One method for wind speed measurement is to connect a permanent magnet motor
to a wind vane.  The motor will act as a generator and the CEMF generated is
proportional to the speed of the motor.  May be a 100v dc if your gearing is
to step, but a higher max speed is better to get out of the IR drop RPMs
CSS

                -----Original Message-----
                From:   James Paul [mailto:jim@JPES.COM]
                Sent:   Friday, January 14, 2000 1:50 PM
                To:     PICLIST@MITVMA.MIT.EDU
                Subject:        Re: Windspeed circuit?

                 I believe lvdt stands for "Linear Variable Differential
                 Transformer".

                                                        Regards,

                                                           Jim




                On Fri, 14 January 2000, "Smith, Clay" wrote:

                >
                > What you describe is called an lvdt.  Run an AC current
thru a transformer
                > or inductor and move a spring loaded ferrite core in
against a calibrated
                > spring and rectify the output.  You will have a voltage
proportional to the
                > force on the lever
                > CSS
                >
                >                 -----Original Message-----
                >                 From:   Wagner Lipnharski
[mailto:wagner@USTR.NET]
                >                 Sent:   Friday, January 14, 2000 12:20 PM
                >                 To:     PICLIST@MITVMA.MIT.EDU
                >                 Subject:        Re: Windspeed circuit?
                >
                >                 You can develop any kind of sensor, by
wind pressure,
                > differential
                >                 pressure, weight lifting (wing),
rotational blades (most
                > common), or any
                >                 other. Some will generate a linear voltage
(requires an ADC
                > conversion),
                >                 some will generate pulses (that should be
accounted by
                > time).
                >
                >                 In any case, the most difficult task is to
calibrate the
                > unit. Even if
                >                 you install the unit outside your car and
drive in a not
                > windy day, who
                >                 ensures that your car's speedometer is
calibrated?  If you
                > want to go
                >                 for some accuracy you will need to use a
professional
                > laboratory or wind
                >                 calibrator.
                >
                >                 Is there any practical method to measure
air speed (low
                > accuracy)? as
                >                 for example, imagine a 12x12 inches 1/8"
aluminum plate hang
                > by two
                >                 nylon wires 3 ft high, wind directly over
the plate, how
                > much will be
                >                 the deflection of the plate at 10mph?
20mph? is there
                > anything like that
                >                 for practical purposes? as is the original
knots measurement
                > in
                >                 boats...  (I am curious about that).
                >
                >                 Wagner.
                >
                >                 "Peter L. Berghold" wrote:
                >                 >
                >                 > Hi there folks,
                >                 >
                >                 > Anybody out there know of plans on the
web for a wind
                > speed indicator?  I
                >                 > would assume that it would involve some
sort of pulse
                > counting scheme...

                jim@jpes.com