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  #1  
Old 27 September 2010, 04:41 PM
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Jenn Jenn is offline
 
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Fright Static-powered light show

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  #2  
Old 27 September 2010, 05:34 PM
Singing in the Drizzle Singing in the Drizzle is offline
 
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Light show and some acting, yes. Defiantly not powered by static.

Static is very high voltage with very low amperage. Amps are what do all the work. So unless you make transformers reduce voltage and up the amperage, it ain't doing much to power things. To add to this static is suppose to be very hard on electronics do to its very high voltage. And how much DC current do you think was needed to power that, or do you think they used a really big inverter to make AC current.

Now lets consider the very painful and noisy problem of discharging static electricity. As I'm sure all of you have experienced at one time or another. Discharging static makes a noise and pain where it jumped to or from the skin. That was very small voltages. We should see sparks of static from this guy fingers and him screaming from pain every time his finger got withing several inches if not feet from the wires considering the voltages need to power the system.

With that much static going though the body, you would think his hair would start to stand on end. Not even a little movement.

Notice he does not keep his feet on the spinning thing after the start.

That should be enough for starters.
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  #3  
Old 27 September 2010, 06:39 PM
jimmy101_again jimmy101_again is offline
 
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Very possible. Down right easy in fact.

The kid's body does not have to conduct measurable current. Though getting enough current through a human body to light a single LED is easy to do.

For the arrays of LEDs there may be driver circuits that simply detect his body's potential. An FET amplifier array between him and the LED arrays would be more than enough. The FET requires basically zero current to operate and will easily switch several amps of current.

In fact, with FET drivers he wouldn't even need to touch those wires. Just waving his hand in their vicinity would be enough to switch the FETs on and off.

A 9V battery, and jFET and an LED will detect the voltage generated by lifting a socked foot off of a floor at a range of a couple feet (in dry air). http://amasci.com/emotor/chargdet.html
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  #4  
Old 27 September 2010, 07:16 PM
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Eddylizard Eddylizard is offline
 
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I think part of Singing ITD's point was that the whole setup could not be powered by the static electricity alone (as is implied in the title), and an external power source would be required to at least power the lamps, rather than it being merely controlled by the static electricity affecting an FET which in turn controls the flow of electricity to the lamps which is what you are saying.
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  #5  
Old 27 September 2010, 07:33 PM
Singing in the Drizzle Singing in the Drizzle is offline
 
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As Eddylizard is saying. It is not powered by static. How ever if you watch his hands and the wires touched even if it is only from his bodies natural electrical charge. The wires touched and grabbed are random and do not correspond to the display. He will grab one wire to light one box one way. The next time he lights it the same way, it is a diffent wire.

If he was using a static charge to control the lights. Then why were his feet not on the spinning wheel shortly after first showing how it works. The do occasionally touch at the beginning but that is all. To go with that, there is still pain associated with discharging static from your body if not properly protected.

I do like it as a work of art. How ever I do not even remotely believe that it is anything more than some good acting to a pre programmed light show.
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  #6  
Old 27 September 2010, 08:32 PM
jimmy101_again jimmy101_again is offline
 
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The current required to light even several LEDs is not enough to be noticed by a person. A typical red LED requires about 20mA at 1.7V. When you walk across a carpet, in your socks, in the winter, and touch something metal the spark you throw is at least a couple thousand volts. Even at low current, and it really isn't all that low, there is a heck of a lot more power in that "carpet' shock than is needed to light an LED.

Heck you can touch your tongue to the contacts on a 9V battery, which will source about 1 amp, and you don't get shocked noticeably. The battery terminals have more of a "taste" than a shocking sensation. That same battery will instantly fry an LED connected to it.

In summary, the current required to light an LED is insufficient for a person to even feel, let alone get a shocking sensation from.
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  #7  
Old 28 September 2010, 01:29 AM
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Shoe polisher != van der graaf.

It's Disneyesque cinema. Nothing more.
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  #8  
Old 28 September 2010, 02:02 AM
jimmy101_again jimmy101_again is offline
 
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Quote:
Originally Posted by redspider View Post
Shoe polisher != van der graaf.

It's Disneyesque cinema. Nothing more.
Maybe a creation, but the basic science is accurate and design is doable. A shoe polisher most certainly does equal a van der graaf. I think you are confusing the basic VDG concept with the ones you might see in a museum. Ones that'll generate tens of thousands, even hundreds of thousands of volts.

