Alright, my only disclaimer is even though I am the son of a carpenter (its too bad he lives so far away) I didn't inherit any of his skills. I'm amazed that he made it look so easy the many times I lent him a hand. So not all of my cuts are 100% straight and some of my joints aren't 100% flush, but its pretty darn close in most places. I used dimensions close to what Drudgemart posted as his 'revised' dimensions in his PLOG.

First I stripped down my LCD and put it back into his metal frame...

Front:


Back:


I may have a small FFC issue , you can see a 90 degree angle cable in the upper right of the Front picture that shows it, but I figure since I will be watching mostly DVDs on this in Widescreen, it probably won't be too noticeable. I was also messing around with it and I noticed that cable has enough play in it to tape out of the LCD pixel range.

The LCD is a MAG 15" LT565 which is a 350:1, 12ms panel.

Then I built my box, wow what fun. Before this I had never operated a circular saw, so I had quite the time trying to get straight lines. But here are some pictures of what I ended up with:

Back to Front:


Front to Back:


Inside:


For the wood I used 5/8" Sanded Pine plywood. I plan on doing something similar to what Drudgemart did for his sliding focus as well.

Here is a picture of some black plastic channeling I found that I plan on using to mount my optics and LCD:

Channel:


I'm going to cut that lengthwise and use the first skinny part to mount my Lexan, then use another skinny part of it to mount the fresnel, and then use the wider part to mount the LCD. I haven't decided how to do the forward fresnel yet.... but I thought it was really neat that I found this stuff and everything happens to fit snugly in it (even the LCD in its frame fits exactly in that larger middle section of the channel).

There's where I am so far, I'm still awaiting a ballast and a mogul, but I will probably begin mounting the optics and the LCD, and making sure the LCD still works, sometime tomorrow.

Nice job so far...
One question for you...
Were did you get that black plastic for the lcd and len's?

lesko

Good job Anthony ...keep going!!!

hard to tell from in that picture.. but make sure you have 15-16mm / 5/8" between the frenzal and the lcd might not get that much spaceing in that plastic strip... though the idea is good and would look neat

I got that black channel stuff from Home Depot, it was near the Lexan in the screen section.

There isn't enough space in that channel to mount it all in one piece, thats why I am going to cut it lengthwise and add the space I need For instance, one piece I can cut in half (top to bottom) and have the Lexan piece and the fresnel piece, and another piece I can trim off the outer edges and have a frame for the LCD, this stuff is really cheap and easy to cut / drill / whatever.

Update.. recieved all of my parts finally, a Electronic Ballast and mogul socket were the last pieces. I have wired everything up with wire terminals, etc. And everything works! The picture quality isn't bad, but it isn't 'Wow' yet either. Its lacking in brightness and its a little gray at times. I'm not 100% convinced my optics are all lined up, and I'm not using a Norpro yet (Don't have the tools to cut one though, so sort of worried that even if I get one, I'll still be SOL) Also, some ambient light issues are really being a pain. Here is a blurry pic that illustrates what I am talking about (Sorry I couldn't hold the camera still enough)



I have a dryer vent type of thing on the back to try and stop some of the light, I also have some flashing shaped around the fan to block the light, but it still isn't enough apparently. Will adding the reflector help with this problem?

Also, has anyone thought about doing something like this to get rid of the ambient light that comes out of the air intake slot?



And finally, the last problem I am having, my image is a little bit trapezoidal in shape, I assume this is from the rear fresnel not being completely parallel to the LCD?? Or is there something else to blame?

I'll take some pics of my enclosure and the wall mount later... just hoping I can get to the bottom of these other issues

Oh, the final image size is like 11.75' diagonal

Yes, I will be using a 'auto hood scoop design' to block the light from the air intake. My thinking was just put a 'scoop' over the vent, off-set towards the front and with the lite coming straight-up hitting the underside of the 'scoop' very little would 'leak' out the front (depending how long your scoop would be of course).
Nice design, should work fine...

