Progressive LED TACH

Hey guys. I just had another idea I had about changing the interior is printing out the tachometer guage templete on clear paper. In photoshop I would mod the tach so that the lines that are originally yellow to red into being clear. See the reason for the clear paper? I would then take the black backing where the tach originally was and use a roto-zip to make a continuse hole around the clear tacho line. Here is the clencher. I would get several different color led's and solder them togeather. (need help with pin-out and what not in this step)

The whole reason for this is so that lets say I am at 3,000 rpm which would be yellow only the white to yellow leds would show up. The lights that cover 1,000 to 3,000 rpm. But... If I rev it to lets say 6,000rpm then all of the lights would light up. From 1,000 to 6,000. You see what I'm getting at?

The only problem is how the leds would detect what rpm the needle is at. I didn't know whether or not the needle is giving out any voltage. If it isn't then how would you detect the right amount of voltage.

I thought that this would be a pretty cool idea but, just need some help finalizing everything.

that would be difficult to do since we have an analog tach.

thats what i was thinking, it would be easier it was already digital or something :\ suppose you could put your own meter or sensor or something in there somehow.. for your LED's... but sounds difficult =>

I was thinking the same thing. How hard would it be to put a honda s2000 guage cluster in our cars? Forget about making it fit and what not. I mean making the readings right. I was at carmax today and saw one. Whoo! Those things are so clean. Thanks