Projector....?

snowpenguin

snowpenguin

Frequent Poster
I want to make an overhead LCD projector or another type, but I have a question.

When people make the overhead style, what do they use as an LCD? I've yet to see ANY overheads that have a glass area big enough for a 15" LCD and LCD screens of a good resolution are not altogether common in 12-14" sizes.

Hail, I know you do projectors and you're a member of a forum on them, do you have a link, or anyone?
 
Hmmm... I never saw something like that before.

Will have to keep an eye out for a cheap one.

Thanks for the link, will take this issue there, I'm sure there's ample info to keep me happy.
 
snowpenguin said:
Will have to keep an eye out for a cheap one.
Click to expand...

You "might" be able to find one with a bad backlight. But $99 is EXTREMELY cheap for a 720p 12.1" screen.
 
Well, after looking around on the site, I can't seem to find much on the overhead subject. I did fins a guide on tomshardware.com though, and interestingly enough they said they used a 15" LCD on a stock overhead. :confused:

I'm torn as to what to do about the LCD. I've got a 15" TV here, but I assume it's only 640 X 480 even though it has a VGA input, and I could use it if I could find a big enough overhead, but I dunno if that's a good enough resolution for a computer to run at well. Everything else of course besides PS3 would look fine, since that's the highest the resolution will get, but I don't know.

But then again I'd have to pay $100 to get an LCD that can handle 720p at a usable inch size. Even then ps3 probably wouldn't look good as it won't just go straight through the vga.

And I can't just use a normal computer monitor at 1024 X 768 as then there's no composite input of any sort.

I also read something about the ability to modify an overhead so that it will have a larger usable area and thus a 15" LCD can be used.

Any thoughts on how well a 640 X 480 res would work out?
 
Anything less than 1024x768 will look horrible. The pixels when blown up to 100" will be huge and blurry.

It is incredibly hard o modify an overhead to accept a 15"

The reason there isn't much info on using an overhead on that site is because most people don't use an overhead. the results are terrible when compared to the results of building your own. using an overhead is really just for a proof of concept that it will work :)
 
Ah. Then, I'll have a better look around around there to find out the other types people do.

Do you have a link or something to another type of DIY projector on hand, so I don't seem like a total noob if I decide to make a thread asking questions or a worklog?

EDIT: Found this, right there on the front page. :dah:

http://lumenlab.com/wiki/index.php/DIY_Projector_Guide_-_Part_1_-_The_Parts

Do you know where I can find links to the stuff in the links to the lumenlab store which seems borked as of now?

EDIT: At first part 2 of the guide seemed to not make much sense, but I think I'm starting to get the idea now, I wish there was a build instructions with pictures and direct, specific instructions isntead of giving you all these lengths to mess with etc. etc.

Wondering where to get parts now as the lumenlab store seemed to be the place to get them, need lenses, bulb, bulb power circuit etc.
 
Boy that stuff's not cheap. I didn't really intend to make an HD projector, was about to get a 1024 X 768 15" from palmer but now... I dunno. Maybe I'll still do it but with an overhead, but I'd still have to find a small screen and replace the bulb circuit.

But if I just get a normal projector used I'll have to pay for $300 bulbs.

So maybe this is an option to revisit once I have the money, and instead of paying roughly the same amount for a used projector I'll do this and not have to buy expensive bulbs.

:gonk:
 
You can get a 900 lumen LED from DX for $20 I think. ::3:

Or get one of those projectors like they have in school, and they put the see-through paper on them. :p
I see them free on craigslist RARELY but I do see them.
 
hailrazer said:
The reason there isn't much info on using an overhead on that site is because most people don't use an overhead. the results are terrible when compared to the results of building your own. using an overhead is really just for a proof of concept that it will work :)
Click to expand...
 
epicelite said:
You can get a 900 lumen LED from DX for $20 I think. ::3:

Or get one of those projectors like they have in school, and they put the see-through paper on them. :p
I see them free on craigslist RARELY but I do see them.
Click to expand...

A 900 lumen Led will get you less than 10 lumens on the projection screen. Not good by anyone's standards.

The overhead projectors will work IF they have a 400 watt or higher Metal Halide bulb in them. If they have a Halogen in them they are worthless as a projector.
 
bump for great justice!

i decided im sick of my 7" screen that i use for gaming in my room (cant afford, nor do i have room for a TV). so, i figured i would make a projector. however, i cant find that one instructable, and i dont want a big one (seriously, im gonna use a 3.5" or 5" screen. can anyone help me out here? (and by "anyone", i mean hail.)

and, in case youre wondering, yes, i know about lumenlab, i just figured i would ask here first.
 
What do you want to know.

A 3.5" or 5" screen is going to have a max resolution of 640x480. More likely it will be a "true" 320x240.

With that resolution the max projection size you will want is around 60" .

You will need a lamp and reflector, a 200mm collimator and a 220mm condenser fresnel and a 220mm triplet for the smallest possible box.

You will need to build a box that is at least around 17.5" long and the height and width of the Lcd plus an inch or so around it on all sides.

For the lamp you could use a 250 watt MH lamp.

Add a pre-con for more brightness.

Etc, etc.
 
im only looking at a projection size around 32" 4::3:, and the resolution isnt a problem. i doubt if i will need it bright at all, since my room is always quite dark (curtains FTW). also, is it possible to go any smaller than 17.5"? say, a more angled collimator and condenser? (they are laser etched glass plates to invert/ focus the image, yes?) would it be possible to use a bank of LED's instead of a MH lamp?
and, could you give me a ballpark price estimate on the simplest setup possible? youre the best :awesome: ([/kissass])
 
samjc3 said:
im only looking at a projection size around 32" 4::3:, and the resolution isnt a problem. i doubt if i will need it bright at all, since my room is always quite dark (curtains FTW). also, is it possible to go any smaller than 17.5"? say, a more angled collimator and condenser? (they are laser etched glass plates to invert/ focus the image, yes?) would it be possible to use a bank of LED's instead of a MH lamp?
and, could you give me a ballpark price estimate on the simplest setup possible? youre the best :awesome: ([/kissass])
Click to expand...

Led's are extremely expensive and not nearly as bright as MH bulbs right now. And no a Led bank will not be nearly bright enough and it is incredibly complicated to build and power, etc. There is a pretty neat high lumens led out but I have not tried it and it is $600 for the kit.

You can do a folded design which uses a front surface mirror and cut your box length in half but it will double it's width.

Ball park estimate.

Triplet --$35
Light kit -- Between $125 - $225
Reflector --$15
Pre-con --$15
Fresnels -- $50
Front surface mirror -- $35
Wood -- $20
Fans -- $25
Electric parts -- $20
 
so basically, too expensive to really be practical. i can get a cheap last gen projector of a higher resolution and smaller size than that for about 100$. thanks for the info!
 
As for LED's for the projection light:
http://www.allinbox.com/GohtanBox3/GohtanBox3.htm
(translated) http://translate.google.com/translate?j ... auto&tl=en

He did have this to say about the cost, however. ;)
"Total Project Cost: unreasonable (prototyping is expensive, especially over several developments)
"

Photo01.jpg


Photo09.jpg
 
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