PC to Composite Video Converter

[Nuer Tek]

I am currently looking to build a circuit that converts vga signals to composite video; however, I would also like it to crop. All video would be cropped down to 320x234. If possible I would also like buttons to move the cropped area. Where would I start if I wanted to make something like this?

Here is a sample of what I would like it to do:

As you can see, it will be used to display the screen of a gps.

Thanks for any help!

 

[Nigel Goodwin]

It's very complicated, and expensive to do, you need a standards converter plus someway of cropping to the part you want. It's not something you could casually get answered on a forum, it's more like a University final project.

 

[Marks256]

Use a computer with a video card that can output composite. Then set the screen resolution to 320 x 240!

 

[Nuer Tek]

Is there a way to (or does anyone know of any resources that I may reference to find out if I can) crop the video before or after the conversion to composite video?

 

[Marks256]

Yes, a PC or a MAC. Don't reinvent the wheel.

 

[Nuer Tek]

Yes, a PC or a MAC. Don't reinvent the wheel.

Please elaborate...

Does this mean with the graphics drivers? (if so, that probably won't work because I'm using an old compaq armada 7800.) I can look and see if it is possible.

Using a resolution of 320X240 is also out because I have to use a key to mouse command for one of the functions of the gps. Therefore, the entire unit must be displayed on the monitor.

Trying to save some money here and there tends to lead me to reinventing the wheel sometimes; however, I find it educational.

Thanks,

Nuer Tek

 

[Marks256]

Maybe tell us a bit more about your project, eh?

 

[Nuer Tek]

Sure...Currently I'm planning a simulated cockpit to expand my flight simulation software. One of the first things that I want to build is a simulated GNS garmin unit. I have the software to do this and also the ability to interface buttons and rotary dials to the simulator. My question pertains to the lcd screen that will be in the simulated unit. I have found a tft monitor (5") that has the same resolution as the unit...320X234.

Hopefully this helps. A link to the GNS unit: **broken link removed**
(It's the bottom unit)

Please ask anything about the project that needs clarification.

Thanks

 

[Marks256]

I used to have a small LCD DVD player hooked up to a computer to use as a monitor on vacation (i would take a computer with us in the camper, and use my wireless to torrent )

I was able to set the screen resolution to 1024x768, but the monitor worked fine, even though its' screen resolution is like 350xSomething.

Just try sending raw video into the unit at a higher resolution, and see what happens.

 

[Nuer Tek]

I have the reverse problem...I need to display only a small part of the screen on the tft display. I have to see the entire software window (not just the part on the tft) on the laptop I'm using for certain commands. The commands are only accessable by mouse click. Thus, they have to be visible on one of the screens.

 

[Marks256]

Oh. Ok. I understand what you mean, now.

I don't think such a device exists. Sorry.

Perhaps you could make something?

 

[Nuer Tek]

Do you know any good sources of information on this (books, etc.)? I think it may be monetarily wiser to focus on just the cropping. I already have a pc to tv converter that converts 640X480 to NTSC. I guess the easiest thing would be to crop the outputted TV signal.

Once again, if anyone has good sources for information, such as this, I would be greatly appreciative.

 

[mneary]

If you're running XP on appropriate hardware, you can add a second display card with whatever characteristics you want. If you display the gps on the 'secondary' screen you might not be able to display it on the 'computer' screen.

 

[Nuer Tek]

I can't remember if some nVidia cards can zoom a second display (that's being mirrored). If anyone knows of the cheapest ones that can do that, please let me know. I have an old Gateway G6-300 that I could use. Not sure of the interfacing technologies that it supports. The only constraint for the card is a video out (yellow composite) and vga.

Thanks (forgot that there was this possibility)

 

[Marks256]

I know nVidia cards can zoom a mirrored display. Not sure what chipsets, though.

 

[mramos1]

Will something like this work for you.

**broken link removed**

 

[Nuer Tek]

The only problem is it needs to work in real time to send a signal out.

 

[ericgibbs]

The only problem is it needs to work in real time to send a signal out.

hi NT,
Can you say where you are located.?

 

[Nuer Tek]

Northeastern USA...if this is in regards to video formats...NTSC

 

[ericgibbs]

Northeastern USA...if this is in regards to video formats...NTSC

hi NT,
Thats spot on.!

I have a VGA to Composite external box, bought it about 3 years ago, only used it for a while.
Its 640 * 480 PAL, full colour, complete with UK wall wart.

If you had been wanting a PAL/UK system, it was yours, free gratis.

Regards