Yes, he's biassed. No, that doesn't mean he was lying. The realism is about the subjective experience. If you went into the room, you probably would feel "this isn't bad" before you went to Meh.
https://www.youtube.com/watch?v=aJ4TJ4-kkDw
This light is sold by https://www.coelux.com/. They might also hold the patents on this technology.
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!
https://en.wikipedia.org/wiki/Whittier,_Alaska
> 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.
https://en.wikipedia.org/wiki/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".
https://www.amazon.com/dp/B07T8RDF8F
Might not be as awesome as a $60k CoeLux, but for 1000x less cost, maybe it's worth a shot?
(Edit: come to think of it, with an 8x10 fresnel lens, it might be way too bright for the size.)
https://www.nhs.uk/live-well/healthy-body/how-to-get-vitamin...
>Using sunbeds isn't a recommended way of making vitamin D.
Low dose UV light would also be a good addition.
A billion of them cost $1.1 billion to make.
For full immersion you would also want a number of different light sources since leds are have very narrow spectra.
[0] Applied Photovoltaics, Earthscan Publications, 2007: http://www.eng.uc.edu/~beaucag/Classes/SolarPowerForAfrica/B...
I was looking at building one last winter, but on CraigsList people tend to overestimate the worth of a TV with a broken screen. "Awesome 4K TV, paid $1200 3 months ago, just need to replace broken screen, $250." You gotta talk them out of that with a "A new panel costs more than buying the whole TV."
You can also buy just fresnel lenses on Amazon, but then you gotta build the and line it with foil.
Also, are there fresnel lenses with a much shorter focal length? The dream would be to have something like this in a ≈ 10 cm (4 in) thick picture frame hung on the wall...
The lenses I've seen at EO have focal lengths that aren't much shorter than the side length---20cm for 25cm sheets. I'm pretty sure this is a limitation on the refractive index plus maybe the precision required for steep incidence angles.
And I think they really could be a good option. Unlike the lenses, there would be no chromatic aberration with a reflector, right? Plus, you can set the focal length to whatever you want (taking practicality into account of course).
I might have to try it out...
Honestly for this use case, just sliced and stacked a single dish would give you mostly-collimated light, right? If you put this behind a mild diffuser you could probably still trick your brain unto thinking it's sunlight coming through the curtains.
If my understanding is correct, fresnel lenses effectively operate as a larger lense surface by concentrating light with flat or curved steps getting smaller in size packed towards the core.
https://www.bhphotovideo.com/c/product/592006-REG/Dry_Lam_50...
A Frensel reflector doesn't led light through bit instead reflects the light. Basically the same idea as the parabolic dish, but as a flat sheet.
Ever since I seen it I've become convinced something similar will be part of a future garden office I'm planning. With a IR panel heater to add the warming effect. I was also wondering about whether UVB could be incorporated by but frankly I'd be too chicken to mess with that.
1. heat would be more evenly distributed reducing the need for large heatsinks
2. smaller fresnel lenses could be positioned much closer to the light reducing thickness
3. with a lot of LEDs there'd be a less noticeable grid at the edges of each fresnel lens from chromatic aberration.
I'd totally buy a 'sunlight window' product like this.
Because you also really want the light to come out of the vertical window at something like a 45° angle downwards.
The physics of it should be fine, I've just never heard of them being manufactured.
And then just add a translucent blue diffusing layer on top.
It seems highly commercializable.
I saw it at the Tate Gallery. It was one of the most impressive art installations I have ever witnessed.
It was a semicircle against a mirrored ceiling which is a neat trick to double the effect. People naturally lay on the floor like being on a beach and saw themselves reflected back way overhead.
Some other fun things to do with it would be to point it through some plants in front of a fan to get the filtered-light-through-leaves effect, or to shine it onto moving water.
e.g. has the hormone regulation & vit d synthesis benefits, without the skin damage?
Because it seems like we're getting there: https://www.sciencedaily.com/releases/2017/09/170913193101.h...
