Yeah i was just thinking out loud there, after doing a few hours of googling, i learned a bit about the principles involved, and how the main idea i proposed is in no way ideal, or possibly even practical.
But, given the cost of readymade uv spectrometers/flourometers, and the inaccesability of hlpc, even the cheapest options, i think a diy approach to the concept might be something worth looking into.
Out with the uv led idea, except perhaps the exception of a multi-wavelength array to give you the full spectrum of uv. But thats a digital solution, where ideally you'd want a linear or "analog" uv source. You can add resolution by different nm leds in an array, but i think you'd want a light source that is not only very stable and well designed, especially in how its powered, and not the focused and exclusive light source in terms of wavelength led's provide. to give you any degree of accuracy.
I havent really searched much in that regard, but did do a bit of googling on photodiode sensors, particularly the ones that read the full spectrum of uv light. In lieu of a mechanical swithing mechanism to move the sample between invivdually unique diodes of fixed wavelength. They are in no means cheap (the photodiode sensors), but i think you might be able to find something for around $100 or so.
If its possible to build a uv flourometer or spectrometer for under $200 in parts, i'd take a crack at it no doubt.
I think the main factors you'd have to consider in such a device are-
1)- Power source, and how clean and stable that is. Otherwise AC jitter from a smps, might distort your readings. For all parts involved that need power. Most importantly your uv source. Either pre made, or using low-pass/other filtering circuits, as well as voltage regulation to ensure accuracy.
2)- Light source, and most importantly its UV specrum. LED's don't seem like a good idea unless you want to solder a array of different wavelength diodes together, one for each nm of uv in the spectrum. Once again, haven't looked to closely into what that might be.
3)- diode sensors, amplification circuits to read the output (if necessary), and how you want to read that data. My thinking is an arduino would be your best bet here. Simply because you can program it to process that raw input and factor in unforseen variables if necessary. Also with a bit of coding, you could have it output the data on a lcd as a function of uv flourescene of the sample in terms of wavelength. But to start, a simple voltage/current analog system would be easy to work with.
4)- Practicality, and if its even possible to make a device, without interference from the multitude of factors that could skew your readings, like power source jitter, airborne particulate, dust, the medium you would have your sample in, etc. How sterile does it have to be in simple terms.
5)- Saftey. If your working with UV light sources, particulary 1000mw+ sources, you have to be aware of the potential for optical damage, and other skin/health concerns. Just something to think about if you want to try and work out a "tekable" design, that people who might not know in complex terms what is going on might undertake as a project.
I would spend up to $200, not including the arduino i already have, to try and diy something, but its only an idea in my head atm. I've learned from past expirence in diy electronics, don't buy anything until you have a plan that you've run by people more knowledgable than yourself in the subject matter.
Alot more compelx than i assumed in my intitial post. It might be useful, to know what range of light the substances in question flouresce under, particulary psychoactives/psychadelics/etc and go from there.
The multi resolution diodes needed for such a device are not cheap, and the main thing to look into here i think. Otherwise you will need a bunch of diodes to read different wavelengths, and the economy of scale will inhibit design of a device not exclusively tied to a particular wavelength of uv. Theres alot of sensor diodes worth looking into, anything readymade is probably going to be too expensive for me. Might as well just buy a used flourometer/spectrometer off ebay/etc at that point, hence my $200 price ceiling.
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