====== Spectrophotometer ======

  * https://polaridad.es/sensor-radiacion-ultravioleta-arduino-indice-uv-uvm30a-guva-s12sd/
  * https://snowmix.sourceforge.io/Intro/about.html
  * https://publiclab.org/system/images/photos/000/026/339/original/DSLR_spectrometer.pdf
  * https://publiclab.org/search?q=chromatograph
  * https://publiclab.org/questions/falbriard/02-11-2019/is-a-spectrophotometer-able-to-detect-contaminants-and-traces-of-heavy-metals-like-lead-mercury-cadmium-chromium-arsenic-copper-and-nickel-which-is-the-best-method-for-continous-tracking-of-contaminants-in-river-water
  * https://publiclab.org/notes/gaudi/04-03-2014/diy-micro-volume-spectrophotometer
  * https://old.publiclab.org/search?q=spectrophotometer
  * https://ru.aliexpress.com/item/32859370682.html?spm=a2g0o.productlist.0.0.2ff67f5aWdVTBg&algo_pvid=2eac1486-97d9-430d-a4a9-dea032743078&algo_expid=2eac1486-97d9-430d-a4a9-dea032743078-3&btsid=25307ba2-2b1e-4515-ba76-96051ece0022&ws_ab_test=searchweb0_0,searchweb201602_4,searchweb201603_53
  *