EL wire circuits advice

Hey Choof,

my name’s luke and I want to make some clothes lit with EL wire that 
have separate sections that respond to different frequencies coming in 
from a mic. I need some advice about how to go about it.
I’m trying to do it without spending too much and there are cheap led 
boards that almost do what i need but they output dc when i need ac, do 
i need to attach inverters to every output? do inverters even work on 
variable input? Is this even the right aproach?
I came across your page a couple of times trying to find a solution so i 
figured id ask. I work for an events staging company working with high 
end lighting, sound and vision equipment, I don’t know that much about 
electronics but i pick up on it fairly easily.
also my friend is really into your jacket with the underglow. I’ll 
probably try to make one of them too.

Cheers Luke

Hi Luke,

If you’ve got an LED board that does what you want, you’re in pretty good shape.  You suggest connecting an inverter to each LED output, but this would be very complicated, and might not work very well because inverters don’t like being turned on and off rapidly.

What I’d suggest is using a bank of TRIACs.  A TRIAC is like a switch for AC current.  You can have the inverter turned on all the time, and just switch current to each section of EL wire using your TRIACs.  A TRIAC has three terminals, two for the AC line and the third is called the GATE.  When current is pulled out of the gate, the TRIAC will turn on and pass AC current across the two other pins.

If you look at your LED controller board, it likely contains a low side driver.  You’ll have to check this, but it basically means that one side of the LEDs is constantly connected to the positive rail, and a transistor connects the other side to the negative rail.  When that transistor is turned on, it completes the circuit and turns your LEDs on.  This is actually what I did with the DJ jacket.

If your circuit is indeed made like this, you can simply connect the LED driver pins to the gates of your TRIACs.  Then connect one end of your inverter to the EL wire and connect the other end to the EL wire through your TRIAC.  The last thing you’ll need to do is connect some part of the EL wire circuit to the positive rail of your TRIAC circuit (so that the two circuits aren’t “floating” with respect to each other).

You can find TRIACs here http://www.digikey.com/product-search/en/discrete-semiconductor-products/triacs/1376385

Just make sure to select “through hole”.

Let me know if you have any questions. Thanks for writing.

~ch00f