DIY Video Projector

[MuzzMan]

Originally posted by gabriel
Does any of you know if it is possible to make a cable to connect an LCD panel directly to the DVI connector placed on these newer vga boards? I downloaded some pinout descriptions for the DVI connectors, but I don't know what to do next. Or it's not possible at all? I mean I wouldn't have to buy a separate driver board for the lcd panel if I could hook it into the dvi...
Any idea?
Will I still need some sort of signal processor/converter between the vga and lcd panel, no matter which cable I am using?

Sorry, but no, not possible without serious circuitry in between. It seems very tempting to grab a dead or really cheap notebook with a TFT LCD (even an early TFT screen will be 800x600 or more), but the problem of how to drive it is a big issue. These 'bare' lcds have a parallel interface specific to each manufacturer. You can buy industrial graphics cards with support for some panels. Apart from the newer LCD monitors available, there are standalone industrial LCD's out there with VGA interfaces, some with touch screens (that you would have to remove). One of these would be great. Still have to drive it from a PC though. The prices aren't cheap, the only option would be to score it from salvage somehow.

[Myren]

anyone happen to have suggestions for how to do rangefinding? I'm working on autofocus now, but havent turned up much.

I need like 4% accuracy or better, good between something like eight and fourty feet.

anyone know how the pro's do it?

myren

[Grumpy_Git]

I've been looking around the net and for anyone who has money to byrn and wants a small 5" VGA compatable lcd should check out:

http://www.distel.co.uk/

and do a search for TFT, the only hurdle is the £250 price tag.

Myren-
you're getting far too into this, have you thought about trying some sort of infared "radar" system to bounce light from a screen and measure distance? stupid but just an idea...


Nick.

[Axeman]

Did you get your new screen? Any new developments?

[Axeman]

I put an IR detector in my PC for use with a remote- I imagine if you had an IR emitter as well, you could bounce it off the wall and see how long it too to come back- but you would need some incredibly fast timing- it might not be possible in software.

[Scot_lad]

Cheers for the RGB info earlier lads - it was pretty handy.

As for range-finding, you could consider an ultrasonic ranging system. Polaroid used to supply suitable transducers as used in their cameras, although I'm not sure where to get them. This could be the easiest and cheapest way to go.

If you're any good at programming PIC microcontrollers, (and they're very easy if you know anything at all about assembly language....er ok then if you know how to search the web for other people's programs), you could easily make a rangefinding device from one of those. I will try and dig up some info for you if you're interested.

Cheers.

Chris.

[lokost]

Myren ,

Try these links:


http://www.micromint.com/appnotes/ti01/ti01_data.htm


http://www.robotprojects.com/sonar/sonarprj1.htm

[mosgaard]

Hi,
I am new to the concept of building a projector, but after reading through this forum I can't see why I shouldn't.
But...what is required to connect my PC to a projector? I am not interested in connecting my TV. Do I need some sort of controller board?
Another question...should the lens be bigger than the LCD or is it possible to use a smaller lens?

Thanks,
Mosgaard

[fender4]

Muzzman,

I have a feeling that you are correct. The point source vs. "broad source" seems to be a very important after some thought. I will probably give it a try anyway (I have access to an LOA), but I am looking for new ideas. The HID route is very appealing, and the headlight idea is nice too. Have you had any experience with the 'HID' headlights you mentioned earlier? It looks like you could just run them from a 12VDC power supply, with sufficient current, of course. Here's a site just to give others an idea of what this looks like:

zenon bulbs

mosgaard,

Welcome to the thread. I don't know much about hooking a computer up to a projector, but I think you have a few options. One is to use an LCD monitor for the projector source (like the 15" model that has been mentioned several times). These are the large, flat panel LCD screens that can directly replace the standard CRT monitors that is common with most PC's. This is a mor expensive route, but it has the potential of giving very high resolution.

Another would be to find a purpose-built projection panel (Ebay is a good start) that is made for placing onto an overhead projector. Most of these have standard monitor hookup ports, so you could plug a computer directly into one of these.

Lastly, you could get one of those "video out" cards for your computer. I think they are pretty cheap now on the internet. This would allow you to send the output of your computer into any device with a composite video input. Most devices that only have video inputs, however, are designed for mobile applications and have relatively low resolution.

Again, I haven't dealt with any of these options first hand, so hopefully someone will jump in here if I am leading you down the wrong path. Good luck with your project!

-f4

[skilzygw]

I was wondering is it worth it to get an hdtv card to run of my pc to my lcd and onto my OHP?

Basically Im asking that is the image so pixalated and blurry that you wont see a benefit from high definition signal over convcentional signal?

I havent received my projector yet its coming next thursday. So I dont know what the image quality is. Can someone tell me?

Will the lcd+OHP give a good enough picture to see the benefits of an hd signal?

I know crt and commercial lcd projector looks great. Will our setups come any where near that?

Thanks! Cant wait for next week.