by bdring » Wed Dec 09, 2009 6:50 pm
I have some of those and some ultra sonic sensors too from some old robotic projects. As I recall, my real world accuracy results were pretty good, but maybe not quite good enough. I think it would work well to get you very close, then just do a quick verify. It would also work well as a limit switch to prevent you from crashing the table into the lens holder (...did that once). With both methods it just gets you to the top of your material. If you cut anything with any thickness, I think you want to focus on the center of the material, which is another manual tweek.
Bart
"If you didn't build it, you will never own it."