Ok, this thread is really about the questions I am haveing while building my projector. Most of the question are related to projector stuff but some are a little off topic. All questions will be posted in this first post and will be in full; answers will follow question with just a number directing you to the post number. Even if the question has been answered feel free to answer it again please. Unanswered questions will be high lighted in red. All question will be posted twice; once in the thread and once in the first post. Please elaborate (explain) all answers. If you have any question dont be affraid to ask and I will add them to the list. UPDATED 11-23-06


(1). Q:Does the reflector expand when it heats up?
A:Post#3, Post#23

(2). Q:If useing a light engine, will heat from the bulb damage my fan?
A:Post#3, Post#23

(3). Q:Where do you get the fly's eye array and will it work better than a condenser?
A:Post#3, Post#23

(4). Q:Has anyone built a 17'' without any venneting (rox)?
A:Post#3, Post#23

(5). Q:Can i use a polerizer lens instead of a polarbear screen?
A:Post#3

(6). Q:Where can I get cheap temperd glass?
A:Post#3, Post#17, Post#23

(7). Q:Is the glass on a lamp houseing, for a hologen bulb, tempered?
A:Post#3, Post#17, Post#23

(8). Q:Are light boxes for experimental use only or do they improve your projected image?
A:Post#4

(9). Q: Do I have to sand flashing (aluminum) before painting it? Or maybe prime it?
A:Post#4

(10). Q:Do I need 2 bend the middle pin in my mogel base to prevent carbon arcing?
A:Post#4

(11). Q:Where can you get very large lenses ie. 8'' and up?

(12). Q:Where can you get hot mirrors and are they better than tempered glass?
A:Post#6, Post#17

(13). Q:Has anyone played bf 2142?
A:Post#13

(14). Will fans not mounted in series but back to back move more air then parallel fans?

(15). Q:What is this whole lens shift thing about and is it worth pursueing?
A:Post#12, Post#17

(16). Q:Does even light = less elumination ( ansi)?
A:Post#17

(17). Q:Is the ohp the ultimate light box and all should moldel after it? ohp=perfection?
A:Post#17, Post#24

(18). Q:Is useing other peoples patents legal ( in our case)?
A:Post#17, Post#24

(19). Q:Can i use a mutipul image fresnel or will this just degrade lumens? mutipul fresnel= - lumens?

(20). Q:If using the threaded rod design and making correct clean cuts on the fresnels, will the fresnel allready be aligned?
A:Post#17, Post#24

(21). Q:Why doesn't brain child stock precondensers, hot mirrors, hqi bulbs, lexan or thermostats?
A:Post#17, Post#24

(22). Q:When does DIY start and when does it stop?
A:Post#19, Post#22

(23). Q:Do the fresnels need to be ajustalbe for all axises x,y,z?
A:Post#19, Post#22

(24). Q:Is the cheapest and smallest HD screen the 15.4 laptop replacement?
A:Post#19, Post#22

(25). Q:How can you mold plastic into a shape that you want while doing it at home?
A:Post#19, Post#22

(26). Q:Is school the answer to being rich?but bill gates did drop out of harvard?
A:Post#19, Post#22

(27). Q:Will a chip in the glass of an lcd grow because of the heat from the bulb?
A:Post#19

(28). Q:Can the liquid crystals leak out of a lcd?
A:Post#19

(29). Q:Are liquid crystals harmful to your well being?
A:Post#22

(30). Q:Does any one else have a deadly addiction to video games? Seriously, I quit smoking after 8 years but i cant stop playing these dam games which Ive been playing sence I was a young child??
A:Post#19, Post#22

(31). Q:Do the benefits of haveing a adjustable fresnel out way the benefits of a fixed fresnel?

(32). Q:Has anyone every tryed using a xeon bulb from a car head light?Or will a xeon bulb work? NOt the one that asv is using.

(33). Q:Is it possible to use a combination of lights ie. mh bulbs plus leds>? ie. placing the leds between the fresnels??

(34). Q:How come brain uses a hqi bulb in the factory made evo but sells a mh bulb in the diy site?

(35). Q:Is the Hqi bulb better than the Mh bulb? If so please explane?

(36). Q:Is adding a heat sink to the lcd controller necessary?or can it help in any way?

(37). Q:Do you need to add a fan to the eballast from lumenlab?

(38). Q:Is replacing the polarizer the only way to increase contrast ratio?

(39). Q:Does a higher contrast ratio mean lower lumens and less transmissive lcd?
High contrast = -lumens and -transmissive panel?

Are light boxes for experimental use only or do they improve your projected image?

Do I have to sand flashing (aluminum) before painting it? Or maybe prime it?

Do I need 2 bend the middle pin in my mogel base to prevent carbon arcing?

negligibly.

it could. if the fan is too close it would melt or damage the motor. best to block direct light from hitting the fan by using flashing.

dunno.

every DIY projector has vignetting whether you can see it or not. using the pro 500mm triplet w/ a 17" LCD is a good way to minimize it. Adding a precondenser should also help.

sure, but it might block more light.

dunno

it can obviously stand up to high heat. a 400w halogen is going to be hotter than a 400w MH so it will work fine, but a low watt halogen enclosure might not be good enough for use with a high watt MH bulb.

they help by cutting down on off-axis light and controlling heat by containing both.

