DIY Projector - Completed!

Radon199 · Post by **Radon199** » Mon Sep 19, 2005 5:40 pm

This is my latest project. A homemade projector, So far I have the enclosure and the screen (stripped fully). Still need the lense and the light (might have a sutable one in the bacement). Anyways cheak out http://www.lumenlab.com/ if your interested, cheak the forums and look at some of the projects, a $2000 projector for $200 and the best quality you can find.

Reaperman@home · Post by **Reaperman@home** » Mon Sep 19, 2005 6:10 pm

I thought they usually sold a lens with those... oh well, let us know how it works, I'm always looking to replace my old projector.

what kind of bulb do those use? remember that while the photos may be unretouched, you can't know what the shutterspeed is.

HK-47 · Post by **HK-47** » Mon Sep 19, 2005 6:10 pm

I like the diy guide at thg.

http://www.tomshardware.com/howto/20041113/index.html
http://www.tomshardware.com/howto/20041201/index.html

superdeformed · Post by **superdeformed** » Mon Sep 19, 2005 6:11 pm

What are you using for the screen? I'm looking for a screen replacement for mine (something better than a PSone LCD

). http://www.diyprojectorcompany.com is also a great site for this kinda stuff.

edit: Reaperman@home, they generally use metal halide bulbs, which put out anywhere from 20,000 to 40,000 lumens. Needless to say, they're pretty damn bright.

Reaperman@home · Post by **Reaperman@home** » Mon Sep 19, 2005 6:27 pm

I must be missing something.

hk-47's site says you can get 3,500 lumens out of a 400w halogen bulb.
my projector already takes these bulbs (exact bulb) and the factory spec on it is under 500 lumens.
it's a decent brightness for me, but I miss how they're getting 3,500 lumens, and I suspect these specs are more than a little misleading.

maybe it's a terminology thing. does halogen=metal halide?

superdeformed · Post by **superdeformed** » Mon Sep 19, 2005 6:38 pm

Reaperman@home wrote:I must be missing something.

hk-47's site says you can get 3,500 lumens out of a 400w halogen bulb.
my projector already takes these bulbs (exact bulb) and the specs on it are under 500 lumens.

it's a decent brightness for me, but I miss how they're getting 3,500 lumens.

but now 'metal halide bulbs' are something to look up. they can't possibly get much hotter than what I'm using. what are they, and how are they different?

The specs on the projectors light output and the specs of the bulb itself are going to be a bit different. The bulb may have an output of 3,500 lumens, but after the light bounces around off of mirrors, through filters and lenses, and through the screen (assuming its an LCD projector, LCDs "block" a huge amount of light), the overall light output (or brightness of the projected image) would be much lower. In your case, around 500 lumens. All that taken into consideration, 3,500 lumens for a 400 watt bulb seems a bit low...

As for metal halide bulbs, they are much more efficient than halogen bulbs, produce less heat per watt, have a much higher color temperature due to smaller arc length, and last several thousand hours. The downside of them is that you will need a ballast to run it (usually $100+) and any bulb bright enough for a projector would be huge (atleast 6" long).

There's a little info and a size comparison for metal halides here: http://www.diyprojectorcompany.com/theory/lighting.htm

Reaperman@home · Post by **Reaperman@home** » Mon Sep 19, 2005 6:56 pm

thanks for the info.
my unit actually looks like a pretty easy upgrade to those bulbs. The lower heat would be quite a benefit.

...of course while I'm in there, I might as well upgrade the lcd...and while I'm doing that I might as well just build myself a new one and sell my current unit

it's a project I'd actually like to add to my queue.

Reaperman@home · Post by **Reaperman@home** » Mon Sep 19, 2005 7:03 pm

here's a neat idea...
how big is a hipgear screen? and what quality are they? (640x480? 800x600?)

medium format slide projectors take slides that are 6cm x 4.5cm, and they're built to cool relatively hot halogen or incandescent bulbs. (and are dirt cheap on the ebay)

it shouldn't be too hard to buy one, replace the light (or don't) and place the hipgear screen right where the slide would go.

needless to say, the lens on a medium format projector is usually very nice compared to their 35mm brothers.

superdeformed · Post by **superdeformed** » Mon Sep 19, 2005 7:14 pm

Reaperman@home wrote:here's a neat idea...
how big is a hipgear screen? and what quality are they? (640x480? 800x600?)

medium format slide projectors take slides that are 6cm x 4.5cm, and they're built to cool relatively hot halogen bulbs. (and are dirt cheap on the ebay)

it shouldn't be too hard to buy one, replace the light (or don't) and place the hipgear screen right where the slide would go.

