Summary

SPECTROMETER ONE
Here I present the first of my variants, of Les' Lab Spectrometer https://youtu.be/T_goVwwxKE4?si=wcPzeDK-d2dmEW38

I've chosen to use an 8MP USB Camera for this version https://www.amazon.com/dp/B0C3L8S68N?ref=ppx_yo2ov_dt_b_product_details&th=1 and I've removed the IR filter that sits in front the CCD element. Just use an X-acto blade at the edges, it removes easily with a little patience.

I've opted to use ta 12mm f1.6 zoom lens https://www.amazon.com/dp/B09CNXF3BF?ref=ppx_yo2ov_dt_b_product_details&th=1 and this 25mm dia diffraction grating. https://www.amazon.com/dp/B005LY493O?psc=1&ref=ppx_yo2ov_dt_b_product_details

In this version I am trying Theremino as the GUI software https://www.theremino.com/en/downloads and future versions I will try Les' approach using a Raspberry Pi and his very capable software approach.

My Diffraction Grating has just arrived, and here are my PLA 3D printed files for the mounts, base, etc.

I've attached the Solidworks files in both SLDPRT and STL formats for your convenience.
CAD: SolidWorks 2010
CAM: Orca Slicer V1.9.0
Printed on: Creality Ender3 V3 KE, using Creality Black PLA
Adhesive used: Thin Cyanoacrylate (mounts to base only, use sparingly and only after testing and alignment)

HARDWARE (Stainless Steel):
12 pcs M3x8 Bolts
1 pc M3x40 Bolt
1 pc 1/4-20 Nut

A really nice pistol-grip for it can be had here:
https://www.thingiverse.com/thing:1966894

Feel free to explore and modify as you see fit,
Enjoy!