BY MICHAEL SIMPSON
area or a voice that announces various
weather or alarm data.
I tried several Zigbee modules
and selected the Maxstream (www.
maxstream.net) XBee modules shown
in Figure 2. I recommend the whip
antenna module as you get a bit more
range over the small chip-based antenna module. The XBee whip antenna
module will cost you about $19 each
and you will need at least three to
build your weather station network.
Because each module’s firmware
must be loaded with special mesh
network firmware, you will need to get
a starter kit (Maxstream #XB24-DKS)
which consists of the following:
■ FIGURE 3
• RS-232 development board
• USB development board
• Two XBee OEM RF whip antenna
• Various cables and connectors
• AC adapter
• Configuration software
With the purchase of this starter
kit, you will need at least one
additional RF module; more if you
want to add additional sensor
networks and display systems.
Before I continue, it’s important
that I point out that Maxstream has
just released a set of Series 2 modules
and development kits. The Series 2
modules are not currently compatible
with the existing XBee modules and
will not work with the instructions
presented here. I can assure you, however, that the current mesh network
firmware for the existing XBee
modules works just fine. My wireless
weather station has been up and running for months now and has handled
all sorts of power outages and other
interruptions without a single glitch.
wanted to collect data
from a nearby barn.
The barn is out of
range of my current
network. By placing a
module in a small shed
located between the
two buildings as
shown in Figure 3, I
was able to add the
barn to my network.
This also has the benefit of allowing me to
monitor the pool temperature.
Our weather station mesh
network is set up in such a way that
all the modules broadcast their data.
This allows any module placed in
the network to be able to collect or
transmit telemetry data.
■ FIGURE 4
have special mesh network coordinator firmware loaded. All the other
modules need to have special
mesh network router firmware loaded.
To load the proper firmware into
the modules, you need to follow
Just What Do You
Gain by Using a Mesh
Network in Your Home
I had three Zigbee/sensor
modules located in my work area but
When setting up
your weather station
mesh network, you
will need to have one
coordinator. All the
other modules are set
up as routers. The
coordinator needs to
■ FIGURE 5
September 2007 47