Magic LED ball

[Gazucha]

Hi all,

 something has just popped into my head which I encountered about 10 years ago and never understood how it worked.

 The 'something' in question, was a a transparent ball (about cricket or baseball size) which was packed tight with LED's. It was a just a ball of LED's until you passed your hand near - or on - the ball, at which point the LED's sprang to life, flashing away in a random manner (not so dissimilar to a plasma ball).

 When you put it down it turned off again.

 Me being me, had to see how it worked, so promptly set about disassembling the ball yet didn't understand when there was no battery nor pcb of any kind.

Just LED's! Unsoldered, loose LED's.   

LED's which no longer flashed once I had rammed them all back into the ball.

Does anyone know about these balls? My friend had received it as a gift from another friend of ours in the Czech Republic and was none too impressed with my breaking his party trick. 

 Any info would be greatly appreciated.

 

   

[Gazucha]

Just to add...

 none of the LED legs were shortened nor insulated in any way. They appeared to be touching several LED's at the same time.

 No battery, mains input, capacitors, transistors, inductors or resistors.

 I originally thought that all the LED's must be connected +ve to -ve and in someway forming an extended closed circuit, but do LED's light up just from human proximity? News to me!

 

Apologies if this sounds impossible but I personally saw this thing working and personally emptied it? contents.    Doh!

 It is possible.

 And I would love to know how.

[amyk]

LEDs will glow visibly at very low currents; combine that with this and you might well have an explanation for the effect.

[Zero999]

You may get more help if you post a picture.

[Gazucha]

Thanks for the replies chaps.

Amyk,

I reckon you are onto something there. It would suggest that even though the LED's appeared to be randomly inserted, that there had to have been specific connections between them all and possibly special LED's.

Maybe someone on here wants to experiment with this?

Can LED's become more sensitive when placed in series and/or parallel?

Hero999,

 Unfortunately didn't take any pictures, as at the time assumed it would be the latest craze and be seen everywhere. The ball (sphere) was clear plastic about 3 1/2" (8cm) across, which separated in the middle with a slight turn. The LED's were uncoloured (transparent) which glowed blue.
 If you want half an idea. Grab  a glass, stuff it full with LED's and that is more or less how it looked from the outside. But as mentioned, there has to have been a special way to place them -unsoldered - inside the ball.

[matseng]

http://www.ubergizmo.com/2010/09/ball-lighted-up-with-internal-leds/

[Gazucha]

Ah Matseng,

 I think you may have solved the problem   

 .... and that the battery slipped through my fingers (so to speak) when I opened the ball.      Perhaps it was also a super small battery?

 The only difference was the LED colour and that the ball was smaller and packed solid.

[amyk]

That device doesn't correlate with this though:

When you put it down it turned off again.

[matseng]

I guess that OP doesn't remember exactly how it actually worked after 10 years - I for sure can't remember minor details of stuff that happened just one year ago, I have problems remembering what I had for dinner last week :-)

[atferrari]

A battery loose amongst those LEDs has a chance of getting shortcircuited and nothing could stop that.

[Gazucha]

 The thing was, is that I was shown this ball (and opened it) in a dark field during night-time. I have to admit, a battery could easily have slipped the net and been lost in the grass. As mentioned, after 10 years (and at a party) anything could have happened. 

 The decent thing to do now, would be to build another one to replace the one I ruined for my friend.

 At least I finally know how the pesky thing worked!

 Thank you.

 

[PA0PBZ]

At least I finally know how the pesky thing worked!

I don't think so...

The only difference was the LED colour and that the ball was smaller and packed solid.

this one would never work when packed solid.

[Gazucha]

Olá PA0PBZ.

 So are you saying that I didn't miss the battery as it fell on the floor?

 Come on then, please enlighten me. How was the ball working?

 

[PA0PBZ]

I didn't say I know how it worked, I'm just saying that when you stuff the ball with leds and a battery it will not show the behavior you described: starting to light when picked up and stopping when put down. I could make such a device but certainly not with just a ball stuffed with loose leds.

The thing shown works based on the fact that the leds and battery can move around freely.

[TerraHertz]

Could it be possible that static electric charges induced on the plastic inside surface by handling the outside, could be making intermittent discharges through the LED-mash? From parts of the ball inside surface, to other parts of the surface?

