Slashdot Mirror
Building a Video Wall out of Old Laptops?
alphakappa asks: "I am interested in building a video wall as a personal project using recycled old laptops so that I can make use of the display controllers that are already present. Is there free or cheap software that can extend the display on Windows and still be capable of showing different videos on different zones (like, say run a video in one zone while showing a powerpoint presentation in another one) What tools would you use?"
Each old recycled laptop will have a different color scheme, brightness and viewing angle. DSTN vs. TFT, relative strength or weakness of the backlight, etc.
yes, yes, I am a troll for mentioning all this, blah blah blah
I want to delete my account but Slashdot doesn't allow it.
Buy a projector for $1000 and be done with it. The display controller is part of the motherboard, so you would need the entire laptop, not just the display. Thus the power consumption would quickly increase since you're powering entire laptops. Also, the lead length between the panel and the onboard controller must be very short - just a couple inches. So the bulk of the laptop will have to be mounted right with the panel. The displays will look significantly different - particularly with respect to white (some will have a yellow tint, others a blue tint), If you sit down and add up the bandwidth - full motion video at say 1024x768, times however many laptops you're driving, equals a crapload of bandwidth. We're talking gigabit requirements. If these are old salvaged laptops then you'll be lucky if they even have 100Base-T.
As I said, buy a projector for $600, plug it in and enjoy.
Dan East
Better known as 318230.
This really doesn't seem feasible, unless you have some serious hardware engineering prowess. What it seems like you want to do is span the laptop video on multiple monitors? If you want to do this with 'external' displays, then the problem is spanning across those individual laptops. With network access, you might be able to fudge something with VNC (although, don't expect great speed on that). Otherwise, I'd say probably not. From what I know, most of those art displays using regular PCs/monitors used specialized software or particular effects not available in a standard configuration to do what they do.
If firefighters fight fire, and crimefighters fight crime, what do freedom fighters fight? - George Carlin
I've not used it myself, but some friends have and it worked pretty well. http://www.maxivista.com/ Also perhaps you could bug the synergy team (this is an open source project), although I don't think this feature is something that will be implemented anytime soon... http://synergy2.sourceforge.net/ Though if you just want to control all the computers from one place, then synergy should work.
Why would it be a requirement that the software has to run on Windows if you're using the laptops sole ly as displays? Even if you'd like to use the display with Windows, the laptops would be able to run whatever you like.
Then you have a server that throws X applications onto the laptop displays where you will get just about any look&feel you like.
OK, it's crude and may require some work. The laptops may never be a really good solution anyway. Also consider the cost of additional hardware involved and you may be better off with a good projector or "standard" flat-screen LCD:s connected to a single computer with multiple graphic cards where you stretch the desktop to cover multiple monitors.
It's possible to run multiple monitors under both Linux and Windows without any problems.
If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.
Well, you will need to mount the whole laptop to the wall, and run power and network to each laptop. Each laptop will look a bit different, and laptop displays really aren't meant to be running 24/7, so plan on replacing the laptops with some frequency. That means that the physical build aspect of a project like this won't be insignificant to make it all work smoothly, look nice, be easy to maintain, etc.
Another poster has mentioned a projector. This is certainly the more sensible option, but for a funky project for its own sake, I'll assume that you just want to go with the laptop wall anyway.
First off, don't try to do this with Windows. It'll work very poorly. As for playing videos, you can ssh into each laptop and run mplayer locally to get any gioven laptop playing a video. For multilaptop video playback, you will need to make yourself some scripts that will log into each laptop and run mplayer using appropriate cropping options on the video so that only a portion of it is played full screen on any given laptop. You may also want to check out VLC's network streaming options. You will need quite a bit of bandwidth. I sometimes have issues playing high bit rate video files over my 100 Mb network with just a switch between the client and server, and no other significant traffic. You will also want to avoid any HD. If you are going to build something for playing serious high bit rate HD across 9 or 12 different systems, you don't need to ask slashdot how to do it.
Past that, you probably want to write some additional scripts to do things like randomly show your favorite online scenic web cams, give weather reports, show traffic conditions. But, you are creating custom hardware, so don't look off the shelf for that sort of thing. You pretty much have to roll your own, because there isn't any standard plug and play interface for video walls.
Good luck.
http://puredata.org/, and it's library http://gem.iem.at/ could be run on the laptop array. Building a laptop hierarchy: 1 laptop recieves the whole 1024*768 and GEM slices four 512*384 screen displays and serves them to a 2*2 grid of laptops on display. or, if you have 21 laptops, you can make a 16 laptop laptop display wall wall. The trick is farming low resolution chunks to the slower machines. The final 4*4 laptop wall only has to have a combined resolution of 1024*768, right? You're not going to get highdef out of this wall.
with rocket fuel siphoned straight offathe rocket my eyehorn glows
The major cost of projectors is in the bulbs. A $600 projector that takes $300 bulbs that only last maybe 2000 hours is no fun. When you have the $300 bulb on your mind you get really stingy about turning the TV off all the time. To get around this, there are about two solutions.
1. Build you own projector, and spec a better cheaper bulb that lasts longer
2. Buy something like the LumenLab Evo which takes $30 bulbs that are supposed to last 6000 hours.
I went with option 2 because I'm a lazy bastard. While there are better projectors with higher resolution, for now (I graduate in 3 weeks) it was worth every penny and then some.
Even those who arrange and design shrubberies are under considerable economic stress at this period in history.
I've tried XDMX on exactly this setup. I had a number of old laptops, (nine to be exact), that I converted to
one large X display. Worked really well. The screen was huge - 3x3 17" laptop screens adds up to a big display. The downside? You have to have a dedicated switch to handle the traffic, (because there is a LOT of traffic - even when moving the mouse the switch goes bonkers). Also, it's slow. Much slower than an individual display, but good for displaying static images.
Once I had it setup I didn't use it much, and in the end just used each laptop as an network mp3 player in each room of the house. Much better use for them.
-- main(s){printf(s="main(s){printf(s=%c%s%c,34,s,34