A few questions about 5" lcd

LaserLine

Member
2002-08-06 5:23 pm
I just had a few questions for a projector I want to make:

I want to get an lcd screen that's no larger then 5" and that has is a 16:9 ratio. I also want to hook up my computer to this and need a way to have the screen fill up the entire area. What I'm afraid of is that the screen will just be a square in the middle because it's hooked up to my computer. Because I'll be using video out the max res is 800x600, so is there anyway to by pass this? I don't care if I have to go to a lower resolution I just want the entire screen filled. And lastly where could I get a 16:9 lcd that's 5" or under?
 
I'm a newbe so dont kill me here.:eek: Why dont you use a video card with s-video tv out? They can adapt to rca aswell and allow a mess of extra features to the image. But by running it through tv out wouldnt it A) be a really cheap deinterlacer? B)better gamma control through tv out C) better scaleing down resolutions wise on any dvd. I'm just asking-trying to learn. I have a Geforce 3 with tv out and am going to try it myself:)
 
Tinker said:
I'm a newbe so dont kill me here.:eek: Why dont you use a video card with s-video tv out? They can adapt to rca aswell and allow a mess of extra features to the image. But by running it through tv out wouldnt it A) be a really cheap deinterlacer? B)better gamma control through tv out C) better scaleing down resolutions wise on any dvd. I'm just asking-trying to learn. I have a Geforce 3 with tv out and am going to try it myself:)

A. Why do you need to deinterlace it? 320*240 input and 320*240 output you won't gain anything if it was 640*480 it would be a different story.
B. Yes you will get better gamma control.
C. Better scaling down??
 
"Why do you need to deinterlace it? 320*240 input and 320*240 output you won't gain anything if it was "

Isnt that how you make 320x240 into 640x480 without scanline probs? This is new to me, but I'm really interested and experimenting with this stuff. This site is great by the way. So I welcome any corrections or info you have.

"Yes you will get better gamma control."

Great thats what I was hopeing!!!

"Better scaling down??"


Like I said I'm a newbe at this. I'm prob. way wrong, but I was thinking that say a lcd that only supports 640x480 with a input of the higher native dvd res (like cheaper dvd standalones not the better ones that switch on their own) would need to be changed to 640x 480? This would be done auto by a pc. I'm prob. wrong-pretty sure I am, but would like to know how that works.

Well 1 out of 3 isnt bad any way. At any rate is it worth my time to run tv and dvd out of my pc. I have all the pc equipment I need to do it. Dvd player, 1500mhz P4 cpu, G3 vid card, ATI tv wonder capture card.
;) Thanks in advance for any info on this.:D
 
Yes that is how you do it. But where are you going to find a 5" 640*480 res panel for cheap?? Only 5" panels I know of take 320*240 res. If you do find one that takes 640*480 I would be very very interested in it. More likely then not a 640*480 panel would have a vga input. What I was trying to say is you cannot put 640*480 res input into a 320*240 panel.
 
O.K., thank you for clearing that up for me. I'm learning one step at a time. I've seen the 640x480 ones but wasnt aware of their price vs. the others. Yea, I noticed that most at that res. did have a vga input. I saw one that was $120 for a 5" lcd no backlight-its for projection I believe. Thats prob. a 320x240 as it only had rca input I think. Wouldnt a rca cable or a s-video have a longer distance ability though than a vga cable. Cause my pc is at the other end of room. Worried about signel degradation. I got about a 20' distance to go. Thanks for your time.:) I'm prob, going for the cheapest lcd I can find to try this all out-whats a reasonable price for the avg. 5" lcd? And is there any in particular that you recomend and where to buy it from online? thanks- I hope I'm not stepping on LaserLine's toes asking these questions in his thread!:(
 
I'd say 100$ is a fair price to pay for an 5" lcd screen. Although I'm not sure of what kind of projector you are planning on using. One cool thing about a 5" lcd is you should be able to make a much smaller projector. But a lot more pixelated at bigger sizes. Where did you see 5" 640*480 panels even if they are fairly expensive I'm still interested if you have a link.
 

eebasist

Member
2002-04-10 5:06 am
The big reason we want VGA and higher is because of pixelation issues that occur when we project them to a 50inch screen or larger. The signal degredation issue isnt really a problem...i know of alot of people on avs forum using cat 5 for a 20 foot jump to their projector....at a lower vga or svga resolution you can do it with good cable.
 
I run into the 640x480 one when searching for a lcd myself. I know they are there just hard to find. My sony handy cam 5" lcd is that from what I understand- http://www.teknom.se/sv/dept_80.html unless I'm wrong-which could be very well the case.
I'll do some digging tonight for it, it was on www.google.com search engine;)
I'm trying for the easiest setup I can on the projection project, nothing to fancy I have the plans (which arent mine)-if you would like to look them over since I'm a total newbee at this I'll post them. So $100 is avg. then. Cool now I now a good price. I've found backlit ones for $89+. but then I'd have to take it apart though. http://www.etronics.com/product.asp?stk_code=pylplvw5mn

http://www.epinions.com/Pyle_5__LCD_Monitor__Flat_Panel_Monitors_PLVW5MN/display_~full_specs


eebasist- that makes sense. Thank you for that info. I'm going for a 50-60" size any pitfalls to avoid when selecting the LCD?
So at the lower res. degradation is less of a issue than say on the pc mon with 1240x1024 32bit etc. That also makes sense.


:) You guys are a great help-thank you!
 
This is the simplest-I have the link to the site aswell. Its pretty easy to build it looks compared to some of those found here that are way over my head I think.
 

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Then this one which is alittle more involved but I think I can handle it. Dont know what power bulb to use though, and should the reflector mirror by the bulb be a cold mirror type? I have found the Delta II projector lens assembly for $15.00 new. I do have the link to that one if your interested in it. Is this what I should use, as in will it fit a 5" image? Thank you for any more advice-youve both been a great help thus far.:)
 

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Hi Tinker,
Just to warn ya, both of the plans that you have shown are not very good projectors. I`ll tell ya why. The first one is bad because the guy is using a Delta IV which has a curved lens while the LCD is flat. The edges on this image will more than likely be very blurry and rough. Look at the pictures on his website and you`ll se what I`m talking about.
As for the second one, I don`t think the light will be spread out enough. So you will have a very bright center, but the edges will be very dark. Perhaps if you had a way to disperse the light this would work. But his would require making the box thinker because you would have to get a dispersion lens and they usually have a focal length of more than 5 inches. That means your box would be inches thicker.
You could try just putting a fresnal or two infront of the light, but you will have to have a way to dissapate the heat, as they get extremely hot.

Anyways, just thought I`d give ya a heads up. If anyone disagrees or knows me to be wrong, holler!
 
I don`t know much about the Delta II. I think its about the same as the IV. Maybe somebody else around here knows more. SPEAK UP!
For a good design, go to page 30 of the Do it Yourslef Projector Part II thread and start reading at Redevil`s post. From then on me and him have a little conversation going on between ourselves in between everybody else. When other people address us read that too cause they give good tips.
His box is pretty long (42"), but I think it could be shortened a good ways with a bit of experimenting and with some good lenses. When you look for lenses, try to get the one with the shortest focal length. `Course, you might already know this.

For some good lenses, try here.

www.surplusshed.com/pages/lenses