DIY True 4K Projector(youtu.be) |
DIY True 4K Projector(youtu.be) |
I've been looking at making a hi-res ceiling projector for a living space. Perhaps not one, but a set of several projectors with an overlap, but the key point is that they need to be placed in a way so not to interfere with the normal flow of life. Nor to be easily shadowed by people walking around, etc. This (likely) mandates placing them around the room perimeter, possibly on the walls at some height. This in turn means that they will be projecting at an angle.
Do I understand correctly that it's not possible in principle to achieve proper focus on the target surface when projecting at an angle like this? That is if I am to project, say, a star field then it's not be possible to have stars close to the projector and far from it to be both in focus at the same time?
See https://en.wikipedia.org/wiki/Tilt–shift_photography for cameras. https://www.projectorcentral.com/Understanding-Lens-Offset-a... learnt me that you can buy projectors that use this method. I suspect that back-projecting televisions (https://en.wikipedia.org/wiki/Rear-projection_television) often use it, too.
There are also ultra short throw projectors that can be mounted a few feet away from their target, designed for classrooms. They probably don't have the blackest black levels though.
IIRC academy of science sf did this in one of the lines for an exhibit.
I would think if you mounted it vertically on a wall, it would be fine. You would still want it centered horizontally though.
When the laptop screen eventually gave up (I think just the connector) I never ended up rebuilding it. Nowadays you can get a really awesome looking projector setup for so little, it's not really worth trying the same approach.
But from what I skimmed through, this is a build of way higher complexity, cost, and quality. I'm looking forward to watching this video tonight.
That thing was heavy and loud as hell, and it wasn't very bright considering it used 400 watts of light power, but it was about half the price of an equivalent projector back then, which effectively allowed my poor student self back then to enter the home cinema scene, which I couldn't have afforded otherwise.
There even was an entire little scene back then of DIY projector enthusiasts (at least in Germany) with bulletin boards and even some niche online shops specialized in selling suitable lenses and LCDs and matching controller boards. It was great fun and a great learning experience, especially since you could get help from like-minded people and ideas from other people's projector projects.
A few years later it all quickly went down the drain when the first Full-HD projectors with acceptable quality dropped into price ranges that were affordable for the general public. It simply wasn't possible to compete with that anymore, neither in terms of quality nor in terms of price. I myself replaced my hunk of a self-made projector after about 4 years of use or so, with one of these entry-level full HD home cinema projectors (which I'm even still using today, so that was a really good investment in my book). But that self-made device was worth every cent and every hour of work, and I still have fond memories of building it and tweaking it for maximum quality and then watching movies with it, all the while thinking "man, I built that thing basically from scratch".
I hit about 20 before I said "this project is way beyond my skill level." But I still got a vicarious sense of pride from watching his success!
This guy is a true hacker.
Pretty cool, but just buy a damn projector. Do not approach this as something practical that's going to be useful, because it's not. It's huge, probably loud, you'll get dust and stuff stuck in all sorts of places messing with the image and it lacks advanced focusing like keystone transform https://en.wikipedia.org/wiki/Keystone_effect
It was a cool project and when it was just me and a friend sharing an apartment, we didn't care that it was janky (especially since any large format screen was way too expensive for us at the time). But now you can get better performance from a cheapo projector and for a bit more, you can even find decent short-throw models these days.
My current project (that is collecting dust) is a big dual-lamp auditorium sized Epson that I snagged when it was getting tossed out at work. Sadly, while it was working when I picked it up, somewhere along the way from the office and through a couple of moves the auto-iris got stuck/damaged.
It's the most frustrating thing because the projector works fine but when it powers on, there's an error message stating that the auto iris has an error and it won't let you proceed. I don't even care about the auto iris and while I've dismantled it quite a bit and blown out/lubed everything I could find, I still get the error. Apparently they all had this problem but it's way out of warranty and I don't see much point in paying to have a free projector repaired.
Now imagine, with no right to repair, manufacturers locking all components making these things impossible.
I wonder if phones can deal with USB audio cards (that have surround options), or if there are any Bluetooth audio solutions that offer surround sound.
Or I guess you can replace the phone with a PC/laptop, and have the display connected to an LVDS driver..
Edit: Something of this sort: https://crossbeats.com/collections/all-products/products/con... (No affiliation to the company or the product)
No idea if it handles surround sound properly though, but considering phones are offered with HDMI outputs and there's the whole Android TV lineup I'd imagine there's some kind of support in there.
Current generation non-laser short throw projectors may already hit the price/performance you need, just mount them so they face the ceiling, on top of a bookshelf. (Laser projects are still quite expensive.) If they don't, then physics, specifically optics, has the equations to calculate the mirror specifications you need for your exact use-case. Custom-made mirrors aren't the cheapest, but what you're asking for sounds possible, though it's impossible to say without more information, specifically the dimensions and the brightness needed - you'll lose a lot of brightness from the mirrors.
The setup for Fishbug was two projectors facing a hemispherical mirror. https://www.youtube.com/watch?v=ThtF-FY28hM