DIY Video Projector

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#263
About how you power a headlight indoor, well, I don't know, but when I buy my ultra white headlights in a mall, they always open the case up in front of you and test it out showing that the bulbs are good. So, I guess there are things you can buy to attach those bulbs.
 
#265
LCD pixels can not be completely off, the pixels still pass light when closed, so you get a kind of dark grey instead of black. The higher ratio the better for true black color. This is where DLP excels at 800:1. A DMD's mirrors can be completely off or on.

If you guys figure out the buld situation, I'd like to hear or see about it.
 
#266
Depending on the type of bulb configuration, you'll just need to find a matching connector. A 12VDC 10Amp power supply is good enough for testing purposes. Passive (as opposed to switching) power supplies in this power range are easy enough to throw together, or grab some ham radio gear. I just got a supply rated for 13.8V @ 40 Amps from a swapmeet.
 
#267
AgentDavis: no concrete evidence is to be had on my part right now (except for one <b>blindingly</b> bright projector sititng at home) because I havent got all the parts together yet. LCD is in the mail.

Speaking of which, where can I get UV filters for relatively cheap? I imagine I'll need some pretty heavy duty ones to prevent my dual 650 watt metal halide bulbs from baking my LCD matrix to a crisp.

Matt
 
#268
lcd panel & OHP

Hi,
I've been following this thread and the one at:

http://www.greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=006hui

for awhile and just wanted to give some feedback to the people interested in using a commercial LCD panel in combination with an overhead projector to watch movies. I posted on the site listed above my results with the setup. Overall the results are immpressive except for the fact that the brightness of the panel seems to be cycling with 8 seconds bright then 13 seconds dimmer etc... For a full description of the problem you can check out my other post. Any input on this problem would be appreciated!
 
#269
8 ON,13 OFF

tony5000,

Have you tried an "RF MODULATOR"? The same thing happens when you connect a DVD player to a non cable ready tv; the image tends to fade in and out. You can pick them up at RADSHACK for 10-20 bucks . THAT SHOULD TAKE CARE OF YOUR PROBLEM, "SHOULD".

THUNTER
 
#270
THUNTER-
Thanks for the suggestion- I'm not sure this will solve the problem. After spending far too much time on the internet I think that the macrovision used to prevent copying dvds to vhs is screwing up the brightness. The only fix for this I can find is to hack my dvd player (I can't find a good hack) or to add a sima color corrector to my system but at $150 I may hold off! If anyone has any ideas let me know!
 
#271
Hi, I've been lurking for a few days and it's great to see so many ideas and experiences being shared.

Hopefully, if I can get hold of some cheap parts and time, I'll try and do some experimenting. I do 35mm film projection in my spare time, and I've been wondering about the feasibility of doing a "digital film" conversion - but the cooling might be a problem 🙂 - the heat from the bulbs can tend to distort glass lenses within a few minutes!

Tony - about your brightness problem, it sounds exactly like the Macrovision problem I had when connecting a Wharfedale 750 DVD player to my (old) RFinput only TV. Initially, I connected it via my video player but I got the brightness cycling. THUNTER is right, a cheap RF modulator will solve the problem (it's what I'm using now). There's a slight drop in quality from composite, and make sure everything's well shielded - interference can be a problem.

neil
 
#277
hi..

i dont think so because this panel(resolution : VGA) have computer in port (using cable 15 pin Vga) and monitor out (15 pin) and serial port(din type 8 pin)

i hope that serial port actually for video input. i have read this panel can be use for project data and video (ntsc,pal and secam).

i have another QA1200, they have RCA input for video.

tq
 
#279
New to this forum

Hi everyone,
I only found this forum yesterday and can I just say, where have you all been hiding?!! I've started on a DIY projector project recently, but I've not ordered any parts yet. With the help of this forum I reckon I will be well on the way.

I have been experimenting with a Casio 2.2" hand-held TV, which is rubbish. I inherited an (enormous) projection TV, the three-CRT type, which worked except for one tube arcing. Needless to say I've left it in dad's garage and stole the lenses from it. These lenses are enormous - they can fit an image of about 6" across on the lens. Each lens set consists of three lenses, two of which move to focus. I have three sets, although I haven't really seen anything decent through them yet. Here lies my problem...

The 2.2" LCD I'm using has no decent backlight that I can use, and I'm not buying 10 LEDs to try it out until I get a decent screen (the LEDs cost £2.99 each in my nearest supplier). I've been looking at TFT LCDs, around 5.6" diagonal, but the nice 640x480 ones are around £600, so I was going to stick with cheaper ones, with a resolution of 960x234 with a PAL decoder. I'm not really bothered about having a VGA input as it's just for watching TV and DVDs on.

I had thought of using one of those giant 500W floodlight halogens, but with some form of cooling fan, as a backlight.

Will the kind of screen size and resolution I'm speaking about be any good? Also, can someone explain the whole fresnel lens thing please? As far as I can see (being an electrical engineer, not a physicist), the fresnel lens doesn't transmit an image. Can you use it to point light through the LCD so it converges? Thereby using a big LCD with a relatively small lens? That way I could use a normal, say 14", TFT and get a great picture, no?

Cheers guys,
 
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