My church currently has an old professional projector. It uses two bulbs to bring it up to the proper lumens. Little by little the projector grew dimmer and dimmer. One of the bulbs blew and it cost $75.00 just to have a professional look at it. It is up to me fix the church's situation. I researched the lamps it uses and it will cost (you better be sitting down)...$400.00 best internet price to get a replacement. Even if I fork over $400 of the church's money what is to say the other lamp won't blow in a week? Then I would need to spend another $400 to get this old projector working...not worth it as it can't do above 800x600 anyway.

A DIY pj sounds like the perfect solution. The church would get longer running hours, less costly lamp replacements, non-professional fixable components, etc. The projector is mounted on a pole hanging from the roof. The peak of the roof stands about 45 feet tall. The church has a retractable projector screen to shine the image onto. I measured the screen size and distance to the projector. I plugged the values into the focal calculator, but I am getting fuzzy results. The dimensions are as follows (prepare yourself for some jaw dropping ASCII art):




I originally thought I needed a 17" or larger LCD, but now I am beginning to think that would be too large of a screen. If I did the measurements correctly that would be like a 155 foot screen at this distance. When I plugged in the values for a 15" LCD it still gave me a 44 foot screen prediction. We don't need the absolute best quality. We just need to read text at a distance on the screen of about 26' - 50' from the screen. What LCD size, frensel lense focal length, etc do I need?

Also, what kind of light source would this take? It will be run in a very well lit room. We do have window covers and can turn the lights off which is fine when we watch a movie. However, we can't do that during a morning service when we want to read the song words off the screen. Also, keep in mind that there are elderly people in this church with bad eyesight.

Thanks in advance. P.S. Jesus rules!

A 16' x 14' screen? Wow.

Plugging everything into the focal calc shows that with a standard triplet at those exact
distances (a 4:3 image is 210" diagonal with that width of screen) you'll need an LCD
that's ~7.25" diagonal to fit on that screen horizontally, in which it's tough to find a decent
resolution on easily and cheaply.

If you use the pro triplet then you could use a screen up to ~11.5" diagonal, which would
at least give you a decent resolution, since there are plenty of ~10" diagonal screens for
cars that should probably work.

That's just my opinion. I know that some people have expressed concern that you would
have a tough time getting enough light out of the projector at that kind of distance or if
you have any ambient light. I'd also want to research about using any kind of HID bulb
in something that's not an approved enclosure.

But to answer your original question, these are the measurements I would say are at least
close to what you would need, split design since you would need to keystone:

Lightsource - 220mm Fresnel - 10" LCD - 650mm Fresnel - 500mm Pro Projection Lens

Anyone else please chime in...

I hate to say it, but it is going to be tough building PJ that can withstand that much ambient lighting. But I am no expert. Someone will chime in who knows more than I do.

Oh BTW

Jesus does Rule!!!

I agree. With a throw of over 36 feet and lots of ambient light, you'd have a difficult time reading text.

What model of projector is it?

Victor

Point of fact, Jesus rules, God doesn't exist. Yay for logic.

I'll try and post it tomorrow.

Easy on the religious quips folks, we like to keep it about projectors, not personal beliefs.