VSS (Not So Long)

[Frederic Breitwieser]

Both Dakota Digital (www.dakotadigital.com) and Cyberdyne make electronic
boxes that manipulate the signal.  Dakota also uses the 2000 pulses per
mile, and one can achieve that with a bunch of magnets on the driveshaft...
We'd have to figure out the number of rotations the driveshaft makes per
mile based on tire diameter, diff ratio, and of course put on a certain
number of magnets, 1, 2, 3... etc.

If you want to keep your analog speedo, and use a digital input for the
rest of it, you might find it not so difficult to tap off the back of the
speedo - using optical sensors would be good here since the speedo is
protected from the environment.  Not an air-tight enclosure - but certainly
not covered with gunk like everything forward of the firewall.  Some
speedos, not sure if your GM unit has it or not, have a little wheel with
holes already in it - most of the Subaru's do, and some of the Fords.  They
use this wheel with an optical sensor to figure out speed, even though the
vehicle has analog guages - exactly what you want to do - you buy/grub a IR
detector/transmitter pair, glue it over the wheel, so the wheel breaks the
light as it does on the oem one.

Then, you have to figure out how many rotations the cable makes per mile,
which because of its size would be more difficult than figuring out
driveshaft rotation, but of course, it doesn't require magnets and glue.

Hope I helped, and didn't lose everyone.


Frederic Breitwieser
Bridgeport, CT 06606

Homebrew Automotive Website:
http://www.xephic.dynip.com/