increased brightness with increased speed

My thought is that I want to light up something... anything really, on my jeep.   BUT  I want the brightness to increase from 0 at no motion to full brightness at highway speeds...

My initial thought on this is to use a DC fan (or several), like out of a laptop, to produce the voltage.  This way, I can mount the fan behind the grill and it's rotation will power the LED.  I am asking the general question of "will this even work?" first, before I begin asking details....

My ulitimate goal is to power a series of underbody lights usign this system... i think it would be a great feat to accomplish!   :D

Thanks in advance

Brad

was that in english?   dang, I'm lost...  

I know there are much easier ways to do it... I just wanted to try out the fan, mostly from the standpoint of using an unused energy source (airflow at speed) to produce electricity.  I have a larger picture in mind, but this is step 1 of 1million for that...

A fan out of a laptop isn't going to do what you are attempting to do.

If you want to control brightness based on speed I, too, would recomend using the VSS signal in the vehicle and processing it.  You wouldn't necesarrily need to use a microcontroller, but it would be much, much easier if you did.

Depending on the resolution you desire (ie how many steps between on and off) you could use a series of frequency switches on the VSS signal with current limited outputs.  Everytime a new one turns on more current would be available for the lights.  This would probably work with LEDs, but probably not when neons.