Leds aren’t a good source of full spectrum light. Metal hallide bulbs are the way to go. 250-400 ways worth has a fantastic warm glow. Bonus points you can grow stuff under them really well
Building an artificial sun that looks realistic [video]
31–40 of 129 posts
Re: Building an artificial sun that looks realistic [video]
#32If you have access to a broken LED TV or monitor, or in some cases CFC, you can just buy these. Search for "led panel light", and you can find them in all sorts of sizes.
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.
Re: Building an artificial sun that looks realistic [video]
#33Seems like this idea could scale very well with more LEDs of lower wattage, like a local dimming array in TVs. That way
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.
Re: Building an artificial sun that looks realistic [video]
#34Earlier quoted context omitted.
The main issue is the blue scattering. If you can get away with pre-scattering the light before it hits the dish adding an IR lamp is no issue since you're using a parabolic mirror which has no diffraction. I have no idea if it 'feels' right doing that though. For full immersion you would also want a number of different light sources since leds are have very narrow spectra.
The method proposed in the video already accounts for the narrow LED spectra by using lights that have excellent color reproduction (the part where he recommends a CR rating of 95%+)
It's not really good enough: https://www.oscars.org/science-technology/sci-tech-projects/...
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.
Re: Building an artificial sun that looks realistic [video]
#35In 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!
I looked into it for a client's commercial building. $40k each for parts only.
A computer chip costs $1 billion to make.
A billion of them cost $1.1 billion to make.
Re: Building an artificial sun that looks realistic [video]
#36A fun modification would be to add a mask directly in front of the LED to change its shape, for instance to mimic the weird crescent shadow effect that many of us saw during the last solar eclipse. 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.
It looks amazing already, however another fun thing to do will be to vary the light intensity over time to make it more like the sun.
Re: Building an artificial sun that looks realistic [video]
#37How about one for moonlight? My room doesn't have windows, and the nightlights I've tried are too harsh and make it harder to go back to sleep after waking up in the middle of the night.
Re: Building an artificial sun that looks realistic [video]
#38Wow. For some reason I thought it is already product on market with ton of alternatives. Fascinating.
Re: Building an artificial sun that looks realistic [video]
#39A fun modification would be to add a mask directly in front of the LED to change its shape, for instance to mimic the weird crescent shadow effect that many of us saw during the last solar eclipse. 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.
It looks amazing already, however another fun thing to do will be to vary the light intensity over time to make it more like the sun.
Then you need to vary the spectra as well.
Re: Building an artificial sun that looks realistic [video]
#40How about one for moonlight? My room doesn't have windows, and the nightlights I've tried are too harsh and make it harder to go back to sleep after waking up in the middle of the night.
Just change the color temperature and brightness.