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I tried making artificial sunlight at home

622 points by fouronnes3 2y ago

softbuilder 2y ago
This is a great build and report. Even though you don't have great photo gear, you should try capturing a picture of steam in the light (as DIY Perks did).
- fouronnes3 2y ago
  That's a great suggestion, thanks! I'll give it a try. It already works with dust quite well though, hehe.
NotGMan 2y ago
Those in dark winter places can check this out for a home bright light setup. Some people report much better mood in dark winter days: https://meaningness.com/sad-light-led-lux https://meaningness.com/sad-light-led-lux https://meaningness.com/sad-light-lumens https://meaningness.com/sad-light-lumens Buy a cheap lux meter if you will be doing this since otherwise you are flying blind.
- astrange 2y ago
  This definitely helps for me, but it's hard to place the lights without glare, since they can't be anywhere that's ever directly in your vision! I'm also a little worried it's going to burn the houseplant near it. But it was a big change; my Silicon Valley apartment has little overhead lighting, and I mostly use Hue lights which just don't get very bright, so it turned out I'd accidentally built a depression cave in the winter.
  - dylan604 2y ago
    Personally, I hate overhead lighting and much prefer lamps or wall sconce type of lighting. I did replace my overhead bulbs with Hue bulbs, but I don't feel the not very bright aspect. My overhead bulbs are most often at 25%. Anything over 50% is just too much for me. I love my Hue lights and am trying to switch over to all Hue bulbs. I still have a few regular bulbs in places that just don't get a lot of use, so they get ignored
  - J_Shelby_J 2y ago
    The 1600 lumen bulbs are worth it - if they fit your fixtures. Still nowhere near as bright as a window on a cloudy day though.
    - astrange 2y ago
      Part of my problem is my place has a lot of windows and is on the ground floor. So those are both good things, but the combination means I have to keep the curtains closed to maintain any privacy. Lighter curtains or something might help.
proudestmonkey 2y ago
This is super cool, and a great project. As someone more on the software side as well, I’m inspired to take on something similar. But more importantly, as someone who rented a windowless room for a year, I would have loved to make a smart light like this to wake up to in the morning.
- fouronnes3 2y ago
  > windowless room Thankfully that's illegal where I live. I'm even tempted to suppress my own work here, because I don't want it to be used to unlock new levels of dystopic housing. Just kidding, thanks for the feedback!
ge96 2y ago
The interactive 3D models are nice
deleted 2y ago
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woah 2y ago
Would it be possible to make it look like the light was coming in at an angle from above and the side like real sunlight?
- fouronnes3 2y ago
  I've given some thought to this, I agree it's one of the obvious improvements. I think with a refractive design like this one it's difficult, because of the way a lens works. Most other projects like this including commercial ones like CoeLux use a reflective design, and I believe that's partly for this reason.
- hinkley 2y ago
  I’ve seen the video he links at the top of the article, a few years back. They took an old satellite dish, silvered the surface, and put a giant LED where the receiver had been so the light produced was nearly parallel. Otherwise the shadows look wrong. In his case he sacrificed a doorway or a closet to make a window with “real light”
  - j_bum 2y ago
    I was thinking of the same video! Link: https://youtu.be/6bqBsHSwPgw?si=nV7nGdRhGvkivc1p https://youtu.be/6bqBsHSwPgw?si=nV7nGdRhGvkivc1p
- ericmcer 2y ago
  There was a project posted here awhile ago with something similar, but the light was larger and he positioned it outside a fake window with a curtain across it.
- goda90 2y ago
  Would moving the box itself help provide that effect? Maybe put it on a track to move throughout the day?
stephenpontes 2y ago
DIY Perks also attempted to make artificial sunlight at home, also focusing on things like Rayleigh scattering! This was a great watch: https://www.youtube.com/watch?v=6bqBsHSwPgw https://www.youtube.com/watch?v=6bqBsHSwPgw EDIT: After reading the article, I see the OP calls out DIY Perks specifically - the OPs design is much more compact :) > It's compact. The total size is 19cm x 19cm x 9cm. This is quite compact for a 5cm focal length and an effective lighting area of 18cm x 18cm. Reflective designs like the DIYPerks video or commercial products like CoeLux do not achieve this form factor.
- this_and_that 2y ago
  If you want a jankier but cheaper version, here's a (much less nice) version for about $50: https://worstplans.com/2021/05/10/led-artificial-skylight-for-cheap/ https://worstplans.com/2021/05/10/led-artificial-skylight-fo... It uses a trash can plus a super-bright LED bulb plus a plastic book magnifier. The main trick is that you can get a big magazine-sized flat plastic fresnel lens for like 10 bucks. The original poster's solution is definitely better, but it's also possible to do this on the cheap with no 3D printing (or in fact, any skills whatsoever).
brcmthrowaway 2y ago
Wait, you can order custom fabrication of lenses online?
- fouronnes3 2y ago
  Turns out you can yeah! I'm not sure the quality would be anything useful for imaging applications though. But for lighting / non-imaging stuff go for it!
  - isoprophlex 2y ago
    Well, there goes my idea of DIYing a telescope...
    - hatthew 2y ago
      DIY telescope discussion on HN 2 weeks ago: https://news.ycombinator.com/item?id=43351988 https://news.ycombinator.com/item?id=43351988
    - dekhn 2y ago
      It's not that hard to find decent lenses. I bought a lens with a long focal length and wide aperture from surplusshed.com and installed it into a PVC tube, then attached my camera to it (no lens). I used it for solar observation- a few times, the focused light ended up melting the tube, part of the camera, and anything else it came in contact with. But it makes more sense to buy a cheap but decent refractor or reflector unless you are truly invested in DIY. there's a lot of fiddly details to get right to get decent image quality.
  - brcmthrowaway 2y ago
    What was the cost details?
- deleted 2y ago
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jclarkcom 2y ago
Very cool. I’m the CEO of Innerscene (https://innerscene.com 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 spent a lot of time working on perfect collimation and hiding lens edges and making sure the view into the sky was seamless and artifact free. I’d say the last 10% of that problem is 90% of the work. :). I think we successfully cracked the nut but currently using a lot of expensive parts so working on brining the cost down. If you search Innerscene patent many of our approaches are spelled out. We also spent a lot of time on simulation and software…
- fouronnes3 2y ago
  Are you hiring? I'm looking for a job currently. Contact info is on my website :)
  - jclarkcom 2y ago
    Let’s chat! Are you the article author?
    - fouronnes3 2y ago
      Yes that's me! Happy to chat :)
      - the_arun 2y ago
        This is a great way to pitch for a job & half the interview is already done.
        johnmcaller 2y ago
        True!
      - 2y ago
huzeifad 2y ago
Great project! Instead of routing ground traces, I would recommend to use a ground plane on the bottom layer of the PCB
Const-me 2y ago
> the main thermal issue when scaling up would be the cooling of the power supply itself, not of the lamp If I would be scaling up that device, I would consider an ATX power supply. These are relatively large and typically include an active cooler inside, but they can easily supply hundreds of watts at 12V, often have an on/off switch on the back, are relatively inexpensive (at least unless you need much more than 500W of power), and are available everywhere. Usually, you just need to connect the PS_ON wire with the ground to make them turn on once powered.
- brcmthrowaway 2y ago
  Could you wire them in parallel for more watts
  - Const-me 2y ago
