If you want to find out what something is made out of, you’ll probably be using a spectrometer. These devices allow scientists to determine what something is made of by shining light through an object and recording what colors are absorbed. Professional spectrometers cost many thousands of dollars, but you can build your own using a simple USB web cam, an old DVD-R, and a VHS cassette case.
In this tutorial of Public Labs’ DIY video spectrometer, [Jeffery] takes us through the process of building a spectrometer. After cutting a small bit of plastic from a DVD-R and mounting it on the lens of a web cam, [Jeff] puts the webcam in a VHS case and shines a light through a small slit. The result is a rainbow pattern captured by the webcam, and by putting different translucent materials in front of the light source, the spectrum slightly changes.
Of course a DIY spectrometer is nearly useless without a library of materials and their associated spectra. [Jeffery] is working on this as well with a wiki-style app called Spectral Workbench.
There’s a video tutorial for making your own DIY spectrometer available after the break. It seems like an easy build, if you can find the requisite VHS cassette case in your basement and/or attic.