| Do
you need something to wake up those yawning vampire bats
infesting your haunt? How about your own
customized thunderstorm complete with lightning?
Professional lightning machines can cost up to $200, but
if you're itching for a new project and you're handy
with a soldering iron, you can build your own for around
$25. |
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The
heart of S. Blue's lightning machine is a single channel
color organ circuit. This device has been around
longer than dirt and is easy to build using the kit
(C4738) supplied by Electronic Goldmine .
Watch out, though. This kit
utilizes 120VAC. That's line voltage! Do not
build this kit if you're unfamiliar with AC safety
precautions. Never touch any part of the circuit
when power is applied. In fact, don't apply power
unless the circuit is inside an enclosure. |
| Parts
list |
| Single
channel color organ kit part # C4738 |
Electronic Goldmine |
$8.50 |
| Cheap
portable CD player |
Target |
$13.00 |
| Stereo
amplifier & speakers |
Garage
Sale |
$3.00 |
| Phono
plugs |
Radio
Shack |
$0.97 |
| RCA
jacks & wiring |
Your
closet |
$0.00 |
| Theory |
| Essentially,
you plug the color organ circuit into a wall
outlet, then plug your light source into the AC
plug that's part of the circuit. Sound will
energize the light, and the sensitivity can be
adjusted to suit your needs. View our test
rig in action - MPG
Video (2.6M) |
| Construction |
 |
Building
the color organ is fairly simple. The
C4738 kit includes all the necessary
components.
Make
sure to use rosin core solder as opposed to
acid core or you may end up with a melted
pile of goo when voltage is applied. |
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|
Mount
the kit inside a wooden or plastic
enclosure. Radio Shack sells several
different sizes of plastic project
enclosures, or build your own out of scrap
wood. |
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|
Drill
holes for the adjustment knob, AC
outlet, and supply voltage. I
also added an RCA plug for the sound
input. |
I
used hot glue to cement the AC outlet
and adjustment knob. I also
filled around the hole I drilled for
the supply voltage cord to keep it
from moving around in there. |
RCA-jack-style
female plug thingies are better than
wires sticking out of the
enclosure. Just attach the two
wires to their respective poles on the
plug, then cement the plug in your
enclosure. |
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| Be
careful when cramming everything into
your enclosure. If you have to
use any real force to put the final
cover on, your box is too small and
you risk causing a short. |
Here
we see our test rig. I plugged a
small lamp in as my lightning
source. One channel from a mini
disc recorder goes into the audio
input port. My voice causes the
lamp to energize. I control the
very light with my voice!
Aaah-ha-haa! |
This
extremely cheap stereo came from a
yard sale for $3.00, but it has two
important features; auxiliary inputs
and speaker outputs. It won't
drive much, but it's cheap.
Cheap, I say! |
|
Keeping
with our near-rubbish cheapness theme,
I bought a seriously cheap portable CD
player from Target. It didn't
even come with an AC adapter, but who
doesn't have an extra 4.5V wall wart
lying around? |
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Wiring |
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Since
the color organ can't handle more than
25W, you don't want to amplify the
signal before sending it to the color
organ. Split the left and right
channels directly out of the headphone
jack and run the left channel into the
color organ, then continue both audio
channels to the amplifier.
(Note: you can opt to send only
the right channel to the amplifier if
you don't want to pipe your
"control" channel through
the speakers. More on this in a
minute.)
Plug
your light source into the AC outlet
on the color organ, then plug the
color organ into a wall outlet.
If nothing smokes, it's time to make
that light flicker on and off. |
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Audio
& Control Channel |
|
Your
thunder soundtrack is what pulls the whole
effect together. Going back to the
well of cheapness yet again, you can
download storms of thunder from the internet
in the form of mp3 and wav files. I
mixed several different files together to
create a soundtrack
for my test rig. I use Cool Edit
to work with audio files, but there are lots
of alternative (read "free") audio
editors out there. Download
the test rig soundtrack if you need a quick
and dirty soundtrack for your own box. I
designated the left channel as the control
channel. The control channel is fed
into the color organ and is what energizes
the light. If you're not planning on
broadcasting the control channel, you can
experiment with alternative sounds to
energize the light. For example, you
may find that clapping your hands or
shouting "God Thor commands you!"
results in a better effect than simply
relying on the natural thunder sounds of
your soundtrack. Another neat trick is
to place control channel commands a split
second before the audio channel sound
effects. This will cause the lightning
to flash just before the thunder booms. For
simplicity's sake (and because I couldn't
wait to see if this thing would work) I
mixed a few thunderclaps and rumbles
together into a single wav file and burned
to an audio CD. (This CD player
doesn't know anything about MP3 files)
The left and right channels are out of synch
in areas to get that flash-boom effect, and
I monkeyed with the levels on the left
channel to enhance or suppress the flash
effect. I was happily impressed with
the result. You can make lightning
flash more or less often by adjusting the
color organ sensitivity and the output level
of the CD player. Your
soundtrack doesn't really need to be very
long. The test
rig soundtrack is only two minutes, 29
seconds. Simply put the CD player in
loop mode and let it run all night. |
|
Input
& Output |
|
This
particular color organ circuit is great, but
it's not terribly robust. In other
words, you're going to be really
disappointed when all those 100W bulbs you
strung together don't light up. Well,
they might've lit up that first time for
just a second. I would limit my light
source to a single 100W incandescent
bulb. You'll be surprised how good
this looks when it reflects off the side of
a house and casting tree shadows.
A
strobe light makes a cool light
source. However, this particular color
organ circuit doesn't have the gravitas to
drive a strobe for very long. You'll
soon burn up the SCR. You can still
use a strobe as a lightning source, but just
not with this kit. However, you can
experiment with different colors of bulb and
even theatric gels to get that blue-purple
color of a good lightning strike. |
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Placement |
|
Do
*NOT* place this color organ circuit outside
where it can get wet! You risk
injuring yourself and your visitors.
It will perform its job perfectly well at
"Haunt Central" indoors with the
rest of your controllers, computers, rope
pulls, and mice hooked up to
treadmills. All that needs to go
outside is the lamp and possibly the
speakers. Place it up in a tree or
behind a bush facing away from visitors and
make sure it is protected from excessive
moisture. Use only heavy duty
outdoor-rated extension cords, and keep them
well away from haunt paths. Speakers
can be hidden behind tombstones and covered
in plastic, or just poke them through a
strategically placed window. |
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Let
me know! |
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If
you have any questions, or ideas to enhance
this neat little project, drop
me a line. S. Blue spends too much
time in his shop and doesn't have many
friends.
Download
video of the test rig in action (2.6M)
Download
test rig soundtrack (2.9M) |
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