Transforming\nPixels into Spectra: The Educational\nJourney of Recycling an Old Optical System

The academic community increasingly embraces the possibilities\noffered by the Maker movement, with a notable rise in the creation\nof homemade instruments, particularly in the field of spectroscopy.\nThese instruments are being leveraged to enhance engagement in classes\nand educational projects. Most of these homemade instruments designed\nfor educational purposes rely on simplified 3D-printed components\nand/or adapted materials, such as compact discs used as diffraction\ngratings. This article proposes yet another solution by recycling\nan optical system from an old liquid chromatograph decommissioned\ndue to obsolete communication protocols. The entire instrument’s\noptical system is used, and the original photodiode array (PDA) was\nreplaced by a modern PDA that could be easily controlled by Arduino\nand a user interface developed for this intent. A flowchart illustrating\nthe interface operations related to absorbance calculations is presented,\nfollowed by a discussion on how the shape of the acquired spectra\nmay be influenced by positioning of the sensor. The raw data obtained\nin this work can also be utilized to teach concepts related to dark\ncurrent, baseline correction, instrument calibration, and absorbance.\nThe visible spectra of several substances from the resultant instrument\nare presented and compared with those of a commercial benchtop spectrophotometer.\nThe approach described here can inspire the recovery and recycling\nof other outdated instruments, providing opportunities to explore\nand teach both the physical and computational aspects of chemical\ninstrumentation.