and clean look when the Peek-a-Boo is resting on the
ground. Glue the stand as shown in Figure 9. The stand
helps with a couple of things. First, it keeps the ghost
upright, and second it’s a neat place to hide the
electronics. Also, the weight of the batteries and
electronics keep the ghost from tipping forward. Now that
we’re done building our ghost, let’s get him wired up and
moving!
Hardware Description
The processor I’ve chosen is the PICAXE-08M2
mounted on a servo driver board kit (Figure 10). It is an
inexpensive four-output version with one input carrier
board which is a perfect fit for this project. The board
has four “servo” style three-pin connectors. The servos
connect to ports 0 and 1, the sound board to port 2, and
the LEDs to port 4. Servo extension cables work perfect
here. I used some leftover PC parts to connect the LED
eyes and to provide a speaker for the sound board.
The Parallax model #555-28027 (Figure 11) is a
passive infrared motion sensor. It’s a simple discrete
TTL/CMOS output device that can detect motion up to
20 feet. It’s an easy device to connect to the board using
either a female to female servo extension or simple .100
experimenter’s jumpers. The pin configuration is the same
as a servo with a ground pin, positive pin, and output
signal. I connected this sensor to port 3.
The last item to hook up is the LC Technology sound
playback card (Figure 12). This is a cool little easy-to-use
device that allows you to record up to 10 seconds of
September 2014 21
FIGURE 9. Stand glued in place, showing
installation of the eyes, servos, and PIR sensor.
FIGURE 10.
The PICAXE-08M2
servo driver board.
FIGURE 11. Parallax’s passive infrared motion sensor.
FIGURE 12. The LC Technology voice card.
