Dear Sir or Madam.

I am the engineering editor of a 1500 world wide subscriber news letter
devoted to the enhancing the power of Mazda rotary engines.

I am attempting to design a turbo charger tachometer using fiber
optics. The temperature of the compressor part of the turbo charger
housing can be up to 250 F so I suspect we need glass fibers rather
than plastic. There can be two holes in the housing about one or two 
mm in diameter. We can use high temperature epoxy to attach the
fibers to the housing. The angle of the holes will converge on
a spot on the edge of the compressor wheel.

The compressor wheels are 2 to 3 inches in diameter.
Half the of circumference of the wheel can be painted black
and the other half can be polished aluminum. 

The turbo charger rotates at speeds up to 150,000 RPM.
Therefor the pulse response of of the system must be 
2500 Hertz or better.

My first guess is to use a laser to illuminate the edge of the 
wheel through a glass fiber and a logic receiver on another glass fiber
to out put a TLL or CMOS pulse to a counter.
The glass fibers only need to be  3 or 4 feet long.

Can you makes some recommendations on where to start?

Thank you in advance.

Paul Lamar

 
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