BY MICHAEL SIMPSON
we are going to be using the I2C
interface with our weather
station. To power the display,
anything from 3V to 6.6V will
work. I am going to use a
DiosPro microcontroller because
of its low cost and the fact that it
already has a complete set of
built-in ezLCD001 and 1-Wire
libraries. We will be using the
DiosWorkboard Basic as the
carrier for both the DiosPro and
ezLCD001.
Initial Construction
We need to add a couple of
headers so that we can plug the
ezLCD001 into the Workboard.
Schematic 1 shows the display
hookup. Note that we have
connected the display to ports
10, 11, and 12. You may use
other ports as well, but keep in
mind you will need to change
the ezLCDinitI2c parameters if
you do.
Before you continue, you
need to think about how you are
going to mount the Workboard and
the external modules/connectors. I
mounted mine to a 5” x 7” piece of
compressed PVC. I used a narrow
RJ11 jack for my outdoor network, as
shown in Figure 2. This can be
attached by screws or double-stick
foam tape.
The Workboard is attached using
1/4” standoffs but could have been
attached without them.
■ SCHEMATIC 1
the Hobby Boards barometer. In order
to do this, we need to supply at least
16V to the DiosPro coax. This will
yield approximately 14V to the input
of the 5V regulator. With the added
load of the display, as well as the
outdoor 1-Wire network, the onboard
regulator starts to get warm. The
heatsink will keep the temperatures
within the operating range.
After building the board, plug in
the DiosPro and test the board as per
the included instructions.
STEP 2: To mount the LCD, we need
to add a couple of headers and run a
few wires.
Take a six-pin header and attach
it to the pads marked RC2-RH2, as
shown in Figure 4.
Next, take a 13-pin header and
attach it to the pads marked XC4-
XO4, as shown in Figure 5.
Now, take a second 13-pin header
and attach it to the pads marked YC1-
YO1, as shown in Figure 5.
STEP 1: Build the Dios Workboard
Basic as per the instructions included
with the kit available from Kronos
Robotics (see Web Links). The only
modification that you need to make is
to add a TO-220 heatsink to the
onboard 5V regulator. This is done by
gently bending the regulator so that it
is standing up. Once this is done, you
can slip the heatsink over the regulator as shown at the top of Figure 3.
Why do we need a heatsink
anyway? We need to supply 14V to
■ FIGURE 3
■ FIGURE 2
June 2007 31
