battery connector. This is because there is no
corresponding hole on the Arduino proto shield (which
doesn't matter since the shield is mostly held in place by
all the male/female pass through connections and the
other bolts). We see the Arduino placed on the bolts in
Figure 8. The two bolts at the top of the photo should
have nuts added to hold down the Arduino. The bolt
nearest the USB (in Figure 9) may have a nut added on
the older models, but in the Uno R3 the extra connections
are too close to allow it. We can see the Arduino proto
shield added in Figure 10. Note that the nuts are on top
only, since they are not needed underneath the PCB to
support the board since it is already supported by the
male/female shield connections.
We saw in Figure 7 that there is an extra set of nuts
about three-quarters of the way up the shaft of the bolt.
These are used to support the IMT as shown in Figure 11
(with the LCD removed).
■ FIGURE 11.
I2C mini terminal
PCB bolted on
I2C Connection For Old Arduinos
Versus New Arduino Uno R3
There are two types of I2C connections for the
Arduino (at this writing). For the newer Arduino Uno R3,
we wire the four-pin female connectors straight onto each
other as shown in Figure 12. For the older non-R3
Arduinos, we connect analog A4 to SDA, and analog A5
to SCL as shown in Figure 13. Notice that the I2C wires
cross each other in Figure 13 but are parallel in Figure 12.
Finally, we add one side of the Velcro to the bottom
of the IMT PCB and the other to a nine volt battery. Then,
we add the snap connector to the
battery and the barrel connection
to the Arduino as shown in Figure
14. Be sure to unplug the battery
from the Arduino when you aren't
using it since the Arduino may be
running (you can't see the 'on' LED
under the proto shield) and you
will deplete the battery.
■ FIGURE 12. I2C R3 connection.
■ FIGURE 13. I2C non-R3 connection.
The main goal for this device is
to help you prototype your own
designs. I'm always amazed at the
stuff folks are doing, and I'm
looking forward to hearing from
readers who use this device to see
what sorts of things are developed.
Last month, I promised to
discuss how to create a fresh air
controller for a castle, but I'm
putting that off till next month
when we will apply the handheld
prototyper to a practical project.
This is a perfect application for our
new tool, even if you don’t own a
■ FIGURE 14. Assembled with battery.