October
2005, Issue 183
The
Silicon Wallet
CY8C27443-Based
Data Manager
PROTOTYPE
Before
building the prototype, I refined the design, fitting
the Invention Board in a solderless breadboard. Thus,
at the time of the first power-up, I was confident that
everything would work well. Well, almost. After switching
from USB to battery power, I quickly discovered that
the unused parts on the Invention Board were drawing
significant power. I suggest you use a bare CY8C27443
for the best battery life.
My
prototype uses point-to-point wiring and a few drops
of hot melt glue to bond the parts to a 60 mm × 90 mm
plastic box. (A photo of the prototype is posted on
the Circuit Cellar FTP site.) Placement isn’t critical;
just try to shield the phototransistor from ambient
light.
After
powering up the device, turn the encoder knob to enter
the combination: the default code is three to the left,
four to the right, five to the left, six to the right,
and seven to the left. After the combination is accepted,
the knob scrolls between the data records until the
device is powered off.
