Things Newbies Should Know

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yep

Guy Grotke

Yep, you're right. I totally ignored the reflective part even though I remember reading it. I was just thinking that since I already had the optics it would be neat. Unfortunately they're not for a set of reflective LCDs. I suppose that for this kind of thig you would have to use an extra set of fs mirrors to redirect the light reflected from the LCDs into the prism. Or do they even use a prism for this type? I doubt that I could pull it off anyway, I've never been very good at sneaky stuff.
 
searching for my lcd

ok, searching for a lcd, i found my old compaq presario 1700T, and it has a 1024 x 768, 60 hertz refresh rate, 32 bit color

is that good enough

I'm wondering, am i going to run into problems if i try to use a laptop lcd, this is going to be my first project but i would still like to take the time tobuild a quality projector

p.s. - i have scoured this site for about a week, but i haven't found any actual plans for the projectors, am i missing a thread that's got some plan info
 
problems with laptop LCD

If you just want to use your projector to run windows (or linux), games, and DVDs, then a laptop LCD will work fine. Just use the built-in controller in the laptop to run it, & add a DVD player if needed.

If you also want to show other video sources (ie. TV), then it is much harder. You need hardware that can do real-time video capture for display on your laptop screen, which is hard to find for a laptop. The other option is to find a stand-alone LCD controller board, that will turn your LCD into a video monitor. That will cost you easily twice what a comparable new LCD video monitor would cost. That's why almost nobody does this.

You can buy any number of different 15" XVGA LCD monitors that do 1024 by 768 fast video with terrific contrast ratio, for under $200 US. You can also buy a tv tuner box with XVGA output to drive it, for under $80. Most of those have S-Video inputs which will give you a great picture from a cable box, satellite decoder, or DVD player, as well as a VGA passthrough for driving it from a computer.
 
jobailey32


Hi, just some ideas for you:

Toms Hardware used a laptop and an overhead projector in their project.

If your laptop has a DVD drive does it play movies well enough for you?

Do you want to play pc games and is the laptop fast enough to play all the games you want to play?

There are external pc card tv-tuner video capture devices available (expensive in my opinion).

If your laptop is in good working condition, you could sell it and use the money to pay for at least part of your projector project.

Since most people are using different LCDs, light sources and optics the plans for each projector are different.

There are some basic plans here somewhere but I couldn't find them with a quick search. I download most of them and will email them to you if you want.
 
starting with an OHP

There is one big problem with OHP-based projectors: They almost all have 10.5" by 10.5" stages, which does not match the size of the most available LCDs. You either use a 15" LCD monitor and get the edges cut off, or a 7" LCD monitor and then don't use much of the available light.

LCD projection panels ARE designed to fit, but they generally are older technology, so they have limited color depth, resolution, contrast ratio, and slow response time.

The other problem: The lamps don't last very long. (Buy some spares on eBay.)

But it is an easy way to start: You will get an image on the screen the first time you turn it on.
 
I have to ask

When trying to make a thread it comes up with 'Please search the forums'. Now that is fair enough except i have searched the forums ALOT for questions i have had, but like anyone i still have some questions which i hoped to make a concise thread about so i could get my first projector up and running. Could anyone tell me how i can by pass this to make my own thread as i don't think i am trying do something which would be unbenifical to the forum and which may help other people who are new anyway. I have read alot of the FAQs and 'newbie threads' so i do not want to start off on the wrong foot.
 
Okay, I've searched most of the forum already and would just like to hear some of your opinions and answers. I think I know what I'm going to go with, but I just want to understand this a little better.

For the experts, I'm was planning on getting an UXGA 15" LCD screen for my OHP setup. But I found out that you need a VGA controller for it since it's meant for a laptop. So that UXGA screen goes for about a little under $200 and the VGA controller goes for around $150 making it about $350 for those two components.

I'm kind of stuck here because I think I also need something for the LCD screen's power. And I was wondering if there is a VGA controller inside any random laptop that I could use to do this instead of getting a new one.

