Audio Sensitive Leds

[DLR Guitars]

I've been reading these forums for a while, but never needed any additional information until now! I'm trying to figure out how to do audio driven leds like this for an over-the-top Xmas guitar build that I plan on starting soon.

From what I've learned here is that I'll need an LM3915 chip. However, I have no idea how to wire it up, and have been unsuccessful looking on Google for the information. Does anyone have a layout that I could follow? Thanks in advance

[Xaromir]

Could that also be done with a piezo or something, like in the neck pocket,

so that it's reacts on vibration and not on sound?

Edited April 23, 2010 by Xaromir

[DLR Guitars]

No idea....

[pmarlin]

I just found this. and they said replace speaker with LEDS

LM386

http://www.hobby-hour.com/electronics/lm386-power-audio.php

[DLR Guitars]

Hhhhhmmmm. That looks interesting. I'll have to check that out.

[Prostheta]

Easy easy easy. For my electronics minor project at college, I created an LED array spectrum analyser for a Walkman. Which was over a metre square in footprint ;-)

Basically, it isolated several specific bandwidths of frequencies, applied full-wave rectification to the signal, smoothed the peaks to ascertain a signal level, and fed that to a bicolour LED array driver which referenced a voltage divided set of levels with an adjustable degree of hysteresis for the green "peak falloff" LED....

Pretty much the same would work here. Figure out which frequency range is most reactive to picking (play through a parametric EQ and sweep through, wah-like) and use that value to create a discrete component bandpass filter. Then apply rectification, smoothing and adjustable hysteresis for "fadeout". use that signal to drive a transistor or op-amp buffer circuit for the LEDs. Apologies for not having a specific circuit, but I hope the theory will be useful.

[DLR Guitars]

The theory makes sense. The know-how... not so much.

[ArMelvin1]

It's really easy use this video

it shows you how to do it however i'm not sure if you are looking for something more complicated. If yio want lights to go off at different times this video won't explain it however it does show to wire the op-amp to make them sensitive to sound.

[DLR Guitars]

No, that is perfect!!! I've been looking all over youtube. I can't believe I didn't see this!

The idea is for the neck to have LEDs that are always on (that part I can do!). Since this is an Xmas themed guitar, and my band plays the Trans Siberian Ochestra song, I thought this would be a cool thing to have, like the houses do with the lights.