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.
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!
In his case he sacrificed a doorway or a closet to make a window with “real light”
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.
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).
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.
Subtle, nice. Maybe you can give the man a job. ;)
Emphasis mine. I think this was already answered :)
Please don't have your marketing department destroy the real sun. Doing so would break antitrust regulations.
I love the idea of high quality lighting inside especially for my Chicago place.
The one you linked is a stand alone lamp and they seem to focus on red light which I don’t quite understand. Red light (or very low CCTs) is used for skin therapy but typically requires direct exposure to the skin because irradiance levels need to be super high for that - from my understanding you wouldn’t have any benefit from a red lamp even at 750w. But blue light does can have lots of health benefits at low levels (search for ipRGCs).
e.g. McMaster-Carr with a 10 year in-home repair warranty.
And you can still offer discounts via other lower price channels.
The vendor travels to the house and repairs it? One warranty claim could wipe out a startup.
Oh but I do absolutely love this concept. I’m curious if you’ve had lots of interest from these billionaires building bunkers, if that story is even true!
Still, I'll keep this in mind on the off chance it ever becomes relevant to me.
It’s clear that your company leaves no stone unturned.
* You mentioned focusing the spectrum on humans, but I have always wanted to have light that works well for both humans and plants (e.g. houseplants) as they are also beneficial for human spaces. Why not do both?
* Exposure to near IR has significant health benefits and seems like it should be included in an ideal lighting fixture that attempts to replicate the sun: https://pmc.ncbi.nlm.nih.gov/articles/PMC9855677/
What do you mean when you say IR can be produced in other ways more efficiently?
* How does your product compare with the Yuji Skyline?
Yuji is similar to a lot of Chinese brands doing something similar which is a backlit Raileigh Scattering panel. The show images of the sun in their marketing and sharp sunbeams on the wall, but these are complete fiction. The also advertise color tuning, but the only natural color they can produce is a blue because Rayleigh Scattering doesn't allow very good color control. Still, for some applications like wall washing if you don't need a dynamic sky color and you can hide the view of the sun it could be a reasonable option.
We haven't researched plants a ton, but did some test to confirm they can grow under this light. Here is a cool time lapse video showing this in action: https://www.youtube.com/watch?v=2TDIVnXfE9I
Here is a video showing the units suspended in the air https://www.dropbox.com/scl/fi/e0p4rsx31cqag42cklc61/A7_freestanding.mp4?rlkey=o4hhhus6twd7mc07il0rm5exz&st=mpw51y5d&dl=0
[1] https://www.dailymotion.com/video/x97hx8g (from 39 mins in)
I actually decided to let go of this idea after OP’s warning and reading a bit about it. Because one problem will be that I will have to enter to switch off and on and even though it could be a short lived exposure I was scared. Though I’d read more on this what it could kill in the room. The thing is it might not help anyway. It is seasonal/situational and it happens in other places as well or outside if sun is not up. So whatever it is (general guess is pollen, dust, dust mite, sudden temperature changes?, general pollution etc) it is already in me or on me or everywhere around me. So I guess it might rather help more with an allergy test and if I am lucky I can find what I am allergic to.
The problem is with manmade stuff like sheetrock, where the mold grows and then incorporates the binder chemicals into their spores, which are too small to see and yet get inhaled and then leech into our sinuses or whereever.
I've had problems in both work and home situations. I was tested and confirmed allergic; I don't think most people are, but it was rough for me. I'm always on the lookout for those water circles in drop ceilings; they're notorious mold colonies. Once a natural material stays wet for 12 hours, molds will begin to grow.
Just something you might be able to check off your list. Good luck.
The actual spectrum of commercial LEDs is all over the place when you start measuring it it with a spectrometer, even when they supposedly have a high CRI. Especially if you want some temperature that isn't 6500K.
It was so bad that when I was building a night light for my eink desktop I ended up using halogen bulbs which I could undervolt. The main issue was that I wanted to be able to shift the spectrum of the lights from natural sunlight at noon, down to candle light at night.
I did have big plans for doing a neural network to control a bunch of LEDs against a reference temperature, but having to build and calibrate a spectrometer and jig as part of a back prop algorithm was a bit beyond my interest, especially since for halogens I just needed a lookup table with temperatures to voltages that worked for all the bulbs from the lot I used.
Looking at the spectrum graphs for your lights I'm seeing the telltale phosphor coating spike for both warm and cool white leds. An understandable tradeoff, but with the brightness of monochromatic LEDs you can get today one that's not essential any more.
With the drop in costs for both controllers and pcbs since then you should be able to get telelumen quality temperature spectra without the matching price, especially if you can get LEDs that have consistent spectra for their nominal wavelength - you only need to tune the controller once instead of for each light.
One other variable is energy efficiency, there are a lot energy codes around the world that limit how much energy you are allowed to use to light a space. In California for example it can be 0.6w per sqft. Sunlight is more like 100w/sqft so you end up having to optimize the spectrum for what humans can see and feel. I like to compare it with jpeg compression for light. In jpeg we throw away components you can’t see very well, you can do the same for light for an energy efficiency sake and maintain a close perceptual proxy.
