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From: Greegor on 6 Jun 2010 15:24
Why were you unable to get indications
from very low wind speeds?

I used an old vU meter D'arsonval movement
from an old junked out component stereo
and I was able to get deflection from
VERY tiny amounts of movement/wind.

It was amazed that it was so sensitive
that you could see bumps that resembled
half waves from the individual armature windings.

You could probably build a circuit that counts
those pulses, or you could have the
wind mill drive a (larger the better) wheel
with black/white marks or flower petals
to count optical interruptions.

The opto-interrupter method gets away
from the loading effects of measuring
voltage or current over a long lossy wire,
but generally you'd do part of the signal
counting close to the windmill either way, right?

Somebody mentioned an embedded
microcontroller with a look up table which is
often done where conversion is non-linear.

In this application what feature induces
a non-linear response that needs
a table lookup?

Why wouldn't it be a straight ratio?

When it comes to measuring wind speed,
isn't it LOCATION, LOCATION, LOCATION?

Putting the windmill cups in a spot
affected by valley, trees, building walls,
eddies from walls etc. would be a huge
factor for accuracy wouldn't they?

IE just placing it outside a window would
distort the results differently depending on
which way the wind is blowing because
of the building and or eddies, right?

Just a d'Arsonval movement with a big face
driven by a common toy motor and a hand marked
scale or face on the meter looks like it
would do pretty good if you don't need
some rediculous kind of hyper accuracy.
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