LED lights on pedalboard flash to music?

[Henrigates]

This isn't about a guitar pedal, more of a pedal accessory.

I want to buy 2 LED light bars (automotive lights, 12V each) to light up my pedal board. I could easily wire them to an adapter/ battery, but I'd really like to make them sound activated so they flash to the beat.

Where/How would I get the proper electronics for this? The LED bar is already ready to go at 12V. Any advice would be appreciated.

Also, I know Monkey Dream pedal boards light up with a temporary footswitch, I'd be open to that option as well.


Thanks

Henri

[Big John Studd]

That would be cool. Here's one way you could do it.

Use a cheap electret microphone element to pick up the music. Amplify it with a 741 op amp...have a potentiometer in the feedback loop so you can vary the gain. Run the amplified signal to a comparator...I can't recall the part number of this IC, but they are garden variety devices. Use the output of the comparator to trigger a 555 timer set up in monostable mode with a variable duty cycle...or maybe fixed duty cycle...just figure out how long you want the flash to be. Finally use the 555 output to close a switch allowing current to flow in the LED(s)...the "switch" here could be a relay or transistor depending on how much current you are switching. If it's a relay, you'll need a few additional parts...a transistor and a diode. Actually a 555 may be able to pull enough current to drive the relay...I can't recall exactly.

These are all parts you could find in a junk drawer or even the local Radio Shack.

[FenderLover]

Any op amp could be used as a comparator, then drive the base of a transistor to turn your lights on.
Google for Color Organ schematics for more ideas.

[Lostinthe50s]

get one of these too!
http://www.youtube.com/watch?v=I8av_jNbWq0

[Big John Studd]

The LM339 is the comparator I was thinking of. You can use an op amp as a comparator if cost, convenience, space, etc. make that appealing. I've done it, and had it work. But op amps and comparators are not exactly the same thing...even though they are often drawn that way. I guess what I'm suggesting is, if you're at Radio Shack (Digikey, Mouser, etc.) buying parts grab a few comparators. They are useful parts.