In a sci-fi future where people are making long journeys on spaceships I can imagine rooms decked out with these to mimic a natural day/night cycle and outdoor spaces.
I remember first seeing lights like these a couple years back before from CoeLux (https://www.coelux.com), iirc theirs are very expensive though. Awesome that this guy managed to DIY one!
> Whittier is a city at the head of the Passage Canal in the U.S. state of Alaska, about 58 miles (93 km) southeast of Anchorage.[6] The city is within the Chugach Census Area, one of the two entities established in 2019 when the former Valdez–Cordova Census Area was dissolved.[7] At the 2010 census the population was 220, up from 182 in 2000. The 2018 estimate was 205 people, almost all of whom live in a single building, the Begich Towers.
> The Begich Towers Condominium is a building in the small city of Whittier, Alaska. The structure is notable for operating like a small-scale arcology, being the residence for nearly the entire population of the city, as well as containing many of its public facilities. This has earned Whittier the nickname of a "town under one roof".
Riding the coattails of your comment to ask the hive mind: any reason I shouldn't try to build the simpler version from the tutorial using a more powerful (100W) LED from Amazon?
Don't forget that the volume of the device has a cost too. The video shows the construction of a really really nice, but takes up the whole hallway outside that room. Most of the time you'd probably prefer to use your hallway for walking in. On the other hand, maybe your house has an attic above one of your rooms that; there will be a lot less opportunity cost to using up that volume.
Use Fresnel lenses with a shorter focal length and reduce the depth.
It would be useful to start with a standard home-type window from, say, Home Depot, and build a unit about 120mm deep using multiple shorter focal length Fresnel lenses.[1] Then, in a basement or windowless room, mount some of these into a wall. Add curtains. Nice if your home office or workshop is in a basement.
This has commercial applications. Houses have few windowless rooms, but commercial structures have many.
The idea is to build this as a light box behind a standard windowpane frame. Like this one.[1] With a 120mm short focal length, the unit only needs to be about 150 - 200mm deep, if you angled the optics so you get light at a 30 degree angle or so. (Horizontal sun rays would look wrong.) That's a convenient size; you could hang it on a wall, like a rather bulky picture.
I have a chromatic film on my actual windows because I like the effect so there's technically a market for it , especially if it makes it cheaper and smaller
You'd still have to deal with the glare and chromatic aberration from the mirror sheets. Also the area covered would still be confined to the size of one sheet and you'd have to make a "bank" of them to cover any reasonably large area.
There's at least some evidence that LEDs can be more effective than sunlight at synthesizing D. There's a specific wavelength of light that triggers it and I'm not sure if a standard tanning bed emits it.
I’m confused by this comment. There is evidence that Vit D deficiencies have all sorts of health impacts, and that supplements raise in-blood levels.
What other evidence is needed?
Most things related to vitamin D are just correlation. If you are weak and frail you may not get out much and won’t have so much vitamin D. That doesn’t mean giving you vitamin D will make you strong. I heard that most studies don’t show benefits from vitamin D a supplements but maybe I’m wrong.
Oral vitamin D supplementation between 700 to 800 IU/d appears to reduce the risk of hip and any nonvertebral fractures in ambulatory or institutionalized elderly persons. An oral vitamin D dose of 400 IU/d is not sufficient for fracture prevention. https://jamanetwork.com/journals/jama/article-abstract/20087...
High levels of vitamin D among middle-age and elderly populations are associated with a substantial decrease in cardiovascular disease, type 2 diabetes and metabolic syndrome. If the relationship proves to be causal, interventions targeting vitamin D deficiency in adult populations could potentially slow the current epidemics of cardiometabolic disorders. https://www.sciencedirect.com/science/article/abs/pii/S03785...
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At this point I got bored of looking at results (I omitted a few which only looked for correlations).
So while there is some evidence of some benefits for some people, I didn’t find evidence of vitamin d being the magic panacea that it sometimes feels it is claimed to be by people on the internet.
I think you need to add "among people with sufficient levels of vitamin D" to that statement.
It follows almost from definition that if you are deficient in something, supplementing that something is beneficial. There might be some exceptions, but then we've really just got deficient defined poorly or no effective method of supplementation.
I had a room in an apartment that had no sunlight, and was lusting after CoeLux after it launched. Almost goes without saying, but the first to manufacture an affordable solution at scale would make a ludicrous amount of money, especially with much of the world in lockdown.
I remember first seeing lights like these a couple years back before from CoeLux (https://www.coelux.com), iirc theirs are very expensive though. Awesome that this guy managed to DIY one!