Nope. I did see a yahoo group that talks about it though:
http://tv.groups.yahoo.com/group/DIYProjectionTV/
I couldn't really get it though. If you can summarize it for us, that'd be cool
http://tv.groups.yahoo.com/group/DIYProjectionTV/
I couldn't really get it though. If you can summarize it for us, that'd be cool
I read through some of that. It seems like they are taking regular TVs, putting them in a box, with a Fresnel on the front. Its probably not worth it to build though since already built ones can be found on EBAY for a couple hundred bucks. Only thing that bothers me about CRT projection is from my reading, the Tubes last as long as a bulb so...
Thought I should chime in (I havent been here for a while! I got a commercial CRT projector, running 1080i now )
Well first of all - currently diy crt projectors are made out of flat screen small tvs (14-20" tvs), modified for higher brightness, and use large triplet lenses (the one I used had a diameter of 175mm, and one of 135mm, since Im no longer into that project, anyone interested?)
Also a nice Ultra High Gain screen designed by Prof does wonders for it.
I acheived a decent 480i 80" image, not very bright, but definately watchable.
Cheers,
Alex
)Well first of all - currently diy crt projectors are made out of flat screen small tvs (14-20" tvs), modified for higher brightness, and use large triplet lenses (the one I used had a diameter of 175mm, and one of 135mm, since Im no longer into that project, anyone interested?
)Also a nice Ultra High Gain screen designed by Prof does wonders for it.
I acheived a decent 480i 80" image, not very bright, but definately watchable.
Cheers,
Alex
Basic premise of this can be demonstrated by holding a fresnel lens or cheap page magnifier in front of a CRT TV set with the brightness turned up full
This is basically the method that has been around for ages, grab a page magnifier from Staples (UK) of similar office supplies store, construct a box to go round your TV - swap the wiring round inside to give your a picture that is the right way round and hey presto you've got yourself a cheap PJ!
Only problem is, the picture is awful, the brightness is awful and the focus is awful
So to summarise, its awful!
But definetly a project that EVERYBODY interested in DIY projectors should undertake, it gives the beginner a good understanding of basic optics and projection principles...
But REMEMBER, no matter what anybody on ebay tells you, it definetly won't be a match for an LCD projector! Don't beleive the hype!
Below are a couple of pics of some of this type of DIY PJ...
An externally hosted image should be here but it was not working when we last tested it.
This is basically the method that has been around for ages, grab a page magnifier from Staples (UK) of similar office supplies store, construct a box to go round your TV - swap the wiring round inside to give your a picture that is the right way round and hey presto you've got yourself a cheap PJ!
An externally hosted image should be here but it was not working when we last tested it.
Only problem is, the picture is awful, the brightness is awful and the focus is awful
So to summarise, its awful!
But definetly a project that EVERYBODY interested in DIY projectors should undertake, it gives the beginner a good understanding of basic optics and projection principles...
But REMEMBER, no matter what anybody on ebay tells you, it definetly won't be a match for an LCD projector! Don't beleive the hype!
Below are a couple of pics of some of this type of DIY PJ...
An externally hosted image should be here but it was not working when we last tested it.
Yeah i agree,i got taken for 12.50 on ebay,thinking this was some sort of slick trick,i did get a image,but like the guy above said it was awful and no amount of foodleing with it would get a better image,but then what do i see DIY LCD projector and have been obsessed ever since. though i did come up with something for a CRT projector that's fun to foodle with.
1 5" color travel tv
1 projection lens (im using a Fujinon lens from some sort of rear projection tv,when i hold it up to a cheap LCD screen it Does a great job of projecting big images at very short distances but the lcd is just way to dim for full time use.(trying to come up with some sort of low profile led array to make it just a bit brighter.)
ive been tinkering with this for a few years now just by holding the lens up to the tv,haven't really delved deeper into the theory and physics of it but the images ive been getting are great,im considering using a culminating lens (when i learn more about lenses) to shrink the TV's image and kind of "miniproject" it onto/into the projection lens to get a better screen and also perhaps reduce the graininess of the magnified pixels. yeah its amazing what one can come up with when his house gets foreclosed on and you have to go camping for 9 months.
1 5" color travel tv
1 projection lens (im using a Fujinon lens from some sort of rear projection tv,when i hold it up to a cheap LCD screen it Does a great job of projecting big images at very short distances but the lcd is just way to dim for full time use.(trying to come up with some sort of low profile led array to make it just a bit brighter.)
ive been tinkering with this for a few years now just by holding the lens up to the tv,haven't really delved deeper into the theory and physics of it but the images ive been getting are great,im considering using a culminating lens (when i learn more about lenses) to shrink the TV's image and kind of "miniproject" it onto/into the projection lens to get a better screen and also perhaps reduce the graininess of the magnified pixels. yeah its amazing what one can come up with when his house gets foreclosed on and you have to go camping for 9 months.
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