Tuesday, October 13, 2009

Don't Go Into The Light...!

Catching your breath as you chase helplessly through this unending night, a light through the trees catches your eye. Praying for salvation you plunge headlong into the thicket once more, heedless of the danger, until you are brought up short by the eerie spectacle before you.

You find not assistance, but an eldritch swirl in the forest. A sanguine vortex manifests within the weald, swirling and rippling, silent as the grave. Every impulse in your lower brain screams to flee, for this is the antithesis of life itself, a beckon ingress to the world of the dead and damned, but your legs find themselves as rooted into the very earth below. Your eye is captivated by the dance and sway of the light orbiting and swirling that ebon center, and you feel your life's journey nearing its slow, torturous end.

You find yourself having moved from your stationery position ever closer to the void, but not remembering taking a step. Reaching out a quavering hand, you yearn for release and the cold quiet extinction. It's only the snap of a branch from another arrival to this portal that breaks the spell, and you recoil in horror and begin to flee once more...

Lasers are really, really cool...
I've always loved the dance and play of a laser show at concerts and other events and had wondered how I could incorporate one into my Halloween display. But ghosts and witches typically aren't seen wielding blaster or other such, and unless I change the theme of my display from graveyard creepy to alien invasion creepy, I never figured out how to do it. Until I found this link: http://www.instructables.com/id/Laser-Vortex/.

Basically, it's constructed with a motor that spin (in this case the fan off an old computer power supply) with a mirror glued to it's front and tilted (the mirror, not the motor) with a laser pointer aimed at it. The changing angle of the tilted mirror, as it spins, creates, in effect, a cone of laser light. When particles in the air, be it dust, fog or fog from a fog machine, intersect the laser light, the light gets scattered. The result being a thin slice of the fog being lit up, making a really cool effect.

The intensity of the laser affects the brightness of the fog. In these test shots, I used a 100mW laser I bought off eBay. While it makes nice photos, I don't recommend anything near that power rating for real use as that intense of light can damage the eye. For Halloween, I will be using a 5mW laser pointer.

One of the photos I shot actually caught the laser mid-sweep. I was playing around with exposures trying to find the right one. The angle that was captured was 90degrees and the exposure time was 1/160th of a second, which works out that the motor I am using is spinning 40 times a second.

I had another idea similar to this in which I take a motor and place a series of mirrors on the sides and spin it. If the laser is level with the motor, then the rays should radiate out in a horizonal plane. Couple that with ground hugging fog (like from a fog chiller, which I have) then you get a glowing layer of fog on the ground. I've seen this effect before and it is very nice, so I might try this later.

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