In message  <9606041855.aa22724@device.data.co.za> PICLIST@MITVMA.MIT.EDU
 writes:

> > The unit has no moving parts, but uses ultrasonics to detect wind speed and
> > direction.  The unit has four prongs with ultrasonic sensors on top of them.
> > ....
> > displayed on LCD's inside the cottage.
>
> Nice sensor, remember to ignore values that have a large delta comapred
> to previous readings, you may be measuring rain or hail effects.
>
> > I also will monitor temperature with a transistor and will also display this
> > out on a LCD inside the cottage.  But the temperature will also activate
> > small heaters which will warm the ultrasonic tips to prevent icing in the
> > winter.  I have no idea where to start with some low power heating elements
> > to do this.

A small British company developed these type of anemometers for use on
sailing yachts. It was shown on the TV program 'Tomorrows World' a few
years ago, they won a LARGE! competition run by British Gas to design
a new gas meter. They used the same technique to measure gas flow through
the meter.

Nigel.

          /----------------------------------------------------------\
          | Nigel Goodwin   | Internet : nigelg@lpilsley.demon.co.uk |
          | Lower Pilsley   |                                        |
          | Chesterfield    |                                        |
          | England         |                                        |
          \----------------------------------------------------------/