[kevinkrg]

I have been itching for 2 years now to build a projector ever since I found this site. I'm going for something small, and bright enough for just a basement or a bedroom. I have experience with soldering fans, etc because I've messed around with my xbox before. I'm trying to make this as cheap as possible. Here would be my part list:

250w Metal Halide Lamp - $11 - http://www.1000bulbs...lide-Bulbs/548/
250w Metal Halide Ballast - $50 - http://www.1000bulbs...-Ballast/32969/
15" Lcd Panel (1024x768) - $70 - Ebay
Lumenlab Triplet Lens - $30 - Lumenlab
Wood, Fans, etc - $50 - Home depot, Circuit city, etc
Tax, Shipping, etc - $20

TOTAL: $231

$231 is not a bad price for a projector, at all. I would be using it for gaming and movies. I have a few questions though:

-Would that lamp and ballast be compatible?
-Is 250w bright enough? (again, only for a bedroom or basement with lights out) Hoping for a 60"-90" image Max.

I would use a standard lumenlab style box, and I would include a focus box.


At first I would just project on a wall but eventually build my own screen.
I think I can go without the fresnels for now but if the brightness is really bad I'll have to get some.

If anyone can assist, please help in answering my questions.

IM FINALLY GOING TO DO THIS!!! YAY!!!!


I can't wait to watch transformers.....

[jakebrick]

I think you need the fresnels for it to work at all. If you don't have any lenses there will be nothing to focus the image back to the projection lens. You might get the center of the image onto a screen, but not the whole picture. Also, the fresnels spread the light evenly. I don't think it will work without them. And for 60-90" in a totally dark room, 250w will be enough.

[kevinkrg]

Yes I think your right, I know that the rear fresnel that goes behind the panel isn't required but the collector in front is. I will probably have to buy one.

[fmerrill]

kevinkrg, on Dec 1 2007, 02:56 PM, said:

Yes I think your right, I know that the rear fresnel that goes behind the panel isn't required but the collector in front is. I will probably have to buy one.

Why would you think that the rear fresnel is not required?
Without it, you will simply get a central spot of light that gets through the LCD, and your projection will be simply be what is on the center of the LCD.
You need to buy or obtain both a rear and front fresnel.

[kevinkrg]

Ok, I guess I'll have to get both then.

Right now I'm trying to figure out where Im going to put the projector because they are so big.

This post has been edited by kevinkrg: 01 December 2007 - 08:33 PM

[cardeag]

The size limitation of the PJ isn't necessarily fresenl size, they can be cut. The size of the box has more to do with the size of the LCD and the focal lengths of the lenses that you get. Also, depending on the LCD that you have and what you plan to project, you may need to get an RCA to VGA converter or line doubler. They aren't too terribly expensive, but should be figured into your budget.

[SupraGuy]

I would also add a reflector to the parts list...

But you most definitely need a set of fresnels.