    Personally, I would avoid it if possible. Even if they are of the same model, small discrepancies may cause their +12V to be slightly different. At the very least, will cause very non-uniform load distribution. Luckily, seems the OP only needs one. The current light only uses 36W @ 12V, even if they make the new light 10x more powerful, a single 400W PSU should do the job nicely.
    - foobarian 2y ago
      It's not like the fixtures consist of a single LED either. Should be trivial to parallelize.
    - brcmthrowaway 2y ago
      What about wiring them in parallel with a voltage regular after.
      - mystified5016 2y ago
        Then you waste a ton of energy on the conversion and still have the same problem. You won't ever get two regulators at exactly the same voltage. One will always take most of the load. You get around this with load balancing resistors, but that comes with its own set of problems. The way you get around that is to chop up your load into multiple independent power domains. That way each segment is powered exclusively by one supply. If you can't do that, you will always be better off with a single larger supply.
petsfed 2y ago
Is there a reason why you went with traces rather than pours? I count 7 signals per board, and they're all meant to be low impedance. You could even expose copper on the back of the board to be used as ad hoc heat sinks without spending any extra money. The weird little triangle loops on the back really stand out to me, even though you probably don't need to worry about the impacts of a loop in your circuit.
- fouronnes3 2y ago
  Thanks for the feedback. Everything I know about PCB design is self-taught. I'm a total beginner, so I'm sure there's a lot to improve! There's only 2 routes per board, VCC and GND. I initially planned for SMD header pins that I didn't end up using, because soldering wire on bare pads was good enough. I also planned for 8 connection pads per PCB, but only used 2 to 4 in the final assembly. So yeah, lots of room for improvements in the PCB design! Definitely would need to spend some time on it for a higher power version 2.
  - zamalek 2y ago
    My first few boards had exactly the same problem, it wasn't mentioned in any of the tutorials that I watched. All you need to do is add a fill region that encloses the whole board, and usually set it to GND. You probably don't need to worry about EMI and EMC with DC, but if you want to make these dimmable you definitely want a ground pour "behind" any high frequency lines. You additionally don't need to worry about that if you aren't manufacturing, but it's still worth learning it the right way IMO. The sig/pwr-gnd-gnd-sig/pwr stack-up is well worth getting into the habit of (it has great EMI characteristics), and translates relatively easily to gnd-sig/pwr-sig/pwr-gnd stack-up once you've nailed down the design (which has amazing EMI characteristics). Rick Hartley made these stack-ups popular (if he didn't outright invent them): https://youtu.be/52fxuRGifLU?si=8W1WXfJRHg3Oeep5 https://youtu.be/52fxuRGifLU?si=8W1WXfJRHg3Oeep5
null_name 2y ago
Really neat, thank you for posting. I took a different angle when trying to figure this out - my goals were high spectral similarity to the sun, high brightness, adjustable warmth, and low cost. The existing lower-cost solutions people have posted about end up with high brightness, but the lights are evil. I ended up with a photography light that's /alright/. It's not nearly as bright as I want, and I can't automate changing the warmth. When I next take a crack at this, I'll look deeper into some of what you've posted about here.
- fouronnes3 2y ago
  Thanks! Feel free to reach out, I love to chat about this stuff. Contact info is on my website.
- deleted 2y ago
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sberens 2y ago
Really cool! I'm working on a lamp that gives you daylight levels of light indoors (albeit no raleigh scattering and columnated light). On the bright side (pun intended), it's 50,000 lumens instead of ~4500. https://getbrighter.com/ https://getbrighter.com/
- polishdude20 2y ago
  Oh this is cool! Reminds me of led grow lights. You can get a panel with hundreds of LEDs on it for growing plants for like $200
- izuchukwu 2y ago
  Had the chance to see one of these in person - did not believe you could achieve “daylight indoors” before I did.
  - reaperman 2y ago
    If you have a chance to chat with the staff again, I notice their marketing language says "Nearly perfect spectrum matching with daylight" - but they don't publish a Spectral Similarity Index. They only claim a (relatively low) CRI of 90+. Edit: In other materials, they claim a very high CRI of 95+. Also the advertised wattage is sometimes 400W, other times 500W.
  - gblargg 2y ago
    I have a 200W LED flood light and it was the most depressing thing to shine indoors. EVERYTHING was covered in dust and filth that you wouldn't see under normal-intensity light. It felt like things had collapsed and I was surveying the remains of someone's house.
- Aeolun 2y ago
  500 watts! I won't need a heater any more if I turn one of these on. I had a 10k lumen led matrix lamp, but I found that it completely threw off my natural rhythm to sit under it for any length of time. It felt like it was perpetually early morning.
- 2y ago
polygot 2y ago
Very cool! I'd be curious to see an HDR version of it using bracketed exposures--it might give a better sense of how it actually looks in person. It seems really bright in the photos, so the shortest exposure would probably need to be very low to capture a good dynamic range for the HDR.
alejohausner 2y ago
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 falls off sharply, and has almost no energy in the red end. The color sensitive cones in our eye have three peaks of sensitivity, the S cones in the blue range, the M cones in the green, and the L cones in yellow. The L cones are what your brain uses to see red colors, but they are actually pretty insensitive to deep reds like 700 nm. That’s why you THINK that LED lamps produce red, because they stimulate your L cones, but they do so without actually emitting much red energy at all! Our bodies are sensitive to deep red light. The cytochrome in our mitochondria respond to it. There’s an experiment where shining red lights on the skin improved sugar metabolism. That makes sense, because we naked apes evolved under red-rich sunlight. So these lamps may look like sunlight, but they’re missing some crucial wavelengths.
- fouronnes3 2y ago
  That's a good point, but not much I can do about that. Such a DIY project is limited to off the shelf LED suppliers. It would be cool to do such a lamp with both the high CRI and some infrared, also for heating (infrared lamps are a thing after all).
  - alejohausner 2y ago
    I don’t think manufacturers will make LEDs with strong deep-red emission. If they made LEDs that emitted lots of red light, they probably would have a peak in the red end of the spectrum. But since they’re not monochromatic single-wavelength sources like lasers, there would be a spread of wavelengths around that red peak, including substantial infrared emission. And that IR emission makes heat, and now you’ve created an inefficient lamp, similar to the old incandescent filament lamps.
    - ajolly 2y ago
ludicrousdispla 2y ago
Nice, Mojang should set one of these up at their headquarters.
vincekerrazzi 2y ago
Honestly this area is so interesting to me because of how incredibly strongly light (or lack thereof) affects in the winter. It also seems to affect me more strongly than most in regards to sleeping patterns. Too much blue light in the evening and bam, brain refuses to sleep until 2am or later. So for me the biggest factor missing in these kinds of projects is a dynamic color temperature. While we get that from products similar to apples adaptive lighting, that’s missing in products like this. It seems we can only really have one or the other. My dream is something like this build but with full adaptive and programmable color temperatures based on time and seasons. Honestly I want to build something like this but my area of expertise is too far into the software domain, and not very far into the hardware or electrical engineering domain.
