breathing led?

Hey everyone, new guy here. Not new to car electronics and wiring, but definitely still learning. Anyway, I'm wiring up a push button start system into my car, and would like to do a "breathing" effect with the LED under the button itself. Like how a computer status indicator fades in and out when it's on standby. I found this video for a very simple circuit that runs on 6 volts: http://www.you tube.com/watch?v=Klengns3oQg My question is: would any of the components in this circuit have to be changed to compensate for a 12 volt circuit in my car? Or is there a simpler way to accomplish this effect with a circuit that's already built? Thanks! -Jerry

You could reduce the voltage via the properly sized resistor or you could use a DC-DC converter to get to 5-6 volts. Search for 7805 for the DC-DC converter, they are common and even RadioShack should stock them. I had trouble viewing the link.

Sorry for some reason it put a space between "you" and "tube" in the link. Let's try again: http://www.you tube.com/watch?v=Klengns3oQg Anyway here are the parts: 555 timer chip npn transistor 220 microF capacitor 10K potentiometer LED Schematic: I'd think the potentiometer would vary the resistance in the circuit, so it's good to go? Thanks!

That will run on 12V too. But the pot at low resistance could blow the 555 timer. IE - if pin #3 to 0V or 6V goes under 30 Ohm, or 60Ohm @ 12V.. Pin #3 is usually limited to +/- 200mA; hence include (say) an 82 or 100 Ohm resistor from pin #3 to the pot.    You might want to add a 270 or 330 Ohm resistor in series with the LED to limit its current...