Control Your World
a small plastic spacer.
Leave this in place and
bend that lead as
shown in Figure 5B.
With a couple pieces
of 1/16” heat shrink,
solder two 24” lengths
of wire to each lead as
shown in Figure 5C.
STEP 8: Attach the
reed to the PVC cap.
Attach the reed to
the cap as shown in Figure 6. It is
important that the magnet passes over
the spot indicated by the arrow. You
can always change the lengths of the
3/16” bushings after the reed is in
place. There is a great deal of leeway
for the placement as the Neodymium
magnets are very powerful. You can
use a small twisted wire to hold the
reed in place while the epoxy dries.
■ FIGURE 7
■ FIGURE 8
damage due to its simple design.
• Of the three, this is the most rugged
This anemometer uses
• Aluminum cups.
MPH = counts
period + 2
• This is the most professional looking
■ FIGURE 9
That’s it for the mechanical assembly of the homemade anemometer. At
the end of this article, I will talk about
the hookup and testing.
For those of you who don’t want
to build an anemometer from the
ground up, your next option is to purchase a complete kit. A company
called Fascinating Electronics sells the
perfect anemometer kit to get your
home weather station started.
The kit costs $49.90, and this is
one nice kit. You get everything you
need to build the anemometer. We will
use the Hobby Boards counter board
as before to interface to our PC. Of the
three units, this is the most rugged
anemometer. It features real aluminum
cups and the design makes for a really
water-tight system. Like our homemade
anemometer, it comes with a reed that
is triggered twice with each revolution.
The hookup is identical as well: Simply
connect the anemometer reed to the
counter as shown in Schematic 1.
Features of the Complete Kit
• This device is very resistant to water
• It has a matching, very heavy duty
wind vane that can be purchased.
• Not restricted to 1-Wire. You can
use several interface options.
• 1-1/2” PVC mounting gives you
many placement options.
The only downside I have found
with this anemometer is that since the
hub assembly has so much mass, it takes
a bit more wind than the other two
devices tested to get moving. Normally,
this will not be a problem as we are
talking about one MPH, and at those
low speeds, it’s a moot issue any way.
The assembly of this kit will take
you one to two hours. The anemometer, once finished, mounts on 1-1/2”
PVC pipe as shown in Figure 8.
Use a couple of 1-1/2” U-bolts to
attach a 1’ section of PVC pipe to
your weather pole, then all you need
to do is slip the anemometer on to the
pipe as shown in Figure 9.
Fascinating Electronics sells a T
mount for mounting the anemometer,
as well as an electronic weather vane.
This weather vane features a full 360
degree reading with no dead zones.
We will be looking at this instrument
in detail next month.
Take a counter reading, wait 1.67
seconds, then take another. Subtract
the first from the second and add 2.
The result will be the MPH.
A while back, Dallas offered a small
weather instrument to demonstrate the
use of their chips as sensors. This was a
perfect solution for those wanting to
build their own weather station. They
no longer offer the device, but a
company named AAG Electronica does.
The unit that AAG offers is actually an
improved version of the original.
Hobby Boards is a US distributor
of the AAG unit. I prefer to work with
them because the owner Eric Vickery
has been very responsive. Hobby
Boards also offers several other 1-Wire
sensors, many of which we will be
looking at in the upcoming articles in
Features of the AAG Instrument
• Very sensitive to wind speed and
• Self-contained unit features three
instruments: wind speed, wind
February 2007 37