JB>>> my little wind-speed sensor died. - it was made from a
 JB>>> CPU-fan chassis with the iron removed and the sensor in
 JB>>> the motor wired to the joystick port.

 ml>> interesting! how did you determine how many PPMs per mph/kph??

 JB> on my first attepmt I fitted it to a tower on my car's
 JB> roof-rack and tried to record useful data (clicks, and my
 JB> voice announcing speeds) on a cassette tape.
 JB> but I found the analysis of the data too complex in the end

not to mention dealing with other forces like natural wind ;)

 JB> finally I fitted it on a long arm and swept it in a circle at
 JB> a known rate (indoors)

by hand?

 JB>>> it worked pretty well until the ball-bearing went rusty
 JB>>> and then the cups (cut from ping-pong balls fell off)

 ml>> i hear that...

 ml>> i've also seen "swing meters" for measuring the
windspeed... basically
 ml>> its a vertical rod with a flat piece hinged to the top of the rod...
 ml>> as the wind blows, it lifts the flat piece. the angle that the flat
 ml>> piece is raised to is used to determine the windspeed... this is done
 ml>> based on the weight of the flat piece and the width of it, or so i
 ml>> guess... seems that a wider piece would raise higher if both are the
 ml>> same weight...

 JB> but how would you read something like that electrically?
 JB> (i gues if it was big enough it could turn a potentiometer, or
 JB> move a a piece of ferrite inside a coil that's part of a tuned
 JB> circuit oscillator (a fragment of a ferrite ring would have
 JB> the right shape)

actually, the ones that i've seen have a triangle on them that acts as a
vane to keep it turned the proper way... i was thinking of a resistive
wiper riding on that vane and setting the measurements at the specific
reading for that point... the arm that the wind raises has a pointer to
this vane where the speed marking are located...

)\/(ark