- fouronnes3 2y ago
  This is the reason I decided to use 4000K instead of the more physically accurate 5400K. I picked a less middle of the day color temperature and closer to evening time, basically. I spent a lot of time looking at LED suppliers and there's quite a range of options in terms of color temperature. Some manufacturers even have 2 color temps on the same LED package, meaning you can sort of do what you describe by mixing two light sources at a distance less than a millimeter. > Honestly I want to build something like this but my area of expertise is too far into the software domain, and not very far into the hardware or electrical engineering domain. That was me last year before starting this project! You'd be surprised what you can achieve with time and effort!
  - vincekerrazzi 2y ago
    Thanks for your response, that’s actually very encouraging. I e definitely spent a lot of time looking at LED suppliers too. Currently my favorite bulbs are the ones that are as you describe- two LEDs, one as high as 6500k and one as low as 2200k and it mixes depending on the state of the dinner. Automateable!
- xandrius 2y ago
  Start small and this goal will give you a nice direction. Don't think you'll be able to do this in 6 months or a year but if you had started doing little electronics/hardware projects 10 years ago, you'd be ready now.
johnea 2y ago
Yea, I can relate. I tried making an artificial Big Bang at home. But my neighbors kept complaining 8-/ Haters! Probably the same people that keep flagging comments on the articles I'm interested in...
- deleted 2y ago
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hubraumhugo 2y ago
That's the most HN headline I've read in a while
14 2y ago
Very cool. I do think the DIY perks version just pops a little nicer but it could also be the photography of the project. But the firm factor if your project is much nicer as well. I think both projects would be better suited for different needs so again very cool. If you had lots of space the diy perks would be the way to go. If you only have a thin wall or ceiling then yours would be best. All in all thanks for posting this.
- fouronnes3 2y ago
  It's partly the photography but definitely the reality as well. Mine is only 0.03m², the DIYPerks parabolic reflector is 1.13m² :) One of my goals was to explore the feasibility and scalability of a refraction based design.
trallnag 2y ago
I've just mounted tons of full spectrum LEDs in my home office. Off the shelf, fairly cheap, easy to replace. My plants like it, except for the Goeppertias that keep dying on me
davidw 2y ago
Ah... the intensity, not actual nuclear fusion. Well, still a nice project!
- simonebrunozzi 2y ago
  At first I thought the same! Well, we're safer now.
Molitor5901 2y ago
Sunrise alarm clock lamps are a really great way to wake up, especially if you have a larger room.
spl757 2y ago
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 looking at them, so you can either buy ones from which you trust the manufacturer or do what I did and build a cheap optical spectroscope using a raspberry pi with a small camera attached, a spectroscope lens, and some python code. I'm sure there are guides you can find with a quick web search if interested in making one.
- atoav 2y ago
  This is covered by the CRI95+ value, note that the LM301 you mentioned only has a color rendering index of 70. Maybe it has predominant wavelengths that are relevant for plant growth, I don't know, but a CRI of 70 isn't impressive at all. 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.
  - spl757 2y ago
    Thanks for the insight. Most of what I know about LEDs, and specifically the LM301 series, comes from research I did prior to setting up a small indoor grow tent several years ago. It was a "spikey spectrum" precisely that I was trying to avoid. For growing Cannabis you do want spikes at red and blue, but better LEDs also emit a wider spectrum along with the spikes and that results in a better result. Having only spikes at red and blue alone works, but not as well. The lights I ended up buying had LM301H EVO LEDs with a CRI of 80 and were designed for a 2'x2' tent. You can also get LM301H LEDs with a CRI of up to 90, though. The lights I ended up buying only cost 80 BezosBucks at the time. I don't spend BezosBucks anymore, though, due to enshittification of everything Amazon, but I digress. While they aren't designed for growing, and to use them would be a complete waste of $8k, I bet the Arri SkyPanel S120-C SoftLight with a CRI of 95 would do a fine job for growing. You weren't kidding about them being extremely expensive.
nayuki 2y ago
Nice project. A few miscellaneous notes: > 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.
reaperman 2y ago
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 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.
- kulahan 2y ago
  I think most people at least know the difference between warm and cool light, which helps a lot, but otherwise I agree. As I’m reading this, I’m realizing I have no vocabulary for this topic. That’s… kinda strange to experience!
- fouronnes3 2y ago
  Do you have any insight on how to take spectroscopy measurements at home on a <1k€ budget? And how to select an LED manufacturing supplier when CRI is often the only thing available on the datasheet?
  - reaperman 2y ago
    Starting points for first question: Look into i1Pro (later models of the first generation), which can be had for $200-400. Combine with some free or $99 Windows/Mac/Android software [0] [1]. Second question: It is still too hard even to find CRI for most offerings. It's pretty much a "buy, test, return the ones you don't like" situation. If independent reviewers start publishing spectrograms and making YouTube/etc videos, perhaps the industry will move forward some day. 0: https://www.argyllcms.com/doc/instruments.html#i1p2 https://www.argyllcms.com/doc/instruments.html#i1p2 1: https://rmimaging.com/spectrashop_brochure.pdf https://rmimaging.com/spectrashop_brochure.pdf
Vox_Leone 2y ago
This project is fantastic, but you also deserve congrats for the 'Lens Maker'[0]. "If we have a compound optical system made of a series of lenses, mirrors, etc., we can treat each optical element as the layer of a neural network." Kudos. [0]https://victorpoughon.github.io/torchlensmaker/ https://victorpoughon.github.io/torchlensmaker/
dekhn 2y ago
Projects like this are a great demonstration of just how far hobby projects can go today by exploiting some fairly recent innovations. In particular, designing a custom lens geometry and having JLC manufacture small runs cheaply is especially impressive; and of course, what you can get out of a modern LED is just absurd.
- fouronnes3 2y ago
  I agree, thanks for underlying that point. I did not intend to write an ad for JLCPCB, but honestly I kinda did. I feel like it's deserved praise because the service is really great. Low volume custom PCBs with assembly service and 5 axis CNC with a minimum order quantity of 1 is game changer for prototyping. Combined with a software first approach to design with tools like build123d, the flexibility of 3D printing and 5 axis CNC, and the addictiveness of the high dopamine feedback loop of software dev starts to bleed over to hardware dev. Shipping delay is the last hurdle. About the lenses, I did consider injection molding during design, and one supplier even quoted me for $20,000. So yeah, very glad for JLC!
MrMcCall 2y ago
Years ago, I remember seeing that a firm was using fiber optic bundles to bring sunlight in from the roof into the inner spaces of an office building. Does anyone know anything about that?
- ecolonsmak 2y ago
  I've been tracking that on and off for years - https://parans.com/ https://parans.com/ Not sure it's really caught on, but it's out there
  - MrMcCall 2y ago
    Thanks! That looks like it. I wonder what the light's spectra and intensity are. I'm guessing that its cost is prohibitive, or maybe the light's characteristics are just not so great. I'd love to be able to do some low-intensity tanning at home, for vitamin D and skin health. Thanks a ton.
softgrow 2y ago
