The Virtual Window Project FAQ.

Last updated: Oct 12, 2004

Q: How much did you spend in total?

A: Not counting wood working or soldering tools that I bought, I spent about $500 on the project. And the majority of that is in heavy-duty power supplies. The main power supply running the PC and video for the panels is a 550 Watt PS and ran about $170. I was lucky in that I didn't have to buy any of the panels, video cards, or inverters and the PC I already owned.

Q: Can you send me the program you used to display the images?

A: Sure, here is the source code in Visual Basic. I've elected not to provide the binary because the resolution is custom for my configuration anyway, so you'll want to change it for yours.

Q: Can you send me free or discounted LCD panels? I'll be your friend for evah!

A: Sorry, these are prototype screens and Samsung wouldn't be happy if the prototypes cut into sales of real product. My job's still important to me, so I can't let any of them go. Besides keeping your eye on deals sites, I don't know of any way to find cheap LCD panels. Every day they are coming down in price, though!

Q: Why is video so difficult?

A: With several smaller displays, you have the problem of splitting and scaling the video at 30 or 60 frames per second. There are some consumer-level PC graphics chips that can handle splitting a video between two displays, but with more than two displays, you've got quite a problem on your hands. Given the fact that with today's systems (2004) even playing back a DVD onto one monitor can greatly task a computer, sending that same info to be displayed on multiple video cards and multiple displays is a tall order. But processors, memory, and disks are getting faster and the faster PCI Express buses are becoming common.

Also note that those big displays at Best Buy and the local sports bar are a very specialized system. They do the work in hardware that is specifically designed for this application. They also don't touch the high resolutions that we are talking about here.

Some people had some ideas on this Slashdot forum. You might try reading there.

Q: I have some old LCD panels from laptops laying around, can I hook them up to DVI?

A: Each panel is different. Some use older LVDS signalling and some are completely proprietary. If you can find the spec for your panel from the manufacturer (I mean the LCD manufacturer, not Gateway or Dell, etc), then that's your first step to finding out if it's possible. If your panel uses TMDS signalling, there's a chance that it will work with DVI, but need unique power.

Q: Can you give more detail on building the video cables?

A: The LCD displays have a proprietary TMDS interface on them, which meant that they were DVI-compatible, but I would need to build custom video cables. The distance from the computer to the farthest display would be as much as fifteen feet which is really pushing the limits of TMDS signaling at 1024x768x60Hz.

I had access to the proprietary Samsung interface connectors, so I spliced in an extension between the Samsung interface and the DVI interface. I managed to get some DVI-I sample connectors from Molex and used two shielded CAT-5 cables for each display to carry all of the digital signal pairs. The wires coming from the Samsung interface are super-tiny (smaller than 30 gauge), so it was a lot of work to splice in those CAT-5 cables.

At the DVI end, I also had to build a connector system to inject a 3.3volt power into the video signal cables. For this I used standard Molex PC power connectors and pulled 3.3v power from the system's ATX power supply.

Q: What resources are available on the web?

A: You can find the DVI spec online. You need to register or something, then can download the spec.

Q: Where is that anime background from?

A: She's from the Danger Girl series of comics. Here's the desktop image.