There are so many budget friendly portable spectrometers available, I thought I'd post some photos of when I opened one, an hopocolor HPSC330, to replace the battery and recalibrate it afterwards. It seems to use a crosses Czerny-Turner geometry with a linear CCD

Have you ever had the need for a custom size glass filter or first surface mirror or need many at a low cost? You should know cutting them yourself from a larger stock is a lot cheaper and not nearly as hard as you'd think with a regular high quality glass cutter.

Sometimes you do what you gotta do to get your measurements

Sometimes you just don't get a lot of space to work with. There will be modules where the headers are, one Arduino Nano ESP32 and one ADS1259 ADC