■ FIGURE 2. Schematic for the
frequency synthesizer.
A PCB & programmed chip to go with
this article can be purchased online
from the Nuts & Volts Webstore
at www.nutsvolts.com or call our
order desk at 800-783-4624.
depending on the DIP switch.
Voice Chip
The voice chip is a CMOS
device which uses five volts to
power it. It has 10 seconds of
memory for storing the
sounds, a microphone
preamplifier, and speaker
outputs. I added a 1/8” jack
so that you can plug it into a
stereo amplifier for big claps
of thunder. Instead of using
pushbutton switches as shown
in the ISD1110P schematic
which can be downloaded
from the Nuts & Volts website
( www.nutsvolts.com) or from
Jameco.com. It is driven by
the microprocessor so that the
timing coincides with the
lightning flash.
I got the thunder sound
off of the Internet. The
“PLAYE” input was used as
this allows the PIC to return to
its high state and the voice chip will continue to run. The
chip is capable of providing 12. 2 milliwatts. Once it
finishes, it goes to sleep.
■ FIGURE 3. “All is Vanity” photo.
■ FIGURE 4. The flash.
Construction
The board files, along with several other downloads,
October 2010 33
