Hey, I know that my questions have already been answered... I looked around but I don't know what I should be asking.
Anyway..
1) How do you handle the trapazoid effect of having a projector on the floor and/or the ceiling. Can you effect this by moving around the LCD? (I guess what is the name for this for searching if thats all that I need)
2) Is there any other designs that are easier / smaller for those who don't want to increase the size that much? I'm hoping to have a 5" or 7" lcd project onto a 3foot x 4foot item... hopefully only about 2 or 3 feet away or so.
3) Is there any design changes that I can do if I am expecting this to be used in shade / near darkness?
The searching problem is everyone seems to be interested in high light.. I'm looking for cheaper hopefully smaller in dark 🙂
I'm hoping to to project to the back of a box basically... It would be in lighted room, but I'm expecting/hoping it to be deeper so no direct light will be shining in.
Also, I've seen some of those projector plans where you don't really pass light through the LCD, but instead you bounce the light off... Do those work at all?
Thanks
Anyway..
1) How do you handle the trapazoid effect of having a projector on the floor and/or the ceiling. Can you effect this by moving around the LCD? (I guess what is the name for this for searching if thats all that I need)
2) Is there any other designs that are easier / smaller for those who don't want to increase the size that much? I'm hoping to have a 5" or 7" lcd project onto a 3foot x 4foot item... hopefully only about 2 or 3 feet away or so.
3) Is there any design changes that I can do if I am expecting this to be used in shade / near darkness?
The searching problem is everyone seems to be interested in high light.. I'm looking for cheaper hopefully smaller in dark 🙂
I'm hoping to to project to the back of a box basically... It would be in lighted room, but I'm expecting/hoping it to be deeper so no direct light will be shining in.
Also, I've seen some of those projector plans where you don't really pass light through the LCD, but instead you bounce the light off... Do those work at all?
Thanks
What your talking about is called keystoning by the DIY proj. community. The standard fix for it seems to be to pivoting the fresnell that's closest to the projection lens. Just do a search on keystoning and you'll find some good fixes for this problem.
Pertaining to smaller projectors, perform searches on the words Lilliput or PSone.
Not sure what you mean by question #3?
Pertaining to smaller projectors, perform searches on the words Lilliput or PSone.
Not sure what you mean by question #3?
As for #3, I'm trying to build a projector that will project into a box (with the open side where you look into). The sides will be painted flat black and the back side either a paint or maybe a small piece of screen...
The question is if you don't care about how much light is there any other designs that work well? Like the ones where you don't shine through the LED but have the mirrors over it.
Its just seems like everone is optimizing for a 10ft wall. but I'm hoping for a 2, 3 or maybe 4 foot screen on the back in near total darkness.
The question is if you don't care about how much light is there any other designs that work well? Like the ones where you don't shine through the LED but have the mirrors over it.
Its just seems like everone is optimizing for a 10ft wall. but I'm hoping for a 2, 3 or maybe 4 foot screen on the back in near total darkness.
oh, so that's whay keystoning is.....
but i'm still not exactly sure what it looks like or how to correct it.
do you mean if someone tries to hang a projector from ceiling and then tries to aim the projection down, thereby not having a flat even image?
well hell, i could of realized that would be a problem.
that's why i think it's best to set up a straight projector and just have it directly flush and plum with the image/screen
but i'm still not exactly sure what it looks like or how to correct it.
do you mean if someone tries to hang a projector from ceiling and then tries to aim the projection down, thereby not having a flat even image?
well hell, i could of realized that would be a problem.
that's why i think it's best to set up a straight projector and just have it directly flush and plum with the image/screen
What I'm trying to do is this...
I want to build a small 3d computer monitor. It will be a box on my desk (size up in the air right now... ) with two projectors point onto the same spot. Something like this
______
\ P\ | SSS | /P /..
.\ P\| |/P /...
..\___ ___/...
VVV
So if this shows up correctly...
Two projectors (left and right... or maybe top and bottom) will hit off a mirror and point back. The top / bottom / sided would be covered and painted a flat black and the back would be a screen.
Then two polarized filters on the projectors. So the left side would be horizontal and the right would be vertical. So with the cheap movie 3d glasses would filter one side or the other.
Next... using NVidia 3d card and their shudder glasses software, there is an option for two monitor support.
so in the end, I would all 3d games (both opengl and d3d) true 3d without having to have the screens flashing.. plus it would be in an enclosed area that should help the perspective... (like I might not paint the corners black so they give a 3d effect on the sides)
But I wanted to build both projectors if possible.
Since the idea is to have it enclosed, with a dark top... I don't care about a projector that works only in the dark. I was hoping there might be some other byo projector that might be cheaper that didn't have the light output... (like using cheaper bulbs... or maybe that didn't require additional lenses... or one that didn't require light behind the lcds... or cooler yet... one that would work with two CRT's like those old ones used to be on TV orders... but I know they wouldn't really do).
