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A guy came over to my house today to buy a sandblaster so I could have more money for shelving. And he was telling me he had what sounded like something between a CRT or a 3 gun LCD and all he needed were lenses for it and it was supposedly a spectacular image worthy of a 16 thousand dollar projector, but you had to put it together yourself because the way he described it, it sounded like tearing apart an old rear projection to make it front projection. I guess there is a big fan base for this and they have their own website. I can't remember the name of it but I remember it started with an L. or had two L's or two words that started with an L.
 

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 http://www.lumenlab.com/

This kind of thing comes up on the 'bay every now and again. Probably not worth the effort.
 

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I've thought of tearing apart a CRT RP with an HDMI input and seeing if, somehow, the analog signal could be extracted and fed to a scaler or CRT FP. Probably not too practical or cost effective, but I'd like to know if could be done and how difficult it would be.
 

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Quote:
Originally Posted by alan halvorson
I've thought of tearing apart a CRT RP with an HDMI input and seeing if, somehow, the analog signal could be extracted and fed to a scaler or CRT FP. Probably not too practical or cost effective, but I'd like to know if could be done and how difficult it would be.
I tested my 55" Tohisba HDTV on the wall at 10ft wide and it's what made me decide to get a CRT FP.


Turning one into a FP will be more difficult than it seems though. It would need new lenses, because the ones they start off with are incredibly short throw. I mean REALLy short throw. So short that the projector would actually block the image from normal seating positions. It also needs to projector from the middle of the picture, because it has no offset. Perhaps this could easily be corrected though. I'm not sure.


I was wanting (actually planning at the time) to turn a $1,000 widescreen CRT HDTV (I believe it even had wideneck CRTs) into a CRT FP. It would be a great idea if some of the problems could be overcome.


I got my ECP4500+ for only $700 total, so I'm not sure it's worth the hassle or not to make a RP HDTV into a FP.
 

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Actually, I don't want to make a FP out of an RP, I just want the electronics to the point where the HDCP encrypted bitstream is de-encrypted and converted to analog. In other words, a method of defeating HDCP that virtually eliminates the possiblity of key revocation.
 

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Hmm... I just read that site. It's an interesting project. I think I'll build one for fun and see just how well it works. Looks like a great toy.


Marc
 

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Quote:
Originally Posted by alan halvorson
Actually, I don't want to make a FP out of an RP, I just want the electronics to the point where the HDCP encrypted bitstream is de-encrypted and converted to analog. In other words, a method of defeating HDCP that virtually eliminates the possiblity of key revocation.
The current external boxes use the keys (and chips) from existing RPTV models. If their keys are revoked, then there will be an aweful lot of RPTV owners with non-functioning TVs.


Dave
 

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Quote:
The current external boxes use the keys (and chips) from existing RPTV models
You'd think that the HDCP cops would have thought of this obvious workaround and done something about it. I guess we won't know until high-def players and discs are released.
 

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Actually (flame suit on) the lumenlab thing is not bad...


Just like the CRT Forum, they have a lot of guys (some who actually know what they are doing) constructing home built LCD projectors, organising cutom made triple lenses, custom made fresnels, etc...


Some of the topics are very interesting, like the WUXGA (1920 x 1200) 15.4 inch widescreen LCD panel used in high end Dell laptops being used with a separate controller as the panel in a home built LCD projector...


Yer - some guy is charging $20 US for the priviledge of joining the forums but I have found it to be worth it, (we all hate him because he thought of it first).


A home built LCD projector for playing video games on, or taking to your friends house, or for football parties in the back garden (shone on a cheap screen or painted wall) that does not burn in AND the bulbs are cheap; all for about $500US + effort.


It's no CRT in terms of contrast or colors, but it has it's place.


Paul
 

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My brother just finished building a DIY projector based on the lumenlab design. It puts out quite a vivid picture. Everything is replaceable and upgradeable. The bulb is a Mh and should last about 8000 hours. And to replace it is about $60. The only electronics that could go bad is the 15 inch LCD screen. We are planning a drive-in movie in his drive way this fall with it.


It still lacks in quality compared to the CRT, but at least he can carry his by himself.


Jon
 

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Quote:
Originally Posted by alan halvorson
You'd think that the HDCP cops would have thought of this obvious workaround and done something about it. I guess we won't know until high-def players and discs are released.
I've mentioned this before, but if it was my job to disable those existing boxes and not disable all those RPTVs or plasmas from an upcoming HD-DVD or BluRay player, I doubt that it would be difficult. There are a lot of things that can be asked for over a digital connection besides keys. We'll see, as you said.


--Darin
 

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Quote:
Originally Posted by darinp2
I've mentioned this before, but if it was my job to disable those existing boxes and not disable all those RPTVs or plasmas from an upcoming HD-DVD or BluRay player, I doubt that it would be difficult. There are a lot of things that can be asked for over a digital connection besides keys. We'll see, as you said.


--Darin
Yes, we don't know yet. But, I have worked on cryptography software and these types of handshakes before. What you see as not difficult, I see as VERY difficult. Could you please explain to me why you think it is so easy? If it is the exact same chip supplying the exact same data (keys, manufacturer, etc) in all contexts, exactly how are you going to do this without a scortched earth approach?


