Tell Us About Your Picture Quality!!

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Mitch,

Seems to me like you want to open up a clam and find a diamond. Remember, these are home made projectors. no possible way of getting HDTV quality with the lcds and the modules we are using. they have limited resolution. HDTV (for the moment) is for the big boys.

ap0the0sis
 
not necessarily...

i had one panel that i just sold that could do 1280x1024 res. with appropriate converters, a HDTV signal could be fed into a computer, and then into the panel. however, it was a slow refreshing panel, so it kinda blurred.

if any of you are veterans to this project (which most arent), you will know that this whole idea was started becuase vdi_nenna wanted a professional grade projector... not home-made. it all started with wanting VERY high res ,high quality, not the stuff that is being built now. it is possible, it just costs money. no one wants to spend $1K on this project. seems more like $200 is the limit. but at that price, you get what you pay for.
 
Thats right

cowanrg has a point. If you want to drop 1k on the project you might as well just save your money and try to get lucky on ebay. At least that way you would be assured a professional product.

In the mean time there are a lot of people doing a great job on this thread. And if you want to spend $500-$700 on a high qual lcd monitor and then rip it apart to get hdtv quality resolution, go for it. This place is all about trying things out. However, before you spend that kind of money you should research all the parts that you need and make sure everything is compatable. and usable.


Joe
 
well said, tech head.

why spend $2K+ on a laptop just to get the screen out of it? when you can go and buy a screen for less? and then to have that laptop create limitation for you? such as tv inputs, cable spacing, etc...

look at the ultimate goal. a high res LCD panel. the attached DVD is nice, etc... but a desktop monitor has that. plus, who wants to reach up to the ceiling, or take apart a projector just to put in a DVD? not i.
 
true... true,

but my point was that everyone is using regular lcd panels and 4" video monitors etc. i havent seen one person yet trying to build a high resolution setup because of cost, for that you just go purchase one on ebay. but as far as DIY, the common is 800X600 which will not provide HDTV, at least not like in commercial PJs.


ap0the0sis
 
Hi guys
I understand that those little monitors aren`t going to produce a plasma TV for me. But I`m going to be spending about $500-600 USD on this. That includes the Da-Lite Rear Projection screen.
See, it seems that everybody else is setting their projectors about 10 to 15 feet away from the screen. I`m going to buy a 6X lens and use a 14" computer LCD screen, use the size control and make the picture about 11x8", then stick the projector behind the rear projection screen (which will be built into the wall) as close as I can get it to the screen and still have a 48 x36" picture.
I know I`ll proabbly have to mess with the focus alot, and buy a brighter backlight, but I`m convinced that I can get a very good quality picture that way.
I`m sure everybody here started out by looking at the 100" Projection TV!!! thing going around the net so everybody here has probably been to that BSTV site where they show you how to build it.
And probably everyone has see the picture quality they got with that. The picture of the guy jumping down frm the wrecked airplane with army guys all around him. Thats not bad quality for a trashy TV.
So I asked myself, what kind of quality could you get with a LCD screen with a brighter backlight and setting the projector really close to the TV? I`ve read that the closer to the screen the projector is, and the smaller the picture is, the better the quality.
Seems to me that this would almost have to give me alot better then the picture they got.
I`ve done tons of research on this, but I`m still a newbie at it. So I`m sure you guys know a heck of alot more than I do. Please tell me what you think of my little plan...

Thanks,
Mitch
 
Mitch said:
Hi guys
I understand that those little monitors aren`t going to produce a plasma TV for me. But I`m going to be spending about $500-600 USD on this. That includes the Da-Lite Rear Projection screen.
See, it seems that everybody else is setting their projectors about 10 to 15 feet away from the screen. I`m going to buy a 6X lens and use a 14" computer LCD screen, use the size control and make the picture about 11x8", then stick the projector behind the rear projection screen (which will be built into the wall) as close as I can get it to the screen and still have a 48 x36" picture.
I know I`ll proabbly have to mess with the focus alot, and buy a brighter backlight, but I`m convinced that I can get a very good quality picture that way.
I`m sure everybody here started out by looking at the 100" Projection TV!!! thing going around the net so everybody here has probably been to that BSTV site where they show you how to build it.
And probably everyone has see the picture quality they got with that. The picture of the guy jumping down frm the wrecked airplane with army guys all around him. Thats not bad quality for a trashy TV.
So I asked myself, what kind of quality could you get with a LCD screen with a brighter backlight and setting the projector really close to the TV? I`ve read that the closer to the screen the projector is, and the smaller the picture is, the better the quality.
Seems to me that this would almost have to give me alot better then the picture they got.
I`ve done tons of research on this, but I`m still a newbie at it. So I`m sure you guys know a heck of alot more than I do. Please tell me what you think of my little plan...

