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Digitizing VGA? (take 2)

Posted by Cliff on from the forget-printscrn-go-digital dept.

urgent asks: "In March of 2002, Ask Slashdot ran this article, wherein advice on 'hardware to digitize the VGA output of a PC' was sought. Most of the responses seemed to assume that remote administration of PC's/servers was the end goal. If you've got control of the software and/or hardware, it's pretty clear there are easier solutions for that. On the other had, there are many legacy and embedded systems where it would be nice to monitor and record display output. For instance, integrating old computerized factory equipment into a SCADA system, or recording old embedded maritime and medical displays (hint: jobs). My dream hardware would be a dongle that connected to a VGA out and could be polled over ethernet or CAN."

2 of 49 comments (clear)

  1. Re:Better solution? by Satan's+Librarian · · Score: 2, Interesting
    I may be off base, but for what you're wanting (although not the original poster) I'd think you could just burn an EEPROM with a custom program quite similar to the DOS TSR's you describe and stick it on just about any network card with an empty socket on it.

    I'd think polling the screen for changes and providing a way to push keys would be about all the code you'd need on that level. If you want remote access over a network, you'd need to use the EEPROM for what it was meant for as well - to boot off a network - and add a bit of custom code to turn over control to a network host. That'd be a task, but not too bad.

    Otherwise, it'd be a simple project to create a basic TTY interface to an RS232 port or somesuch within that space that would allow you to do BIOS manipulations - the bootstrap code off your cards gets run before you can enter the BIOS setup.

    A long, long time ago I wrote a bootstrap program to do port-level I/O with IDE drives and burned it onto an EEPROM, stuck it in my 3C905 (or was it 3C509?). I used it to autodetect IDE drives on machines with BIOS's that didn't support autodetection. Worked like a charm.

    This was back in the day of 386's, but I've noticed most network cards I buy still have that empty socket.... I suspect if you put something at a 0x2000 boundary with a valid bootstrap sig and checksum, it'd get run in pretty much the same manner.

    --
    I write code.
  2. Re:First Post... by pauldy · · Score: 3, Interesting

    LCD monitors do this. There are KVMs that do this. Don't forget that two of those signals are simply trigers and not data that must be captured. The other two break very nicley into 3 8 bit streams. They run at about 300Kbytes per frame or 18000Kbytes per second at VGA uncompressed 60hz. Using a microcontroler this data can be piped directly into an mpeg encoder chip like the one Tivo uses form IBM which could compress that down to a manageable size with little effort. The stream should be able to be distributed with relative ease using a microcontroler with a built in ethernet controler like the tini from dallas. The end result would be a very small device that was relativly inexpensive that did the job he was looking for while being very dongle like. It would also have the ability to distribute it via a controler area network if need be.