Right then lads,
There is a signal from the ECU that goes to the rev counter to give you the display. Im not sure exactly how the dial itself works but it is digital.
The wire goes from the ECU into the ignition pack then out into the loom and to the dash.
I spliced into the wire just after the ignition pack (black box with two connectors on the inside of the left turrett). I will check which one it is, i cant remember of hand.
The signal is a frequency not a voltage so you need to condition it using an LM2917 chip (easily available from Maplins, RS etc. as is a whole ciruit board and component list). Then feed the output of this into an LM3914 which drives up to 10 LEDs (can do 20 but 10s enough).
I have an orange LED for idle, 7 greens and 2 reds but you can have any combination. You set it up with a variable resistor or 2 and get it hitting red just before the limiter.
You can by all the bits you need for about £10-15 from electronics suppliers.
And yes Lofty, that was me and Wiggy on TV again, and I bloody missed it! Which rally was it? The Trackrod? Should be good next week, the Tempest rally well get loads of coverage and hopefully our interviews will be shown!