I built a very bright light source using a lamp stand from Ikea and the brightest, narrowest beam LED reflector I could find from my big box hardware store. The project works and gave about 10,000 lux but had a few drawbacks. After reading a book for a while a got a headache. The slightest imperfection (read dirt) in the arms of the armchair becomes super obvious. When I look at my right arm holding the book, it's so bright I'm sure I can see veins and arteries. I ended up getting a lamp less bright and that's great for sewing/electronics/fine work but there are limits for how bright you might want to go indoors. I kept the too bright globe for demonstration purposes.
- greg9381 2y ago
  Why did you want a very narrow beam? It seems like the opposite of what you would want from a lamp but I think I'm misunderstanding. And do you have the name of the less bright lamp you got?
- mr_toad 2y ago
  Sunlight can be 3-10 times that bright. No wonder the outdoors looks so dirty.
- jannyfer 2y ago
  The headache could have been from LED flicker. I bought a corn cob LED bulb and it had some high frequency flicker that was visible when using a camera with no anti-flicker compensation.
Wistar 2y ago
I cannot remember if I first saw this here on HN but, here is a detailed video of an incredible artificial sunlight rig build. It's big but the results look, well, amazingly real, at least to the camera. https://www.youtube.com/watch?v=6bqBsHSwPgw https://www.youtube.com/watch?v=6bqBsHSwPgw
- actionfromafar 2y ago
  This is what immediately came to mind.
- ANighRaisin 2y ago
  This was referenced in the article.
  - Wistar 2y ago
    Yeah, and right up front, too. I noticed that only after it was too late to delete my comment.
wmanley 2y ago
Really cool. Did you consider using hexagonal lenses? It seems like they would tessellate, while being closer to being circular.
ANighRaisin 2y ago
Cool, but you can get brightness enhancement film for very cheap in AliExpress: https://www.aliexpress.com/i/2255799825024246.html https://www.aliexpress.com/i/2255799825024246.html The brightness enhancement film is a transparent optical film. It consists of a three-layer structure. The bottom layer of the light-incident surface needs to provide a certain degree of haze by back coating, the middle layer is a transparent PET substrate layer, and the upper layer of light-emitting cotton. It is a microprism structure. When the microprism layer passes through the fine prism structure of the surface layer, the light intensity distribution is controlled by refraction, total reflection, light accumulation, etc., and the light scattered by the light source is concentrated toward the front side, and the unused light outside the viewing angle passes through the light. So, it's similar to your design, but the grooves are very small.
- fouronnes3 2y ago
  I wasn't aware this existed, thanks! Very interesting.
Havoc 2y ago
Toyed with making lights from loose smd LEDs too. Hit thermal issues pretty fast unfortunately. They get really hot when you drive them hard
neilv 2y ago
It you put out enough light, you can diffuse it more, such as by bouncing off the ceiling or a light-colored wall. You can also use photography modifiers, like the various kinds of reflectors. Even white photo lighting umbrellas (which you shine a bright light through) help a lot. Whether or not you add diffusing, you might want to make your light source mountable on a photo studio light stand, so that you can position and aim it however you want (just like you would with a studio strobe or hotlight).
mac-mc 2y ago
I did something similar last year, but I was more focused on spectrum and used high powered movie lights, since their spectrum output is much better and you get a lot of lux. You can get most of the parallel light ray effect by adding a hyperrefelector which conveniently comes with most lights. I then added an incandescent heat lamp to fill in the IR part of the spectrum and some dedicated UV LED lights for the UVA part. I'm not brave enough to put in a UVB specific lamp. I wrote about it here: https://metrep.substack.com/p/improve-your-focus-productivity-and https://metrep.substack.com/p/improve-your-focus-productivit...
jedbrooke 2y ago
I've been down the artificial sunlight at home rabbit hole too (also inspired by the same DIY Perks video). Ultimately the solution I settled on was a much lower budget 300W equiv LED Corn style bulb (4000lm) with good CRI, and a 250w incandescent heat lamp (like you'd get for a reptile). I decided to focus on heat from the light source rather than the parallel rays. Total cost was around $75 (LEDs were $25 for 2, heat lamp was $10 for 2, plus $20 each for 2 lamp stands that clamp to a desk and can support 250 watts).
dave333 2y ago
Are you aware of Brilliant Light Power and their Suncell (R)? See https://brilliantlightpower.com/plasma-video/ https://brilliantlightpower.com/plasma-video/ and scroll down to the February 10, 2023 COMMERCIAL SUNCELL® INITIAL SHAKEDOWN video.
ashoeafoot 2y ago
Idiotic question, but can you have an "angled mode" that lets the godray travel during the day, following the real suns position, given the location and mounting direction of the light?
KolibriFly 2y ago
This is one of the most satisfying DIY reads I've seen in a while. I love how you approached this as a software dev and essentially built a full stack for hardware iteration.
mleroy 2y ago
I’ve been thinking about the potential benefits of incorporating something like this into VR headsets. Since VR already controls the user’s visual perception, would adding a high-intensity blue light (not via the OLED displays but indirectly) allow for a more effective way to simulate bright daylight conditions? Achieving 10,000 lux at the eye would be much easier this way.
Gud 2y ago
There already exists a fairly good replica of sunlight, Philips CDM. I used it when I was growing weed, lushest bushes I’ve ever seen. 10/10 buds. It was discontinued for a while but I’m happy to see it’s back in production? https://www.futuregarden.co.uk/philips-ceramic-discharge-metal-halide-cdm-315w-lamps https://www.futuregarden.co.uk/philips-ceramic-discharge-met... I would pick a CDM bulb any day over the alternatives, including LED, unless power consumption is an issue. “ Philips daylight CDM lamps are extremely efficient ceramic metal halide lamps with a spectral output close to natural sunlight. As a result, plants form more lateral branches, have smaller inter-nodal spacing, more flowering sites, and larger root systems, culminating in strong, healthy growth and high-quality yields. Philips CDM bulbs have an amazing operating life. They maintain their high output for a lifespan of 30,000hrs on average.”
- z3t4 2y ago
  What is the lifetime before you have to replace it?
  - Gud 2y ago
    30,000 hours. Which amounts to 3,4 years of 24/7 operation. I replaced my HPS/MH setup with a CMH light and used it for a few harvests. Never had any issue.
rbanffy 2y ago
Is there any reasonable tool to design fresnel lens for this? They'd be slightly more compact.
lo_fye 2y ago
I remembered seeing, loving, and saving that original DIY Sunlight video back when it first came out, and I went to your article hoping for more, and that's what you gave us. Brilliant job, and thanks for sharing!
jrklabs_com 2y ago
https://store.yujiintl.com/ https://store.yujiintl.com/ has broad spectrum LEDs/lamps/fake skylights that may also appeal to others interested in the OP--just noticed Yuji was mentioned in OP. I'm not affiliated with Yuji but have ordered some of their products and been very happy with their performance.
yohbho 2y ago
From the first videos, I thought this as a one meter square, or larger. 500 W of luminosity in such a small package, as it turns out, seems close to a thermal limit, even with 90+% efficiency.
- jclarkcom 2y ago
  how does this compare with heat dissipated per square cm when you compare with desktop CPUs?
ape4 2y ago
Might be useful for psoriasis treatment?
- romanzubenko 2y ago
  What’s the mechanism for sunlight/artificial light psoriasis treatment?
dfawcus 2y ago
He's doing it wrong, the obvious approach being to extract sunbeams from cucumbers! :-)
valunord 2y ago
I would be more interested in making a SUNSET sunlight vs regular sunlight. That would be actually amazing.