First thing. Look at the back of the projection lens while the projector is running and see if there is any spillage around the triplet.

There is some spillage, what should be a beam of light is more like a rectangle of light, here are some images to illustrate what I am talking about:



And a close up.. sorry about the green tinge, the lamp was still warming up...



Any ideas of what is causing this will be much appreciated

That spillage is severe. The primary reason for this happening is lamp to rear fresnel distance is wrong.

Hmm... too close or too far?? I was pretty sure that it was the correct distance, but I'll look again...

Actually it could be either. Also looks like the lamp is a little low. You need to make that adjustment while the lamp is running. The first 5 minutes at start up is the best time.

Measuring from the middle of the envelope, I get 8.5", so that would be 3/16 of an inch off...

When you split the fresnel lenses that distance can change. Trial and error are needed.

Damn, and on the front instead of 12 5/8", I have an even 12". Not good

Alright, I'll keep trying things out Thanks for the help with this, should I just try moving the lamp or should I try moving the spacing of the fresnels as well?

First try the lamp while it running. You can see quite clearly what is happening at the back of the pj lens. Get the spot as small as possible.

Ok, with the help of one of my roommates, I moved the lamp backwards a little bit, and centered it more on the lens, he also moved the forward fresnel back a little, but no matter where we moved, we could not get all of the light to fit inside the triplet...

There is usually some minor spillage, just get it as good as you can.

I think I can attribute most of my problems to bad measurements on my part. Tonight while I was verifying the measurements, I noticed that between my back fresnel and front fresnel is a distance of around 2 1/16", instead of the design's 1 7/16", I believe I have an extra 1/16" from the rear fresnel to the panel, and quite a bit of difference between the front fresnel to panel (because I measured from the panel's frame instead of the panel itself!! doh!). This causes the distance from the front fresnel to the triplet to be off as well.

I will remedy this and see what happens from there.

Wow, homework, real work, and my consulting work have all gotten in the way of my hobby. I realigned everything, remeasured everything, and after that, here is a picture of my new spillage. (You'll also notice I painted the front of my box black) Is this spillage acceptable? What kind of spillage do other people experience?

Thanks

Try moving your lamp forward and backward to get that spillage as small as you can. Otherwise it looks centered.

When I move the lamp back, its hard to tell if the spillage is actually getting smaller or just out of focus... but I'll give it a try and snap another picture

Here's what I have now... Moving the lamp forward from where it was made the spillage worse, so I moved it back...

EDIT: Better pictures, taken when bulb fully fired up.

Originally, before I started moving the bulb today:



Moving bulb backwards:

Alright, after messing around with it, I've come to the conclusion that that Original picture is as small as the spillage gets, moving forward or backward from that point only makes larger.

I haven't built mine yet, but what about the distance from the LCD to front fresnel, or better, the fresnel to triplet - how are those distances??

Those distances are exact from a reworking of all the framing I did a couple weekends ago...

Its just frustrating that I can't get that horizontal beam of light to fit inside the triplet, move forward and the beam extends past the triplet, move backward and its more of a huge circle that overflows the triplet.

Well I'm officially stuck, I can't get the PJ any brighter, and no matter where I move the bulb, thelight circle only gets bigger... I'm open to suggestions. I've verified and reverified the lense distances, and have only manipulated the bulb to rear fresnel distance to no avail. Maybe that spillage is the lowest I can get?

Hi Anthony..Do you have pics of the projected image???maybe with that spillage level you can achieve good results.

Pictures were taken with a 2MP, Fuji Finepix 2600 digital camera, on a timer, on a stationary table source.

Source for all of these is my MythTV powered HTPC, running on FedoraCore1 with a Nvidia TI4200 in it.

