a cold "object" ( 15-20 C. less than the ambie=
nt temperature).
> A possible complication is that the cold "object" isn't a solid but reall=
y a localized flux of COLD air that rapidly
> cross the sensor area and that may be very near ( from 5 to 1 feet from t=
he PIR).
> A real case: ambient temperature 25-30 C. and a cold air flux of =A05-10 =
C.
>
>
> thanks,
> Marco
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I've noticed that my outside sensor often turns the lights on when I
open the garage door in the winter. So the warm air must be setting it
off.

So quite feasible I would think.

RP

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