> >  Hello,
> >
> > I intend to build such a device too,
> > for my small yacht, that has a Sabb 8 hp Diesel engine.. no ignition
> > by
> > electric means, and mechanical fuel injection.
> > Has anyone EXPERIENCE  with getting RPM info out of a diesel engine?
> > Please no
> > untested ideas, I have plenty myself, just proven technology!
> Accuracy
> > is not
> > the primary goal.
> > One of my better ideas is using the jerk of the fuel injection
> pipe..
> > anyone
> > tried that?
> > Must be verry reliable, and sea water resistant, in a dirty
> > environment...
> > The engine has a flywheel with a diameter of about 50 cm (20"), that
> > is
> > difficult to access from the front. The clutch is in the engine
> block,
> > so the
> > outgoing shaft may be disconnected, so using that is not absolutely
> > reliable.
> > The engine drives an AC generator through a V-belt. The start motor
> is
> > a Bosch
> > Dynastart, attached by V-belt also.
> > No more V-belts can be driven.
> > Getting the RPM info is in my opinion the hardest part, interfacing
> it
> > to the
> > PIC is a challenge, the rest is FUN though a challenge to me, as a
> > novice in
> > PIC world!
>
        If you have access to the front of the crank shaft, try mounting
a disk with a notch cut out on to it and use a hall effect sensor. You
will get a 5V pulse which is easy to count with the PIC's. It works for
auto engine control so it should work here.

        If you have any questions email me.

        Peter G.
        peter.graham@dsto.defence.gov.au