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Author Topic: DIY Projector Help
Peter Berrett
Jedi Master Film Handler

Posts: 602
From: Victoria, Australia
Registered: Nov 2000


 - posted 08-07-2006 06:15 AM      Profile for Peter Berrett   Author's Homepage   Email Peter Berrett   Send New Private Message       Edit/Delete Post 
Hi all

Today I just purchased a projector - an overhead projector to be exact. My plan is to build a simple low cost lcd projector by getting a lcd panel and hooking it up to a dvd player.

I have done this once before with some limited success. The main problems I experienced were

(1) the OHP was too noisy and

(2) the throw wasn't long enough.

(3) The OHP sat where I wanted to sit.

So I sold my equipment and left it at that.

However recently I thought I'd have another go at the same idea so I bid on an OHP on Ebay. I picked up a Gilkon 250W OHP for $A51.50 which was a bargain.

I have just taken it home and fired it up and had a pleasant surprise. The OHP is unbelievably quiet which makes it idea for a home projector setup. The lumens arent huge but in a darkened room it should be ok.

However I have noticed one immediate problem. At a distance of about 2 metres it throws up an image of about 1 metre in diameter. That is ok but I am wondering how one could increase the throw distance? I find that if I increase the distance between the glass/fresnel & the lens the image gets smaller however after a point it starts to lose focus. And the further I pull the OHP away from the screen the larger the picture gets (a lot larger)

I have heard that one can buy long throw lenses but the prices I have seen advertised have been pretty high. Has anyone any suggestion (at minimal cost) on how I could increase projection distance without sacrificing image quality or making the image too big?

If all fails I can just sell the OHP and probably make a tidy profit but I see that if I can iron out a few problems I can probably end up with a half decent DIGITAL projection arrangement.

Hopefully my working system will one day looks like this

http://www.denguru.com/2004/11/13/supersize_your_tv_for_/index.html

At least I have so far solved the noise problem. It's a fun project to build. When the weather warms up it will be great to try out projecting some dvds.

Regards Peter

[ 08-07-2006, 08:36 AM: Message edited by: Peter Berrett ]

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Paul Mayer
Oh get out of it Melvin, before it pulls you under!

Posts: 3836
From: Albuquerque, NM
Registered: Feb 2000


 - posted 08-07-2006 09:39 AM      Profile for Paul Mayer   Author's Homepage   Email Paul Mayer   Send New Private Message       Edit/Delete Post 
I would assume those long-throw OHP lenses should be out there and readily available as surplus, perhaps on eBay or through the local university. For instance, the USAF used hundreds of them as standard equipment in lecture halls and briefing rooms at all of their major bases and installations. And virtually all of them have been replaced by the now ubiquitous PC running MS PowerPoint. So they should be out there, at prices far below new.

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Phil Blake
Jedi Master Film Handler

Posts: 558
From: esperance western australia
Registered: Nov 2003


 - posted 08-08-2006 01:43 AM      Profile for Phil Blake   Author's Homepage   Email Phil Blake   Send New Private Message       Edit/Delete Post 
This all sounds very interesting Peter , I had a browse over the link , correct me if I am wrong , but the process just involves taking the LCD display from a 15" PC monitor and draping it over a OHP and bingo you have a big screen tv ?

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Peter Berrett
Jedi Master Film Handler

Posts: 602
From: Victoria, Australia
Registered: Nov 2000


 - posted 08-08-2006 04:24 AM      Profile for Peter Berrett   Author's Homepage   Email Peter Berrett   Send New Private Message       Edit/Delete Post 
Thanks Phil

That is it at its simplest. Mind you you can go further than that such as modifying the overhead projector to have metal halogen lighting and,as I am interested in doing, modifying it for a longer throw.

But some even want to go further - building the whole lcd projector from the bottom up Some of the results are pretty impressive too. I'd post a link to the photos but apparently posting links to other forums is a no-no.

Here is however another link to a DIY home projector made easy.

I realise that some are quietly laughing at this whole idea but I will post the results when I get a suitable lcd monitor or panel and people can judge then.

Regards Peter

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Phil Blake
Jedi Master Film Handler

Posts: 558
From: esperance western australia
Registered: Nov 2003


 - posted 08-08-2006 07:56 AM      Profile for Phil Blake   Author's Homepage   Email Phil Blake   Send New Private Message       Edit/Delete Post 
Is it particularly difficult to connect a video input source into the lcd display ?

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Paul Mayer
Oh get out of it Melvin, before it pulls you under!

Posts: 3836
From: Albuquerque, NM
Registered: Feb 2000


 - posted 08-08-2006 10:44 AM      Profile for Paul Mayer   Author's Homepage   Email Paul Mayer   Send New Private Message       Edit/Delete Post 
The ones I used to use had the standard DB15HD (or was it DB9? [Smile] ) VGA and RCA video inputs - connecting things up were as straightforward as with any other other home video device.

