Hi,
I am looking into a project to measure the specific gravity of beer in a fermentor, my current approach is to use a pressure sensor and distance sensor to get the pressure and liquid level and then work out the density from there (P = rho * g * h).
Now beer can foam up a bit so what would be the best sensor for the liquid level, ultrasound? Or is there a better way to go about this?
Cheers!
Here's an idea, but I don't know how well it would work, nor how easy it would be to implement it:
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Set up a "sight glass" on the side of your vessel that holds the liquid. You might want a small floating ball inside, you might not.
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Attach to the sight glass a long, single-row CCD (you can pull one of these from an old scanner), face the element toward the liquid in the sight glass, and on the other side side directly opposite, hook up a cold-cathode florescent bulb or LED array (pull the same from the scanner, as well).
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The hard part: figure out how to hook up and read the CCD.
If you can figure out step three (which should be a matter of clocking data out serially in some manner), then you can read the CCD, and based on the light levels, determine (probably pretty accurately) the level of the liquid.