It would help. paint tends to flake off flashing and will be easy to scratch.

only if its not making good contact.. of course, its tough to tell with the bulb screwed in, so you might want to bend it a few mm.

thank you tame, can always count on you to be looking at every post theres is.thx but now I got more.

Where can you get very large lenses ie. 8'' and up?

Where can you get hot mirrors and are they better than tempered glass?

Has anyone played bf 2142?

I have not finished building my projector, but I bought my hot mirror from B & H Photo Video. Do a search for 'hot mirror' and then filter the results for Rosco. Their prices seemed quite competetive when I did my research a few months ago. I did not buy any tempered glass, so I cannot give a good comparison.

thank you pirin. Im gonna change this post around today to just one post with answers so it can help others.
sorting ?'s by date>

Will fans not mounted in series but back to back move more air then parallel fans?

What is this whole lens shift thing about and is it worth pursueing?

updated some more ?'s

How do I change the topic desciption?

edit your first post (full edit, not quick)

only if you plan to build your pj off axis (coffee table type or high celling mounting) it helps kill the keystone effect. if you don't plan to have your PJ more then 5-10 degrees off center a regular split setup will work fine.

nope, but i loved 1942 and bf2 so i'm sure 2142 will be good

Still not getting how to change the topic?

Click to view attachment

got some more?'s

Does even light = less elumination ( ansi)?

Is the ohp the ultimate light box and all should moldel after it? ohp=perfection?

Is useing other peoples patents legal ( in our case)?

Can i use a mutipul image fresnel or will this just degrade lumens? mutipul fresnel= - lumens?

If using the threaded rod design and making correct clean cuts on the fresnels, will the fresnel allready be aligned?

Why doesn't brain child stock precondensers, hot mirrors, hqi bulbs, lexan or thermostats?

Like tameone said, tempered or not the glass on those halogen lights can withstand high heat, which is the only quality tempered glass has for our purposes. I bought a halogen work light at walmart for $9.

I also got a hot mirror from B&H Photo and Video, it took about 2 weeks though. I'd say a hot mirror is vastly superior to tempered glass. The Rosco hot mirror (like Pirin got) blocks both IR and UV (unlike tempered glass, where it's questionable whether it blocks either) and is very clear/transparrent (unlike tempered glass, which often has a greenish tint). The problem is, hot mirrors are expensive, expect to pay $50 +. The work light manufacturers chose the glass on those halogen lights because it's cheap, the Rosco glass is made to block IR and UV without altering the visable spectrum.


Lens shifting info. I'm using lens shifting and it works perfectly. Most people agree that using an "unsplit" setup gives a better picture, using lens shifting you can have an unsplit projector with keystone correction. I'd say: unless you're going to change how the projector is mounted (on the ceiling, on the floor, or on a table) often, give lens shifting some serious consideration.


Not necesserially, I suppose how you go about evening out the light that makes the big difference. If you start with the same light source I'm pretty sure the ANSI lumens would be the same, no matter how "even" the light is.

dunno, I doubt OHPs would be considered "perfect" though.

I'd be willing to bet that it is NOT legal to use other people's pattents without permission (no matter the circumstance).

I'm not familiar with multiple image fresnels.

If you mount the fresnels perfectly they'll already be alligned no matter what method you use. Getting perfection without adjustability is very dificult though.

Good question. My guess is that he's not really focusing on DIY projectors any more for the most part and therefor doesn't want to take the time to find a good source for these components. Either that, or he has found sources for these parts, but the quantity he'd have to buy and sell to offer a competitive price is too high.

thx for the answers guyes . If you think of a better answer than some one elses then feel free to put in your own input....

Ok heres some more.

When does DIY start and when does it stop?

Do the fresnels need to be ajustalbe for all axises x,y,z?

Is the cheapest and smallest HD screen the 15.4 laptop replacement?

How can you mold plastic into a shape that you want while doing it at home?

Is school the answer to being rich?but bill gates did drop out of harvard?

Will a chip in the glass of an lcd grown because of the heat from the bulb?

Can the liquid crystals leak out of a lcd?

Are liquid crystals harmful to your well being?

Does any one else have a deadly addiction to video games? Seriously, I quit smoking after 8 years but i cant stop playing these dam games which Ive been playing sence I was a young child??

DIY starts when you do it and stops when you have someone else do it

no, fresnels should be placed parallel to and lined up with the lcd unless you need to adjust keystone or lens shift for placement of projector

its my understanding that controller boards for laptops are more expensive so no a 15.4 moniter would be cheaper

polycarbonite(lexan) plastic can be bent and folded using a heat gun

school is not the answer to being rich. but it can be the answer to being successful. depending an how you decide to define it.

a chip wont but a crack will

yes

i dont know

i too have an addiction to video games ,though i woudnt call it "deadly"

thank you thank you

Do the benefits of haveing a adjustable fresnel out way the benefits of a fixed fresnel?

Has anyone every tryed using a xeon bulb from a car head light?Or will a xeon bulb work? NOt the one that asv is using.

