I seem to remember a DIY design in the dim & distant past based on split
ping pong balls and some SS hypodermic tube, various dia's silver soldered,
with PTFE bearings housed in a brass 1/2 inch tube. Electrical pulses using
one or more reed switches and a small magnet on the rotor. Try asking on NG
uk.sci.weather, some of the old stagers may remember the description and
refer you to the original publication.
Cheers

"Tim Mitchell" wrote in message
...
I'm sure the collected wisdom of uk.diy can help with this. I'm making
some electronics for a rather unusual sculpture which reacts to
environmental conditions. One of its triggers is wind speed. I have
googled for ages trying to find someone who supplies anemometer
mechanisms, the 3 cup sort of thing, which will attach to a nearby
building.

It does not need to be calibrated or anything, just output a pulse train
which has frequency proportional to wind speed.

Maplin used to do one, but don't seem to any more. The only other ones I
can find are pukka meteorological ones which cost about 500 pounds. If
anyone knows a supplier for the maplin-type thing I would be most
grateful. I have in the past diy'd an anemometer but the bearings proved
to be problematic so I would rather buy a mechanism. I will however be
doing the electronics myself!
--
Tim Mitchell