audio using the built-in microphone. There’s a complete
description of the board features and interfacing details
online, but for our purposes I just connected VCC,
ground, and PlayE. The PlayE is a “one shot” activation
signal from an external source. The PICAXE board takes
this pin from LOW to HIGH, then back to LOW to cause
the entire recording to play. Once I had power connected,
it was simple enough to record myself saying “Peek A
BOOOOoooo!” in a high squeaky voice. I then used the
convenient onboard buttons to play back the audio to
make sure it worked. Though the board can directly drive
the small speaker, in my opinion, you will likely need to
run the output to an additional small amplifier if you plan
to use your ghost in a loud area.
To finish up, I hot glued the PICAXE board down
with the programming jack facing backwards for easy
access. I then glued the sound board right next to it.
Lastly, I used some dabs of glue to hold the servo
wiring in place. When you finish wiring everything
up, it should look something like Figure 13.
Software and Programming
To program the Peek-a-Boo, I use the PICAXE Editor 6
Integrated Development Environment (IDE). It’s a simple-to-use program that comes with an editor, simulator, and
flowchart designer. The original flowchart editor has been
replaced with another PICAXE product called Logicator.
All their software and manuals for their current hardware
and software are made available as a free download from
their website (see Resources).
To program the PICAXE, your computer needs to have
a DB9 or DB25 serial connector. If you don’t have one of
these original serial connectors on your computer (and
let’s face it, most modern machines no
longer provide these ports), you can use
a USB-to-serial adapter or adapter cable.
Revolution UK (the makers of the
PICAXE) sell a PICAXE-specific USB-to-serial cable that has the 3. 5” male plug
on it to match most PICAXE carrier
boards. This cable is available from
many places, including resellers such as
RobotShop, but I was able to “roll my
own” by following Tommy Tyler’s
instructions in his article, “Building Your
Own PICAXE Download Cable” in the
July 2014 issue of Nuts & Volts.
The Peek-a-Boo code is relatively
simple in operation. I set up program
constants at the top of the code to
make it easy to adjust values that you
will need to alter for your specific setup
as shown here:
FIGURE 13. The major components mounted
22 September 2014
FIGURE 14B. Finished Peek-A-Boo with eyes covered.
FIGURE 14A. Finished Peek-A-Boo
ghost eyes uncovered.
Peek-A-Boo source code:
Parallax PIR sensor
LC Technology ISD1820
voice sound module
Original inspiration for the
A special thanks to my
friend, Mathias Bohn for
helping me with the artwork
and to Widgetwerks for