Is it possible to use a combination of lights ie. mh bulbs plus leds>? ie. placing the leds between the fresnels??

How come brain uses a hqi bulb in the factory made evo but sells a mh bulb in the diy site?

When does DIY start and when does it stop?

It starts when you say "hey, I can do that" and it stops either when you say "f#%! this, I'll just buy one" or when you say " I did that?!" and you actually stop to enjoy it

Do the fresnels need to be ajustalbe for all axises x,y,z?

I wouldn't say that they need to be adjustable, but depending on how well you line them up in the first place, and how much you want to tinker with every aspect of the projector it may not hurt

Is the cheapest and smallest HD screen the 15.4 laptop replacement?

A 17" lcd monitor can output 720p HD, and there are 15.4" monitors available with a resolution of 1280x800. The laptop replacement requires a controller board which can be pretty pricy, but WUXGA can deliver 1080p

How can you mold plastic into a shape that you want while doing it at home?

If you just want to bend it, heat it slowly and apply pressure until it's the shape you want. If you're looking to mold it, first you need to create a mold and then melt the plastic and pour it into the mold...seems like a messy proposition.

Is school the answer to being rich?but bill gates did drop out of harvard?

School seems to be one of the few ways to get your foot in the door for most professions, but it will crush your soul and you'll lose a lot of time that could be spent playing video games.

Are liquid crystals harmful to your well being?

Only that they can cause you to waste a lot of time

Does any one else have a deadly addiction to video games? Seriously, I quit smoking after 8 years but i cant stop playing these dam games which Ive been playing since I was a young child??

The first step is admitting you have a problem. The second step is realizing that it's not that big of a problem and heading down to Blockbuster. Gears of War kicks ass!

does the reflector expand when it heats up?

Everything expands as it heats, but it should maintain a hemispherical shape with the center in the same place

If useing a light engine, will heat from the bulb damage my fan?

It may be a good idea to not have the light shining directly on the fan, but as long as there is good airflow it shouldn't

Where do you get the fly's eye array and will it work better than a condenser?

I'm not sure I know what you mean, but I got this out of an old commercial projector that was destined for the rubbish bin. It looks cool, but I haven't used it for anything yet.
Click to view attachment

Has anyone built a 17'' without any venneting (rox)?

I think you may mean vignetting, and I'm pretty sure it's not possible to totally eliminate it because the light that travels through the center of the optical system has a shorter path length than light that travels through the edges. So your image will always be a little brighter in the center, but you should be able to get it down to the point where you don't really notice. I'm not there yet

Where can I get cheap temperd glass?

I got a piece that is 4" x 5.5" out of a cheap worklight from Home Depot for about $6. It included a cord and a base for the bulb I am using, so it was a pretty good deal. I also read that scanners use tempered glass, so you might be able to score a piece out of an old one. It might not be tempered glass though, since the piece I got out of a scanner seems a lot less substantial than the one from the worklight.

Is the glass on a lamp houseing, for a hologen bulb, tempered?

I'm not sure, but it seems like it may have to be given the extreme temperatures those halogen bulbs reach. I'm just guessing on this one.

Is the ohp the ultimate light box and all should moldel after it? ohp=perfection?

I wouldn't go so far as to call it perfect, but if these OHP manufacturers have been making them for decades, it has to be somewhat efficient. It seems like the bulb with a reflector and condenser lens is the way to go.

Is useing other peoples patents legal ( in our case)?

I think as long as you don't make any money off the use of the patent you should be OK. The knowledge is public domain, you just can't implement the idea into something you are selling...besides, who is going to send you a cease and desist order for building a projector in your garage?

If using the threaded rod design and making correct clean cuts on the fresnels, will the fresnel allready be aligned?

There are always variations in the manufacturing process, so double check that the centers are lined up. There is a raised dot in the middle of each fresnel that should be in the center of the light path, and lined up with one another.

Why doesn't brain child stock precondensers, hot mirrors, hqi bulbs, lexan or thermostats?

I think these are still considered experimental, easily obtainable elsewhere, or not worth the time, money, and effort to keep in the store. Remember, brain is trying to make money from this venture, and breaking a few delicate items here and there can really drive down the profit margin.

Cant thank you enoff phdeviant. thank you thank you

huge update!!

Is the Hqi bulb better than the Mh bulb? If so please explane?

Updated every thing.
Still need more answers and ?'s.

and another

Is adding a heat sink to the lcd controller nesessary?or can it help in anyway?

Do you need to add a fan to the eballast from lumenlab?

Is replacing the polarizer the only way to increase contrast ratio?

Does a higher contrast ratio mean lower lumens and less transmissive lcd?
High contrast = -lumens and -transmissive panel?

not necessary. The controller would get hotter sitting inside the original monitor than it probably will sitting in the front of the PJ. If there is no heatsink stock, let it be.

If you place the eBallast in the bulb chamber, I would definitely give it some active cooling. If sitting in the front of the PJ, no cooling should be necessary. Mine is on the outside of the enclosure and it only gets warm to the touch, never hot.

don't know.

I don't think so. Don't know if anyone has linked contrast ratio to transmissiveness