Pretty much everything will be in the garage again. Vegas tends to be too windy for long-term setups outside, and I don't trust the any cool decorations (cooler than styrofoam tombstones) would survive unmolested more than a day or so. After sketching out a few plans, I decided on a basic graveyard theme, with (subject to change...it is only February, after all) a zombie busting through a half-buried coffin, featuring a servo-driven three-axis skull and sound, another blood fountain, a female zombie with some kind of simple automation, lightning, and a Pepper's Ghost in the window.
I decided to start early this year to spread the work and expense over a longer timeline--I'm busy, and I'm cheap, and I thought a large DIY element would make it more rewarding, if not a little less expensive. I started with the pursuit of lightning.
It seems simple enough to find a way to emulate lighting--my first thought was to buy off-the-shelf. Unfortunately, a lot of the devices I found were too expensive (like, full-on DMX kits), too cheesy, or just unavailable. I looked for several weeks, and found a good solution: a sound-to-light modulator. There is a company called electronics123 that sells the kit in it's component pieces ($20 shipped); all you have to do is solder it together. Sounds simple--except that I've never soldered in my life. So, of course, I ordered it.
And here's what I got:
I boned up on soldering on the intertubes, got a $20 iron at Radio Shack (along with, luckily, extra solder and solder removing braided cord). I put it together, and voila:
I set it up as seen in this picture: split the audio at my iPod (per the documentation, most MP3 players should work fine...more on that later), one line going to the modulator, the other to the speakers. Basically, how it works (as best as my feeble mind can understand) is there is a switch that opens and closes in response to the voltage coming from the audio input jack; that switch allows IR light from an LED to flow through the system and into another switch that regulates the voltage coming in from the mains on the other side of the unit up or down according to the amount of IR light being pushed through the system. The end result is louder sounds coming in, more voltage out to the lightbulb. The cool thing about this type of setup is that is is a smooth, gradient change, not just a switch on/off.
And, of course, it didn't work. Everything pointed to my weak soldering job: some of the joints were cloudy and crusty, and when I cut the ends off of the two resistors, I discovered that my wire snips had at some point in their long life become magnetic. Electonics just fricking LOVE magnets. Love 'em. I de-soldered and re-soldered several times to no avail, and pulled my hair out for a week trying to figure out how to solve this little problem without spending money on another kit. Eventually, I decided to measure the voltage coming from the iPod. Not really sure if I was doing it right, but the docs specified that the gate triggered at 2-2.5 volts, and the line from the iPod was barely pushing .5v. So, I hooked it up to an amplifier that we use to drive our poolside speakers, and it worked. I was so amazed that I almost cried.
And the effect is awesome:
The modulator can drive up to, I think, 500 watts, so once I move it into the haunt, I'll put in a 100w or higher floodlight, maybe with a twig in front of it so it looks like it's shining through trees. The thunder audio track is from the Freesound Project. I had to really jack up the lightning sounds to get a response during my garage test (I bridged directly into a speaker wire, hoping to avoid having to set up an amp in the garage); I really need to find a way to dampen the rain sound so it isn't white noise.
So far, so good.
