FIGURE 3. Schematic view of the CdS photocells, PropBOE, and L298 motor driver board. The PropBOE is operated from its
own nine volt battery, connected to the barrel power plug.
and motor driver.
48 SERVO 12.2011
Mounting the PropBOE
The PropBOE measures 3” by 4” inches. You’ll
want to securely attach it to the Beginner Bot (just
like in Figure 2), using a mounting deck with
The PropBOE is just a tad bigger than the
second deck we’ve used in previous installments for
mounting the PICAXE and Arduino microcontroller
boards (see Part 2 of this series for dimensions and
mounting details). Construct a new mounting deck
that’s about 3-1/4” by 4-1/4” with mounting holes
in the four corners that match those in the PropBOE.
Use 1/2” (or longer) threaded spacers to act as
standoffs between the mounting deck and the
For the deck material, you can use the switch
control panel described in Part 1 of the series, or cut
a new piece of plastic or wood to size. I opted for
the latter, but feel free to adapt parts from an
earlier phase of the Beginner Bot to save money.
You can keep the control panel with its original
dimensions, or cut it down to size.
By using longer standoffs, you can tuck extra
components underneath the PropBOE — just be sure