Re:
Howdy,
I've actually been contemplating the same project as Rory, and came to a somewhat nearer solution to yours Pilot. My additional query would be...To avoid the complexities in using a PIC, wouldn't a simple Frequency-to-Voltage converter suffice? Then the frequency created by converting the speedo cable rotation into pulses, can be fed into the F-V converter and displayed using a simple Digital Panel Meter.
At least thats the way I see it...does this sound viable at all? My only block is the method of converting the actual voltage to a readout corresponding to the actual speed. I presume that's where the use of a PIC would be handy. Is there any method otherwise that you know of?