The screen size is approximately 11.5' diagonally, the projector is approximately 15' from the screen. I am beginning to wonder if I'm not stretching the range of the regular lenses. This is currently projected onto a flat white wall, haven't convinced the boss I need a screen yet... but I do think I need to project a smaller picture somehow. The PJ is currently running with a bowl for a reflector, but the bowl has around a 3inch, maybe 4 inch flat bottom, it doesn't necessarily seem to help the brightness situation.

Talk Sex with Sue Johansen...




Father of the Pride, HDTV capture...

Saved!:





The Matrix:

anyone have any ideas on how to fix my severe spillage issues?

Where a condom?

The possibility exits that the bulb is not functioning properly. Perhaps it is somewhat defective. I would consider buying another bulb and compare results.

John

Hiya Anthony!

We'll see what we can do here... I haven't had time to crack into my box and check the spillage, but there is a little bit if I recall -- just depends on how "light-tight" you make your backend optics, and I haven't gone back and sealed a few leaks I have here and there with my original box, because I'm planning a rebuild.

2 things on yours, though:

1. Please take an aerial shot of your open box, showing all of the internals -- with a yardstick laying across it for reference just so we know how you have things laid out.

2. 15' might be pushing it with the standard optics -- especially if you are still not running with a Norpro and using a 350:1 monitor. 10' diagonal is about the most I can get with a decent image brightness. (I still don't have a Norpro, but I'm planning on incorporating one into my rebuild.) Builders report about a 40% average increase in output with the Norpro -- which might get you enough photons to go the full 15' if you still want to go that wide.

~DM~

Surely if there is too much spillage, it would mean the forward fresnel is too close to the triplet? Any light hitting the fresnel would be focussed down to a point at the len's focal length, therefore if the light hitting the triplet is too large the distance from forward fresnel to triplet is wrong, or am I misunderstanding something?

Well, that flat bottom is a big problem. Some of your spillage could be coming from that, but most of the errant light from the flat bottom should be rejected by the LCD.

Start by removing the reflector altogether, though, and see what the spillage looks like.


Take it easy,
Phil.

Yep, I have been going sans-crappy reflector for all alignment purposes, and all the pictures I've taken of the spillage so far are sans-reflector. I'll mess with it some more today and take some pics of what I come up with.

Thanks for all the suggestions guys.

I'm going to try this - I have the lantern so if it dosent work for the PJ I'll still get use out of it.

But it looks just like the right size for the lamp. The company is local but in process of moving to a new store so they are only doing the mail order side of bussiness right now -Once I physically get it I'll post some good photo's and measurements - It may be more suited to a Light box design but we'll see.

Are your fresnel lens placed in the right way????

220 mm focal lenght (rear fresnel)
320 mm focal lenght(field fresnel)

Grooves facing each other.

Wow, been a long time.. finally got around to taking some pictures... also finally installed the real reflector... Hopefully someone can spot what my problem is because I sure cant.

All of these pictures were taken without the LCD in, just the lenses appropriately positioned...

Something weird on my camera lens in this one...

Example of spillage I still experience..

lamp warming up...



fired up...

Looks like your bulb is to far into the Norpro.
The arc is to be 1/2 in 1/2 out with the center lined up at the lip.


peace

The lamp arc is also off center. Some minor spillage will occur but you are spilling a couple hundred lumens to the right of you projection lens. Unmount the lamp and move it when it's warming up to know exactly where it needs to be. You can only work with the lamp for about 3-4 minutes so be ready. If you have exposed 120v electrical connections BE VERY CAREFUL NOT TO KILL YOURSELF.

The problem I seem to be having is that the point of light from the lamp is the smallest at this distance from the rear fresnel, unfortunately, at its smallest is still not small enough to fit inside the triplet.. so moving the lamp to the left produces this effect:



I even tried diagonal placement, which has seemed to work for others:



I'll keep experimenting, this is just frustrating seeing as how so many other people have aligned apparently perfectly and I am having endless difficulty.