71–80 of 243 posts
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How do you guys go about doing sheet metal design? It looks pretty clean
Thanks! It’s powder coating that gives it a super clean look, great for sales demos but I’d suggest that anything not visible from the room side should be cost optimized
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> So these lamps may look like sunlight, but they’re missing some crucial wavelengths. Which means they're also not going to give me a tan... bug, or feature?
Tan is the other end of the spectrum (UV)
For me, the problem with this setup (and with most high efficiency LED lights) is the lack of red wavelenghts. Real sunlight has a substantial amount of energy in the very red end of the visible spectrum (700 nm) and also of course quite a bit in the infrared. These lamps have two spectral peaks: a narrow peak in the blue range, around 450 nm, a broader peak in the green, centered around 580 nm. That greenish peak fa…
My issue with this setup is that it doesn't emit as many neutrinos as the Sun.
Very cool. I’m the CEO of Innerscene ( https://innerscene.com ) and we make a commercial artificial skylight that uses some of these concepts. Actually the coelux ht25 model is almost identical to what you made but using smaller lenses and more LEDs - however the effect they were able to achieve still isn’t that great, the sun looks like a giant orb and once you get a few feet away you can make out a sun at all. We s…
Please don't have your marketing department destroy the real sun. Doing so would break antitrust regulations.
For me, the problem with this setup (and with most high efficiency LED lights) is the lack of red wavelenghts. Real sunlight has a substantial amount of energy in the very red end of the visible spectrum (700 nm) and also of course quite a bit in the infrared. These lamps have two spectral peaks: a narrow peak in the blue range, around 450 nm, a broader peak in the green, centered around 580 nm. That greenish peak fa…
> So these lamps may look like sunlight, but they’re missing some crucial wavelengths. Which means they're also not going to give me a tan... bug, or feature?
Ah... the intensity, not actual nuclear fusion. Well, still a nice project!
> Kinda cool that you can see a lens flare effect in the shape of the lens grid array.
A lens flare is just a copy of the scene you are photographing, but strongly attenuated in brightness, and possibly rotated 180°.
> 100,000 lux
Your notation is correct, and there are other ways to write it. The SI unit "lux" has the symbol "lx". Your quantity can also be written as 100 kilolux or 100 klx.
I'd be interested in seeing the optical spectrograph of the LEDs. If you want to simulate sunlight you want a full-spectrum LED like a Samsung LM301 series LED which are popular in grow lights. Not all LEDs are created equal, and even the LEDs in many "grow" lights only show two sharp peaks at red and blue wavelengths. A full-spectrum LED will output colors across the visible spectrum of light. You can't tell by look…
For an accurate rendering of the suns spectrum you basically would like to simulate the spectrum of a blackbody radiator with a surface temperature of 5500°C minus the absorption bands of water vapors, atmospheric gases thst are typically inbetween the sun and us. Also note that the suns spectrum extends both above and below the visible range, which gives you the feeling of warmth (infrared) and tan/sunburn (ultraviolet).
In reality most commercially available LEDs still have a extremely spikey spectrum compared to sunlight — this can be somewhat fixed by mixing different LED types and adding filters. But this is only done in extremely expensive movie lights like Arri skypanels.
https://www.youtube.com/watch?v=lH_owRxupC0
This is great video on the shortcomings of "CRI" - it explains in detail CRI, CRI extended, TLCI, TM-30, and SSI.
Brightness and color temperature are only two small parts of lighting - more people should start investigating the utility of taking their own spectroscopy measurements to figure out what lighting works best for them personally. My friends have very, very diverse opinions on what spectral distributions they like/hate, but they lack the language and experience to identify or communicate their preferences except for "Ooh I like/hate this bulb".
I mostly use LED bulbs to keep heat generation down (I pay for the heat twice in Houston: once to generate it and again for the A/C to negate it). But I always mix in a bit of incandescents / halogens (2400-3000K) which provide full-spectrum blackbody radiation to see ALL the wonderful colors in my world.
I saw "artificial sunlight" and thought "oh wow I'd love to see the spectrogram of the lighting solution this person came up with". I was disappointed to merely see "CRI 95+". https://www.youtube.com/watch?v=lH_owRxupC0 This is great video on the shortcomings of "CRI" - it explains in detail CRI, CRI extended, TLCI, TM-30, and SSI. Brightness and color temperature are only two small parts of lighting - more people sh…