Based on the ideas I was brainstorming a few days ago, I put together a 3d model of a sort of countertop smartphone-based coffee spectrometer which uses eyedroppers as the sample container. It has a built-in light in a closed chamber, and shines light through the eyedropper full of coffee, and into the smartphone camera.
I'm going to try to have this 3d printed at Shapeways.com, and see if I can get it working.
Here's the Sketchup file I made: coffee-spec.skp
Here is another Sketchup file which I tried to make "watertight" for 3d printing: coffee-spec-for-printing.skp
And a few more file types:
coffee-spec-for-printing.dxf (AutoCAD '12)
The 3d print came back! It looks super nice, although I'll probably polyurethane it to make it shinier and more spill-proof. It needs black paint on the inside, as well. I'll try to outfit it soon and see what we can get done with it: