Control Your World
the first from the second. Multiply the
difference by . 68
There are several ways of interfacing to the various sensors needed to
build a weather station; the three most
• PC to 1-Wire interface.
• PC to microcontroller interface.
• Microcontroller to 1-Wire/other.
Each has its advantages and as the
series progresses, we will go into each
type of system in detail. For this
article, I will keep things simple and
will be concentrating only on the PC
to 1-Wire interface.
So far, most of what I have gone
over relates to the mechanical construction or make-up of each unit. It is
now time to hook up each unit and do
some tests. In order to simplify things
here, I chose to use a 1-Wire network
for each of the three devices. This
makes the actual software needed for
each of the three nearly identical.
In order to connect 1-Wire devices
to your PC, you will need a 1-Wire to
serial adapter. A DS9097U is shown in
Figure 11. They can be purchased for
under $30 and will allow your PC to
connect to any 1-Wire device. I have
added direct support for this adapter
to Zeus. (Zeus is a custom program
available on the Kronos website, which
is listed under Links.) You will not need
any drivers or runtimes to support it.
All the test applications written for this
article require this adapter and will not
work with any others.
The AAG unit has two RJ12
connectors with only four of the six
pins wired in each. One of these
connectors will have a small jumper
installed. For now, leave the jumper in
place. An 8’ coiled RJ11 cable was
also included with the AAG. Plug one
end of this cable into the remaining
RJ12 connectors and plug the other
end into the DS9097 adapter. This is
all you need to do to start testing.
An important note is the cable
that comes with the AAG instrument
is not the same as a standard telephone line cable. If you wish to use a
normal telephone line cable, you will
need an adapter. One way to do this
is to use a line cable link and two line
cables as shown in Figure 13. This will
effectively allow you to connect two
line cables, thus double-reversing the
two center pins on the connectors.
The other two anemometers
require a little more prep. As you
recall, we are using a 1-Wire dual
counter available from Hobby Boards
as our interface.
In order to facilitate a connection to
the PC, we will use a RJ11 surface
mount box, available from most home
centers. We are going to place the dual
counter inside this box so make sure
you get a standard sized box, not one of
the small ones. In order to prep the box,
you need to remove the yellow and
black wires. The green and red wires will
need to be bent as shown in Figure 14.
Cut a small length of wire, about
one inch, will connect it to the box’s
green lug and then to the DQ terminal
■ FIGURE 15
on the counter board. Cut another
piece of wire and attach the red lug to
the Gnd terminal on the counter
board. You can now connect the
anemometer reed leads to the 5V and
A terminals as shown in Figure 15.
You can use a standard telephone
HOMEMADE ANEMOMETER PARTS
ITEM PART NO.
❑ Anemometer Cup and
❑ Two Neodymium Magnets
❑ Bearings Team Associated #6589
❑ Reed Relay #275-232
❑ 1/2” PVC Cap
❑ 1/2” PCV Tubing
❑ #4 1-1/4” Stainless Steel Machine Screw
❑ #4 Stainless Steel Washer
❑ #4 Lock Nut
❑ #5 Hex Nut
❑ 5/32” Brass Tube
❑ 3/16” Brass Tube
❑ Dual Counter
❑ AAG Weather
❑ AAG Weather Instrument
❑ 1-Wire to Serial Adapter DS9097U-A
❑ AAG Weather TAI8515
❑ 1-Wire to Serial Adapter DS9097U
❑ Standard Anemometer WEA-ANKIT-A
❑ RJ11 Surface Mount GE TL26101
February 2007 39