Jon Petty wrote:

> I want to use a laser or led as a light source and some kind of a
> diode array receptor to measure the critical angle of refraction for a
> automotive fluid.

> Does anyone know of an inexpensive diode array receptor or way to
> measure where light is received?

  No specifics, but I have read a few answers thus far and the
mechanical approach has been noted where a stepper motor directs a LED
or even laser beam to one receiver.

  It seems to me that receptor electronics is much more complex than
emitter electronics, so unless you use a linear CCD device out of a
barcode scanner, which has integrated electronics, it would be easier to
implement multiplexing of an array of LED sources (LED bar array) than
individual receptors.

  I daresay you'll be looking at barcode sensors then.
--
  Cheers,
        Paul B.