Knock alarm

[bruce plecan]

Knock Alarm, look at the tech notes/archives, 
HTTP://ni.umd.edu/gnttype/www,  there's also a 
LED Air Fuel Ratio Display.  Electrical area in tuneups-recipes.
HTH    Bruce   nacelp at bright.net

----------
> Tony Cooper wrote:
> >
> > David Piper wrote:
> > 
> > > Can someone comment on the availability of a knock sensor alarm. 
Which
> > > sensor would have universal applicability?  How could I fab a circuit
to
> > > ...
> > 
> > You may have a problem here. 
> > The sensor sounds about right, but you will have a problem making a
> > generic system. 
> > All engines knock at different frequencies - no 2 engines are the same.
> > What you need is
> > some intellegence built into the system, something like a DSP would do
> > the trick, but even then
> > the system may need some 'tweaking' just to get the correct frequency,
> > and that would only
> > ever work on that engine. Even aging can move the frequency of knock.
> 
> Is there somewhere I can go to learn more details about how knock sensors
> work? It sounds like they use a resonant sensor, chosen & tuned for the
> application, and maybe look for a build-up of oscillation?
> 
> I had this idea to use something like a (non-resonant) quartz transducer,
> maybe one per cylinder, to get a signal when each cylinder fires. Then I
> could monitor the signal under normal conditions, to get a baseline. A
> knock should give a stronger, shorter signal, a bit earlier, right? Even
if
> it needed a DSP, and tuning for each engine, it'd still be useful to me.
> 
> I had heard that some aftermarket ignition system had this kind of setup,
> but I can't find any info on any such thing. 
> 
>    TIA,
>    Chris Conlon
> 
> p.s. Hi, I'm new :)
> 
>