LED Tail-lights

[Hexxle]

Hey everyone,

I'm currently trying to find out how to swap out my existing incandescent tail-lights on my car to rings of LED's, but the problem is, I can't find a reliable how-to guide anywhere, and circuit building isn't my expertise.

I'm after info (hopefully resulting in me building my lights) on PWM to control the current, and if anyone could help me make up a circuit diagram, that would be great.

Here's a picture of my final goal (i.e. the tail-lights):

I can find out the voltages feeding the lights as is, and I have a basic electronics understanding, but I'm gonna need some help on this.

Cheers.

 

[nbw]

You could probably get some Vero-like board with single coppered holes, cut out a ring to fit your light, and then solder the LEDs as a start. You'll want all the same sort to match brightness. At a nominal 12V, and a typical forward drop of say 1.8V per red LED, you'd use 6 in series to give 10.8V, leaving approx 1 volt to be dropped across the resistor. PWM would be one way of doing it - make sure it's fast enough so you don't get flicker. Another option would be for the brake signal feeding into the LED rings to add another resistor in parallel, to instantly decrease the resistance and make the LEDs go brighter. Depending on the LEDs you using, you might be able to run them at say 20mA as a normal tail light, with the brake light running at 30 mA. You'd need to experiment to see how much brighter you want the brake lights to be over normal tail lights.

Good luck!

P.s. that's a nice Supra. I wanted one of those but my 2 kids got in the way

 

[Hexxle]

Thanks mate, you've given me something to start off with.

 

[nbw]

That's ok. I've just finished building a tail light for my motorbike with LEDs, similar kind of principles - one bank of Cree 3W LEDs in series, so 5 x 1.92Vf, with a small resistor to limit the current. A little less chance of me getting rear-ended now!