I don't wish to discourage this because anyone with the drive can build an adequate spectrophotometer. However in the example of this product one has to ask themselves are they really getting what they hope for?
Let's compare some basic specifications:
Spectronic 20 UV-VIS ( a basic spectrophotometer used in colleges)
Spectral Slit Width: 20 nm
Wavelength Range: 340 to 950 nm
Wavelength Accuracy: ±2.5 nm near 525 nm
Photometric Range: 0 to 100%T; 0 to 1.95 A; 0 to 1999 C; (0.1 to 1000 Factor)
Photometric Accuracy: ±2%T
Photometric Noise: ±0.5%T
Stray Radiant Energy: %T over entire wavelength range*
Display: LED %T, A, C Factor, Wavelength
vs
around 400-900 nanometer range, maybe wider (what you can see with the naked eye, plus some infrared)
5-10 nm spectral resolution
20-30 samples per second
~ $15 in materials
< 1 hour construction time
I imagine the output isn't all that great, and find it suspect how little they say about the accuracy of their device. This may work for basic tasks but you get what you pay for. Such as a DVD chunk for a diffraction grating prism. Will this tool be able to tell you if there is hydrocarbons and conjugated pi-systems, maybe? Will it be useful for chemical analysis, I wouldn't put money on it.
Look at what their fold-able spectrometer design is...
Foldable Spectrometry Starter Kit Granted this design is a step up, but all it is is a chunk of a dvd and a cardboard box relying on a smart-phones webcam. And a look at the operating principles of this device:
Desktop Spectrometry Kit, same thing only it has a plastic case and uses a web-cam.
Now let's see how a basic optical schematic of a real UV-VIS (U-2001 UV/Visible Spectrophotometer) looks
. Notice the different light sources and a reference, as well as the use of cuvettes? Very different situation.
Finding a surplus real UV-VIS will be more reliable and produce accurate results. These can be found from 60USD to 150USD depending on the day of the week. There's something to be said about cheaping out on analytical instruments.