622 points by fouronnes3 2y ago

This is a great build and report. Even though you don't have great photo gear, you should try capturing a picture of steam in the light (as DIY Perks did).

fouronnes3 2y ago
That's a great suggestion, thanks! I'll give it a try. It already works with dust quite well though, hehe.

NotGMan 2y ago

Those in dark winter places can check this out for a home bright light setup. Some people report much better mood in dark winter days: https://meaningness.com/sad-light-led-lux https://meaningness.com/sad-light-led-lux https://meaningness.com/sad-light-lumens https://meaningness.com/sad-light-lumens Buy a cheap lux meter if you will be doing this since otherwise you are flying blind.

astrange 2y ago
This definitely helps for me, but it's hard to place the lights without glare, since they can't be anywhere that's ever directly in your vision! I'm also a little worried it's going to burn the houseplant near it. But it was a big change; my Silicon Valley apartment has little overhead lighting, and I mostly use Hue lights which just don't get very bright, so it turned out I'd accidentally built a depression cave in the winter.
- dylan604 2y ago
  Personally, I hate overhead lighting and much prefer lamps or wall sconce type of lighting. I did replace my overhead bulbs with Hue bulbs, but I don't feel the not very bright aspect. My overhead bulbs are most often at 25%. Anything over 50% is just too much for me. I love my Hue lights and am trying to switch over to all Hue bulbs. I still have a few regular bulbs in places that just don't get a lot of use, so they get ignored
- J_Shelby_J 2y ago
  The 1600 lumen bulbs are worth it - if they fit your fixtures. Still nowhere near as bright as a window on a cloudy day though.
  - astrange 2y ago
    Part of my problem is my place has a lot of windows and is on the ground floor. So those are both good things, but the combination means I have to keep the curtains closed to maintain any privacy. Lighter curtains or something might help.

proudestmonkey 2y ago

This is super cool, and a great project. As someone more on the software side as well, I’m inspired to take on something similar. But more importantly, as someone who rented a windowless room for a year, I would have loved to make a smart light like this to wake up to in the morning.

fouronnes3 2y ago
> windowless room Thankfully that's illegal where I live. I'm even tempted to suppress my own work here, because I don't want it to be used to unlock new levels of dystopic housing. Just kidding, thanks for the feedback!

ge96 2y ago

The interactive 3D models are nice

deleted 2y ago

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woah 2y ago

Would it be possible to make it look like the light was coming in at an angle from above and the side like real sunlight?

fouronnes3 2y ago
I've given some thought to this, I agree it's one of the obvious improvements. I think with a refractive design like this one it's difficult, because of the way a lens works. Most other projects like this including commercial ones like CoeLux use a reflective design, and I believe that's partly for this reason.
hinkley 2y ago
I’ve seen the video he links at the top of the article, a few years back. They took an old satellite dish, silvered the surface, and put a giant LED where the receiver had been so the light produced was nearly parallel. Otherwise the shadows look wrong. In his case he sacrificed a doorway or a closet to make a window with “real light”
- j_bum 2y ago
  I was thinking of the same video! Link: https://youtu.be/6bqBsHSwPgw?si=nV7nGdRhGvkivc1p https://youtu.be/6bqBsHSwPgw?si=nV7nGdRhGvkivc1p
ericmcer 2y ago
There was a project posted here awhile ago with something similar, but the light was larger and he positioned it outside a fake window with a curtain across it.
goda90 2y ago
Would moving the box itself help provide that effect? Maybe put it on a track to move throughout the day?

stephenpontes 2y ago

DIY Perks also attempted to make artificial sunlight at home, also focusing on things like Rayleigh scattering! This was a great watch: https://www.youtube.com/watch?v=6bqBsHSwPgw https://www.youtube.com/watch?v=6bqBsHSwPgw EDIT: After reading the article, I see the OP calls out DIY Perks specifically - the OPs design is much more compact :) > It's compact. The total size is 19cm x 19cm x 9cm. This is quite compact for a 5cm focal length and an effective lighting area of 18cm x 18cm. Reflective designs like the DIYPerks video or commercial products like CoeLux do not achieve this form factor.

this_and_that 2y ago
If you want a jankier but cheaper version, here's a (much less nice) version for about $50: https://worstplans.com/2021/05/10/led-artificial-skylight-for-cheap/ https://worstplans.com/2021/05/10/led-artificial-skylight-fo... It uses a trash can plus a super-bright LED bulb plus a plastic book magnifier. The main trick is that you can get a big magazine-sized flat plastic fresnel lens for like 10 bucks. The original poster's solution is definitely better, but it's also possible to do this on the cheap with no 3D printing (or in fact, any skills whatsoever).

brcmthrowaway 2y ago

Wait, you can order custom fabrication of lenses online?

fouronnes3 2y ago
Turns out you can yeah! I'm not sure the quality would be anything useful for imaging applications though. But for lighting / non-imaging stuff go for it!
- isoprophlex 2y ago
  Well, there goes my idea of DIYing a telescope...
  - hatthew 2y ago
    DIY telescope discussion on HN 2 weeks ago: https://news.ycombinator.com/item?id=43351988 https://news.ycombinator.com/item?id=43351988
  - dekhn 2y ago
    It's not that hard to find decent lenses. I bought a lens with a long focal length and wide aperture from surplusshed.com and installed it into a PVC tube, then attached my camera to it (no lens). I used it for solar observation- a few times, the focused light ended up melting the tube, part of the camera, and anything else it came in contact with. But it makes more sense to buy a cheap but decent refractor or reflector unless you are truly invested in DIY. there's a lot of fiddly details to get right to get decent image quality.
- brcmthrowaway 2y ago
  What was the cost details?
deleted 2y ago
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jclarkcom 2y ago

Very cool. I’m the CEO of Innerscene (https://innerscene.com 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 spent a lot of time working on perfect collimation and hiding lens edges and making sure the view into the sky was seamless and artifact free. I’d say the last 10% of that problem is 90% of the work. :). I think we successfully cracked the nut but currently using a lot of expensive parts so working on brining the cost down. If you search Innerscene patent many of our approaches are spelled out. We also spent a lot of time on simulation and software…

fouronnes3 2y ago
Are you hiring? I'm looking for a job currently. Contact info is on my website :)
- jclarkcom 2y ago
  Let’s chat! Are you the article author?
  - fouronnes3 2y ago
    Yes that's me! Happy to chat :)
    - the_arun 2y ago
      This is a great way to pitch for a job & half the interview is already done.
      - johnmcaller 2y ago
        True!
    - 2y ago

huzeifad 2y ago

Great project! Instead of routing ground traces, I would recommend to use a ground plane on the bottom layer of the PCB

Const-me 2y ago

> the main thermal issue when scaling up would be the cooling of the power supply itself, not of the lamp If I would be scaling up that device, I would consider an ATX power supply. These are relatively large and typically include an active cooler inside, but they can easily supply hundreds of watts at 12V, often have an on/off switch on the back, are relatively inexpensive (at least unless you need much more than 500W of power), and are available everywhere. Usually, you just need to connect the PS_ON wire with the ground to make them turn on once powered.