Thanks,
Mitch

I see some problems with your approach.

1. Where are you planning on finding a 14 inch hdtv panel for cheap? A hdtv panel will likely cost more then your whole budget for this project.

2. Many lcds don't allow changing of the actual picture size. Some like the Viewsonic vg150 do but it causes major distortion. Even if it didn't cause distortion you still have the problem of why make the picture smaller?? The light doesn't get more focused on that one part of the screen.

3. Why not just build a custom box with your lcd panel? Or use an Overhead projector. Because with your fresnel and all thats pretty much what you are doing.

4.Brightness will be an issue. The one picture on that one website of the army guys probably didn't come from one of the 100 inch projectors. LCD's generally aren't as bright as CRT"s. Take an lcd in complete darkness and then take a crt monitor the same size and see which one is brighter.

5. With a big enough lens you should be able to get your projector fairly close to the screen and still have a fairly large picture.


My plan for you would be to buy a good metal halide overhead projector. A good overhead projector panel like one of the later infocus or sharp panels these are MUCH MUCH easier to use for projection then a deksktop panel and about the same res. Then buy a rear projection screen.
 
Hey, thanks for the input. I appreciate any I can get.
I wasnt planing on getting an HDTV, I`m going to get a LCD Computer monitor. The flat panel,... ya know what I`m talkin about? Then I`m going to put in a brighter backlight of at least a couple thousand lumens.
I think I have no reason not to believe that the picture of the army dudes was real cause this website wasn`t making any money off of it, it was just showing people how to make it so there`d be no reason to decieve.
Um, you brought up something that I`ve been wondering. I see all those peoples results of their projectors (the box itself) and they`ll have like a 13" screen, but their magnification lens is about 6 inches wide. How does that 13" picture fit through the lens?
Also, do you know how an overhead projector costs?

Thanks,
Mitch
 
Mitch said:
Hey, thanks for the input. I appreciate any I can get.
I wasnt planing on getting an HDTV, I`m going to get a LCD Computer monitor. The flat panel,... ya know what I`m talkin about? Then I`m going to put in a brighter backlight of at least a couple thousand lumens.
I think I have no reason not to believe that the picture of the army dudes was real cause this website wasn`t making any money off of it, it was just showing people how to make it so there`d be no reason to decieve.
Um, you brought up something that I`ve been wondering. I see all those peoples results of their projectors (the box itself) and they`ll have like a 13" screen, but their magnification lens is about 6 inches wide. How does that 13" picture fit through the lens?
Also, do you know how an overhead projector costs?

Thanks,
Mitch

Overhead projectors are not that much money used buy them at thrift shops or on ebay all day long. It's going to be hard to get a better backlight for your lcd panel. The way I think the lens works is it has to be several inches away from the panel this lets the lens get far enough that it can see all the image which it projects. But with all the trouble to modify a desktop panel a good projection panel is much cheaper and easier.
 
6X? I don't Think So...

I`m going to buy a 6X lens and use a 14" computer LCD screen...

A 6X fresnel lens? There is no such thing as a 6X fresnel (100" projection tv lens sold on ebay) lens that would be the size you need. People say that sell them, but I have talked to the top manufacturer in the trade, the bigest is a 3X 7" by 10" lens. Did you mean 6X fresnel, or are you are getting a real projector lens. I suggest the delta IV... It's about 30 bucks on ebay
 
ohp dukane 4003

i am looking for a second dukane 4003 which i am going to completely take apart and keep the bulbholders, fan. mirrors and all the lenses
all these things are put in a new casing horizontally with a cone between panel and prejection lens so no light bleeds away in a disturbing mode.
i think that will be my ultimate before going on a hunt for a real lcd projector - i have made 3 diy projectors and assembled 2 with a lcd panel. one more and i retire!
 
