Ever since DIY Perks started projects on creating artificial daylight, I've always wanted to attempt it. The thing is that I didn't want to drill (more) holes into the ceiling or apply adhesive that could be difficult to remove if needed.

I've mostly been interested in the laptop one since the panels are small and, likely without suprise if you read the explanation behind the #T^2 TyMist [gd0138] project, I find overcast sky lighting relaxing and improves my focus.

Due to the hanging infrastructure in rgow tents, it means that I could mount the panels with ease. I also think it's a requirement to make the office feel more spacious / disconnected / time-invariant. Now that it's 2023, I also wanted to see if there were any new options that had been developed.

The reason why LCDs are used is because they include plastic layers under the LCD array which causes light rays to be more collimated, resulting in light paths similar to that of an overcast sky. It turns out Alibaba now has 2 or 3 manufactuers of artificial skylights, but interestingly, none of them are on AliExpress.

Since this Tent Office is the equivalent of a small room under the stairs or something, I imagine a long and narrow skylight would be fine. It's also smaller to store and probably cheaper than larger options. These lights can also do sunrise/set hues but none can actually change the angle of light.

Unfortunately, it does seem that these skylights start at $300. Additionally, the light that comes through looks like it went though a skylight diffuser material and it doesn't seem to produce sharp shadows.

Well, I did find one that looks good:

At these prices, I'm somewhat dissapointed that they don't feature a PDLC film to also simulate clouds passing overhead. Imagine if there was an addressable grid over a large fake skylight that had low-resolution clouds passing though?

Through this research I found out that photographers also look into ways to get fake daylight, but the solutions used are kind-of large and quite expensive (>£1000).

What isn't expensive are high powered LEDs similar to the ones DIY perks used in his largest but most convincing LED daylight.

I was thinking of some kind of motorised solution to get multiple light angles, but with prices like this, It's trivial to install maybe 3 - 5 LEDs and address them via a binary relay system (to guarrantee that only one fake sun is on at once). With this method, each LED only needs to have a single colour temperature whereby the LEDs on the ends have a warm colour temp (2500K) and the LEDs in the centre have a neutral temp (5600K).

There's 2 LEDs in this diagram above and those rays are probably parallel enough to look convincing. I should be working not looking up at the fake sky anyway, so it's not like I need the fancy light scattering to replicate the actual sky. The idea is kinda large though when you bring in a parabolic mirror that is large enough to make sense:

Maybe it's possible to use a 3D printed base and apply reflective tape over the top. A fresnel lens could offer a solution, but after taking focal lengths into account, is likely too large to store when the tent is down.

Going back to the LED plan, there's actually some cheap job lots on ebay currently.

Very helpfully, the actual screen models are listed such as the size and the model code.

One listing was a bit of a mixed bag, but this listing has many identical screens such as the 13.3", the 10" and some 14" panels. This is ideal because then I can group these screens up to create a larger screen fixture. I'm also planning to address these LEDs so that I can have a low-budget version of Unbox Therapy's latest studio ceiling.

(How convinient. He has a video on grow boxes when I'm talking about a grow tent office. Back to the ceiling, the first time I saw it, I thought they were addressable white LEDs but it seems to actually be RGBW or very well calibrated RGB LEDs)

The "LCD job lot" I ended up buying was the one below since it had many 14" screens that were quite similar, and I was able to find the datasheets for both of them online easily.

The datasheet shows some similarities, such as that the backlight can take 6 - 21V, with 12V being the nominal, but the power consumption differers for some reason (Ordered AUO, LG):

And here are the screens:

I wouldn't be suprised if the shipping the seller had to pay was over 50% the price I paid, because 25 broken screens are suprisingly heavy.

Hopefully, the LCD layer protects the other layers that I actually need. Still though, I only need 1 to work to see if LCDs can actually be used as artificial overcast daylight.