Building a realistic artificial sun (for dark winter days)
Why Hacker News recommends it
Whenever HN discusses seasonal affective disorder, myopia, or bright home lighting, people point to this as the most convincing buildable example of sunlight-like illumination.
What it is
DIY Perks builds a realistic artificial sun for dark winters, using a powerful water-cooled LED, a satellite dish reflector for near-parallel rays, and a scattering layer to mimic the blue sky. The video explains the optics behind why most lamps do not look like sunlight and shows the build and its results.
Recommended by 9 HN commenters across 8 different months, 2020 to 2025.
What Hacker News said
Strong rec hackererror404 · 2022-06 · on “Shortsightedness has become an epidemic”
There's an amazing youtuber/creator I've been following for a while and he does exactly this. Goes into the science of what it takes, and the results are really stunning. I'd love to give something like this a try, just need time. [this video] Also there was a breakthrough a while ago with LED ceiling lights that mimic natural sun. I haven't heard much since their release, so I'm sure cost is still a major issue for these sadly. [LINK]
Strong rec deltasevennine · 2022-07 · on “Ask HN: Why are there so few artificial sunlight or artificial window products?”
[this video] If you want one, you can build one following the video above. The result is quite stunning. I've never seen anything like it. [LINK] The one above is an easier build that takes up less space.
Strong rec Wistar · 2025-03 · on “I tried making artificial sunlight at home”
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. [this video]
Recommends UnpossibleJim · 2022-02 · on “Someone should probably start a bright home lighting company (2019)”
This isn't quite what you're looking for, but this has some of what you're looking for, which is how to get the "parallel light effect" that the sun has, so it doesn't look like a bulb, and diffuses properly: [this video] Hope this helps a little.
Recommends implements · 2022-03 · on “Quicker and easier ways to get more light”
Relevant YouTube video with 2M views: “Building an artificial sun that looks unbelievably realistic …” [this video] [LINK] Uses a water cooled LED lamp reflected off a satellite dish to produce parallelised rays and through a soapy filter to provide diffuse light. Bulky, but literally lights a room as if from a morning sun on a spring day.
Recommends snozolli · 2023-01 · on “DIY triple-screen laptop based on the framework”
This guy also showed how to make an "artificial sun" that's proven very helpful to me in Oregon winters: [this video]
Recommends bmelton · 2025-01 · on “How to improve your WFH lighting to reduce eye strain”
I'd wager they're pretty good. If you can leverage a parabolic reflector at a light's focal length, you can get them to collimate in a way that approximates the sun by appearing to be pinned near-infinitely far away. The reflector is generally what takes up the space, but it's necessary(ish) -- you could approximate the effect by using a fresnel lens at the light's focal length, but it yields a smaller light with rainbowing effects. [This video]( [this video] ) does a good job of showing how to make your own, as well as illustrating how good the effect is, while also demonstrating why space-hog implementations are likely to yield good results and slimmer ones not.
Recommends stephenpontes · 2025-03 · on “I tried making artificial sunlight at home”
DIY Perks also attempted to make artificial sunlight at home, also focusing on things like Rayleigh scattering! This was a great watch: [this video] 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.