So would it be better to just settle with a XGA or SXGA LCD screen that I can get from a stand-alone 15" TFT monitor?

See... I'm a gamer and I watch movies, so I figure a higher resolution would be better, but most 15" TFT monitors usually don't come in anything better than XGA/SXGA resolutions. Do you guys think there will be a major significance between the projection quality in UXGA and XGA resolutions? And what LCD would work well if I wanted to get HDTV quality to play my PS2 on this projector using the Vdigi Transcoder?

Thanks in advance
This newbie thread is really helpful. :)
 
My following comments are based on my personal experience of making an excellent DIY projector:-
(1) The size of the projector depends on the size of the LCD screen. I have used screen of a XGA monitor 13.3" and hence my projector is much smaller than those using 15" or 17" monitor. If I have to build second projector, I will go for lowest available LCDs of XGA resolution, which may be of 7" size. As a result, the size will further come down. In commercial projectors they are using LCDs of even 1".
(2) Right from beginning I went for a standalone monitor as it had all inputs like composite, S-video, VGA and a TV Tuner. Accordingly I did not have to bother about controller cards TV Tuner card. This option was also much cheaper than buying separately controller and tuner cards
(3) I got a VDIGI converter for using component video output of my dvd player. But mostly I use VGA output of my computer
(4) I have used a long throw lens so that the projector is kept at corner of the room on top of an almirah at a distance of 22 feet from the opposite wall used as a screen. Thus my projector does not have any akward placement in the centre of the room or hanging from ceiling.
(5) The DIY Projector needs lot of final adjustments and hence right from the beginning I kept provisions for such adjustments in the design of the enclosure so that all components of the projector are adjustable from the front during operation withn reference to the final image on the screen.
(6) I am using the projector only for playing movies. I intend to use software route to enhance quality of the image further
(7) Since I am not playing games, I have no comments to offer for your specific query on games, Other memebers of the forum having experience in this field may throw light on the same.
 
Internal dvb-t analogue FM tuner card

justme said:
jobailey32


Hi, just some ideas for you:

Toms Hardware used a laptop and an overhead projector in their project.

If your laptop has a DVD drive does it play movies well enough for you?

Do you want to play pc games and is the laptop fast enough to play all the games you want to play?

There are external pc card tv-tuner video capture devices available (expensive in my opinion).

If your laptop is in good working condition, you could sell it and use the money to pay for at least part of your projector project.

Since most people are using different LCDs, light sources and optics the plans for each projector are different.

There are some basic plans here somewhere but I couldn't find them with a quick search. I download most of them and will email them to you if you want.

Hi, I recently bought a PCI DVB-T analogue FM tuner from ebay, only cost £16.00.
With postage it came to £20.00, and i can say that it is excellent at what it does.
It has an Svid input, and composite, with audio in, for adding cameras, video players, etc, so does away with the need for anything other than your PC for media playback!
I think the price was reasonable for what you can do with it.
When i get around to re-routing my broadband into the sitting room, im going to bring my PC down and use it in place of, basically, everything! i.e. video, hifi,(except for amp), Digibox etc.
:)
D2D
 
I have also recentlly upgraded my HTPC to P4 2.6 GHtz and added graphic card Asus N6200TC 256MB and DDR RAM 512MB. In ordert to improve the TV reception, I have added DTH. Hence there is tremendous improvements in the overall result. I have tried video enhancement according to which the XGA 1072x768 picture is enhanced to 1772x1000 whereby improving the sharpness.
 
manaseeker said:
Okay, I've searched most of the forum already and would just like to hear some of your opinions and answers. I think I know what I'm going to go with, but I just want to understand this a little better.

For the experts, I'm was planning on getting an UXGA 15" LCD screen for my OHP setup. But I found out that you need a VGA controller for it since it's meant for a laptop. So that UXGA screen goes for about a little under $200 and the VGA controller goes for around $150 making it about $350 for those two components.

I'm kind of stuck here because I think I also need something for the LCD screen's power. And I was wondering if there is a VGA controller inside any random laptop that I could use to do this instead of getting a new one.

