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Tesla coil between Lego base plate

Josephine

Oct 29, 2017
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Like most I have been patiently waiting for an official Lego wireless lighting solution, and with enthusiasts filling the gap with Tesla coils and normal LEDs, I though I'd just make my own.

My approach would be to simply sandwich a flat coil module between two baseplates. However, I am concerned with it becoming a possible fire hazard from any heat given off ?

ref : https://www.aplicum.com/product-page/large-bifilar-tesla-coil-module

I play to place little LED bulbs in transparent Lego pieces, using the electric field directly above the plate. The concept works, but only out to a certain distance of course, plenty for Lego scale.
 

Nanren888

Nov 8, 2015
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MIght be viable and safer to google "magnetic induction" and maybe other forms of pancake coils. Would make the lighting blocks a little more complicated, maybe even with a little ferrite, but generally easier to control.
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I'm biased. I can't see how a bifilar coild as illustrated generates much of a field.
 

Josephine

Oct 29, 2017
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Thanks.

I thought that the bifilar coil was the same as a pancake coil.
 

Nanren888

Nov 8, 2015
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I may be interpreting the image incorrectly, but it seems that the current goes into the center in one direction, say clockwise, then back out again, anti-clockwise. This would seem to mean that the net magneticc field will be very low.
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The ones I've seen have either two sides, so the current is always going the same way round, or, a wire just comes out from the centre.
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Magnetic induiction is all about creating a magnetic field.
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The site that you linked seems to include rather a number fo things that might not be considered mainstream. YOu might want to compare what they offer with other info you find as a cross-check, whether it be tesla coils or magnetic coupling, or whatever.
 

Nanren888

Nov 8, 2015
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This page
https://en.wikipedia.org/wiki/Bifilar_coil
Seems to include something they call non-inductive and inductive bifilar coils.
The one you linked looks as if it might be non-inductive, which I'd guess will not excite a tesla coild much.
There's a figure on how an inductive bifilar coild mught be used. Not that the two windings are not connected together in the middle and the current arranged so that it always circulates the same direction, to create a magnetic field.
 

Nanren888

Nov 8, 2015
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Sorry, just catching up on what I think is going on.
A man called Tesla patented bifilar coils. From the text, I assume he worked with inductive coils, possibly also non-indiuctive.
He also has a high voltage transformer style named after him, commonly known as a "Tesla coil".
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The linked coil is not what is meant when people now talk about a "Tesla coil".
A Tesla coild is a transformer with a few turns on the primary and many turns on the secondary that produces very high voltages ad RF frequencies.
The coil above is not a "Tesla coil" in this sense and will not work to make one. The site seems to claim that being a bifialr coil it is somehow connected to the man.
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I've not tried to power leds from a tesla coild, but I'd be dubious that it could be done reliably. Others with more experience may be able to report differently.
 

Josephine

Oct 29, 2017
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I need something that won't melt Lego plates, as thin as possible, which will do the following:

 

Nanren888

Nov 8, 2015
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The i-brix site says thattheir technology is inductive, which makes sense to create a magnetic field. If your coil in the bottom is low resistance it won't get hot. The more turns, the lower the current you;ll need.The lights need to likewise pick up the magnetic field, so, a small coil, maybe a diode, usually some ferrite is the easiest way to get efficiency up. Would need some claculation and/or experimentation to get it right.
Magnetic field will go a lot easier than electric.
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As they say on the site, the orientation of the LED bricks will matter.
 

Josephine

Oct 29, 2017
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I should have checked their site, not been for a while, but thank you all the same.

I found this explanation, it's pretty good:

 

Nanren888

Nov 8, 2015
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I suspect the bifilar thing is a bit of a red herring. Probably can wind it with any wire you like, multi-core or not. Amperes (current) and turns are what will matter; also area, but fixed by the area you want to cover. So, multi-core cable just sometimes makes it easier to wind, but each two turns of single-core or one turn of two-core (in series) counts the same, in that the current goes round in the samew direction twice for each one. As illustrated you'll usually want lots of turns. Adding ferrite, if you have room, will help the receiving end, in that you'll be able to make it to take up a smaller area foir an otherwise similar result.
What will you drive it with? Do you have a choice of frequency?
 

Josephine

Oct 29, 2017
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I just wanted to use a 9V battery, or possibly set a specific input with a fixed plug, not variable.

I have since found out that if the track goes in a different direction it cancels out the magnetic field, so they have to run parallel.

I was hoping for something flat like the PCB board from my first post, rathe than a thick wire, the benefit being it all on a single plane. I am now unsure if I can get a coil in this fashion.
 

Nanren888

Nov 8, 2015
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I have since found out that if the track goes in a different direction it cancels out the magnetic field, so they have to run parallel.

Sorry if my message before was not clear.
but it seems that the current goes into the center in one direction, say clockwise, then back out again, anti-clockwise. This would seem to mean that the net magneticc field will be very low.
.
The ones I've seen have either two sides, so the current is always going the same way round, or, a wire just comes out from the centre.
.
Magnetic induction is all about creating a magnetic field.

I was hoping for something flat like the PCB board

The ones I've seen have either two sides, so the current is always going the same way round, or, a wire just comes out from the centre.

Yep, can be done with a single-sided board & a single wire to the middle, or a double-sided board.
The bifilar thing is not particularl;y relevant. Just a simple coil wil do if you use a PCB.

Notes
Yes, for magnetic field the current should all go the same way round. (as in in-phase for the ac)
You can't use DC on the coil. There must be AC, maybe best at high frequency. Likely will want to create the ac yourself. There will be lots of circuits online.
Magnetic, wireless power transfer has been ragey for some time.

Google wireless power transfer and magnetic induction.
Just have to filter out a few examples that are written by a few people with strange ideas.
 
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