brcmthrowaway 2y ago
Could you wire them in parallel for more watts
- Const-me 2y ago
  Personally, I would avoid it if possible. Even if they are of the same model, small discrepancies may cause their +12V to be slightly different. At the very least, will cause very non-uniform load distribution. Luckily, seems the OP only needs one. The current light only uses 36W @ 12V, even if they make the new light 10x more powerful, a single 400W PSU should do the job nicely.
  - foobarian 2y ago
    It's not like the fixtures consist of a single LED either. Should be trivial to parallelize.
  - brcmthrowaway 2y ago
    What about wiring them in parallel with a voltage regular after.
    - mystified5016 2y ago
      Then you waste a ton of energy on the conversion and still have the same problem. You won't ever get two regulators at exactly the same voltage. One will always take most of the load. You get around this with load balancing resistors, but that comes with its own set of problems. The way you get around that is to chop up your load into multiple independent power domains. That way each segment is powered exclusively by one supply. If you can't do that, you will always be better off with a single larger supply.

petsfed 2y ago

Is there a reason why you went with traces rather than pours? I count 7 signals per board, and they're all meant to be low impedance. You could even expose copper on the back of the board to be used as ad hoc heat sinks without spending any extra money. The weird little triangle loops on the back really stand out to me, even though you probably don't need to worry about the impacts of a loop in your circuit.

fouronnes3 2y ago
Thanks for the feedback. Everything I know about PCB design is self-taught. I'm a total beginner, so I'm sure there's a lot to improve! There's only 2 routes per board, VCC and GND. I initially planned for SMD header pins that I didn't end up using, because soldering wire on bare pads was good enough. I also planned for 8 connection pads per PCB, but only used 2 to 4 in the final assembly. So yeah, lots of room for improvements in the PCB design! Definitely would need to spend some time on it for a higher power version 2.
- zamalek 2y ago
  My first few boards had exactly the same problem, it wasn't mentioned in any of the tutorials that I watched. All you need to do is add a fill region that encloses the whole board, and usually set it to GND. You probably don't need to worry about EMI and EMC with DC, but if you want to make these dimmable you definitely want a ground pour "behind" any high frequency lines. You additionally don't need to worry about that if you aren't manufacturing, but it's still worth learning it the right way IMO. The sig/pwr-gnd-gnd-sig/pwr stack-up is well worth getting into the habit of (it has great EMI characteristics), and translates relatively easily to gnd-sig/pwr-sig/pwr-gnd stack-up once you've nailed down the design (which has amazing EMI characteristics). Rick Hartley made these stack-ups popular (if he didn't outright invent them): https://youtu.be/52fxuRGifLU?si=8W1WXfJRHg3Oeep5 https://youtu.be/52fxuRGifLU?si=8W1WXfJRHg3Oeep5

null_name 2y ago

Really neat, thank you for posting. I took a different angle when trying to figure this out - my goals were high spectral similarity to the sun, high brightness, adjustable warmth, and low cost. The existing lower-cost solutions people have posted about end up with high brightness, but the lights are evil. I ended up with a photography light that's /alright/. It's not nearly as bright as I want, and I can't automate changing the warmth. When I next take a crack at this, I'll look deeper into some of what you've posted about here.

fouronnes3 2y ago
Thanks! Feel free to reach out, I love to chat about this stuff. Contact info is on my website.
deleted 2y ago
[deleted]

sberens 2y ago

Really cool! I'm working on a lamp that gives you daylight levels of light indoors (albeit no raleigh scattering and columnated light). On the bright side (pun intended), it's 50,000 lumens instead of ~4500. https://getbrighter.com/ https://getbrighter.com/

polishdude20 2y ago
Oh this is cool! Reminds me of led grow lights. You can get a panel with hundreds of LEDs on it for growing plants for like $200
izuchukwu 2y ago
Had the chance to see one of these in person - did not believe you could achieve “daylight indoors” before I did.
- reaperman 2y ago
  If you have a chance to chat with the staff again, I notice their marketing language says "Nearly perfect spectrum matching with daylight" - but they don't publish a Spectral Similarity Index. They only claim a (relatively low) CRI of 90+. Edit: In other materials, they claim a very high CRI of 95+. Also the advertised wattage is sometimes 400W, other times 500W.
- gblargg 2y ago
  I have a 200W LED flood light and it was the most depressing thing to shine indoors. EVERYTHING was covered in dust and filth that you wouldn't see under normal-intensity light. It felt like things had collapsed and I was surveying the remains of someone's house.
Aeolun 2y ago
500 watts! I won't need a heater any more if I turn one of these on. I had a 10k lumen led matrix lamp, but I found that it completely threw off my natural rhythm to sit under it for any length of time. It felt like it was perpetually early morning.
2y ago

polygot 2y ago

Very cool! I'd be curious to see an HDR version of it using bracketed exposures--it might give a better sense of how it actually looks in person. It seems really bright in the photos, so the shortest exposure would probably need to be very low to capture a good dynamic range for the HDR.

alejohausner 2y ago

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 falls off sharply, and has almost no energy in the red end. The color sensitive cones in our eye have three peaks of sensitivity, the S cones in the blue range, the M cones in the green, and the L cones in yellow. The L cones are what your brain uses to see red colors, but they are actually pretty insensitive to deep reds like 700 nm. That’s why you THINK that LED lamps produce red, because they stimulate your L cones, but they do so without actually emitting much red energy at all! Our bodies are sensitive to deep red light. The cytochrome in our mitochondria respond to it. There’s an experiment where shining red lights on the skin improved sugar metabolism. That makes sense, because we naked apes evolved under red-rich sunlight. So these lamps may look like sunlight, but they’re missing some crucial wavelengths.

fouronnes3 2y ago
That's a good point, but not much I can do about that. Such a DIY project is limited to off the shelf LED suppliers. It would be cool to do such a lamp with both the high CRI and some infrared, also for heating (infrared lamps are a thing after all).
- alejohausner 2y ago
  I don’t think manufacturers will make LEDs with strong deep-red emission. If they made LEDs that emitted lots of red light, they probably would have a peak in the red end of the spectrum. But since they’re not monochromatic single-wavelength sources like lasers, there would be a spread of wavelengths around that red peak, including substantial infrared emission. And that IR emission makes heat, and now you’ve created an inefficient lamp, similar to the old incandescent filament lamps.
  - ajolly 2y ago

ludicrousdispla 2y ago

Nice, Mojang should set one of these up at their headquarters.

vincekerrazzi 2y ago

Honestly this area is so interesting to me because of how incredibly strongly light (or lack thereof) affects in the winter. It also seems to affect me more strongly than most in regards to sleeping patterns. Too much blue light in the evening and bam, brain refuses to sleep until 2am or later. So for me the biggest factor missing in these kinds of projects is a dynamic color temperature. While we get that from products similar to apples adaptive lighting, that’s missing in products like this. It seems we can only really have one or the other. My dream is something like this build but with full adaptive and programmable color temperatures based on time and seasons. Honestly I want to build something like this but my area of expertise is too far into the software domain, and not very far into the hardware or electrical engineering domain.

