Here is my 7inch lcd projector. It is quite rough on all edges, so to speak, but I just wanted to see if I could be successful.

Similar "smurf" project:
-- $6 Lense (Ebay find, old slide projector)
***Just ordered a InFocus Projection lens for $13 from Ebay, the seller had 7 more, email me for link, I am not sure of the link posting rules.
-- $30 for (3) three 7" LCD (3 non working portable DVD player - Ebay)
***LCD stripped really easily
-- $8 four (4) Fresnels (yet another Ebay find)
-- $6 for a 250W hallogen lamp (home depot - portable halogen worklight, I want to go back for the $8 - 500 watt)
-- Wood - Still need this..........


Ok well, it's now 2 months since I originally started this project. I didn't use the Kodak slide projector lens, nor the InFocus lens. I actually used a large lens from an Old over head projector, but it did the trick.

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The big lens actually weighs more than the rest of the projector.

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I still can't wait to try the 500 watt halogen lamp from Home Depot.

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The 2 fresnels in the projector are in really horrible shape. One is bent and scratched, but I can't find the other 2. And I finally went and bought some MDF.

Ok these pics really look like crap, but I have not put the rest of the casing on as yet. Plus, I have no idea how to take pictures in the dark.

Currently the projector is only set up for RCA Composite video. I attached a wire directly from the GoVideo circuit board so it can plug into a dvd player or vcr. I will get a Composite to S-Video adapter so I can use my computer with the projector.


I really can't wait till I get better quality parts. For the fans I am going to use two 120mm PC fans for exhaust for the lamp and I will use an 80mm fan to exhaust for any build up air on the other side of the LCD.

Other info:
I am using the white wall at the head of my bed. The projected video size is 2 feet high and 4 feet wide.
The projector is approx. 20 feet from the wall.

Any suggestions are extremely welcome and appreciated.
-Does anyone think it would be a good idea to bring the LCD closer to the lamp. I thought it might be bad for the LCD so I didn't want it too close, but I realize alot of people have there LCD way closer.

And now the pics........(they suck, but the video did come out ok looking, better than the Zoombox, which I bought from Toys' R Us to do a one day test run, then I returned it.)

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Wow, that is a HUGE lens you got over there.

I think a new and more powerful light source would do the trick about your dark images. And, I hope you know, the light source should be placed at the rear fresnel lens focal length.

With best regards,
SnakeDragon

Thank you for saying this... I just realized that this is what I should do for my project. Three compartments = trapped hot air. Duh.



Really, all you should do for the moment is move your projector closer until you get a better lamp. Your brightness will jump quite a bit if you even get another 4 or 5 feet closer. I know it will drop your size, being kinda small as it is... but brighter is definitely better. And I totally agree with SnakeDragon, just put the lens at the focal length from the bulb and make sure that if it's close, you cool the LCD well. No scorchy.

That is a huge lens... Actually, assuming the optics are all reasonable quality it's probably a great lens for this application as it will capture lots of light - no FOV issues for you.

Unfortutely, since it does capture so much more light than the projection lenses most DIYers use, you should probably be a little more careful about stray light. Building an enclosure, with a matte-black finish on the interior should improve the clarity of your image significantly from your current wide-open setup. Also, by blocking as much light from the source that is not needed (ie. that doesn't go directly into the rear fresnel) you'll also be able to cut down on this stray light problem.

Other than that, I'd recommend what the others above have said. The arc of your bulb should be at the focal length of your collimator (rear) fresnel. Some users have toyed around with this distance to improve brightness, and have found that being slightly closer (or was it farther??) than the focal length produces a brighter image... So I guess I'd recommend trying different distances close to the focal length of that fresnel.

Also, brightness varies according to the sqaure of the projected image size. So doubling the size of your image means it will be 1/4 as bright, or you can expect four times the brightness with half the image size.

One last thing, you want to make sure that the focal length of your projection lens matches the focal length of you field (front) fresnel reasonably well. For example, the standard 15" lens kit has a 320mm projection lens, and a 317mm field fresnel. This minimizes any FOV issues and ensures that all the light that passes through the LCD makes its way into your projected image.

Hope some of this is useful,

Dave

Yeah, the lens is approx. 5 inches in diameter.

The fresnel lens that I used is the cheap one on ebay. It honestly doesn't have much of a focal length.

Actually the video displayed on the wall way brighter than in the picture. But the digital camera I use always makes images dark, except for when you us ethe flash. Still trying to learn how to use it.

Well I will definitely be happier when I get a better lamp, I next want to try the 500 watt halogen lamp which costs $8 as opposed to $6 (the cost of my current 250 watt halogen lamp).

And your rioght when it is a few feet closer than the current location, the screen is smaller, but quite brighter. The cool thing for where I put the projector is that it is extremely out the way.



Future upgrades:
1.) 400 watt Metal Hydride lamp
2.) Real quality Fresnel Lens

Thanks for all the suggestions, my only problem is the comment above. For some reason I feel like either I just don't understand or it went way over my head.

Basically it means the bigger the image gets the dimmer it becomes and likewise the smaller the brighter by a certian ratio. So if you double your current projection size it will be .25 times as bright. But if you were to cut your current projection size in half it would be brighter by a multiple of 4.