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Peter Berrett
Jedi Master Film Handler

Posts: 602
From: Victoria, Australia
Registered: Nov 2000


 - posted 08-09-2006 05:57 AM      Profile for Peter Berrett   Author's Homepage   Email Peter Berrett   Send New Private Message       Edit/Delete Post 
That is correct.

I used to own a Panelbook 550LS. It had a standard RCA input. If I recall correctly there was also a plug for connecting one's computer - I think this may have been a monitor style plug.

From a picture perspective the biggest problem was contrast ratio and second to that perhaps lack of light in semi-lit conditions. The colors on older panels such as this were also a little mettalic.

One alternative to a lcd panel is to use a TV Box along with the lcd stripped from a 15" lcd monitor. This gives 1024 x 768 resolution. Newer monitors have better refresh rates (better for video) and presumably have better color. The TV box takes a VGA input and will scale the picture up to the monitors resolution. They are not very expensive.

Time for LCD Panel 101

http://www.diyprojectorcompany.com/theory/lcd.php

Regards Peter

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Christopher Meredith
Expert Film Handler

Posts: 126
From: Jackson, MS, USA
Registered: Apr 2006


 - posted 08-09-2006 09:22 AM      Profile for Christopher Meredith   Author's Homepage   Email Christopher Meredith   Send New Private Message       Edit/Delete Post 
You could always just buy a digital projector for $300...

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Peter Berrett
Jedi Master Film Handler

Posts: 602
From: Victoria, Australia
Registered: Nov 2000


 - posted 08-09-2006 11:43 PM      Profile for Peter Berrett   Author's Homepage   Email Peter Berrett   Send New Private Message       Edit/Delete Post 
???

Where can you buy a digital projector for $300?

cheers Peter

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Christopher Meredith
Expert Film Handler

Posts: 126
From: Jackson, MS, USA
Registered: Apr 2006


 - posted 08-10-2006 07:51 AM      Profile for Christopher Meredith   Author's Homepage   Email Christopher Meredith   Send New Private Message       Edit/Delete Post 
eBay. Would have linked but apparently, that's not allowed.

I got my ScreenPlay 4800 (X1) for $300 and an auction for one ended yesterday just over $300. A couple weeks ago, one sold for $275. It's a little hit-and-miss, and this is only for this particular model (Infocus Screenplay 4800/X1). You might have just as good luck (or even better) looking for other makes and models.

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Phil Blake
Jedi Master Film Handler

Posts: 558
From: esperance western australia
Registered: Nov 2003


 - posted 08-10-2006 07:58 AM      Profile for Phil Blake   Author's Homepage   Email Phil Blake   Send New Private Message       Edit/Delete Post 
My Middle name is McGiver , so i am going to have a crack at this Peter.
More fun than surfing Ebay.
Will keep you posted.

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Peter Berrett
Jedi Master Film Handler

Posts: 602
From: Victoria, Australia
Registered: Nov 2000


 - posted 08-10-2006 07:26 PM      Profile for Peter Berrett   Author's Homepage   Email Peter Berrett   Send New Private Message       Edit/Delete Post 
Thanks Phil

The lumenlab site & forums has lots of useful information.

Are you going to use a OHP or build the projector yourself?

Regards Peter

[ 08-10-2006, 09:44 PM: Message edited by: Peter Berrett ]

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Phil Blake
Jedi Master Film Handler

Posts: 558
From: esperance western australia
Registered: Nov 2003


 - posted 08-12-2006 08:22 AM      Profile for Phil Blake   Author's Homepage   Email Phil Blake   Send New Private Message       Edit/Delete Post 
Peter it looks like I will be using an OHP , as luck has it one of my staff here has an Ex school one they don't want so already I have the OHP.
"McGiver" is making fast progress.

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Peter Berrett
Jedi Master Film Handler

Posts: 602
From: Victoria, Australia
Registered: Nov 2000


 - posted 08-12-2006 08:54 PM      Profile for Peter Berrett   Author's Homepage   Email Peter Berrett   Send New Private Message       Edit/Delete Post 
No problems McGiver

Next you will need either a lcd panel or a monitor.

If looking for an lcd panel here re some links that will help. Make sure you get an active matrix one and do some research on the lumenlab forums to see how others have found the panel.

Some useful links

Projection guide

Lcd Panel Guide

DIY Cinemas

DIYBeamer (Dutch)

And if you are like me and inspired by the idea of havng a drive-in in your own backyard you are not alone - check out the pics!

Backyard Theatre

Quite inspirational these setups.

I am at the same stage as yourself and am looking around for an lcd panel. One went on Ebay for about $A100 just recently. In hindsight I wish I had bid on it.

cheers Peter

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99


 - posted 08-16-2006 08:33 AM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
You might want to consoder using LED's. They don't make much noise....
DIY LED/DLP Projector

It is possible to build a color DLP based projector without a color wheel... sequential RGB LED's.....

There are a bunch of other threads also doing what you've done there at this same site.

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