DIY Video Projector

[tim0]

Hi Vince,

the high start voltage is needed to "turn on" the arc.

still, that doesn't mean that a LED can't be retrofitted. It will need external PS (and probably external space for LEDs and optics) though.
The MH bulb socket should be insulated if it isn't used.

But your warning is justified; don't play around with high voltage, people!

Regards
Timo

[vdi_nenna]

Tim,

I have been to that PEC Lamp site. That's a possibility if you want to go that route. You'll just need to use UV filters and a 45 degree angle cold mirror to keep the heat off of the LCD. It a shame they don't have prices for their lamp systems. Could make a project very versitle, if used correctly.

Vince

[tvi]

I was thinking, you might be able to use one of the OHP LCD panels, theses have a clear light path.

<hr width="95%" align=center>
<a href="http://www.anchor-supplies.ltd.uk/smartview.htm">In-Focus SmartView 3600 LCD Projection Panel</a>

The Smart View 3600 has a resolution of 640x480 Pixels (PC VGA) and a projectable range of upto 14 Million colours. It can project both computer and standard Video Images and features a built in speaker to allow sound to be included in presentations.
<hr width="95%" align=center>

I have seen these at IT auctions and they go fairly cheap, most people have no Idea what they are.

If you can find a local library with one maybe they would let you play with it?

Regards
James

[vdi_nenna]

These are good because some have s-video inputs, have high resolution. They cause other problems though, like you need distance from the lens to capture the image in the optics, like then used w/ it's counterpart the overhead projector.

But, I read that one guy used a 10.something inch laptop screen to make a projector. It was 800x600. But these people never really tell you how they do it, they just tell you they did. Does me little good.

I have thought about using flat panel displays too, but opted for the 5.6 and all its problems to over come.

Vince

[vdi_nenna]

I finished putting together the 48 LEDs into a cluster. I have to say that it is very bright! It is also very white! It's not like most other light. It is very crisp; not yellow. The ultimate test will be through the LCD panel.

I think that it may work well w/ 48 LEDs, but the good news is I can add more for a few more dollars. I'm going to order some condenser lenses this week from the place tvi(James) suggested.

I'm also planning on setting up the optics so I can move them in increments.

I'll report more as I progress.

Later,

Vince

[vdi_nenna]

Found a cool site for optics.

http://www.surplusshed.com/index.cfm

[vdi_nenna]

Just for kicks I placed the extra projector lens I have in front of the mounted lense. The result were real nice. The effect was just like I thought the condensers would provide. It blended the 48 LEDs light into one solid beam. From 10 feet out, the light projected was an eight foot perfect circle. Very bright white and no blue.

So far, I'm please with what I have found. Once I have the imaging (Electronics) part setup correctly, I think things will move faster toward completion. Still have to find how to solder SMD's to build the cable. I haven't been able to find one already constructed. I might have to make a gasless connection between the two cables.

Is anyone else out there trying this or anything like it, or am I just a lone nut-case?

Vince

[tim0]

Hey Vince,

you're not alone....
i have planned firmly to build a projector but at the moment i cannot commit to it because of exams at university.

My plan is this;
use a LCD screen designed for use with an OHP, build a huge LED bank behind it and use a OHP lens. The whole thing will be big, but i want to mount it on the ceiling and have a high ceiling.
I'm hating my monitor more and more each day.

KUTGW!
Timo

[vdi_nenna]

Timo,

The main lense I'm using is used for CRT projectors. It should be big enough to pick up the image from the OH panel.

That's going to be a sweet setup for you because you'll probably have S-Video inputs ready to go. And because they are made tosupport PC outputs, you could upgrade w/ line doubler. I have found them here in the States for about $150 to $175 $US, used. A place called Hammer Head Technology in California.

Let me know how you do. Good Luck on the exams!

Vince

[Evaas]

Yes I'm definitely going to do it. But I still have to finish building my amp first and accumulate new cash for toys but I have been searching around, and I found a site with a bunch of lcd manufacturers/supplier grouped together:

http://ee.cleversoul.com/hotsheet_opto.html#lcds

I've been checking out their offerings, but I only got throught the first 7 so far. I did a project in school that needed a graphical display and I remember researching them and it seem much easier to find suppliers back then. now everything seems to be a full retail product which isn't what I'm looking for. and I want a full vga minimum, and preferably svga. I refuse to believe that they're impossible to find or very expensive. so I'll continue to look.

I was also thinking of using three monochrome displays and using colored light (RGB, one for each) then merging them. I could either use colored LED's (have to find the right wavelength - anyone know the magical combination to get accurate colors?) or a bank of white with a colored filter for each screen. It might be easier or cheaper to find greyscale in high resolutions. I'm also wondering if the picture would be any brigher or if the colors would be better this way? Does anyone know what arrangement the high end commercial products use? just brainstorming here...

I also found a place with some dmd (used for dlp) chips! but they don't know the condition, and I don't think they have controllers, so it would be an expensive experiment. I can look it up if anyone's interested.

Vince, how bright was that 8 foot projected circle of light? I know I asked already but I'm very excited about the nearly infinite life and no fan, so I'm trying to see if it really works. you might have a patent here



[Edited by Evaas on 07-13-2001 at 03:33 PM]