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Displays Portables Hardware

Building a Video Wall out of Old Laptops? 52

Posted by Cliff
from the that's-one-use-for-'em dept.
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?"
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Building a Video Wall out of Old Laptops?

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  • by Gothmolly (148874) on Saturday April 14, 2007 @12:40AM (#18728863)
    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
    • by fbartho (840012)
      Less likely if you happen to have a source of homogenous laptops that all reached end of life at the same time...
    • by NerveGas (168686)
      If you have access to a hardware calibrator, good things can be done. They might not match exactly, but they can often be made to match enough to surprise most folks. You do have to pick a sort of "lowest common denominator" for brightness, though.

      steve
  • Projector (Score:5, Informative)

    by Dan East (318230) on Saturday April 14, 2007 @12:57AM (#18728919) Homepage Journal
    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
    • The Projector bulbs (Score:4, Informative)

      by dj245 (732906) on Saturday April 14, 2007 @02:44AM (#18729315) Homepage
      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 [lumenlab.com] 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.
      • by karnal (22275)
        I have a quick Q for you- how quiet is this puppy? ( the evo v1.1) - I'd be concerned with the thing being a little loud to offset the heat of the bulb. While we're on this subject too, how much power is consumed by this projector? This would directly relate to heat given off, which would probably be more than a few lcd panels...

        Also, since the res is 16:9 - and low at that, I wouldn't have a use for it in a panel display setting. Maybe for something like a conference room or showing movies, but with the
        • by dj245 (732906)
          I have the 1.0. Its a bit on the noisy side. I I haven't gotten around to replacing the stock 40mm fans with something better yet. The 1.0 uses around 170W on my Kill-A-watt meter, which really isn't that much when you compare to the 100W that my mothers 35" tube TV uses.

          The 1.0 isn't 16:9. Its 15:9 or 16:10 or something weird like that. I always use 4:3 mode anyway. Its good enough for movies, and its the best TV I ever had. I have a hard time looking at smaller TV's now, even when they are generall
    • Re: (Score:2, Interesting)

      by prefect42 (141309)
      If you're merely looking to upscale, the bandwidth isn't a killer. Multicast/Broadcast the video and play it back with vlc, and it'll do the tiling for you. You just need a bunch of machines running vlc.
  • Practicality (Score:3, Informative)

    by cephalien (529516) <benjaminlungerNO@SPAMgmail.com> on Saturday April 14, 2007 @12:59AM (#18728925)
    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.
  • by Hard_Rock_2 (804967) on Saturday April 14, 2007 @01:05AM (#18728947) Homepage
    I've not used it myself, but some friends have and it worked pretty well. http://www.maxivista.com/ [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/ [sourceforge.net] Though if you just want to control all the computers from one place, then synergy should work.
  • Windows? (Score:4, Insightful)

    by Simon80 (874052) on Saturday April 14, 2007 @01:19AM (#18729005)
    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.
    • Re: (Score:2, Informative)

      by cephalien (529516)
      Assuming that we're talking about a heterogeneous combination of laptops, some of which are unlikely to be anywhere near current, I think Windows (as far as driver support, at least) would be the sensible solution. Since they all likely come with a license for one or the other version, there shouldn't be much of an issue with legality anyway.

      Linux would be more flexible, yes, but not when you're trying to get old displays working as fast as possible, along with builtin networking or even wireless, without h
      • by Simon80 (874052)
        Well, in this specific context, hardware shouldn't be an issue, since the networking would be wired, and no graphics acceleration would be required. In the absence of those issues, I'd say that Windows would be more tedious to set up, not the other way around. In any case, I'm just nit picking here, since it doesn't look like there's an easy solution on either platform.
        • by cnettel (836611)
          No graphics acceleration required? The guy mentioned video, and it's bad enough trying to get it over the network, but a stupid enough framebuffer driver would be the nail in the coffin.
          • by Simon80 (874052)
            Sorry, I meant no 3D acceleration - I've come to take 2D acceleration for granted.
  • An alternative (Score:3, Informative)

    by Z00L00K (682162) on Saturday April 14, 2007 @01:29AM (#18729045) Homepage
    is to run Linux on all laptops and execute them all as X servers without any window managers.

