Any good UV+Visible USB-connected spectrometers at a REASONABLE price?

[Ben321]

I was considering getting a UVC LED disinfectant lamp on eBay, but am not sure which ones are fake (I've read many of the LED disinfectant lamps on eBay are fake, though I do know that UVC LEDs exist). So my plan was to buy several claimed UVC LED disinfectant lamps on eBay, and then test them one-by-one with a UV-VIS spectrometer (and then keeping only the strongest UVC-output bulbs and throwing the rest), doing the test using something like one of these https://www.oceaninsight.com/products/spectrometers/general-purpose-spectrometer/flame-series/flame-uv-vis/ UV+Visible light USB-connected spectrometers on my computer. The problem is the price of these. Conceptually, a USB-connected spectrometer is simple. Some lenses, a diffraction grating, and a linear CMOS imager (similar to those used in computer flat-bed scanners for scanning paper photographs into digital images). Unfortunately, the price is anything but "simple". Instead of costing about as much as a flat-bed scanner (a couple hundred dollars), their cheapest one costs over $3000!!!!!!!!! YIKES!!!!!!!!!!! It's great in specs, going down to 200nm (well into the UVC range, just like I need it), and all the way up to 850nm (well into the NIR spectral band). It's the price that's the problem

Is there ANY place, even a "cheap Chinese junk electronics" place, that I can buy something with similar specs, but at something like only 10% of the price that this high quality science equipment company is selling it for? It doesn't even need to be completely calibrated, as I can correct the wavelength values using my mercury vapor lamp as a spectral line source (looking up the wavelengths for mercury spectrum online is simple). And the intensity values at each wavelength don't even need to be super precise for my use. I just need to verify if the UVC LED bulbs I want to buy on eBay are actually outputting a decent amount of UVC, in order to kill those nasty corona viruses.

[David Hess]

Could you use a raw diffraction grating, or a quartz prism, and a phosphor screen, say made using glow in the dark paint, to test them with your mark 1 eyeball?

[ace1903]

Everything connected to UV-Vis is expensive due to use of pure quartz that is difficult to be modeled into parts needed.
I had old unit (196x something) on which I wanted to replace old electronic and replace it with modern microcontroller. But source of UV light was deuterium lamp (~200$), diffraction grating is 400$ and sensor element is 100$. Whatever you will find, it will be more than 700$ or fake or broken.
LED is wrong source for UV light for disinfection since low efficiency when compared with standard UV light bulb.
You will save much more if you buy from reputable source like Farnell or Digikey than investing in measuring equipment and spending money on LEDs that half will be fake.
Output of led that are on the market now is not enough to be used for disinfection for any practical use. Just do the math with numbers from datasheet and power need to disinfect cubic meter of air for example.
If you need just for disinfection just buy standard lamp and do the test with UV detection cards.

[DaJMasta]

Those same ocean optics (now ocean insight) USB4000 (and the earlier USB2000) units go for a lot less on ebay.  Some sellers won't have tested it and can't tell you what configuration they are (some can't read much UV because of the grating choices), but they are often functional and some sellers do specify.  Older model USB4000s and older USB2000s can require older operating systems - something about the Cypress USB chip driver not working in windows 7/10 - but they will work fine in a VM if you just pass over the USB device.  If you get a newer variant, there is free software for doing basic stuff, but you can sometimes find an install code for their older software as well, and then there's an open source package for just pulling data from the spectrometer raw.


There are some other USB options available, but the ocean optics units seem to be the most prevalent.

[ace1903]

Here is one youtuber that made experiments similar to you idea:

Unless unit is specifically made for UV, second order diffraction will mess the measurements of the UV LEDs.