Driven by a desire for better indoor lighting, a blogger attempted to recreate sunlight using high-CRI LEDs and a custom-built power supply. He meticulously measured the spectral power distribution of natural sunlight and then combined various LED wavelengths to approximate it. While the resulting light achieved a high CRI and looked visually similar to sunlight, the project was ultimately deemed too complex and expensive for practical home use, especially given the readily available full-spectrum bulbs offering a simpler, albeit less precise, solution. He concluded that accurately replicating sunlight's complexity is a challenging endeavor, even with advanced tools and knowledge.
Embarking on a quest to replicate the luminous splendor of our celestial sovereign within the confines of his terrestrial abode, the author, Victor Poughon, meticulously documents his fascinating, albeit ultimately imperfect, endeavor. He commences his exposition by elucidating the inherent limitations of conventional artificial lighting, particularly its deficiency in replicating the full spectrum of solar radiation, a crucial element for both physiological and psychological well-being. Driven by a desire to transcend these limitations, Poughon undertakes the ambitious project of constructing a personalized "artificial sun."
His methodology involves the careful selection and assembly of high-powered light-emitting diodes (LEDs) meticulously chosen to encompass a broad spectrum of wavelengths, thereby approximating the spectral distribution of natural sunlight. This process necessitates a deep dive into the intricacies of color science, including the exploration of concepts such as correlated color temperature (CCT) and color rendering index (CRI), both critical parameters in quantifying the perceptual accuracy of artificial light sources. He meticulously chronicles his procurement of specific LED components, detailing their individual spectral characteristics and rationale for inclusion in his bespoke luminaire.
The construction process, painstakingly described, involves the integration of these LEDs onto a custom-designed circuit board, carefully managing thermal dissipation to ensure the longevity and optimal performance of the high-output diodes. This technical undertaking necessitates the utilization of specialized equipment and a demonstrable understanding of electrical engineering principles. Poughon further elaborates on the challenges encountered during the fabrication process, including the complexities of achieving uniform light distribution and mitigating undesirable flicker.
Upon completion of the physical construction, the author proceeds to evaluate the performance of his creation, employing sophisticated instrumentation to measure and analyze the spectral power distribution emitted by the artificial sun. He compares these measurements to reference data for natural sunlight, highlighting both the successes and shortcomings of his endeavor. While acknowledging the limitations of his DIY approach in perfectly replicating the full complexity of solar radiation, Poughon expresses satisfaction with the improved spectral quality of his artificial sun compared to conventional lighting solutions. He concludes by reflecting on the potential benefits of such technology, particularly in environments where access to natural sunlight is restricted, and contemplates future refinements to his design, hinting at the possibility of incorporating dynamic spectral control to mimic the diurnal variations in sunlight.
Summary of Comments ( 81 )
https://news.ycombinator.com/item?id=43497394
HN commenters generally praised the author's ingenuity and thorough documentation. Several pointed out potential safety concerns regarding UV exposure and the high-powered LEDs, recommending specific filters and safety precautions. Some discussed alternative approaches using commercially available grow lights or different LED combinations for better spectral accuracy. Others debated the perceived psychological benefits of artificial sunlight and shared their personal experiences with similar projects or seasonal affective disorder. A few commenters delved deeper into the technical aspects, discussing color rendering index (CRI), spectral power distribution, and the challenges of replicating true sunlight. The overall sentiment was one of appreciation for the project's DIY spirit and the author's willingness to share their findings.
The Hacker News post "I tried making artificial sunlight at home" (https://news.ycombinator.com/item?id=43497394) sparked a discussion with several interesting comments.
Several users discussed the importance of the spectrum of light for different uses, beyond just perceived brightness. One user pointed out the distinction between CRI (Color Rendering Index) and spectral power distribution (SPD), emphasizing that two light sources can have the same CRI but different SPDs, leading to different effects on things like plant growth or human circadian rhythms. They highlighted the importance of full-spectrum light for these applications. This spurred further discussion on the challenges of truly replicating sunlight's spectrum and intensity, with another commenter mentioning the high cost and complexity involved.
Another thread explored the potential dangers of high-intensity light sources and the need for proper safety precautions, particularly regarding UV radiation. Users discussed the specific wavelengths of UV light and their different effects, with one commenter cautioning against using untested or unregulated light sources. Another mentioned the potential fire hazards from the high power consumption involved in creating artificial sunlight.
Some commenters shared their own experiences with artificial sunlight and different lighting technologies, mentioning brands like SolTech and discussing the trade-offs between different approaches. One user shared their positive experience with a specific lamp for Seasonal Affective Disorder (SAD), suggesting that even imperfect replications of sunlight can have beneficial effects.
There was also a discussion about the author's specific implementation, with some questioning the choice of components and suggesting alternative solutions for achieving a similar effect. One user suggested the use of metal halide lamps as a more efficient way to generate a full-spectrum light source. Another pointed out potential issues with the cooling system used in the author's setup.
Finally, there were some comments focusing on the practical applications of artificial sunlight, such as indoor gardening and simulating daylight in windowless spaces. One commenter noted the increasing interest in this technology for improving well-being and productivity in environments with limited access to natural light.