The hipgear screen's LCD would probably fit without a problem in a medium slide projector, but it would be terrible quality. It may look nice when its normal size, but make it any bigger and you'll really see all the imperfections in it. I've read a couple of articles on people modifying slide projectors for LCD screens, and cooling was generally the biggest issue. An LCD screen can't take very much heat before the image starts to distort. Despite the fact that slide projectors are meant to cool hot bulbs, a stock set up still wouldn't be enough.

xxxeagle · Post by **xxxeagle** » Mon Sep 19, 2005 7:27 pm

I wonder how good a ps1 screen would work with a couple fans , if it was only projecting 70-90in It would probably look good.

superdeformed · Post by **superdeformed** » Mon Sep 19, 2005 7:38 pm

I used a PSone screen in mine ( http://www.geocities.com/randomblahg/pr ... ector.html if you're interested) and at 67" it still looks decent. Most people stick with around 60". 70" is starting to push it, as the pixels become more apparent, and it wouldn't look good at all at 90".

Radon199 · Post by **Radon199** » Tue Sep 20, 2005 11:50 am

MHD are the godsend of lights at around 33,000 lumens, but they are like $200 USD for the bulb and the mounts and the converter so im gonna go the cheap way >.> At home depo they have lights that plug into any normal lighbulb socket. They are 110W and 3000 lumens and they are also dirt cheap at $5 CDN each. Im gonna get two, maby 3 to get around 9000 lumens and install a big assed fan system to cool down the LCD. Atm im using a screen for my old laptop, it's 15 inch and is broken, but I managed to get it working outside the box. My Laptop can play DVDs and all my riped video not to mention so good games (not amazing but still good). After I get all the stuff I need (just the bulbs and the lenses) im gonna go get a TV-USB adapter so I can play my PS2 and GC on it and also watch normal TV. I havn't got a screen yet but im gonna try to get the best I can, prolly just some high quality linen... tho my dad might still have his projector screen, I might use that but then its only gonna be a 50" TV.

superdeformed · Post by **superdeformed** » Tue Sep 20, 2005 12:42 pm

Radon199 wrote: Im gonna get two, maby 3 to get around 9000 lumens and install a big assed fan system to cool down the LCD.

Do you have a lens to join the 3 light sources together? If not, its not going to work very well. The light needs to be pointing straight through the screen/straight at the projection lens, so if you used 3 lights you would have 3, 3000 lumen sources lighting 3 different sections of the screen.

I havn't got a screen yet but im gonna try to get the best I can, prolly just some high quality linen... tho my dad might still have his projector screen, I might use that but then its only gonna be a 50" TV.

A projector screen would be the best there is. Providing you will be looking at the screen relatively straight on, it will look much brighter than if you were projecting it on normal cloth. If you do go for cloth though, white black-out usually works pretty well.

Radon199 · Post by **Radon199** » Tue Sep 20, 2005 1:59 pm

Ya I was thinking of that. I went to the Kent store (hardware store for eastern Canada) and I found everything I need but I didn't buy, mostly because Im broke and slightly because I need to think some more. There was a 5" tall 300 watt bulb with 6000 Lumens and a smaller 200W (normal size) one with 4000 Lumens.

I think im just gonna go with the big one, its bigger and might put off more heat but if I can only use 1 bulb ill go with more Lumens.

superdeformed · Post by **superdeformed** » Tue Sep 20, 2005 3:22 pm

Are you talking about the halogen flood lights? They won't work (believe me, I tried a 300W one). Whatever you're using for a light source has to have a small arc length, or in other words the light needs to come from a fairly concentrated point. The long halogen bulbs have a very long arc length, so instead of getting an evenly lit screen, you get a thin bar across a small area.