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A UV-Visible-IR Spectrometer

The i-Phos HD spectrometeter, by Chris Wesley, is a ready-made version of the Theremino spectrometer, with the option of a single 1mm slit, or a set of interchangeable slits of 0.5, 1, 2, 3, 4 and 5 mm width. The wavelength range is from about 360 nm (near UV) to 1150 nn (IR), with some fall-off at the extremes. Resolution achievable with  1mm slit is around 1 nm.
     Here we adapt the i-Phos spectrometer by removing the supplied 1 mm slit and attaching a Freseriksen Symmetrically-Adjustable Slit assembly. This gives a continuous adjustment range from 0.3 to 6 mm, with the exact setting easily determined by measuring across the outside of the slit blades (using a dial caliper) and subtracting a fixed amount.

Article under construction.

Fusion 360 CAD rendering of a 3D-printable mount, for attachment of a Frederiksen symmetric adjustable slit assembly to the i-Phos spectrometer. Orange colour is for visualisation only. Final print, in ABS, is black.

Design by Stephen D Knight.
Slit mount CAD drawing


i-Phos HD Spectrometer (Chris Wesley)
Chris building a standard definition version.
Standard 640 × 480 manual-exposure webcam is no longer available, so a dedicated 1920 × 1080 full HD camera module is now used.

Making a DIY Spectrometer [Creative Lab] YouTube Video.

Theremino website (please support this open-source facility).
Theremino Spectrometer Technology .
Theremino Spectrometer Construction .
 Theremino Spectrometer, Sample Spectra .
 Software download .  Help file (instructions) is in the zip file.

Frederiksen Adjustable Spectrometer Slit:
I finally obtained a Frederiksen adjustable slit from Timstar (WF Education Group) but it took 4 months on back order before I got it. Still, I suspect that Timstar deserves praise for getting it for me at all, because when I went back to the Frederiksen Scientific site to give a link to it, the item seemed to have disappeared from their catalogue.
     It is a beautiful piece of precision engineering. Making something similar is not beyond the capability of a good engineering workshop, but certainly not a trivial undertaking.

Ovio Instruments - Frederiksen slit .

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DWK 2021 July 4th