Dave
 

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Quote:
Originally Posted by Person99
Yes, we don't know yet. But, I have worked on cryptography software and these types of handshakes before. What you see as not difficult, I see as VERY difficult. Could you please explain to me why you think it is so easy? If it is the exact same chip supplying the exact same data (keys, manufacturer, etc) in all contexts, exactly how are you going to do this without a scortched earth approach?
One of the things that can be asked for is EDID data over the link. I believe that could probably be used for this. Basically the task of disabling this device and not all those plasmas and RPTVs would be to get them all in the lab (or just get the info for them from elsewhere), look for differences in things that can be requested over the digital link and then write some code for the HD-DVD player to run. Maybe one or some of those displays wouldn't be indistinguishable from these HDCP avoiding devices (like refusing to give EDID data), but I doubt it would be many. HDCP avoiding devices that aren't already for sale don't have the disadvantage of the HD-DVD or BluRay guys being able to get them and look for ways to keep them from working, before the initial players are even out.


--Darin
 

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Quote:
Originally Posted by Tinman
Hmm... I just read that site. It's an interesting project. I think I'll build one for fun and see just how well it works. Looks like a great toy.


Marc


Building that DIY projector will cost you almost as much as an entry level DLP.


Now if you're just into wasting time and money for the fun of it (nothing wrong with that - part of the mission of this web forum :) ) then by all means jump in.


The only interesting part of a DIY projector build is that you can design it around a metal halide light solution. The bulbs last a long time and are cheaper than in a store bought unit. However, I do not know how that affects color balance. Bottom line is that you'll end up with a projector of LCD quality because you'll be using a scavenged LCD display (contrast ratio is gonna SUCK)


Enjoy.
 

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Quote:
Originally Posted by darinp2
One of the things that can be asked for is EDID data over the link. I believe that could probably be used for this.
Huh? That wouldn't be able to do it. If the returned the data structure is the same as when the chip is in the RPTV, you've got nothing to differentiate it. That's my point. The EDID data certainly won't help you here.

Quote:
Originally Posted by spinforu
hey HDCP guys you just hijacked this thread! haha go to one of the 30 that is still going.
Point taken, but I was really curious to see if Darin had a thought I had not considered when looking at this. Please go back to discussing home made LCD projectors in the CRT projector forum. :)


Dave
 

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Quote:
Originally Posted by timtimes
Building that DIY projector will cost you almost as much as an entry level DLP.


Now if you're just into wasting time and money for the fun of it ...Bottom line is that you'll end up with a projector of LCD quality because you'll be using a scavenged LCD display (contrast ratio is gonna SUCK)...
Let's say entry-level DLP @ 800x600 or 480p is in the $700 ballpark. These guys are building 768p or 720p projectors for half or two-thirds that price. More important, from what I'm reading, they look better, have cheap bulbs, are easy to modify and upgrade, and are a fun project.


Some folks have a lot more time than money, and some the other way around. Personally, I don't have a lot of either - but, if I weren't into CRT, I'd probably be looking at a Lumenlab-type project... because any sort of digital projector I can afford/justify sucks the big one compared to my CRT.


SC
 

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Quote:
Originally Posted by Person99
Huh? That wouldn't be able to do it. If the returned the data structure is the same as when the chip is in the RPTV, you've got nothing to differentiate it. That's my point. The EDID data certainly won't help you here.
We should move this to a different thread and I disagree with your assumption, so I put my response here .


--Darin
 

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With the DIY LCD projector thing...


I agree with ecrabb... People are building 1024 x 768 (15" based) or 1280 x 1024 (17" based) projectors for prices 2/3rd's of a normal 800 x 600 projector - plus, the bulbs are cheap to replace.


17" LCD's with 500:1 up to 800:1 contrast are now becoming commen. I saw something recently at Lumenlab about a 2000:1 17" LCD being used for a project, but no indication if this was successful or not, (of course, this is a more expensive LCD panel - thus raising the price of the projector).


For now, I'll keep an eye on Lumenlab & enjoy my 1272. I think the Lumenlab thing will eventually evolve into something with a good price/performance ratio


Paul
 

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Quote:
Originally Posted by timtimes
Building that DIY projector will cost you almost as much as an entry level DLP.


Now if you're just into wasting time and money for the fun of it (nothing wrong with that - part of the mission of this web forum :) ) then by all means jump in.


The only interesting part of a DIY projector build is that you can design it around a metal halide light solution. The bulbs last a long time and are cheaper than in a store bought unit. However, I do not know how that affects color balance. Bottom line is that you'll end up with a projector of LCD quality because you'll be using a scavenged LCD display (contrast ratio is gonna SUCK)


Enjoy.
As if I'd get rid of my NEC. :D


I said "Toy". I have most of those parts already laying around anyway. If it cost me more than $100, I wouldn't try it. It's just for fun.

AND I have 4 LCD projectors already that throw a good image.

It's the novelty of it that appeals to me.


Marc
 
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