Anyway, that is the full story... since I need a projector on each side to get two working, I HAVE to have the keystoning adjustable.
Thanks for any more input.
I want to build a small 3d computer monitor. It will be a box on my desk (size up in the air right now... ) with two projectors point onto the same spot. Something like this
______
\ P\ | SSS | /P /..
.\ P\| |/P /...
..\___ ___/...
VVV
So if this shows up correctly...
Two projectors (left and right... or maybe top and bottom) will hit off a mirror and point back. The top / bottom / sided would be covered and painted a flat black and the back would be a screen.
Then two polarized filters on the projectors. So the left side would be horizontal and the right would be vertical. So with the cheap movie 3d glasses would filter one side or the other.
Next... using NVidia 3d card and their shudder glasses software, there is an option for two monitor support.
so in the end, I would all 3d games (both opengl and d3d) true 3d without having to have the screens flashing.. plus it would be in an enclosed area that should help the perspective... (like I might not paint the corners black so they give a 3d effect on the sides)
But I wanted to build both projectors if possible.
Since the idea is to have it enclosed, with a dark top... I don't care about a projector that works only in the dark. I was hoping there might be some other byo projector that might be cheaper that didn't have the light output... (like using cheaper bulbs... or maybe that didn't require additional lenses... or one that didn't require light behind the lcds... or cooler yet... one that would work with two CRT's like those old ones used to be on TV orders... but I know they wouldn't really do).
Anyway, that is the full story... since I need a projector on each side to get two working, I HAVE to have the keystoning adjustable.
Thanks for any more input.
So it sounds to me like your wanting to build a small, dual, rear projection system. Sounds like a neat idea.
(Edited to say... Or maybe not??? After re-reading your post it occured to me that you may be talking about having an open box where the viewer faces the opening and the back of the box is the projection screen. If this is the case then you can disregard my comments on the rear projection stuff.)
I think your still going to need a fairly bright bulb, though maybe not as bright as the 400w metal halides favored by many. I don't really have much to offer since I have no experience with rear projection systems. But if you don't mind laying out $20 for a LumenLab membership, they do have some excellent forums on small projectors and rear projection.
I think I remember reading a comment by brainchild over at LumenLab that the projected image from smaller LCD panels (like the type you'd need) tends to get washed out when really bright lamps (like the ushio S400DD) are used. He suggested in that post that 250 W HQI bulbs are probably a better choice.... but bear in mind that he was talking about a regular front projection system. I have no idea how this would play out for rear projection.
Another sticking point with the rear projection setup is finding the right screen material to use. Your best bet is probably going be finding a junk rear projection TV and scrounging the screen from it. I think one of the guys from LL has been doing some experimenting with different types of material for a DIY screen. Surprisingly the best material he's found so far is an $8 white shower curtain available at Wal Mart.
On the keystoning, since your talking about having the projectors sitting on each side, pivoting the fresnell will still work, but you'd need to position the pivot points along the y-axis (top and bottom) rather than the x-axis (left and right). Of course this assumes that you'll be mounting each projector high enough so x-axis pivots wouldn't be necessary.
If your really serious about this I couldn't recommend a LumenLab membership more. The info you need can probably be found here or other websites, but you'll have to spend mucho man hours to find it.
(Edited to say... Or maybe not??? After re-reading your post it occured to me that you may be talking about having an open box where the viewer faces the opening and the back of the box is the projection screen. If this is the case then you can disregard my comments on the rear projection stuff.)
I think your still going to need a fairly bright bulb, though maybe not as bright as the 400w metal halides favored by many. I don't really have much to offer since I have no experience with rear projection systems. But if you don't mind laying out $20 for a LumenLab membership, they do have some excellent forums on small projectors and rear projection.
I think I remember reading a comment by brainchild over at LumenLab that the projected image from smaller LCD panels (like the type you'd need) tends to get washed out when really bright lamps (like the ushio S400DD) are used. He suggested in that post that 250 W HQI bulbs are probably a better choice.... but bear in mind that he was talking about a regular front projection system. I have no idea how this would play out for rear projection.
Another sticking point with the rear projection setup is finding the right screen material to use. Your best bet is probably going be finding a junk rear projection TV and scrounging the screen from it. I think one of the guys from LL has been doing some experimenting with different types of material for a DIY screen. Surprisingly the best material he's found so far is an $8 white shower curtain available at Wal Mart.
On the keystoning, since your talking about having the projectors sitting on each side, pivoting the fresnell will still work, but you'd need to position the pivot points along the y-axis (top and bottom) rather than the x-axis (left and right). Of course this assumes that you'll be mounting each projector high enough so x-axis pivots wouldn't be necessary.
If your really serious about this I couldn't recommend a LumenLab membership more. The info you need can probably be found here or other websites, but you'll have to spend mucho man hours to find it.
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