DIY Video Projector

[faidzir]

i hope u are successful. let me know if it working. im very interested but the white led so expensive in my country so
i cannot do any experiments.

[Boticus]

Instead of using one board to contain all your LED's. How
about building several smaller ones then bring all the light
together with a fiber optic bundle? I don't know what the
expense would be, but it seems to me that with this approach
you could probably expand the light source significantly.
Not to mention that you would have a much tighter source.

Just a thought.

[dwalls32]

I'm no expert, but it seems to me that the LED's would be only reduced by using fiber optics. I like Vince's original idea of using either 2 clusters of leds at 45 degree angles to mirrors, angled into the projector, or just bite the bullet, buy halogen lamps and hot mirrors, and get rid of the led's...again, just my opinion

[vdi_nenna]

The halogens aren't a bad idea. You'll just have to change them more often, spend more cash for bulbs over time, and deal w/ the noise. But, as long as it works, you save a few bucks, and ultimately DIY who cares?

(I have myself an expensive light bulb that will last me for a long time.)

If you use halogans, try to build a sheet metal cage around the bulb. If you look at replacement bulbs, they mostly come w/ a surrounding metal cage.

Also, remember to use spot lamps like Faidzir said.

Vince

[Fiat1]

It is just that you loose so much light through an LCD screen, I mean alot of light! Halogen gloabes are what I have in my overhead projector but will be mounting it all in a box like you did Vince and getting a lens, if you mount halogens inside a metal box it is an idead to use a high performance heat sink around it, most data projectors have this, it would help a alot, I don't think that with a halogen globe you need cold mirrors becausemy overhead projector does not, you just needs fans, the LCD Data projection panel has it's own fan to keep it cool as well so it you may get away with it! Where can we find pics of your projector vince?

[vdi_nenna]

It would be helpful to have some kind of heatsink. I have seen cylinder type sinks for CPUs. If the diameter is right, they may provide a point of contact.

As for the cold mirror, they are necessary because the bulb and LCD are in the same enclosure inside a projector in close relation. In an overhead system, the panel is not in the same place as the bulb. There is some seperation. A UV filter would help.

I hear there is about 10-15% loss of light through an LCD.

First I need to figure out this optics issue, then I'll work on the light source.

Vince

[burnout]

Like many others who have been reading the posts in this forum, I am extremely interested in other people's efforts. Thanks to Vince for keeping us posted on his progress.

Just a trifling matter, regarding Vince's lack of webspace. If you like, I could host the images on my httpd, no problem. Not amazing bandwidth, but I doubt that the traffic will go above 80Kb/s ;b

I am really tempted to order an LCD as soon as possible so that I can start tinkering with this interesting stuff. ;b

Contact me if you think you would like me to host them for you, anytime.
sdood@home.com &/or burnout@jungle.breakbeats.org.

[vdi_nenna]

That is a very cool offer! Thank you, burnout! I think I got it though. I signed up for Geocities. I have to find sometime to get my stuff from my PC to Geocities (Yahoo).

I'm going to take a short break from this stuff for a bit. After 16 hour of working on it for 2 days, it got me a bit mental w/ all the problem solving. Now I'm sick w/ a painful sinus infection!! >

Thanks!

Vince

[burnout]

Thanks for the quick reply V. ;b

After reading the contents of this forum, I started looking around for LCDs available from online sellers. One surprising finding was that any number and assortment of relatively high quality LCDs that were once used for laptops are available on ebay for _very_ small amounts of money. Now, I realise that having one of these LCDs would be rather useless unless I had its specifications and knew how to connect it to a video source. Some mention LVDS inputs, and most of the descriptions for others are lacking any mention of input type at all.

IIRC, LVDS hasn't been mentioned as a reasonable video source input type in this forum, so I wonder what the other available LCD screens might use as their input sources / connections.. Pardon my ignorance if I've made some false / stupid statements here.

Why am I mentioning all of this? Well, in my readings, I took a liking to the idea of using an overhead projector as a light source. So I was wondering if any of these LCDs would be classified as light transmissive once their backings were removed, and furthermore, if the common connection type for laptop LCDs is something reasonable (not LVDS, unless LVDS is simple, and I'm missing the whole point. =)

I will admit that my plan is comparatively quite "ghetto", and still all up in the air, with its sweeping generalizations and conjectures. But I like the idea of dropping less than $40 CDN for a 14" TFT 1024x768 LCD that I could slap onto an overhead projector..

I'm sure that all of you projection DIY gurus are laughing or crying after having read this post. I thank you kindly for your consideration, and again for your helpful contributions in the past. All the best.

btw, this veritable slew of LCDs can be listed by simply searching for LCD on ebay ;b - thanks again.

[dwalls32]

The only problem I found with the lcd screens from a laptop (which I agree is a good deal and was my first choice) is that the controller boards that allow you to use them are not cheap ( the cheapest I could find was around $200). Anybody else have the same issue?