Building a simple, low cost lightning machine

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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.

Test rig video - 2.6M

Test rig soundtrack - 2.9M

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
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)

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.

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.

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. 

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?


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.

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. 


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.

Let me know!

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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