■ FIGURE 10
■ FIGURE 11
direction, and temperature.
• Simple 1-Wire interface. It is
possible to install and use this device
without soldering a single wire.
The AAG weather instrument
comes partially assembled. You will
need to open up the main housing in
■ FIGURE 13
order to install the wind direction
vane. This will take you 15-30 minutes.
You will also need to coat all of the
external seams with some sort of
sealant to keep water from entering
the instrument. The PCB inside the
housing is coated for protection but
the RJ12 connectors are not.
I have had more than a few issues
with water. Eventually, I used a
gutter sealant and that seemed
to solve all my water problems.
Once assembled, the anemometer cups are located at the
top and the wind vane on the
bottom as shown in Figure 10.
To mount this instrument,
■ FIGURE 12
■ FIGURE 14
you will need to purchase a U-bolt. I
use a 1-1/2” U-bolt. This size will work
for just about any size mast up to
1-1/2” in diameter.
You will need to drill two holes in
the aluminum mounting rod that
comes with the AAG instrument as
shown in Figure 10.
You should download the
assembly instructions for this device.
They are outdated and refer to the
older V2.0 unit, but contain most of
the information you will need for the
The instrument uses three Dallas
1-Wire chips used to collect weather
data. A DS2423 is used to collect wind
speed data. A DS2450 is used to
calculate wind direction data with a
resolution of 16 compass points. A
DS18S20 is used for temperature
measurements. The instrument can be
made to operate off of 5V, but is set by
default to use 1-Wire parasite power. In
parasite power mode, you only need
two wires connected to the unit to
retrieve the data from any of the sensors. I will be going into more detail
about the use of 1-Wire sensors, as
well as other alternatives next month.
The instrument works flawlessly,
but I do have a few comments about
the effectiveness of the various sensors. I run several temperature devices
on my weather pole and have found
that the AAG temperature tends to
run 2-10 degrees hotter than the
others when the sun is shining. This is
due in part to the fact that the unit has
no ventilation and that the housing is
made of white plastic so it creates a
small solar oven inside. For this
reason, I rarely use the AAG DS18S20
for temperature readings. The wind
vane is ultra-sensitive to wind and
never seems to stop turning. A bit
more surface area and more mass is
needed to make the vane more stable.
The AAG anemometer uses the
MPH = counts over 1.5 second time
period . 68
Take a counter reading, wait 1.5
seconds, then take another. Subtract