Flat screen monitor for panel, works for me!

I have been monitoring these forums for a while, lots of good info. I just bought a flat screen monitor from Best Buy for $220 (after rebate) with the intention of converting it into a projector. I got the KOGi 14.1" screen and took it apart. It had what I expected to find, two boards one on the top and one on the side of the screen which were connected via a little flat brown cable. The cable had 16 connections on it, but on closer inspection, I discovered many are duplicates, and only 8 wires are really needed. I soldered tiny wire wrapping wire directly to both circuit boards (this was not easy and not for the faint of heart), ignoring the flat cable. I moved the boards out of the way, put this on an overhead projector (just to test, think I will build it into a better box eventually) and turned it on. I was treated to a very nice (1024 X 768) looking picture of my windows screen on my wall. I am wondering if anyone else has taken this approach, it only took me a few hours to add the wires. Perhaps I am missing something that is bad about this setup? One thing I did have to do was modify my overhead projector so the whole panel was in view, but that was just a little plastic cutting. Perhaps there is a place to get extensions for those flat cables also, but careful soldering worked fine for me.
 
Re: Flat screen monitor for panel, works for me!

yander26 said:
I have been monitoring these forums for a while, lots of good info. I just bought a flat screen monitor from Best Buy for $220 (after rebate) with the intention of converting it into a projector. I got the KOGi 14.1" screen and took it apart. It had what I expected to find, two boards one on the top and one on the side of the screen which were connected via a little flat brown cable. The cable had 16 connections on it, but on closer inspection, I discovered many are duplicates, and only 8 wires are really needed. I soldered tiny wire wrapping wire directly to both circuit boards (this was not easy and not for the faint of heart), ignoring the flat cable. I moved the boards out of the way, put this on an overhead projector (just to test, think I will build it into a better box eventually) and turned it on. I was treated to a very nice (1024 X 768) looking picture of my windows screen on my wall. I am wondering if anyone else has taken this approach, it only took me a few hours to add the wires. Perhaps I am missing something that is bad about this setup? One thing I did have to do was modify my overhead projector so the whole panel was in view, but that was just a little plastic cutting. Perhaps there is a place to get extensions for those flat cables also, but careful soldering worked fine for me.

hi, yander, I have the same kogi 14.1" and the top and side PCBs that need to be soldered are exactly like you described. I noticed 8 gold solder pads next to the connector on the top PCB which I assume you soldered to 8 of the pins on the side PCB. exactly which pins did you solder, and what is this "tiny wire wrapping wire"? just some sort of insulated (shielded?) wrapped 8 conductor wire? and what was the max length of your wires?

thanks
 
Re: Re: Flat screen monitor for panel, works for me!

rusty42 said:


hi, yander, I have the same kogi 14.1" and the top and side PCBs that need to be soldered are exactly like you described. I noticed 8 gold solder pads next to the connector on the top PCB which I assume you soldered to 8 of the pins on the side PCB. exactly which pins did you solder, and what is this "tiny wire wrapping wire"? just some sort of insulated (shielded?) wrapped 8 conductor wire? and what was the max length of your wires?

thanks

The "tiny wire wrapping wire" is just single strand insulated wire used for making circuit boards that are done with a wire wrapping method. But all that doesn't matter, its just really small single strand insulated (not shielded) wire. I used 8 length's of this (actually 9 since I doubled the grounds) and made the wire about 6" long, but make them as short as possible. I did use those gold pads next to the connector to solder to. On the other board I soldered to the board where the cable is soldered to (a pain in the ***). If you look at the board with the 8 gold contacts and trace them to the connector (right next to it) you can see which pins are doubled and which are not. I would post some pictures but I got kicked out of my apartment so everything is in boxes at the moment. I am interested if you experience one problem that I noticed. I found that the top of the picture was darker than the bottom when I was projecting a uniform dark color such as the blue of the windows screen, on lighter pictures and video from a DVD the image looked fine. I was going to shorten the length of my wires and see if it helped, although I am not sure that's the cause of the problem and it wasn't noticeable with video anyhow. Let me know how you make out, as I haven't finished my project yet, due to not having a home.
 
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