Liquid opacity monitor

Guest,

About as low tech as you can go would be something I used many years ago in a limnology course. Do an internet search for a "Jackson candle turbidimeter". In a nutshell, a candle is placed beneath a graduated cylinder, and your turbid liquid is added to the cylinder until the candle flame "disappears" when viewed from above.

A little more sophisticated would be to utilize a light intensity meter (such as a ready-made one used by a photographer, or even a silicon or selenium photocell coupled with a meter with the appropriate range) in conjunction with a constant intensity light source. Placing your sample between the two would provide you with empirical data. You could interface the light meter with a datalogger or recorder of some type.

Similarly, you could use the light meter built into a digital camera, coupled with the constant intensity light source. Then take a picture of each sample, via the transmitted light. If your camera records exif data, you would have the exposure data available to you after the fact, without any extra hardware necessary...

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Just my $0.02...

Thanks.

We've probably got all the bits and pieces (light souces, photodetectors, micros, etc.) in the storeroom for me to rig up something simple. I just had concerns about making mutliple units have highly similar responses across the range.

What I'm saying there is I'm lazy.

But the more I think about it, for the absolute minimum purpose of this test all we really only need to know is how long a sample takes to get from "opaque" to "pretty dang clear". After much head pounding, I now believe we can fix the value of "opaque" and all other variables to be the same in all the samples.

So it shouldn't be too hard to just get my little homebrew units to all agree on what "pretty dang clear" means. All they'll have to do is start counting when I tell 'em and then stop counting when they see the light - so to speak. Easy enough.