Re: XPL - XAP

[Simon Ryley <simon.ryley@xxxxxxxxxx>]

> snipped
>
> > > PS:  To add some simple examples ... the car tells me when
it need
> > > servicing (needs to go to the garage, depending on usuage,
needs more
> > > water in the washer-bottle, needs the tyres pumping-up,
without there
> > > being pressure sensors on the tyres, etc)
> >
> > I suspect it does a best guess for tyre pressures.


There are a few different versions of tyre pressure monitoring
available.  Some actually use wheel or tyre mounted sensors to determine
pressure, others simply use the ABS wheel speed sensors, then look for
differences.  If one tyre from four is rotating slightly more often than
the others on a straight road with steady state vehicle speed, it may be
deflating.

> >
> > > ... it adjusts under- /
> > > over-steer when cornering, brakes cleanly without skidding
or
> deviating
> > > from the commaned line, checks doors for closure, closes the
windows
> > > when it rains, adjust windscreen wiper speed according to
vehicle
> speed
> > > (eg: goes intermittent when stopped for 'lights), manages
the
> cabin air
> > > environment ... and so-on ... ie: it's helpful &
context-sensitive ...
> >
> > I suspect this involves lots of seperate modules all on a shared
data
> > bus.  There's probably a few processors that control it all.

Depending on the vehicle, up to six data buses with multiple processors
on each. (From memory, a Golf Mk 5 is running five buses)  High end
vehicles with a decent option fit can be running 70+ individual ECUs,
(Electronic Control Units) some of these having multiple processors for
safety considerations.

> Very
> > distributed, and very robust, I suspect.  Coincidentally, I've
been
> > thinking about these sort of systems quite a lot recently.  I
have a
> > company car that's up to date, and does all this automagically. 
I
> > also have a BMW M535i for fun at weekends that does not.  I was
> > thinking about a data bus with lots of sensors and actuators that
> > could automate these functions as a retro-fit for my car.  I
don't
> > have the time at the moment to do more than think about it
though.
> > I'd not considered a xAP/xPL wireless gateway though!