AVR-Chat

--- In AVR-Chat@yahoogroups.com, "William Nachefski" 
<slaphappysamy@y...> wrote:
> --- 
> I guess the 200,000 rpm gave me away.  Yes this is for a jet 
engine, 
> but not a model.  Its a rather large homegrown one.
> 
> In AVR-Chat@yahoogroups.com, "Jesper Hansen" <jesperh@t...> wrote:
> > > I am just getting started into AVR's.  I am seeking help on a 
> > > circuit.  I need to build a tachometer with opitcal pick up.  
The 
> max 
> > > RPM to be counted will be around 200,000 RPM.  
> > 
> > Hmmm. Playing with model jet engines ? ;-)

It doesn't *have* to be for jet engines :)  I'm looking to do the 
same thing, but it's for tracking the speed of the compressor wheels 
in a vehicle turbo.

On the track at 32lbs of boost, loading can spike the turbo speeds 
pretty nastily, which leads to rapid failure.  I need a way to 
monitor turbo speeds to modify the fuel delivery system etc etc blah 
blah.

I've seen the results of a #2 turbo grenading and spewing bits of 
chrome-vanadium steel down into the intake.  The pistons, valves, 
etc, were not at all happy about this state of affairs.  Not my car 
thankfully, but ugly nonetheless, and I don't want it happening to 
mine.  I currently stay below 28lbs, but those 32lbs pulls on the 
front straight are incredibly addictive :)  Gives new meaning to the 
word whoosh.

Dean.