The difficulty of this is a bit above average of understanding.
BUT, i will try and make this as easy as possible, so anyone can build it!
This box will be universal, and you can hook up any lighting to it (that uses DC-voltages of max 50V and 15A) and make it flash.
Step 1: What do I need?
A Dremel can be useful but is not necessary.
A soldering device :)
Cablestripper, and anything else you think you need. .. like good music.
1. Transistor. (NPN)
These come in all sizes and shapes, from my large one, to 35 nanometer.
I'm using a slider. One with a knob works just as fine.
3. On-Off switch.
Well, self-explanatory, but it's used to cut power.
4. A box.
To hide it all in and protect with.
To test and party with!
Because you can't get enough of wires.
Step 2: Preparing the box.
We need 6 holes for this particular design. It's possible with fewer, but it requires some homework :)
I put 4 on the short-sides and two on the longside.
The top two will be where you hook up the power.
The bottom two will be where you connect the LED's.
And the two on the side will be the signals going in. (Speaker wires from the stereo or amplifier)
After the holes are drilled, you either drill a hole on the lid for a potentiometer (knob version) or carve a longer hole for a kind like mine.
Aswell as a hole fitting for the on-off switch.
Make sure your potentiometer fits and slides without anything obscuring the way.
When done, glue it in place or use screws.