Pictures of DIY video projections

[DaViruz]

Hi.
Iv'e been browsing around some threads now, but something io cant find is pictures of how the projections look. If anyone have a link or pic, please post it.

Iv'e been playing around with this even before i saw this forum (which was like an hour ago), i used a CCFL-backlit 2.5" color LCD (only 160x146 px though), and in a totally dark room i could project a great image on the roof (about 1m). I will try this with a better light source as soon i have money to purchase one

 

[noodles]

There wer tons of pics on the old thread we had. But someone shut it down.

You can check out some pics at cowan's site at www.diyprojectors.com

Welcome to the DIY projection scene!

 

[SuperZoboo]

and you can check out pics of our project here. also, links to some great projects (better than ours) at Marklar and Undreams site (links on my links page).

 

[cowanrg]

well, working on site update now. gonna have like 10mb worth of new pictures for contributors...

hopefully tomorrow i will be finished. its really cool that more people are getting interested in this.

 

[Duo]

What's your guys' usual largest screen size?

I made a projector out of a regular tv that gives me an image
that is clear, bright and sharp and is 150" diagonal. I barely had enough room in the audio room to install the screen, which I made myself.

Right now, I'm thinking of making an lcd projector instead to see how much better it is. I'll use a 400W metal halide and fresnel lens and glass projector lens for the idea...

 

[jvisaria]

Duo,

Do you have a web page? Your homemade CRT projector sounds interesting ... it isnt the one with a TV and fresnel is it?

Please give is some details.

 

[Duo]

Yes, actually, mine is the one with a tv and fresnel... I'm into electronics so I altered my tv to go brighter and reverse it's own picture(both very trivial and elementary in electronics) And I simply made a cardboard projection box and painted it black (pun intended if you know the rolling stones) and used an 11X8 fresnel
which I got at staples office supply... It gives a very impressive picture since you can read some small print and also easily play nintendo on there, which is cool cause when the screen is the the wall, (the complete wall) you feel extremely immersed in the game, like you could walk into it. Also, I made a special surround system so you really are "in" the game It's awesome for movies too, my sound is better than that at most theatres to it's a much nicer experience.

 

[xblocker]

Duo,
hey, my first projector was same type, but the brightness was very poor on a white wall, but with a curved aluminized screen fairly good. I didn't use a fresnel, but a huge (140mm dia.)plastic triplet objective, which was very expensive.

xblocker

 

[Duo]

I find that you need bigger than 140 mm by quite a bit to have acceptable brightness. Though, I also know how to modify a television to go brighter than normal... Getting good brightness is extremely tricky with that kind of projector, you need a very dark box inside and it can't reflect any light at all (which will blurr the picture and cause chromatic problems) and the box has to be very solid(no holes or slits)... I tinkered with the thing for a year just to figure out how to make it work properly and I did pretty good, but I figure an LCD projector with 400w metal halide would just be better!

 

[jizmmunki]

Hi, there were pictures of the image and designs (very simple ones) of the fresnel based projector you talk about above at www.diyprojectiontv.tk

ive made one and am very happy with the image (and the price) but the pic is a bit blurry around the edges, any one know how to sort this, and where is a good place to get ridged fresnels from, as the site only sells floppy ones,a ndi feel that may be the prob.

any sites with other plans, or more detailed plans would be greatfull recieved! email... jizmmunki@hotmai.com

 

[Duo]

Hello jizmmunki;

I read in other threads that you need to add extra lenses to the
projector to make the edges focus. Say your fresnel has a focal
length of "x" then if you want two lenses, they each have to have a focal length of x/2 where each lens is half the focal length
of the desired total focal length....

 

[xblocker]

No, each lens has to have 2x to get a total FL of x. (1/f=1/f1+1/f2)

xblocker

 

[Duo]

Dangit, I knew I wasn't thinkin straight! Xblocker is right.
Darn I always get screwed up with things that involve adding reciprocals! Same as resistors in parallel in electronics (1/total=1/r1+1/r2+1/r3+etc) I used to always screw that up too!

 

[cm961]

TV Modification

Hey Duo,

how did you modify your tv to make it brighter and reversed?

Pete

 

[Duo]

Well, I did two special thing to the television to make it reverse and go brigher. First, to reverse the picture properly, I had to make the tv scan backwards, this was done by reversing the horizontal wires to the yoke thus putting the signal 180 degrees out of phase. Then, to make it brighter, I cranked the contrast circuitry and the plate voltage on the tube and made a couple of adjustments to the circuit. I don't remember exactly what i did to the circuit to make it better, but it was to improve the contrast performance of the tv so I wouldn't get black splotching. These to changes made it so I could operate with the tv rightside up. Also, it gave very good brightness.

 

[eebasist]

Duo:
You might want to add that playing with the inside of a TV unless you are properly trained, or take appropriate precautions, can easily be lethal with the extremely high voltages present.

 

[Duo]

eebasist: I might want to add that I would expect most people here to already know that, also, I might add that: If I were you, I wouldn't tell me to add!

Dictionary Implications:

Play: To occupy oneself in amusement, sport, or other recreation;
something a child does simply to do so not intending result of any specific consequence or reason.

Work: Physical or mental activity directed toward the production or accomplishment of something; A person with direct intentions
and a will to practice his doings for a specific result without mistake, if possible.


After this, I may state: One should not work with such units pertaining to or operating by use of high voltages unless oneself is satisfactorily educated in such a field.

I may also state: I was not asked to explain how to alter the normal effect of a television set, I was inquired upon as to how I would do it. I did not imply that one should simply go ahead and do it and I believe that one would only desire to perform such a function under educated circumstances anyway.

 

[eebasist]

Actually you'd be suprised.......when you expect people to know something that we take for granted. This is a DIY forum, but not everyone here plays on the same level. I just wanted to add to your statement that you need to know how to play with the inside of a TV before you do it.

 

[Duo]

okay I get your point, but our intentions aren't to "play" with the tv, they are to work on it. I do think people should know that tv insides can be dangerous, but since most people here are adults and lots deal with electronics, most would know that tv's use high voltages or can read the warnings on the tv though, I don't expect them to. Also, I wouldn't generally reccomend that people work on their tv sets unless they know what they are doing. Simply stated, someone asked me what lengths I had to go to to change the tv and I briefly explained how I did it.

 

[eebasist]

I'm not trying to argue with you. I just want to emphasize to anyone naive that the insides of a TV can be very very dangerous. Only reason I am saying this is I know of an local repair person who got shocked very very badly......luckily he was accross the street from a good ER with people in the room adjacent to the accident