We found 4 chips is a minimum bar for good light and use 5 for virtual sun - more info: https://www.innerscene.com/products/circadian-sky/CircadianSkySpec_NA.html?content=multichip%2Fmultichip.html
The light here looks really good, but the cheaper (less nicer) alternative is just a powerful (natural) LED light - search for SAD lights
Because we recreate the blue sky there is a lot of light in this spectrum
I have real skylights on one side of my house and would love to put these up on the other but it would be weird to have sunny skies mixed with cloudy
I suspect that there are other people like me out there. Forcing me to talk to an agent to just get an idea of the price, even if I'm willing to pay a fair amount, is an automatic pass. A buy now button though, I'd be willing to do that and then discuss anything else.
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.
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.
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.
When you connect them in parallel, the first PSU should detect negative load i.e. actual voltage lather than the target; I have no idea how real-world devices handle that condition.
The second PSU will detect load i.e. actual voltage smaller than the target one, will probably assume it happens because the load is pulling energy and will try to extract more power form the AC source to compensate, to make the output stay at the +12.1V target.
I’m not an expert electronics engineer, but to me the approach looks like a recipe for disaster.
It’s usually fine to connect chemical batteries in parallel for two reasons. They have that discharge curve i.e. the voltage decreases monotonously while discharging. If one of them has slightly higher initial voltage, will discharge until matched with the other one, and then both will discharge at about the same rate. Also, chemical batteries have ~fixed internal resistance i.e. the more current you pull from one, the less voltage you get due to that internal resistance.
AC to DC power supplies don’t have a discharge curve because nothing to discharge, they continuously pull energy from the input AC. They don’t have the concept of internal resistance either: when more output current is pulled from them (i.e. the load increases), they simply increase input current from AC (to a point, and then either a fuse blows up or the device catches fire). The dependency between output current and output voltage is not necessarily monotonous. But the worst of it, it depends on time because capacitors, also because the input is single-phase AC i.e. at some moments of time the input power is zero because the input AC voltage and current are zero.
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.
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
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.
Edit: In other materials, they claim a very high CRI of 95+. Also the advertised wattage is sometimes 400W, other times 500W.
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.
Which means they're also not going to give me a tan... bug, or feature?
The nice thing about them is that they're flavour changing
Check figure 1h in the datasheet of the LEDs author used https://otmm.lumileds.com/adaptivemedia/832eef99dd3139f98fa943e60565a2920b270d04
The second peak is near 650nm and while it drops fairly quickly there is still decent amount of power at even 700nm. In short, they perform far better than your stereotypical crappy white LEDs.
If you look at spectra for stereotypical crappy white LEDs, they’re really no different. Everyone uses the same light emitting compounds, it seems to me.
Abuses of a carve-out aside, having a "Sunlight mimicking" exemption would solve this, with the added conditions that they have to actually stick to the EMF outputs of the sun to get this approval. The article itself does this with “General Wellness Lamps”.
Otherwise, the only non-reg way to solve this would be to find infrared & red LEDs and make the supplementary light sources yourself.
In comparison, the LEDs chosen by the OP have a fairly poor power distribution spectrum. At 4000K the color temperature is also too low to mimic daylight, which is at around 5500K. This is all well as an artistic choice but probably doesn't get you any benefits for seasonal affective disorder.
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.
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!
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!
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.
But my neighbors kept complaining 8-/
Haters!
Probably the same people that keep flagging comments on the articles I'm interested in...
One of my goals was to explore the feasibility and scalability of a refraction based design.
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.
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.
> 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.
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.
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.
Entry (?) untested, $350: https://thunderoptics.fr/product/sma-e-spectrometer/
There is also this commercial one that is Bluetooth and more portable for around $150, similar spectrum range but lower spectrum resolution than the little garden one. https://www.youtube.com/watch?v=MOXryggwr_Q
https://www.amazon.com/Analytical-Wavelength-340-1000nm-Spectrometer-Measurement/dp/B0DK1QXSD1
The hopocolor vis light ones are also fairly widespread and are more stand alone for about $280: https://www.aliexpress.us/item/3256807972511960.html
My current issue is finding a 250-400nm UV spectrometer or IR spectrometers beyond 1000nm that don't go into the $1000+ range. Standard mass market CMOS sensors don't go into those ranges, so they become far more specialized parts and thus way more pricy.
"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.
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!
Does anyone know anything about that?
Not sure it's really caught on, but it's out there
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.
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.
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).
I wrote about it here: https://metrep.substack.com/p/improve-your-focus-productivity-and
See https://brilliantlightpower.com/plasma-video/
and scroll down to the
February 10, 2023 COMMERCIAL SUNCELL® INITIAL SHAKEDOWN
video.
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
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.”
500 W of luminosity in such a small package, as it turns out, seems close to a thermal limit, even with 90+% efficiency.
:-)
Some people report much better mood in dark winter days:
https://meaningness.com/sad-light-led-lux
https://meaningness.com/sad-light-lumens
Buy a cheap lux meter if you will be doing this since otherwise you are flying blind.
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.
Still nowhere near as bright as a window on a cloudy day though.