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Hello! I need to fit a 280nm UV-C LED with a battery and everything into a cylindrical box (1 inch (2.5cm) radius and 0.4 inch (1cm) height). What I need is pretty much this ( but with a much smaller battery. The problem is that I have a very vague understanding of how it all works and what I need to build it. Could anyone advise me on components I need?

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April 23, 2019 07:39

Hi Barakoff, how is your project going? What's your eventual goal?
Boss raised some good points below, especially those regarding determination of the LED output necessary for sufficient disinfection and the means of verifying that sufficient disinfection has occurred.
With regards to the Lark product referenced, I'd suggest expressing some caution before diving in. The test report is patchy at best, the system was challenged against E. coli which is renowned as an easy target for UV disinfection, and used deionised water rather than the "questionable source" claimed in their video. I'd also question why the change in branding away from Quartz, as they were known in their kickstarter.
There's also the bigger issue that, at present, there isn't a regulatory framework to cover products such as this, so there's little that can be done to challenge their claims.

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August 2, 2018 09:29

Interesting project. UVC has been used for water purification for a long time, so the issues that need to be solved are the power required from the UVC led for the water volume. I have no idea what is required and would be interested in your research on this. How far does UVC penetrate the water? That would determine at least on dimension of the bottle.
Once you know the above that will determine the battery size based on the duty cycle, i.e. how long does it have to be on for and how frequently.
It should get easier after this... Search for a high efficiency LED driver chip and design for the UVC LED current matched to your battery voltage. General LED chips should be OK for this application.
Then the mechanics... you may need a special PCB substrate to get rid of the heat from the LED and a good heat sink to dissipate this, then create the enclosure to keep the electronics and battery as cool as possible.
So first steps are the LED selection, I would be interested in what you have identified.

Ultimately the big question is how will you know it works?

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