In this case it needs to generate about 2 volts. Easily done by rubbing just about any two dry surfaces together. A fluffy wool fabric on to a cotton one, or to a piece of glass, or to ... the only tricky part is the "comb" used to collect the charges (since the materials are non-conductive).

A 3v motor, a pair of AA batteries, a rubber band, a glass tube (like from a bus fuse) and a plastic pulley is all that is needed to generate a couple thousand volts. See for example http://scitoys.com/scitoys/scitoys/e.../electro6.html. A shoe polisher should be able to generate the needed voltage and current.
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  #9  
Old 28 September 2010, 02:12 AM
redspider
 
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What are the two dry surfaces being rubbed together in this instance? Where is the comb collecting the charge?

It's not just the voltage that needs to be generated, it's the continuous power.

And it probably needs to generate a lot more than 2 volts given the loss across the human body (all points in between actually)

And what's he supposed to be doing with that LED at the start?

It just doesn't make any sense.
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  #10  
Old 28 September 2010, 02:18 AM
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Eddylizard Eddylizard is offline
 
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My long forgotten cousin (black sheep of the family) had a shoe polisher. I wanted one just like it but couldn't afford one, even I knew where to get one. I'm kind of glad I didn't buy one now.
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  #11  
Old 28 September 2010, 02:28 PM
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WonkoTheSane WonkoTheSane is offline
 
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The LED thing in the beginning is pure baloney, to begin with. You simply cannot light an LED (or anything else, for that matter) without a return path, and you couldn't do any of it with static electricity anyway.

Yes, he might be using his body to trigger LED drivers, but it would be his body's capacitance or resistance triggering the drivers, not static discharge. In any case he would be triggering circuits powered by something else, and not powering the LEDs himself, like the video implies.

The whole thing is a Ray-Ban viral commercial, anyway, apparently.

http://www.ray-ban.com/international

Wonko
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  #12  
Old 28 September 2010, 02:37 PM
redspider
 
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Quote:
Originally Posted by WonkoTheSane View Post
The LED thing in the beginning is pure baloney, to begin with. You simply cannot light an LED (or anything else, for that matter) without a return path, and you couldn't do any of it with static electricity anyway.
I think the lie we're being fed is that there's an electromagnetic field of sufficient potential to create a voltage drop across the LED.

Quote:
Originally Posted by WonkoTheSane View Post
The whole thing is a Ray-Ban viral commercial, anyway, apparently.
Checks. Aaah. I never liked Ray-Bans anyway. My Dad likes to look like Roy Orbison. I don't.
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  #13  
Old 28 September 2010, 11:43 PM
Lawgiver Lawgiver is offline
 
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At around .42 into it, a light behind him lights up before he grabs the wire.

ETA, or what Singing in the Drizzle said, ah, a spanking.
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  #14  
Old 29 September 2010, 12:12 AM
jimmy101_again jimmy101_again is offline
 
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Quote:
Originally Posted by WonkoTheSane View Post
The LED thing in the beginning is pure baloney, to begin with. You simply cannot light an LED (or anything else, for that matter) without a return path, and you couldn't do any of it with static electricity anyway.
Not true. A static field will light a fluorescent tube. The return path is the to the air.
http://en.wikipedia.org/wiki/Fluores...demonstrations
http://scientificsonline.com/product.asp_Q_pn_E_3081446 this second one appears to be a neon bulb. A standard NE-2 neon indicator light requires at least 60V or so to light.
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  #15  
Old 29 September 2010, 12:56 PM
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WonkoTheSane WonkoTheSane is offline
 
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LEDs are not gas discharge lamps, like fluorescent and neon lamps are. A capacitive coupling (which means AC) would be required to excite the gas in these types of lamps for longer than a fraction of a second... and even then the best you can hope for with discharge lamps is an extremely faint glow. In the case of the hand-held neon, the resistance of the air at the second terminal would be what allows the charge to bleed off. Were it actually in contact with anything else, it would discharge extremely rapidly, and you'd just see a faint flash, if anything. He's not doing anything of the sort in the video.

LEDs don't work that way, at any rate. The only thing a static discharge would likely do to an LED is burn it out. There's a reason LEDs come in static safe packaging.

Lighting many hundreds of bright LEDs at the same time would require many amps of current. We're not just talking about a single 20mA red LED here, either, but white and blue super-brights, which can take up to several hundred mA (at carefully regulated voltages!) to light a single one. There is a rather large power supply and driver circuitry somewhere nearby, I guarantee it.

The video's a cute piece of advertising, nothing more.

Wonko
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