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Posted by Peter Berrett (Member # 672) on 08-07-2006, 06:15 AM:
 
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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Posted by Paul Mayer (Member # 355) on 08-07-2006, 09:39 AM:
 
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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Posted by Phil Blake (Member # 2012) on 08-08-2006, 01:43 AM:
 
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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Posted by Peter Berrett (Member # 672) on 08-08-2006, 04:24 AM:
 
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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Posted by Phil Blake (Member # 2012) on 08-08-2006, 07:56 AM:
 
Is it particularly difficult to connect a video input source into the lcd display ?
 

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Posted by Paul Mayer (Member # 355) on 08-08-2006, 10:44 AM:
 
The ones I used to use had the standard DB15HD (or was it DB9? ) VGA and RCA video inputs - connecting things up were as straightforward as with any other other home video device.
 

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Posted by Peter Berrett (Member # 672) on 08-09-2006, 05:57 AM:
 
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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Posted by Christopher Meredith (Member # 3767) on 08-09-2006, 09:22 AM:
 
You could always just buy a digital projector for $300...
 

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Posted by Peter Berrett (Member # 672) on 08-09-2006, 11:43 PM:
 
???

Where can you buy a digital projector for $300?

cheers Peter
 

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Posted by Christopher Meredith (Member # 3767) on 08-10-2006, 07:51 AM:
 
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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Posted by Phil Blake (Member # 2012) on 08-10-2006, 07:58 AM:
 
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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Posted by Peter Berrett (Member # 672) on 08-10-2006, 07:26 PM:
 
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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Posted by Phil Blake (Member # 2012) on 08-12-2006, 08:22 AM:
 
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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Posted by Peter Berrett (Member # 672) on 08-12-2006, 08:54 PM:
 
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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Posted by Mark Gulbrandsen (Member # 72) on 08-16-2006, 08:33 AM:
 
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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Posted by Peter Berrett (Member # 672) on 08-23-2006, 06:23 AM:
 
Stage 2 of my DIY projector has now progressed!

Closed Ebay link

I just purchased 2 Liesegang LCD projection panels which were being auctioned on Ebay. There are a couple of calculated risks involved here. First the two panels are untested and do not have power supplies. Secondly there is little or no information available on the Internet apart from some brief mentions at a German DIY Projector Forum.

Fortunately however I found the following

Archived web page

The page shows that the Liesgang Panel has 800 x 600 resolution, S-Video input, composite input and a 30ms response time. Not to mention 16.7 million colors. Way cool.

640 x 480 VGA panels have sold for $A100+ so a 800 x 600 panel like this would normally go for much more. Where I think I have been lucky is that others have found it difficult to find the specifications and thus unsure about bidding.

As to the power supply no problem. Someone had posted the pin details for the power supply at a German Forum
i.e

Link to Pin details

Problem is I don't speak German so I am not sure whether the plug details are for the male or female din plug. Anyone able to speak some German and assist?

One post from the German Projector forums I machine translated suggested that it would work ok with 12 volts.

Although the specs above show 800 x 600 resolution, the panel will, so I read at the German forum, do 1024 x 768 (I think)

The text I read was...

quote:

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Hi,
endlich hab ich es auch geschafft!!!!

Es schaut so verdammt geil aus!!!!
Heute kam mein Panel an.
Liesegang Data Display 180 für 250€(Das gleich wie Fox).
Daten:
1024*768
16,1 Millionen Farben
Reaktionszeit ?(reicht aber für filme)

Ohp:
Liesegang economy 400
400Watt Halogen(Bin mit der Halogen sehr zufrieden)
Kosten 60€ inkl Versand

Hier die Bilder:
(Sie sind kein bischen nachbearbeitet worden)
PS: Bessere Bilder folgen noch

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