Modeline and a laptop
 

I am new to computer graphic's card systems converter idea but its some thing i wanted to see if it was possible with modeline and with pretty much what i have .
I tried first to see if the program could detect my graphics chip 2 out of the 3 lap tops i have worked
They all have a VGA socked so can do dual screen...
After seeing this page
http://www.nostalgiatech.co.uk/Baird%20240%20lines.htm
i made the circuit first 2 picture's
I was not expecting the VGA signals to stop cut out when the monitor was unplugged and this circuit plugged in so it was a bit useless to me till i worked this out .
i needed a way to access the video signals and leave the monitor in place so i have spliced a vga cable to access the signals RGB and HV siganls ..now this worked .
I am using a old 625 line security camera monitor it have vertical and horizontal sync controls so that helps if as i expected they video may be way off 625 line standard ...its some thing to test the vga out put on and modeline program .
I have started here from scratch first day i just plugged in one colour channel to see if any thing could be viewed on the monitor ...rather ruff results yeasterday.
Today i worked out the line frequency must be at double with 2 images showing if that sounds right ..last picture i will add more on next post .

Re: Modeline and a laptop
 

OK close ups of the results today ,i forgot to add i inserted the horizontal sync reason the pictures better 2 of them they are ..
I tried adjusting modeline to 625 line in the menu but did not seem to do any thing or any frequency changes in the advanced menu ...but screen resolution yes pretty up size of the stuff on the screen only up or down ..no change to line frequency .
wiring wise all i have down so far is use one of the colour channels and insert the horizontal sync pulse with a resistor .
So i have some questions in the next post i will do next if any one knows .

Re: Modeline and a laptop
 

A question is will this circuit simple as it is work its pretty much what i can using now apart from the 2 pins connected to ground ...
Or should i go with the on in the first posting in this thread ?i know there's are that adjusts the sync pulses.
My interest in doing all this is to be able to out put different tv standards from my laptop's video card..
This fellow sort of inspired me viewing he's youtube video.
https://www.youtube.com/watch?v=ahzdx4KgWBg
I should also point out i am making a multi system tv non standard above 64 line so 128 256 so on 6hz 12.5hz 25hz 50hz 100hz frame rates a work in progress !:wall:
So this graphics card tv system converter would come in handy ,before i knew of this and i am still doing it as its finished i had a PMT multi system camera for the video testing for this monitor ..i have just tested in 32 and 64 line so far as i had no monitor to view say 128 line ! this will i hope change all that .
http://www.taswegian.com/NBTV/forum/...hp?f=31&t=2467

Re: Modeline and a laptop
 

Hi Harry, I'm flattered that my Youtube video has inspired anyone!

Peter Scott has coaxed his video card to output the old Baird 240 line system. but it looks as if you want to go much lower than that.

I used to operate with 120 line SSTV back in the early 1980s, receiving on a 5FP7 radar CRT, and transmitting with a sampling camera based on a 625 line videcon security camera turned on its side.

I also wrote some Z80 machine code that ran on a ZX81, it was an 8X8 character generator and grayscale generator for 120 line SSTV. The last few lines at the bottom were always grayscale, just like the Robot 400, and sounded very musical to the ear too!

Anyway, I was inspired by Kat Manton, if you look up her posting history on the forum you will see she was doing the Modeline stuff with Linux over ten years ago and called the project FoTH, Fools on the Hill, which is a homage to the pioneers at the BBC in 1936.

Can you post the hardware details of laptops you are using particularly the graphics chipsets

Re: Modeline and a laptop
 

Hi nice to meet ya ...Yes i loved the video i didn't know you could do this with a pc card till your video ! so giving it a go .

For a start since i have a working 625 line monitor it would be a good first test if i could get it going but yes i would be going lower and all over the place really ! main thing stopping most people playing with television after 64 line and up to 405 is lack of a video signal for testing .

We still love the classic SSTV on the NBTV forum i made similar monitor The Deep image i called it a year or 2 back .
http://www.taswegian.com/NBTV/forum/viewforum.php?f=19
I also interested in the vidicon camera idea ,i am making a vidicon camera after i finish my multi system monitor ..i also have a PMT flying spot classic SSTV camera on my to do list ...a lot more fun than modern micro electronics..i like classic 60's 70s electronics ...i would not have a clue how stuff works these days .

OH yes i think i know that sound its the VIS code we were trying to find a classic SSTV signal without the code a while back there's very little that ever made a prerobot 8 sec sstv signal .
I made a mechanical 8 sec SSTV a while back rather like vintage SSTV !
http://www.taswegian.com/NBTV/forum/...lit=sstv+steps
Something of interest coming up Steve Anderson is making a SSTV and NBTV to 625 line converter on the nbtv forum he's just moved so getting back to working on the project ..

I read a little bit trying to pick up information and i read she had done this amazing and the FOTH i didn't know what that was about as it was mentioned in some postings ...now i know ;D
Great work indeed !

The others in the shed at the moment but this one also works its a Toshiba satellite pro L300..i will have a look tomorrow what the other is it is a older laptop but its the one i am experimenting with in those last postings .
i will see if i can track down what graphic chips they use .or do you just need what modeline uses with them in the menu ?
Harry

Re: Modeline and a laptop
 

Graham:wave: i had a look at the Dell inspiron PP20L the main lap top i am experimenting with modeline screen grab of its settings picture below ...i am not sure if that's enough information on the graphics chip used .
I pretty much just want Composite video ,i don't need an RF modulator .
Not many vintage 405 line sets in Australia,i am sure there's some but can't say i have seen one .
There were tests in the late 1940's Sydney and Melbourne one did 405 line the other 625 line and they went with 625 line in 1956.