Hello mark.

13 Jul 04 13:45, you wrote to me:

 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??

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

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

 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...

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

Jasen

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