> -----Original Message-----
> From: Russell McMahon [SMTP:apptech@PARADISE.NET.NZ]
> Sent: Tuesday, November 05, 2002 11:05 AM
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      Re: [EE]:rain Sensors, was Infra-red Opto help
>
> > >A raindrop falls from at least 500 meters of height and has
> > >a minimum size. I'd use a simple microphone attached to a
> > >drum-like structure (with saran wrap skin I think). This may
> > >react to other things besides rain.
> >
> > Well yeah, if it is actually raining, in a "cats and dogs" sense. But
> often
> > when I'm driving my car, the road is wet, and there is misty water
> landing
> > on the wind screen, so there is some precipitation of moisture out of
> the
> > atmosphere. It certainly does not land on the windscreen with enough
> energy
> > to make any noise.
>
> FWIW - a raindrop has a terminal velocity of a few tens of kilometres per
> second. Actual velocity depends on drop size but in free fall is never
> vast.
> I imagine that wind blown drops assume a speed approaching that of the
> wind
> gust they are carried by.
>
>
Surely tens of *meters* rather than kilometers?

Mike

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