I don't think MEMS is required. For $60 you can get a 2 TB hard drive. It contains platters that are several inches in diameter, and there is a swinging arm tha

I don't think MEMS is required. For $60 you can get a 2 TB hard drive. It contains platters that are several inches in diameter, and there is a swinging arm that is a couple inches long. All these parts move with incredibly tight tolerances. DVD writers are $26, and Blu-Ray writers are $120. Those are an even better comparison, with moving optics. Food inspection is silly unless that is your job. People who keep aquariums, particularly saltwater ones, are a more likely market. 18 channels sounds great for most school labs. It's enough for a crude graph of chlorophyll's absorption and/or florescence. It might even be enough to distinctly identify the four main sources of color in spinach leaves. Repeated sampling at about 10 Hz would be plenty for all the labs involving reaction rates; most could be done with 0.1 Hz. For example, a popular lab involves measuring the changing rate at which Crystal Violet is destroyed by lye. Some less-demanding popular labs involve measuring the amount of copper in brass (as copper nitrate via nitric acid) or the molarity of blue food coloring in drinks.