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Comment by el_don_almighty | Hacker News Reader

The LED components listed in the research aren't listed on the web site as available. In addition, DigiKey no longer appears to carry the product line...

How am I gonna build short duration dosing unit for my shower without access to these parts.

For the purposes of getting this into the public domain...

I propose a small, waterproof, battery powered device that mounts to the shower wall which directs UVB radiation at 293 uM wavelength at the midsection of the user for a timed duration when activated by the presence of water

Activation is delayed once water is detected to ensure the user is actually in the shower. The time duration is limited to ensure nobody gets cooked like Ron Popeil rotisserie.

Everything is open source because everyone needs this

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Meh... just use a tube, like in the old country:

https://www.nationalgeographic.com/content/dam/photography/p... (might be a bit nsfwish for some people)

Can confirm. This was daily routine in children's hospitals and some kindergartens. Aimed to prevent rickets. As were contrast foot baths.

Water droplets create lenses that can cause uneven exposure and possibly burns. I have had trouble sunbathing without using a towel after a swim. Just a warning before you complete your DIY project.

Moving water shouldn’t cause the same issue as stationary droplets lensing in one place.

That's something I've noticed but I think it is the chlorine mostly. Better swim at sea (if possible...)

be sure to have some eye protection in your shower too...

why 293? this fda approved product for example uses 311 (https://www.amazon.com/Angel-Kiss-Portable-Phototherapy-Fluo...)

Note that truly FDA-approged phototherapy devices require a prescription in the US. It's quite likely that device isn't even UVB, much less "FDA approved"

(I have a condition that requires UVb. I wasted so much money, and skin burns, on Amazon's shitty medical grey-market... )

Androv medical makes quality lights. Even though their page seems kind of shady.

Because the study says this is the most effective wavelength.

The study (open-access PDF link in the article) says that in their testing on human skin samples, the 293 nm wavelength was the most efficient, and would require 10 times less exposure to get the same effect as the 305 nm wavelength. They seem to suggest that 30 seconds of exposure with the 293 nm wavelength lamp might be the equivalent of 30 minutes of sunlight.

The PDF also says that D3 is produced from lights all the way up to 320 nm, so the 311 ones sold on Amazon would work. But given the 293 vs 305 effectiveness, how much exposure would you need to actually make a meaningful difference? Probably a lot!

Until we know that 311 nm is rather benign, we must assume that using a stronger UV source is more likely to induce cancer. While I don't know about the size of the effect here, in general you try to use the lowest possible dose when medicating.

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