fouronnes3 2y ago
This is the reason I decided to use 4000K instead of the more physically accurate 5400K. I picked a less middle of the day color temperature and closer to evening time, basically. I spent a lot of time looking at LED suppliers and there's quite a range of options in terms of color temperature. Some manufacturers even have 2 color temps on the same LED package, meaning you can sort of do what you describe by mixing two light sources at a distance less than a millimeter. > Honestly I want to build something like this but my area of expertise is too far into the software domain, and not very far into the hardware or electrical engineering domain. That was me last year before starting this project! You'd be surprised what you can achieve with time and effort!
- vincekerrazzi 2y ago
  Thanks for your response, that’s actually very encouraging. I e definitely spent a lot of time looking at LED suppliers too. Currently my favorite bulbs are the ones that are as you describe- two LEDs, one as high as 6500k and one as low as 2200k and it mixes depending on the state of the dinner. Automateable!
xandrius 2y ago
Start small and this goal will give you a nice direction. Don't think you'll be able to do this in 6 months or a year but if you had started doing little electronics/hardware projects 10 years ago, you'd be ready now.

johnea 2y ago

Yea, I can relate. I tried making an artificial Big Bang at home. But my neighbors kept complaining 8-/ Haters! Probably the same people that keep flagging comments on the articles I'm interested in...

deleted 2y ago
[deleted]

hubraumhugo 2y ago

That's the most HN headline I've read in a while

14 2y ago

Very cool. I do think the DIY perks version just pops a little nicer but it could also be the photography of the project. But the firm factor if your project is much nicer as well. I think both projects would be better suited for different needs so again very cool. If you had lots of space the diy perks would be the way to go. If you only have a thin wall or ceiling then yours would be best. All in all thanks for posting this.

fouronnes3 2y ago
It's partly the photography but definitely the reality as well. Mine is only 0.03m², the DIYPerks parabolic reflector is 1.13m² :) One of my goals was to explore the feasibility and scalability of a refraction based design.

trallnag 2y ago

I've just mounted tons of full spectrum LEDs in my home office. Off the shelf, fairly cheap, easy to replace. My plants like it, except for the Goeppertias that keep dying on me

davidw 2y ago

Ah... the intensity, not actual nuclear fusion. Well, still a nice project!

simonebrunozzi 2y ago
At first I thought the same! Well, we're safer now.

Molitor5901 2y ago

Sunrise alarm clock lamps are a really great way to wake up, especially if you have a larger room.

spl757 2y ago

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 looking at them, so you can either buy ones from which you trust the manufacturer or do what I did and build a cheap optical spectroscope using a raspberry pi with a small camera attached, a spectroscope lens, and some python code. I'm sure there are guides you can find with a quick web search if interested in making one.

atoav 2y ago
This is covered by the CRI95+ value, note that the LM301 you mentioned only has a color rendering index of 70. Maybe it has predominant wavelengths that are relevant for plant growth, I don't know, but a CRI of 70 isn't impressive at all. 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.
- spl757 2y ago
  Thanks for the insight. Most of what I know about LEDs, and specifically the LM301 series, comes from research I did prior to setting up a small indoor grow tent several years ago. It was a "spikey spectrum" precisely that I was trying to avoid. For growing Cannabis you do want spikes at red and blue, but better LEDs also emit a wider spectrum along with the spikes and that results in a better result. Having only spikes at red and blue alone works, but not as well. The lights I ended up buying had LM301H EVO LEDs with a CRI of 80 and were designed for a 2'x2' tent. You can also get LM301H LEDs with a CRI of up to 90, though. The lights I ended up buying only cost 80 BezosBucks at the time. I don't spend BezosBucks anymore, though, due to enshittification of everything Amazon, but I digress. While they aren't designed for growing, and to use them would be a complete waste of $8k, I bet the Arri SkyPanel S120-C SoftLight with a CRI of 95 would do a fine job for growing. You weren't kidding about them being extremely expensive.

nayuki 2y ago

Nice project. A few miscellaneous notes: > 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.

reaperman 2y ago

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 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.

kulahan 2y ago
I think most people at least know the difference between warm and cool light, which helps a lot, but otherwise I agree. As I’m reading this, I’m realizing I have no vocabulary for this topic. That’s… kinda strange to experience!
fouronnes3 2y ago
Do you have any insight on how to take spectroscopy measurements at home on a <1k€ budget? And how to select an LED manufacturing supplier when CRI is often the only thing available on the datasheet?
- reaperman 2y ago
  Starting points for first question: Look into i1Pro (later models of the first generation), which can be had for $200-400. Combine with some free or $99 Windows/Mac/Android software [0] [1]. Second question: It is still too hard even to find CRI for most offerings. It's pretty much a "buy, test, return the ones you don't like" situation. If independent reviewers start publishing spectrograms and making YouTube/etc videos, perhaps the industry will move forward some day. 0: https://www.argyllcms.com/doc/instruments.html#i1p2 https://www.argyllcms.com/doc/instruments.html#i1p2 1: https://rmimaging.com/spectrashop_brochure.pdf https://rmimaging.com/spectrashop_brochure.pdf

Vox_Leone 2y ago

This project is fantastic, but you also deserve congrats for the 'Lens Maker'[0]. "If we have a compound optical system made of a series of lenses, mirrors, etc., we can treat each optical element as the layer of a neural network." Kudos. [0]https://victorpoughon.github.io/torchlensmaker/ https://victorpoughon.github.io/torchlensmaker/

dekhn 2y ago

Projects like this are a great demonstration of just how far hobby projects can go today by exploiting some fairly recent innovations. In particular, designing a custom lens geometry and having JLC manufacture small runs cheaply is especially impressive; and of course, what you can get out of a modern LED is just absurd.

fouronnes3 2y ago
I agree, thanks for underlying that point. I did not intend to write an ad for JLCPCB, but honestly I kinda did. I feel like it's deserved praise because the service is really great. Low volume custom PCBs with assembly service and 5 axis CNC with a minimum order quantity of 1 is game changer for prototyping. Combined with a software first approach to design with tools like build123d, the flexibility of 3D printing and 5 axis CNC, and the addictiveness of the high dopamine feedback loop of software dev starts to bleed over to hardware dev. Shipping delay is the last hurdle. About the lenses, I did consider injection molding during design, and one supplier even quoted me for $20,000. So yeah, very glad for JLC!

MrMcCall 2y ago

Years ago, I remember seeing that a firm was using fiber optic bundles to bring sunlight in from the roof into the inner spaces of an office building. Does anyone know anything about that?

ecolonsmak 2y ago
I've been tracking that on and off for years - https://parans.com/ https://parans.com/ Not sure it's really caught on, but it's out there
- MrMcCall 2y ago
  Thanks! That looks like it. I wonder what the light's spectra and intensity are. I'm guessing that its cost is prohibitive, or maybe the light's characteristics are just not so great. I'd love to be able to do some low-intensity tanning at home, for vitamin D and skin health. Thanks a ton.

softgrow 2y ago

I built a very bright light source using a lamp stand from Ikea and the brightest, narrowest beam LED reflector I could find from my big box hardware store. The project works and gave about 10,000 lux but had a few drawbacks. After reading a book for a while a got a headache. The slightest imperfection (read dirt) in the arms of the armchair becomes super obvious. When I look at my right arm holding the book, it's so bright I'm sure I can see veins and arteries. I ended up getting a lamp less bright and that's great for sewing/electronics/fine work but there are limits for how bright you might want to go indoors. I kept the too bright globe for demonstration purposes.

greg9381 2y ago
Why did you want a very narrow beam? It seems like the opposite of what you would want from a lamp but I think I'm misunderstanding. And do you have the name of the less bright lamp you got?
mr_toad 2y ago
Sunlight can be 3-10 times that bright. No wonder the outdoors looks so dirty.
jannyfer 2y ago
The headache could have been from LED flicker. I bought a corn cob LED bulb and it had some high frequency flicker that was visible when using a camera with no anti-flicker compensation.

