(Note: this is a quick sketch of an idea that I'm pretty sure is feasible, but I don't currently know how to make it work due to lack of knowledge about the physics involved. Check back for possible updates.)
Imagine a rusted closed metal sphere with a projection jutting out the top and 1" wide, 3" long (arbitrary measurement) slits covering the surface at random locations and in random positions. Inside this sphere is a complex array of mirrors and filters (or maybe prisms), all designed to reflect a single ray of light from the top of the sphere in a multitude of directions and colors. The projection at the top is designed to focus light coming from the sun down through the sphere, but is set up in a way such that the sunlight will only be focused when the sun is at the peak of its daily cycle. Around the sphere is an array of solar panels, which act as a battery for a small motor at the base of the sphere. This motor spins the sphere at a fast pace, but only when light is being focused at the top of the sphere. This is accomplished through a small light sensor attached to the inside of the focusing device.
If that was a really confusing explanation (it was for me) here is what should be then end result: For a large part of the day, the sphere simply sits there, seemingly pointless, an eyesore in comparison with the scenery around it. But when the sun reaches its zenith, for a short time it will become a spinning, gyrating tornado of colored light! If you've been following me so far, you will also notice that this light show will occur when the moon is at its zenith also, as moonlight is just reflected sunlight. Therefore, our light-show generator is bi-daily. To insure this, a fence may have to be erected around the sculpture to insure no mischievious individual with a flashlight sets it off at the wrong time.
The artistic statement intended here is that even seemingly worthless things can have almost infinite potential, and that even outwardly dull people can prove most exciting when you get to know them better. A visual proof of the adage "Don't judge a book by its cover".-- Jem, Feb 19 2003 we can go for days here without seeing the sun. does this gizmo live indoors?-- po, Feb 19 2003 Ack, forgot to mention that. In the case of lack of sunlight, the Generator can be affixed with a simple spotlight timed to shine onto the top of the sphere for the appropriate amount of time, at the appropriate times. The motor and the spotlight would be powered by a backup battery when the solar panels are not receiving light. The system as a whole would detect when the solar panels have not receiving light for, say, 30 minutes; at which time the spotlight and backup battery would jump in to keep the bi-daily cycle continuous.
And with the spotlight, the Generator is operable both indoors and out.-- Jem, Feb 19 2003 Well, the moonlight will not work, its 0.001% as bright as sunlight, so solar cells cannot make any power from it to speak of. Also half the time the moon reaches its highest point in the sky during the day. Another problem: the sun's highest point in the sky changes with the season. Still I like the idea, some variation of it would make an interesting art object.-- Python746, Feb 19 2003 I think you'll need to account for the fact that the sun's zenith position moves about the sky throughout the year. I suppose clockwork could shift the sphere or projection each day (twice if you want to track the moon as well).
I'm also not sure that the amount of light you'll get through a tiny aperture will make a very spectacular show no matter how it's split, focused and reflected. It probably won't be noticeable amid the ambient light.
(But if you're messing with backup generators and solar arrays and spotlights and things anyway, you might solve all these problems by just sticking a clock and lightshow lasers in a rusty sphere.)-- Monkfish, Feb 19 2003 Here's the changes I want to make to the original. I'm putting them here first before I change the whole thing so that people will be able to see the original idea, but in bout two days I'll make the necessary adjustments:
1) The "tiny aperture" will be randomly angled every day to match a different point on the current path of the sun through the skies instead of the same time each day (sun at zenith)
2) The "tiny aperture" will not focus the light as was originally planned, but will contain a light sensor. When the sun reaches the point the aperture is angled to, the amount of light passing through the arpeture will be noticeably greater than usual and thus set off the sensor, which will turn on the flashlight and motor.
3) Instead of focused sunlight, the Generator will use a high-powered flashlight (inside the sphere) to create the initial shaft of light. The mirrors/prisms/filters will remain because of cost issues (they're cheaper than lasers).
4)A single rechargable battery will be used to power the motor and flashlight. This battery will be recharged using the mini solar panels arranged in a circle around the sphere.
5) When the light detected by the aperture goes below a certain level (as nighttime cometh), a digital stopwatch will be set to a random time. When the stopwatch goes off, that will trigger the flashlight and motor. (Note: this is only if, as I suspect, the moon won't give off enough light to set off the sensor; you can't just retune the sensor to be more sensitive, as then passing cars with headlights on and such will set it off)-- Jem, Feb 19 2003 Just a small point... bi-daily means every two days.-- waugsqueke, Feb 19 2003 [waugsqueke] You'd figure the literal interpretation ("twice"-"every day") would be the right one, but nooooooooooo... Anyway, it's fixed. Thanks for enlightening a too-mixed-up-in-making-this-crazy-idea-work-to-think chap.-- Jem, Feb 19 2003 It could also mean sex with both genders every day.-- waugsqueke, Feb 19 2003 Good pt. I have to remember to use that in a conversation sometime. <grin>-- Jem, Feb 19 2003 //even seemingly worthless things can have almost infinite potential//
Sounds like us, but the ideas don't cast a shadow.-- FloridaManatee, Feb 20 2003 Sounds like something you'd find buried in a secret Egyptian chamber. Which I'm all for.-- RayfordSteele, Feb 21 2003 I agree with Jutta, how about a nearby windmill/watermill that somehow stores some energy in elastic or potential form - then use this energy at the relevant time to spin the ball/move the mirrors.
As for needing a battery and spotlight - whats wrong with it NOT working at night or when its cloudy? That wouldn't seem to affect the artistic statement.-- drainfood, Jul 18 2003 As far as the solar-power only design goes - you might be able to do something with spherical or fresnel lens to concentrate the sunlight enough to be visible in daylight. How about building the upper half of the dome out of lucite to make a spherical lens that focuses to a point in the middle of the total sphere. You could even wrap this in a series of rusted metal panels that would slide out of the way when the noon light sensor is activated. The basic problem with the original passive design is that you need to concentrate the sunlight in order to make it visible - and this means condensing sunlight from a large area down to a smaller area.
Cool idea - it sounds like something I wuoud stare at slack-jawed for a bit. :)-- gieckboy, Sep 29 2003 random, halfbakery