Calibrating VDO/Audi speedometer to compensate for
isham-research.freeserve.co.uk at pop.pol.net.uk
isham-research.freeserve.co.uk at pop.pol.net.uk
Wed Jan 31 23:00:35 EST 2001
> oh ya, about calibrating the speedo, I don't see anything about adjustment
> in my 5k Bentley. But I think the speedo sensor just outputs a 0-5V signal
> to indicate speed. So you could adjust this by putting a simple circuit in
> between the sensor and speedo.
Pulses. It's a Hall sender - the front differential spins a shaft with
a miniscule magnet on top, and the Hall sender sits on top. On the Type
44, the pulses are actually _counted_ to derive stepping motor pulses
for the odometer - if the rolling radius of the front left wheel is
correct, the system is capable of incredible accuracy.
The digital dash ur-quattros go one stage further - the system is
entirely digital - no analogue values anywhere. Except in Switzerland,
of course.
Since road speed derived from these pulses is used in so many places,
I'd be cautious about messing with it.
--
Phil Payne
http://www.isham-research.freeserve.co.uk/quattro
Phone +44 7785 302803 Fax: +44 7785 309674
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