So would it be better to just settle with a XGA or SXGA LCD screen that I can get from a stand-alone 15" TFT monitor?

See... I'm a gamer and I watch movies, so I figure a higher resolution would be better, but most 15" TFT monitors usually don't come in anything better than XGA/SXGA resolutions. Do you guys think there will be a major significance between the projection quality in UXGA and XGA resolutions? And what LCD would work well if I wanted to get HDTV quality to play my PS2 on this projector using the Vdigi Transcoder?

Thanks in advance
This newbie thread is really helpful. :)
Hi, 1024/768 is fine for playing games on PJ.
Not sure what res you need for HDTV, as there are a number of different HD standards, here is a link to HDTV specs,
http://www.hdtvinfoport.com/HDTV-Resolution.html
Also, where games are concerned, if you can project at 1024/768, natively, ie, not compressed, you should be fine with that, as you cant see the pixels on a projected image of 70in diagonal, unless you are within a meter of screen! I use 1024/768 for games, and 800/600 for internet, and e-mail, etc.
My mate bought a PJ retail, which stated that it was "HDTV ready!" which is'nt the same as being HDTV, as the max native resolution is 848/480! which is a bit wick, with large, visable pixels.
As my Homemade PJ has a native res of 1024/765, "yes, i know, 765 because i killed the top three lines of my LCD making PJ. :( it has a far superior definition to his, even though his brightness levels are probably higher!
Em, not sure if i answered anyones question here, but, compressed images are'nt as good as native resolutions due to compression, duh! (meant for myself, not anyone else!)

D2D

Anyway, games look great at 1024/768, they look good at 800/600, better higher!
Oh, dont spend a fortune for Laptop LCD, get cheap 15in screen, just make sure that it can be dismantled for PJ use first, my screen cost £3.50p, less than 10 dollars, and is still going strong after 8 months use as PJ.
 
Question from a beginner

Ok guys, need some help. perhaps i can find an answer on this question somewhere else on this great forum. But i have searched without any results. I have never built a projektor, but yersterday i decided to build one!

This is what i have now.

Dell 1703 fps 1280*1024 a good lcd screen. (stripped and working)

A brand lens from a magnifier (focus about 34 centimeters) I guess this is gonna work?

2 large fans + transformator. (tested and working).

Then im gonna build a "projector box" and buy a projector lamp.

Heres my question: Do i need a fresnel? Is that nessary?

Please castigate my projector and parts so i can see what to fix.

/Thanks
 
You can use those parts to make a projector, but it will have an image that is only lit in the very center of the screen. And even that part will be very dim.

Fresnels are needed to change the direction of the light rays, so more end up on the screen. If you get the right fresnels and get all the distances adjusted correctly, it makes a much brighter and evenly lit image.

You will need a 200-220 mm fl condensor fresnel at least the size of the LCD, to converge the cone of light from the lamp arc into a parallel beam to pass through the LCD. Place it at least 1 cm before the LCD, with the rings facing the LCD. The distance between the lamp arc and the fresnel should be equal to the focal length of the fresnel (ie. 220 mm).

For your 34 mm lens, you will need a 330 mm fl field fresnel to converge the parallel beam into the center of the lens. Place this fresnel about 1 cm after the LCD, with the rings facing the LCD.

You can get these fresnels from any of the online projector stores, or from www.3dlens.com. They are the most common set of fresnels for a DIY LCD projector. Get acrylic or polycarbonate fresnels, not the cheap vinyl ones.
 
More help about fresnels!

carl-johanS said:
Thank you very much!
I looked att 3dlens.com. Good site with great prices. But i don�0…7t understand witch fresnels i should buy. :xeye:
I need two, one fresnel behind the LCD and one infront of the LCD. And the Focal lenth shoud be from the lamp to the LCD and through the LCD to another fresnel going to the lens with the right focal lenth.

I would be thankful if someone could just give me a link or example for whitch fresnel going behind / infront of the LCD.

/Thanks hope you understand my crapy english ( Im a 15 years old swedish student).
 
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