So, I'm beginning my second projector, hopefully it will be a summer project.

I plan on using:
$200-Pro lenses from LL
$290-10.6" LCD from johnzo
$260-15.4" WUXGA LCD and Realtek-based controller
$20-40-I will make the box as fancy as I can, still out of MDF, I've found it to be relatively fire-safe! Plus, it's easy to cut.

Now, I was originally planning on a 400w bulb, but would a 150/250w with precon and reflector be cheaper, and can you get equal brightness as a 400w with a precondensor?
If a smaller bulb is indeed better, could anyone please provide links or references as to where to buy the lamps and ballasts? I will be looking myself, but I would probably not be able to find the best bulb.


May 03, 2007: I just looked at the LED thread, and that could be another possibility depending on how they are doing on that in a couple weeks.

I'm definitely going with LEDs. The number of LEDs will be determined by the final application of the projector(commercial theater v. home use). Also I'm still kindof debating between white and RGB/RGGB.

July 09, 2007: Some information from the RGB LED thread with phuttons project:
White 6500k light = 3 Lux Red, 6 Lux Green, and 1 Lux Blue. (Quoted from johnzo1995)

So for me, this means that the Luxeon K2's have the best natural color balance, all running at full power. (This would be R=40-45LM, G=87-100LM, B=18-21LM)

Aug 09, 2007: I may end up using a 400w bulb after all, on one condition; If I can get a parabolic/elliptical reflector to work.

Aug 29, 2007: Changing over to a 575w double-ended bulb (if I can get a ballast) with precondensor and eventually reflector. I've seen some encouraging results from people using this bulb, and it will allow me to make a more compact design.

Sep 15, 2007: I recieved a pro reflector 2 days ago (thanks sushijess), and some plano-convex lenses yesterday(from SurplusShed). I've temporarily put the pro reflector in my existing projector, and I believe it does make it a bit brighter. I haven't done much testing with the precons, I don't want to crack them yet.

As for the enclosure, a friend helped me make one all out of metal, but it actually isn't so much lighter like I thought it would be, and it's BIG. It works well for a straight-shooter with the pro lenses, but I want to try to make it small, small enough to be easily carried by one person, especially through doors, etc. So it needs to be short. I'm working on a design that may turn out to be as small as 21" long x 15" wide x 15" tall(533.4x381x381mm).

I am planning on using the lens shifting technique that is used in the commercial units that have been modded recently, I am using jonjandran's in particular as a model.

Keep in mind that the fresnels center point has to be adjusted also. In other words in a standard build the center of the fresnel stays in the center even with the center of the Lcd. In the Ask , the fresnles center is NOT in the center. It is adjusted up/down for the lens shifting. I will have to recheck for sure to see if it is up or down and how much because i can't remember right now.

So that means that if I was to make the lens shifting angle adjustable, the point around which everything would rotate would be beside the LCD, right? Thats what it looks like from the pictures of the commercial PJs.

One thing I'm stumped on. I will have much better tools to make fancier things than I made for the first projector, but I can't figure out a way to make it so that the triplet can slide back and forth for focusing, and up/down for lens shifting. It has to be able to slide vertically along the front of the box, while 1)staying perpendicular to the LCD, and 2)not leaking light out the front of the projector.

I could do one or the other, but cant figure out a way to do both. Even if it was just a little adjustable would be ok, like from straight shooting to angled up a few degrees.

Try this.



The black areas are track material that you can buy at any hardware store. The brown is a piece of wood. The red circles are wing nuts.

You mount the triplet to the wood. Then mount the wood/triplet to the left and right tracks. Now it is adjustable up and down.

Now put the wing nut bolts through the top/bottom tracks and then mount the tracks to the box where you need them with screws. Then attach the triplet sliding mechanism to the top/bottom tracks with the wing nuts. Now the whole mechanism will slide left/right.

Now the piece of wood I drew small so you could see the tracks. But you will want to make it larger than the tracks. About as large as the outside brown box I drew. Then you cut the hole in the front of your box big enough for an inch or two of up/down left/right triplet movement. The larger piece of wood on the inside will still cover the outside hole no matter how far you move it ,covering all light leaks.

Easier done than shown I think

Ah, yes but a good idea! Excellent, now you've got me thinking-I can't wait to get home to make this thing!!!!!

My issue was that I couldnt make the back piece big enough inside the box to allow for covering the enlarged front hole while at the same time allowing for enough movement of the triplet assembly.

Ok, so the triplet movement is 1/3*length between inner edge of box and outer edge of triplet housing.


Pic soon.

Edit:Pic now!

