On Thursday, May 1, 2014 11:20:44 PM UTC-4, Tim Wescott wrote:
On Thu, 01 May 2014 10:15:48 -0700, ggherold wrote:
snip
What's your detector?

Could you use an LED and photo diode?

It's in a very uncontrolled environment both for dirt and for light (it's
gotta work in full sun, in just about every conceivable orientation), and
there's no room to shoot light through an aperture -- it would have to be
reflective.

Hi Tim, I've never done light detection in full sunlight,
so I may be full of ****. But there is some nice 3M retro reflective tape
that Phil H. (of SED) turned me on to. As long as you have enough dynamic range in the detector (to take care of full sun) cna't you you then AC couple the signal? (White leds are blinding these days.)
(Will it kill you if you get a few false counts as full sun blinks through the spinner onto the detector. That's going to be a very small solid angle)
I've no answer for dirt and grease.

George H.



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Tim Wescott

Wescott Design Services

http://www.wescottdesign.com