The reason that people are deficient is because they don't take enough - the US RDA was shown to be 10x too low, due to an arithmetic error in an ancient paper.
Quality high density, and dense time based living is the way forward for the poor to the rich. Be it sleeping downtown in NY city to working suburbs in Hong Kong. Good for efficiency and this is good for mental health.
This is AR that matters. It's nice work.
It might concentrate RF at the focus to some degree, but only if you put your head right at the focus, and even then it’s almost certainly orders of magnitude less exposure than using a cell phone.
Instead, I ended up buying a string light[0] and a box of 1600lm daylight LED bulbs[1]. Installation sucks, but once the whole thing is up, it’s nice that the light is distributed throughout the room instead of coming from a single point source. It was (at least at the time) cheaper than buying corn lights—and as a bonus, you can swap back the bulbs that come with the string light for party lighting.
[0] https://www.costco.com/feit-electric-48'-led-filament-string...
[1] https://www.costco.com/feit-electric-led-100w-replacement-br...
Luckily, we've stumbled upon Sowilo [2], which advertises powerful RGBWW LED strips with appropriate specs (with per-meter max brightness and power consumption listed), provide all the components you need for powering and driving the strips you need, and best of all provide a Hue-integrated controller! (likely from scavenging an actual Hue LED strip controller!). We've ordered a kit last week, and are eagerly anticipating testing out the ~13000lm of purported light.
[1] https://www.evehome.com/en-us/eve-light-strip [2] https://sowilodesign.com/collections/led-strips
Tangentially, we've picked up 4x GE Ultra Bright [3] at Lowes for $10 each to test out the brightness, and those have been great too.
[3] https://www.lowes.com/pd/GE-Ultra-Bright-150-Watt-EQ-A23-Sof...
But when I look at similar 250W corn bulbs on the Home Depot site they only claim 7,384 lumens: https://www.homedepot.com/p/Halco-Lighting-Technologies-250-...
How is that Amazon bulb producing 5X the lumens?
EDIT: To answer my own question, it's because the Amazon bulb actually uses 250W while the Home Depot product listings are "250W equivalent" and only use ~50W. Hence the 5X difference in light output.
What kelvin did you choose, and how large is your room? Did you put something in front of the lamp to diffuse?
Looking forward to get out of the lockdown slump! :)
How expensive are they in the US?
https://www.ledproff.dk/produkter/11907-kraftige-led-paerer-...
Trustpilot doesn't raise any major red flags, but i don't know the shop, it has "e-maerket" though which is official certification.
13.5K for about 400 usd. So it it must at least be legal in EU? They also have 14.8K if you go up 1 level.
Wait a minute, they also have a swedish shop:
https://www.ledproff.se/led-ljuskallor/11907-kraftfull-led-l...
I'd also like a bit of optional IR so you get a tiny bit of that toasty sun feeling if you want it.
[1]: https://www.kjell.com/se/produkter/el-verktyg/belysning/utom...
Mixing violets and greens makes the spectral curve closer to that of sunlight.
Again, without seeing it in person there is no way to know how much impact this has.
Using a parabolic reflector however is the only way to go since you will not get diffraction or blocking of wavelengths.
https://www.bulletproof.com/supplements/vitamins-minerals/vi... (11 scientific references linked at the bottom)
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.
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.
[1] https://www.alibaba.com/product-detail/Fresnel-lens-plastic-...
Turning Smashed TVs into realistic daylight panels: https://www.youtube.com/watch?v=8JrqH2oOTK4
The satellite dish is more dramatic so I don't blame him for leading with it :)
[1] https://www.walmart.com/ip/Darice-Wooden-Window-Pane-w-6-Pan...
It seems supplements help but randomised controlled trials are needed: https://jamanetwork.com/journals/jamainternalmedicine/fullar...
“Vitamin D supplementation appears to reduce the risk of falls among ambulatory or institutionalized older individuals with stable health by more than 20%” http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.578...
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...
————————————
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.