-The black outline, obviously the box.
-The brown stripes on the side are tentatively there and will be to mount the fressies and bulb assembly, and to move the triplet up and down possibly. Basically the vertical shifting control. They are mounted to the sides of the box by rod/dowels next to the LCD.
-Light blue=fresnels, red=LCD, dark blue=pro triplet
-Grayish tinted square is the front piece that the triplet is mounted to, and is riding on tracks like jonjandran said.
-Lighter center rounded area is the enlarged triplet cutout in the very front of the PJ.
-This design allows for .855 inches of vertical travel - is this enough?
That is all.

Ok, I figured it out,
at a 100" diagonal image, if I move the triplet up .855", the projection will move up about 8".

So I think I will want more movement there. I will be thinking about that.

Good start though.

New idea for the front piece:

I concluded that 8" movement of a 100" diagonal projection is simply not enough, I think that lens is capable of much more. So the design is largely the same except for 3 major points,
1. The hole in the front piece of the box will be larger to accomodate more movement-not sure how much yet.
2. The piece the triplet is mounted to will also be larger, to cover the larger hole while being able to move further off-center at the same time.
3. There will be slots in top and bottom, to allow the triplet piece to stick out while keystoned. I think I can work it out so there are no light leaks. We will see.

I realised that making vertical and horizontal image shifting would be such a pain with the fresnel tilting in 2 directions. So instead, to keep it versatile, I am going to make only vertical lens shifting, but make it so the LCD sled can be put in sideways, and the projector can be run on its side. Thus making either horizontal or vertical keystoning possible, just not at the same time. Depending on how far it can move to the side (I'm hoping alot since this pro lens can handle a 19" widescreen), it may prove useful to have the horizontal keystoning.

You can also put foam strips between the box and the inside piece of wood. Just cut it and put it around the triplet hole on the inside and then screw in the tracks and attach the wooden piece with the triplet on it. The foam will stop any major light leaks.

Good idea, not exactly what I was thinking, but it would help. I meant light leaks from the top and bottom, since the top and bottom sides of the box will not extend all the way to the end, so as to leave room for the triplet mount piece to stick out when lens shifting. Also, using this design, the wood that the triplet is mounted to will not be able to move back and forth(for focusing). It will need to be flat against the front piece (and foam) all the time, to prevent light leaks.

So for focusing, I will have to figure out some way to move the triplet back and forward in its moving wooden piece. I will probably go with telescoping PVC, since it seems easiest... Whatever I do should not make the effective outer diameter of the triplet too much bigger, because that will hinder shifting ability.


More later.

I thought you would just go with the small box into the bigger box method for focusing. You know where you slide the whole triplet assembly in and out of the main box. It would only have to be about a 6" square triplet box.

The 'frosted' (for lack of a better term) square in my images represents a wooden (probably 1/4" thick) board that the triplet will be mounted to. I need the mount for the triplet to have the least amount sticking out in front of that board, because it would interfere with the hole in the front piece. The box in box would simply have too much material sticking out the front around the triplet.

With my updated design, the lens can shift up and down about 1.75 inches.
This means that for a 100" diagonal screen (54" tall), the projection can move up and down about 16.5", or 30.5% of the image height. That sounds OK to me. Still will want to test first

edit: pic here:


This shows the lens centered, and then shifted up.

I also added a side view of the lens centered and shifted up-the picture does not illustrate the focus mechanism yet as I dont know what I will use yet.

Finally, I added a pic demonstrating how the panel would look of put in sideways for horizontal shifting. The projector would obviously have to be rotated as well, so the screen projected right side up.

One last thing-

An additional motivation for using LEDs, is with a MH bulb, I will NOT know how to integrate a reasonable cooling system for the LCD/fresnels with all this lens shifting business...

So I think I'm going LED-

Probably getting these parts from: Future Electronics
Part# Mfr-----LXK2-PW14-U00 : Product Details
Description---Luxeon K2 High-Power White LED Lambertian Emitter

Pkg Qty-------1
Unit Price
(USD)---------3.4500

Qty------------52
Amount
(USD)---------179.40

******************

Part# Mfr-----OP-005 : Product Details
Description---Lens for Luxeon K2 High-Power LED

Pkg Qty-------1
Unit Price
(USD)---------0.8700

Qty------------50
Amount
(USD)---------43.50

******************

Total(USD)---$222.90

I may order a few of these before I get the whole bunch, to see if I will be satisfied with the color, brightness, and uniformity.

Tonight I found a neat site that custom makes 3D forms. I am planning on having several made, and this projector is turning out to be a prototype for if I decide to sell a few projectors. I am still hoping to find a good source for LEDs, and be able to use them in the design. It would be nice to have projectors where you never have to replace a bulb. Even if it costs more in the beginning.

I know selling projectors is controvercial among some, but I am just a college student looking to make some money, and I love designing these things. It would also give me alot of experience in businesswork. I've learned alot from watching my parents start up a business, and would like to use some of that knowledge.

