On Fri, 29 Aug 2008 00:46:14 GMT, George wrote:

A spoon and a tilt switch, ...

Complicated, why not use the handle end of the spoon as one contact and a
bolt head as the other. It won't detect light rain fall either, even if
you put a large funnel over the bowl of the spoon to capture more rain.

What you have described is the basis of a "tipping bucket" rain gauge.
What you have missed is that the bucket (spoon) tips it empties of water
and is ready for the next volume of rain.

This would only signal a pulse to the detector, so that would need to
trigger something to sound the alarm long enough to be noticed. Unlike the
"wet plate" detector which will sound for as long as the plate is wet.

--
Cheers
Dave.