>I want to build an opacity meter to check discoloration in a liquid solution.
>New fluid is relatively clear, but as it degrades over time it turns
darker in
>varying stages. I thought of using an infrared sender and receiver, but I've

If you are working with nitric acid (sure sounds like it) there are other
considerations as well.  You would do better with spectral absorption
analysis.

Let's go private if you are working with acids (my father runs mfg for an
ultra-pure chem co (Puritan), my brother makes the RFNA for them, and I can
get the info from them pretty easily - shoot, they might want you to make
something along the same lines).

Andy

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                     Andy Kunz - Montana Design
          Go fast, turn right, and keep the wet side down!
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