| brianuk |
Hello, and thanks for opening!
I'd like to build a small projector.
Im new to this so im going to build a cheap one first - ive got a small psone panel. I know its not good quality for any large projection but i'd like to experiment and then if it works out go for a 7" lilli.
My questions ..
1. I'd like to have an output of about 4'x2' - thats only 54" diagonal. How close to the screen can i have the projector, i dont have a large room - not big enough for a big tv, hence this!
Are there ways, eg wide angle lenses that could mean i can do it from say a few feet.
2. Size length ways of the proj box isnt a problem. Can i therefore keep everything in one line, i think i can looking at the design principles.
3. A trickier qn for me - can i adjust the vertical position of the output up and down my wall as req'd ? (Ie angle the proj or just the lense)
4. No 3 would create a key stone effect ? Is it possible to tilt something else eg the lcd and fresnel(S) to remove the effect to a certain extent.
5. Can i make the screen smaller/larger as req'd like a camera zoom lense ?
Thanks for any starters on any of the above to save me wasting (some) time. I still do want to waste a bit though
Hopefully a sequence like this should occurr ...
:smash: :att'n:
:smash: :hot:
:smash: :confused:
finally ...
:smash: :bigeyes: :D
what are my chances ?
hehe.
Brian. |
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| disa81 |
Hi Brian,
I'm currently working on a small setup, as I'm looking for a result similar to yours (60" digonal). If it can be helpful, I'm working on a "inline" setup with a 5.6" lcd (and trust me, the results I obtained are very good, many people here tell you can't get good results from small lcds..). i'm using a 200w halogen light, one fresnel between the light and lcd and a 3x magnigfying lens for focussing (of course I will buy a good proj lens as soon as possible).
If you want to obtain a 50" image from a close distance you have to work on the focal lenght of your projection lens..for istance, my f lenght is 18cm, and from approz 2 mt I obtain a 40" image.. So I think, if you're going to use a shorter F lenght you'll obtain a bigger image!!
Hope it could help!
Bye!:D :D |
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| brianuk |
Hi Disa (is that your name?)
Thanks for the reply!
:smash: Great to hear you are having success - this is encouraging to me!
Your projection lense is a magnifier glass ?
Can you explain why 18cm give 40" (fine by me!) at 2 metres ?
Is it just the result of a triangle, from the 5.5" at 18 gives 40" at 2 metres ?
I cant work that out.
A 200W halogen too, quite low, well done!
I think keeping in line looses less light, a mirror looses some.
And then small close up projection keeps more light.
When added up i think a smaller light can still do quite good ?
Good to hear from you!
Keep in touch,
Brian. |
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| disa81 |
;) No problem Brian! My name is Marco, Disa is a nick..
ok, I enclose a drawing to try to explain the principle, isvery simple!
In the first image you see a setup with a short F lenght projection lens. In the second one you see a setup with a longer F lenght projection lens!
This is how it works! and for my measurements, they aren't so accurate, I don't know if exactly there are 2 meters from my proj to the wall..I will take some good measurements!
Ah, remember that even if the focal length of your lens is, for istance, 20 cm, you will not have to place it 20 cm away from your panel to get a focussed image!! you will find the explanation on ace3000 thread, one of the last pages.. so my suggestion is, learn by doing, and get a shorter focal lenght lens!
BTW, another problem of my project is the light.. not too much: 3200 lumens and 3000k colour.. S soon I will buy a 70w Sodium Lamp, with 6000Lumens and 5000k colour temp!
Let me know about your progress!! and, hey, if anyone trust in small 5.6" lcds, post here your results..As it seems not many people think you get good results..
;) |
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| disa81 |
| ok, here's a drawing of my "newbie" setup..for whoever wants to start to learn building a DIY Videoprojector!:o :smash: :clown: |
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| disa81 |
ok, just to hel someone intersted in small (and cheap) setups...
I changed my lightsource (halogen 200w) 'cause it was getting too hot and causing problems with the fresnels (cheap page megnifiers)..So I bought a wonderful Dichroic lamp, 12v 50w and.........7200LM!!!! Yep, isn't that good?? Ok, the "trick" is that it project a very condensed light (10°) and it's very bright!
But, as someone has already posted previously, with small lcds 30° or less would be good for projection! Anyway, as soon as I get the final setup, I will post some pics..
Oh, the dichroic costs 6€ and lasts 5000 h, very small heat.. not so bad!:cool: |
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| brianuk |
Thanks Disa.
Im a bit busy this week but did gt chance to play with my psone panel last night, plugged it right into my dvd output and it looks pretty damn good!
Hopefully getting an old ohp today so should have something to play with next week!
:smash: |
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| MicheleRaponi |
| Another one Italian DIY-PRJ supporter!!! :D :D :D |
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| disa81 |
:D :D :D :D
Yes!! Hey, did you get some good results??
Translation:
Si!!Tu hai ottenuto buoni risultati??
Saluti!!
Bye!! |
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| MicheleRaponi |
Yes I'm quite satisfied with my results, I'm using a BenQ fp 567s + DiyLabs' optics (split fresnels setup) + Osram Hqi-Ts250W..
Here's some shots of building process...now the projector is done, but I would like to make it better and...reload it with some changes to acheive other better results.
Unfortunately I cannot show you projected image's pics because of my bad camera.I'm managing with my friend to have some pics soon!
If you have some questions don't esitate to mail me in pvt! :D |
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| brianuk |
| How is it going with your new light Disa ? |
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