Help. Putting an LED in automobile

I'd like to put a blue led bulb in the cup older area of my vehicle. And, have it run when I put the headlight switch on.

Is this possible? I think it would look fantastic since I can't see where to put my coffee when driving at night.

How could I wire this into the existing electrical system without frying the bulb.

Any help would be great.

thanks

Sounds neat to me, pal. I'll keep my eyes on this thread, and, if it doesn't take lots of electronics knowledge or soldering ability, I just might try something similar myself!

LEDTronics used to make LED's for automotive use. I no longer see it on their website. Maybe one of their dealers still have some in stock. If I find one I'll post here.

THIS is what I'm talking about. But I vaguely remember more color choices than white. At least red and green.

I like the replacement bulb idea. But, I was looking for some "mild" illumination. You know, the small little light that illuminates your ashtray when you open it.

If I were to put a colored LED in the "base" of the plastic cup holding area of my vehicle it would look real neat having the cup rest in it. Imagine a bottle of water being lit up by the LED at night.

I just don't know about stepping down the amps for the bulb. I'm sure we could figure out some way to mount the bulb.

Maybe I can take the vehicle to one of those car stereo/alarm install places. I just want one little led.

Oh wait a minute....Maybe one for the cupholder in the backseat too!! Oh no. I'm getting carried away.

I LOVE LEDS!!!!!

Why not just tap into the cigarette lighter leads and resistor down the bulb? Also, I would use green instead of blue since it preserves night vision. I typically hang an Infinity or Photon II around my rear view mirror while driving at night in the Adirondacks. I find the green allows you to see the road better than even turquoise, so I'm sure it would be better than blue.

Jest for fun, and to see if I remember any of my electronics...

Nominal voltage of the car's electrical system (usually assumed to be 12v)= 13.8 v
Max = 14.8 (supposedly)
Min = 12 (technically, 10.x, but that's "near death")

Subract the voltage required to bias "on" an LED (3.6 v for white, 4.0v for blue? Ah, RS 276-316, 2600mcd --- 3.7v)

13.8 - 3.7 = 10.1v

Typical current, 20 mA
MAx current = 30 mA

Typ resistor: 10.1 v/ 20 mA = 505 Ohms

At max voltage, that would yield 22 mA
at min, would yield 16 mA -- kind a low.

Let's try the max conditions...

14.8 - 3.7 = 11.1 v / 30mA = 370 Ohms

At nominal voltage, that's 28 mA
At min, that's 22 mA

So, pick a resistor value 'tween 370 and 505 Ohms, and you should be safe. Try 470 Ohms, it's a common value. If it's too bright still, pick a slightly higher value, or consider "scattering" the light.