Wistar 2y ago

I cannot remember if I first saw this here on HN but, here is a detailed video of an incredible artificial sunlight rig build. It's big but the results look, well, amazingly real, at least to the camera. https://www.youtube.com/watch?v=6bqBsHSwPgw https://www.youtube.com/watch?v=6bqBsHSwPgw

actionfromafar 2y ago
This is what immediately came to mind.
ANighRaisin 2y ago
This was referenced in the article.
- Wistar 2y ago
  Yeah, and right up front, too. I noticed that only after it was too late to delete my comment.

wmanley 2y ago

Really cool. Did you consider using hexagonal lenses? It seems like they would tessellate, while being closer to being circular.

ANighRaisin 2y ago

Cool, but you can get brightness enhancement film for very cheap in AliExpress: https://www.aliexpress.com/i/2255799825024246.html https://www.aliexpress.com/i/2255799825024246.html The brightness enhancement film is a transparent optical film. It consists of a three-layer structure. The bottom layer of the light-incident surface needs to provide a certain degree of haze by back coating, the middle layer is a transparent PET substrate layer, and the upper layer of light-emitting cotton. It is a microprism structure. When the microprism layer passes through the fine prism structure of the surface layer, the light intensity distribution is controlled by refraction, total reflection, light accumulation, etc., and the light scattered by the light source is concentrated toward the front side, and the unused light outside the viewing angle passes through the light. So, it's similar to your design, but the grooves are very small.

fouronnes3 2y ago
I wasn't aware this existed, thanks! Very interesting.

Havoc 2y ago

Toyed with making lights from loose smd LEDs too. Hit thermal issues pretty fast unfortunately. They get really hot when you drive them hard

neilv 2y ago

It you put out enough light, you can diffuse it more, such as by bouncing off the ceiling or a light-colored wall. You can also use photography modifiers, like the various kinds of reflectors. Even white photo lighting umbrellas (which you shine a bright light through) help a lot. Whether or not you add diffusing, you might want to make your light source mountable on a photo studio light stand, so that you can position and aim it however you want (just like you would with a studio strobe or hotlight).

mac-mc 2y ago

I did something similar last year, but I was more focused on spectrum and used high powered movie lights, since their spectrum output is much better and you get a lot of lux. You can get most of the parallel light ray effect by adding a hyperrefelector which conveniently comes with most lights. I then added an incandescent heat lamp to fill in the IR part of the spectrum and some dedicated UV LED lights for the UVA part. I'm not brave enough to put in a UVB specific lamp. I wrote about it here: https://metrep.substack.com/p/improve-your-focus-productivity-and https://metrep.substack.com/p/improve-your-focus-productivit...

jedbrooke 2y ago

I've been down the artificial sunlight at home rabbit hole too (also inspired by the same DIY Perks video). Ultimately the solution I settled on was a much lower budget 300W equiv LED Corn style bulb (4000lm) with good CRI, and a 250w incandescent heat lamp (like you'd get for a reptile). I decided to focus on heat from the light source rather than the parallel rays. Total cost was around $75 (LEDs were $25 for 2, heat lamp was $10 for 2, plus $20 each for 2 lamp stands that clamp to a desk and can support 250 watts).

dave333 2y ago

Are you aware of Brilliant Light Power and their Suncell (R)? See https://brilliantlightpower.com/plasma-video/ https://brilliantlightpower.com/plasma-video/ and scroll down to the February 10, 2023 COMMERCIAL SUNCELL® INITIAL SHAKEDOWN video.

ashoeafoot 2y ago

Idiotic question, but can you have an "angled mode" that lets the godray travel during the day, following the real suns position, given the location and mounting direction of the light?

KolibriFly 2y ago

This is one of the most satisfying DIY reads I've seen in a while. I love how you approached this as a software dev and essentially built a full stack for hardware iteration.

mleroy 2y ago

I’ve been thinking about the potential benefits of incorporating something like this into VR headsets. Since VR already controls the user’s visual perception, would adding a high-intensity blue light (not via the OLED displays but indirectly) allow for a more effective way to simulate bright daylight conditions? Achieving 10,000 lux at the eye would be much easier this way.

Gud 2y ago

There already exists a fairly good replica of sunlight, Philips CDM. I used it when I was growing weed, lushest bushes I’ve ever seen. 10/10 buds. It was discontinued for a while but I’m happy to see it’s back in production? https://www.futuregarden.co.uk/philips-ceramic-discharge-metal-halide-cdm-315w-lamps https://www.futuregarden.co.uk/philips-ceramic-discharge-met... I would pick a CDM bulb any day over the alternatives, including LED, unless power consumption is an issue. “ Philips daylight CDM lamps are extremely efficient ceramic metal halide lamps with a spectral output close to natural sunlight. As a result, plants form more lateral branches, have smaller inter-nodal spacing, more flowering sites, and larger root systems, culminating in strong, healthy growth and high-quality yields. Philips CDM bulbs have an amazing operating life. They maintain their high output for a lifespan of 30,000hrs on average.”

z3t4 2y ago
What is the lifetime before you have to replace it?
- Gud 2y ago
  30,000 hours. Which amounts to 3,4 years of 24/7 operation. I replaced my HPS/MH setup with a CMH light and used it for a few harvests. Never had any issue.

rbanffy 2y ago

Is there any reasonable tool to design fresnel lens for this? They'd be slightly more compact.

lo_fye 2y ago

I remembered seeing, loving, and saving that original DIY Sunlight video back when it first came out, and I went to your article hoping for more, and that's what you gave us. Brilliant job, and thanks for sharing!

jrklabs_com 2y ago

https://store.yujiintl.com/ https://store.yujiintl.com/ has broad spectrum LEDs/lamps/fake skylights that may also appeal to others interested in the OP--just noticed Yuji was mentioned in OP. I'm not affiliated with Yuji but have ordered some of their products and been very happy with their performance.

yohbho 2y ago

From the first videos, I thought this as a one meter square, or larger. 500 W of luminosity in such a small package, as it turns out, seems close to a thermal limit, even with 90+% efficiency.

jclarkcom 2y ago
how does this compare with heat dissipated per square cm when you compare with desktop CPUs?

ape4 2y ago

Might be useful for psoriasis treatment?

romanzubenko 2y ago
What’s the mechanism for sunlight/artificial light psoriasis treatment?

dfawcus 2y ago

He's doing it wrong, the obvious approach being to extract sunbeams from cucumbers! :-)

valunord 2y ago

I would be more interested in making a SUNSET sunlight vs regular sunlight. That would be actually amazing.