> i don't know -- i always thought those "pyroelectric sensors" were what
> elsewhere is called a photodiode :)  what do you think it is if not a
> photodiode? of course there are photodiodes optimized for high speed data
> transmission, and there are thos optimized for temperature measurement, but
> i guess they're still =photodiodes=, however fancy they might be selling
> them. thermopiles is another story, though.
>
> ge

They do not work on the same priciple as a photodiode.  Some of the
pyroelectric manufacturers on the net explain the pyroelectric effect if
you wish to research it...a quick search will turn them up.

JT