The thing might have stopped working when you opened it, due to the ambient air being too moist to allow formation of sufficient charge on the inside of the ball. Or maybe you breathed into the ball while it was open?

When it was working, were the LEDs lighting up in quite short flashes?

[Gazucha]

Hi Terra Hertz,

 yes, the LED's were essentially ´flashing' in very short bursts.

 I should really try to reproduce this ball as it was well cool. From what I remember, it lit up more when it was touched as to when it was moved but I only saw this ball actually working for perhaps 10 minutes before I ruined the show with my 'ignore ants' 

 The ambient air was indeed certain to have been moist and no I did not breathe into the ball.

 Would it need any specific type of plastic (to augment to a sufficient degree) the amount of static within the ball?

 

Come on chaps, let's reproduce this ball as it really was one cool party trick......

[matseng]

The easiest way of checking the feasibility of static discharges lighting up LEDs would probably be to take a piece of PVC pipe and rub it a bit and then approach an ancient (10 year old) LED to it and see if it emits a flash - and if that is repeatable a few hundred times without fscking up the LED....

[TerraHertz]

The ambient air was indeed certain to have been moist and no I did not breathe into the ball.

 Would it need any specific type of plastic (to augment to a sufficient degree) the amount of static within the ball?

I've never seen any data on which types of plastic are the most prone to generating static charge. But I have noticed that some moving coil panel meters with plastic faces are very prone to the needle being deflected when you wipe a finger (or cloth) over the meter face. Sometimes it's possible to get the needle to move as much as half full deflection - and stay there! Breathing onto the meter face clears the charge and the needle goes back to zero.
Other types of moving coil meter don't show this effect at all. And of course it doesn't work on humid days.
Glass-faced meters don't seem to do this noticeably.

The problem with trying experiments to find the best kinds of plastic, is that you'd have to do it in controlled humidity air. Controlled as in ideally zero humidity. Also cleaned plastic, and some way to apply repeatable degrees of 'rubbing'.

Oh hey! I just realized that the LED ball would work a lot better if the inside (surface and all the LEDs in general) were holding a significant charge relative to the outside of the sphere. That way, just putting your hand (at general ground/world potential) next to the sphere would cause a migration of the inside charge to be as close as possible to your hand. And when you let go, the charge would redistribute more evenly again.

I'm pretty sure that's it.

Did the sphere halves screw together and was there something like grease on the threads? It might have been screwed together while the whole thing was at (say) 20KV. When you opened it, you let the magic smoke (literally!) out.

That's quite amusing. Could any product ever rely on a more invisible magic component than a retained static charge?

Edit to add: Ha ha... I'm imagining the assembly line. A platform up on huge insulators, charged up by a van de graph generator. Up on the platform, a row of cute Asian girls assembling the balls, all with their long hair standing straight out in the high voltage manner.

[matseng]

But if the "migrating charges" is used to power the LEDs that converts the charges into head and light then there would be no more charges left to migrate after a few flashes....   Or?

[TerraHertz]

But if the "migrating charges" is used to power the LEDs that converts the charges into head and light then there would be no more charges left to migrate after a few flashes....   Or?

No, you're not understanding it. The charge is just an excess (or shortage) of electrons relative to the normal state in the surrounding world. They can't get out of the sphere due to the very good insulation of the plastic ball. Those electrons are going to move around inside the ball to be as close as possible to the nearest thing with a different net charge. For instance the hand of someone holding the ball. The charges don't get 'used up', they are stuck in there. In moving around (sometimes through the LED chips, but usually just sparking from metal leg to leg) they are dumping energy they acquired from the electrostatic field. And the field was changed (intensified or moved) by external mechanical movement - your hand. So you are seeing a quite direct conversion of mechanical energy to heat and light, via a moving electrostatic field.

It's very similar to how a dielectric material can be heated by an AC electric field (or RF field, for the same reason.) Local charge carriers moving in response to the field changes.

Edit to add: This would work best with bidirectional LEDs - the two color types with (say) red and green LED chips wired back to back. That way no LED would ever get reverse biased to breakdown, which would probably damage them. You could also mix different color LEDs, since the voltages available are going to be far higher than the LED Vf. Extremely small capacitances involved too, so I doubt there'd ever be enough energy in the discharges through the LED chips to damage them, if there's no chance for reverse breakdown.

