LED's connected to speaker wires?

[BumbleBee]

Hi all,

Question: I've seen LED's connected to speakers on YouTube . Would I be correct in assuming the lights will fluctuate in intensity with the electrical currant which creates the sound ? Excuse my ignorance if this sounds like a stupid question .

If they will , I'm thinking I've wiring the LED's which I've created for my cup holders into the additional speaker wires in the bow are and underneath the tower .

[MLA]

I think what you may have seen, are LEDs driven by a controller that interfaces with the music source.

[BumbleBee]

They say there is never a stupid question ;-) thanks for reply

Rob

[ande2407]

Hooking up LEDs directly to your speaker lines is a BAD idea. LEDs are actually just a variation of a diode, which is a voltage controlled device. What would happen, is that your amplifier output, which swings in the +/- 12V range, would get clamped. typical LED turn on voltage is ~1.6 for red/amber, and 2.3 for blue/green. Once on, they pass full current til they can't handle it. So what would happen is the LED would turn on, clamp the voltage to the Vf of the LED, pass current through until it couldn't anymore. Typical current max for an LED is ~100mA for red/amber, ~50mA for blue/green. Your amplifier is putting out way more than this, so your LED would in effect get b**** slapped and explode.

What you would want instead, is a very high impedance op-amp tracking the signal, probably with a band pass filter so that you can trigger only on the frequencies you want. This pre-stage would then drive a current control source to drive the LEDs on and off. There are probably some kits available, but if not I could sketch out a workable schematic for you if you want to play with it on your own.

[Curren]

I was actually wondering the same thing? Can you just use the existing 12V lighting wires that are pre wired in the tower?

[ande2407]

No matter what voltage source you use, the current through an LED needs to be controlled. You can simply put a resistor in series with them if you want, but that will still siphon power from the speakers. It basically becomes a wave shaping circuit.

[BumbleBee]

Ande, I've made LED's with resistors to fit into bottom of my cup holders. If I was to hook up to speaker wire which are tied into the factory stereo wiring harness under the tower (I think these speakers would go into where the cup holders are) , so NO speakers just LED's ? Would that create/set up a sound wave as you put it ?

Regards Rob

[BumbleBee]

Curren, Na mate as far as I'm aware you will need a resistor. I just asked at my local electrical compotes store. I get about 13.7volts on dash board, he fed that into his formula the picked out what I required. I soldered them together and placed them into the bottom of my cup holders & wired to 12volt wiring harness.

Rob

[BumbleBee]

If I knew how to upload photos I would

[scott_fx]

Ande, I've made LED's with resistors to fit into bottom of my cup holders. If I was to hook up to speaker wire which are tied into the factory stereo wiring harness under the tower (I think these speakers would go into where the cup holders are) , so NO speakers just LED's ? Would that create/set up a sound wave as you put it ?

Regards Rob

you need some sort of controller. you can just use your amp to power leds.

http://www.oznium.com/cathode-music

http://www.amazon.com/Music-Controller-Remote-Changing-3322RGB/dp/B005AQPU5Y

Edited May 16, 2012 by scott_fx