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Wireless LEDs

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gary350

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Watch this video it is interesting but what can these LEDs be used for ???

20 years ago I had 950 turns of #24 enamel coated copper wire wound on a piece of 4" diameter PVC pipe. One day I soldered a RED color LED in parallel with the 950 turn coil and left it setting on the work bench all summer. If there was a very powerful thunder storm in the area LED would start to flash when storm was 20 miles away. A less powerful thunder storm LED would flash when storm was 10 miles away. I put the coil in the living room in winter when we have very low humidity 20° weather & no thunder storm LED would sometimes flash for no reason. Probably static electricity.

Someone is probably selling these on Ebay but I have not found them yet? I am probably doing wrong word search. These are probably $2 per 100 free shipping from China. Any ideas what these can be used for???

 
I found a coil with #30 wire on an old TV circuit board. LED in parallel flashes but not very bright. I know a parallel capacitor will make LED much brighter, it took a few minutes of trial & error to find the best capacitor. My meter on 2nf scale reads .008 LED is very noticeable brighter. I tested several things, tooth brush charger and hearing aid charger, will light up the LED. LED does not light up near the microwave. Factory that made these wireless LED lights by the 1000s must have had something useful to do with them?

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the LED rectifies the current from the coil, and the cap smooths out the resulting DC voltage across the LED.
 
Here is something you will really like that I put together about 5 years ago.


The 'cap' in the previous post is most likely aiding in the resonant frequency of the power supply.....
 
The 'cap' in the previous post is most likely aiding in the resonant frequency of the power supply.....

I agree, by carefully selecting the inductance and capacitance of the tuned circuit the transfer from the tooth brush charger will be massively improved.

Anyone know what kind of frequency such chargers use?.
 
Most of the coils I find on PC boards only have, 10. 15, 20, 30, turns of wire none of them will flash an LED. I rewound some coils they need 100 turns to light up an LED using a tooth brush charger. I was worried too many turns will burn out the LED but 500 turns is no problem and LED does not get brighter. 5mm LED needs no capacitor to be very bright. 2mm LED .47nf & 1nf capacitor works best. The smallest wire I have to rewind coils with is #28 enamel coated copper. I made a 60Hz charger it will not light an LED I did not expect it would . It will be easy to build a 200KHz charger but don't really need one. If I had a signal generator I could probably make the LEDs light up at 200KHz..

1st picture is the LEDs that work.

2nd picture are LEDs that don't work they all have 30 turns of wire of less.

This turned out to be a fun educational project.

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I agree, by carefully selecting the inductance and capacitance of the tuned circuit the transfer from the tooth brush charger will be massively improved.

Anyone know what kind of frequency such chargers use?.

Good question. My meter shows tooth brush charger at 38.8KHz.

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Calculator not working. I type in 38.8 KHz and 2.25mh and get = NaN

Capacitor value is always blank after pushing calculate.

I can type in L then guess at C until I get KHz


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It is not easy to find .008mf so I connected .003 & .005 in parallel. WOW.....LED is much brighter than before.

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What is the reason for so many coil shapes? Are shapes designed to fit the available space on the PC board? Do certain shapes have different uses than other shapes don't? Choke coil that looks like a resistor has 20 turns of #40 wire. Top left coil has a magnet inside.

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