LED tach?

I just had a brain storm after looking at the wire diagram for the matrix rsx3.5

It requires you to tap into the tach wire. So can you make LED digital tac by tapping into that wire? that would be cool. Have a line of about 10 led's, one for each 1000 rpms. ever time you rev, it jumps up and down. Think this is possible?

if you were to take a digital multimeter, and hook the black lead to a ground, and the red lead to one of the tack wires, either in the cluster, or off the coil etc... it would register somewhere between 1V - 6V, and by increasing the RPM it would increase by 1V approx. so it wouldn't be very accurate without some sort of chip to regulate it. so if you just rigged up a few LED's you wouldn't have a clue as to what the actual RPM was, you would just know that it's turning over.

hope that helps... Mark

so the difference between 1000rpm and 7200rpm (my redline), is only 1 volt difference? or 1volt per 1000 rpm?

I'm thinking have one resistor to each led, therefore when it revs, and the threshold is met, it will light up.

it doesn't quite work that way, more RMP doesn't mean more pwr. just if you rev it up it will go up by about 1V, and thats if you were at 1500, or 6000.

Mark