[matseng]

Nope, still not understanding it...

You're saying that the charge/electrons inside the sphere can't get out due to the good insulation of the plastic the ball is made up of.  To me that implies that new charges/electrons can't get in either.

If the movements of these internal electrons causes the LED's to light (and get warmer) then the charges must be used up somehow or else you have invented a perpetuum mobile where you can generate light&heat without using up the energy inside the ball.

Or are you meaning that new energy is created inside the ball when it's shaken?

[TerraHertz]

Nope, still not understanding it...

You're saying that the charge/electrons inside the sphere can't get out due to the good insulation of the plastic the ball is made up of.  To me that implies that new charges/electrons can't get in either.

If the movements of these internal electrons causes the LED's to light (and get warmer) then the charges must be used up somehow or else you have invented a perpetuum mobile where you can generate light&heat without using up the energy inside the ball.

Or are you meaning that new energy is created inside the ball when it's shaken?

You have  a conceptual confusion between charge carriers and energy. They are very different things. Electrons don't ever get 'used up'. In the absence of an electrostatic field, they'll just sit in place. In an electric field (which is a voltage gradient by definition) they will attempt to move. In being accelerated by the field, they acquire energy from the field - and also alter the field. (Or course, since they couldn't gain energy without altering the energy of the field itself.) Also, the electrons themselves generate electric fields, which interact with the surrounding field. To say nothing of interactions between varying electric and magnetic fields (radio stuff), and then the whole Relativity sack of weirdness.

I'd suggest googling electrostatics. After that, to finish exploding your head, google plasma physics. Then 'electric universe'. See you in a few years. But it will be fun, really!

Back to the LED sphere. If the sphere internals have a net electric charge relative to the exterior world, it's literally the case that by waving your hand around near the sphere, you are transmitting energy to the interior of the sphere. No magic wand required, even if it does seem magical. It's just physics, and very similar to how radio waves transmit energy through space. Except in this case the fields are very very low frequency, almost entirely electric near-field (virtually no magnetic field component) and more single impulses than repetitive waves.

[matseng]

Hmmm.... Ok, this *almost* makes sense to me.  I think I need to apply the clue bat to myself...

[Gazucha]

Edit to add: Ha ha... I'm imagining the assembly line. A platform up on huge insulators, charged up by a van de graph generator. Up on the platform, a row of cute Asian girls assembling the balls, all with their long hair standing straight out in the high voltage manner.

 So, yes, the ball was screwed together although I cannot recall if it was hermetically sealed...

 I´m honestly not sure that our Czech friend had 20kV toys to play around with at home, although that may explain why he had his hair shaved...   

- Just thought this was a common device, which I why I posted on this forum about it.   

[TerraHertz]

I've been trying to think of something I can use as a clear, hermetically (electrically) sealed and insulating container.
It doesn't have to be spherical, just easily obtainable and free.

So far the only things I can think of are PET drink bottles, and lab glass containers with conical stoppers.

Then there's the problem of how to seal it while the contents are at some HV. One way is to do that while the container and you are on a HV platform.
But also, an easier way. Just put the container on a HV plate (say, positive), dump in the LEDs with a grounded wire into the bottle. The bottle acts like a leyden jar, with the contents taking on an opposite charge to the plate the bottle is standing on. (Better if it was a conducting cup, fitting the bottom part of the bottle.)
Then remove the grounded wire, and screw on the bottle cap (with some insulating grease in the seal.)
Remove bottle from the HV plate. Safe enough with a plate voltage up to about half the air breakdown voltage of the bottle length. And maybe some grounded metal mesh gloves.

The result would be a sealed bottle containing LEDs and excess charge. It should show the 'sparkles when handled' effect.

I have everything  to do this except a big bag of bi-color LEDs. Will have an ebay look for some cheap ones in bulk.

Wonder what's the withstanding voltage of PET soft drink bottles?
Ha ha.. With my 200KV supply, I can probably test some to destruction.

For extra visual amusement, some of those little styrofoam balls used in bean bags put in the bottle should be fun.

I always had an urge to put a big open cardboard box of those on top of the 200KV supply's donut, and turn it on. But resisted the temptation. I know what would happen, and I don't like the idea of having to clean up the mess.