FIGURE 2. The prototyping board lets you stack or sandwich
a shield on top of the AXE401. In the middle of the shield, you
can place a mini solderless breadboard for rapid prototyping.
FIGURE 3. Attach the AXE401 board using jackscrews. You
can insert the male threaded end of the jackscrew from the
top or bottom of the '401 board. You can also use plastic
or metal standoffs.
Tip! You can read more about the PICAXE family of
processors — including the AXE401 — in Ron Hackett’s
columns in Nuts & Volts, the sister publication to SERVO.
Each month, Ron explores the world of the PICAXE, and
demonstrates various programming concepts and projects
you’ll want to try. Be sure to also read the three-part
PICAXE manual that’s provided in PDF format. It’s included
in the programming editor software download.
You need a download cable to program the 28X2 chip
on the ‘401 board. Two versions of cable are available from
the PICAXE folks, or you can make your own if your
computer has an older RS-232 serial port. Ready-made
download cables are available for RS-232 serial (about $6)
The cost of the USB cable is about $25, but keep in
mind you only need one cable, no matter how many
PICAXE chips or development boards you have. This makes
the PICAXE particularly attractive in classroom settings,
where the one download cable can be shared among all
the students. The cable is only needed when downloading
programs to the PICAXE. Once the program is downloaded,
the cable is removed from the AXE401 board, so that the
Beginner Bot can trawl around on its own.
Remember that to use the USB cable, you need to first
install the PICAXE USB drivers. They’re included with the
programming editor software. The USB drivers have their
own installation program which you should run before
plugging in the cable. Once the drivers are installed, the
USB cable will appear as a serial communications port to
Included with the AXE401 is a bare prototyping shield.
It’s intended for expanding the ‘401 with additional
external components. It sandwiches with the main board
via a set of header pins as shown in Figure 2. I’m showing
the board with two sets of male headers: one set points
down and mates with the AXE401 board; and the other set
points up, allowing connection to a mini solderless
breadboard on top. I’ll discuss connecting the AXE401 to a
solderless breadboard later in this article.
Mounting the AXE401 Board
on the Beginner Bot
Use the second “deck” we added in Part 2 of this series
for mounting the AXE401 development board. If you
followed along and built that version, you’ll want to
carefully remove the wiring and components from the mini
solderless breadboard and put them aside — you’ll be
reusing some of the parts.
Remove the second deck from Beginner Bot and
drill two holes to mount the AXE401. Pick the holes in
the upper right and bottom left of the board. Center the
board on the deck (but leave a little more space toward
the front) and mark the position for the two holes with a
scribe or small nail. Carefully drill new holes using a 1/8”
Use a pair of 4-40 jackscrews, nuts, and 4-40 x 1/4”
machine screws to mount the AXE401. Jackscrews are like
miniature standoffs with male threads on one end, and
female on the other. If you used 1/4” thick material for the
SERVO 10.2011 71