Okay, I brought my first projector into the movie theater where I work, and set it up in the smallest theater. The screen area is approx. 7sq meters. This would go in my first projector completed section, except that the purpose of this set-up is to demonstrate to my manager that digital projection could be possible for the theater, maybe even for the larger screens.

My first projector uses a 15" HP LCD, 400 watt setup, eBallast, no reflector/condensor. It just barely works IMO, but I am picky.

At first glance, the manager saw the moire effect from the holes in the screen material interacting with the RGB stripes. I didn't anticipate this, but I think with good alignment. higher resolutions, and a bit of soft focusing, this should not be a problem. I could almost make it invisible with my current setup. Some of the moire effect you will see is from the camera too.

Second, there is vignetting, which I hope to eliminate with an LED setup. It is not too bad, and even a condensor with a smaller bulb setup would make it acceptable. As expected, the screen material causes no hotspotting.

Third, probably most important is brightness. I can spend alot on LEDs for this setup. Like $1,000 USD. However, I have to make sure LEDs will work the way we want first. They should. Cross your fingers. Someone might die if they dont work. Phutton.

Have fun:

This one is an image of the film projector on a bigger screen. I think this is the second largest screen(out of seven).


Here is a co-worker in front of the screen. He is a bit taller than me.

With a bit more work you can get it better. But I think a 15" panel is going to show the pattern no matter what. Your magnifying it so much. A higher rez. might be a bit better.

Oh yes, I'm planning on at least 1280x720 for that screen, and 1920x1080 for the larger screens.

I measured the two largest screens in the theater last night-the one in the last post is about 17 feet wide, the largest is about 20 feet, 2 inches wide.

Just thought I'd put it out there.....so I dont forget and have to measure them again

Hey again, I think I've found something about the glowies that has been discussed in Ronins PLOG alot, and didn't want to flood his thread with pics, so:

And after about 5 minutes:


You can see, the bottom of the screen becomes light even after only 5 minutes of being on. It is all black again if it has been off for a long time. I think (most) of the glowies are from our LCD panels getting even just warm in our projectors.

Edit; I think these glowies are just from the backlight getting brighter after warming up.

No update for a while - I've become interested in elliptical reflectors again , and want to see if I can make one work with the pro triplet, maybe even not needing any fresnels!

We will have to see, I know there is a dark spot in the center as a result of the bulb, but if the light is perfectly aligned so that at the LCD, the diameter of this spot becomes zero, then it would not appear in the projection of the LCD. Only issue I need to work out, is whether I can do this and at the same time make all of the light go into the triplet, which would be at F2 of the reflector.

OK, so I may be getting a damaged reflector the same as the movie theater ones to experiment with my bulb and triplet. They won't let me use a good one, because naturally the reflector costs like $700, and the reflective coating another $700

Again changing my mind.......

I'm looking at precondensors from surplusshed, and have narrowed it down to 2 that might work well in my setup. The 575w double ended bulb has a radius of about 12mm max at the globe part, which would leave it just about touching for both of these precons. With a lightbox and alot of airflow, could cracking be prevented? What if the air leaving the lightbox reflowed over the front of the precon, helping to even out the temp difference between back-front?

Another question, would an anti-reflective coating be a good or a bad thing on the precondensor? One of them has an option to have a coating. I think they are both made of crown glass.

Calculator I used to see how the precons would work.

First one, would provide highest gain according to the calculator(50mm dia, 30mm FL, aspheric):
http://www.surplusshed.com/pages/item/l3467.html
Second one, similar to the first, with broadband anti-reflective coating(55mm dia, 38.5mm FL, aspheric):
http://www.surplusshed.com/pages/item/pl1014.html
Second one without coating:
http://www.surplusshed.com/pages/item/pl1032.html

I'm using a 220mm FL fresnel, 15.4" 16:10 LCD.

Thanks for any help!

One more thing, concerning the 575 watt lamp;

Looking through this PDF, there are several ballast options listed, but I can't find any of them online. Wouldn't these be sold by themselves somewhere(instead of having to rip ballasts out of overhead projectors)??

Hi

Why dont you look on ebay for a broken old dukane projector? the 680 has the 575W bulb inside it, and, after stripping my one down the other month i can say its not hard to work out how to use it all

I would, but I can't seem to find them anywhere.

Instead (when I get the money..), I'm going to use a 600 watt HPS, S106 ballast, with different capacitors to create close to 575 watts. ArizonaVideo has been helping me along with this idea, and the only downside is that those ballasts are huge and heavy. Other than that, they are reliable, quiet, and efficient(will run cool). And they aren't as rare as the Dukane 680.

Any updates?????

Haha, I didn't expect this to come up again. I built a (huge) metal enclosure for a WUXGA and the pro lenses, but never really put it together since it was too big to take to school. It's still here in my room, but I've pretty much stopped work on it since I bought a commercial projector from a fellow member...

Thanks for asking though!