    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.

    • by w4f7z (837544)
      I think the project you're referring to is Xdmx. Here's a decent tutorial [ibm.com].
      • XDMX (Score:2, Informative)

        by MicklePickle (220905)
        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
    • by cgenman (325138)
      It's possible to run multiple monitors under both Linux and Windows without any problems.

      For me, Windows Media Player seems to crash if you run it on a multiple graphics card/multiple monitor setup. All other video playback was questionable depending on if it used WMP to play back or not. YMMV, but it didn't work that well for me.

  • by forkazoo (138186) <wrosecrans AT gmail DOT com> on Saturday April 14, 2007 @01:38AM (#18729075) Homepage
    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.
    • by Redlazer (786403)
      I dunno, i find that streaming with VLC works pretty well. Using my 100MB network, while downloading torrents (granted at around 100k/s, but with at least 100 connections per torrent).

      I used to have a lag issue when i was using a Belkin router - however, now that i switched to (begrudgingly)a Linksys, i've had ZERO streaming-related hiccups.

      Now, im not so sure about the feasability of streaming it across more than 10 or 15 laptops - but an upgrade to a gigabit network would almost certainly solve the pr

    • Hi this is an interesting bolog but i was wondering does anyoneknow how to make an old laptop monitor (not conected to a laptop) be used as a monitor for a video game system, I am trying to modify the old N64 with a old laptop screen, if anyone can help me that would be great thanks
  • Good question and I'm also looking for answers. I have PowerBook G3 Pismos and iBook G3 12" laptops. I've made stripped down 'picture frames' and mounted them in frames for the wall. I'd really like to build an installation with a mount for grids of say 1x4 or 2x2. Or do a tabletop piece that's 3 panels mounted vertically a closed top. Fitting their logic board, dc board, inverter, assorted bits inside. Extremely cool if able to link the DC power together to have one power cable. But I can't imagine how to
    • by TRRosen (720617)
      they wrote a program to do this at MacHack (now AdHoc) a few years ago I believe it basicly used VNC to spread one desktop across any number of networked machines. I think they maintain a page with the hacks somewhere.
  • I had always thought doing something similar to this, but in my dining table. I figured it'd be possible to take one or 2 flat panels and some miscellaneous optics and make a fairly seamless representation of the image appear to be under the glass. Kind of cute if you whack a remote controlled webcam under there and show up your guest's skirts at dinner...

    My first though so far was to use mirrors - reflect the display off a mirror kind of like what they do in some of the arcade games. This lets the displ
  • http://puredata.org/ [puredata.org], and it's library http://gem.iem.at/ [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 g
  • No, it's not what your looking for, just interesting and informative regarding the technical problems.

    HIPerWall [uci.edu] is a 200 Megapixel display, based on 50 Apple 30" Cinema Displays driven by 25 Dual G5 PowerMacs plus one controller. It's a project at the University of California to explore very high resolution displays. HIPerWall is short for Highly Interactive Parallelized Display Wall. The PowerMacs are connected and act as one large display, allowing even video to be split over the whole area. The main

    • by Meostro (788797)
      This seems like a much better suggestion than "get a projector". I want to build a video wall too, but the only 2 reasons to do so over a projector are "because" and high resolution.

      Yes, I could buy a projector for a thousand or two, but that will still only give me 1.3MP, maybe 2MP if I get a really good one. For the price of a high-end projector I can probably get 4 LCD monitors with some moderate hardware to run them, and end up with a 5MP display that's much brighter and sharper than a projector can e
  • Isn't it the case that with laptops, the screen is usually the first thing to break?
  • by slim (1652)
    Let's assume this is a "because it's there" hack, because as others have pointed out, if all you want is a large video screen, you'd be better off spending the time doing a McJob and spending the proceeds on a projector.

    So, you're doing it because it would be kinda cool. Have a play with GGI [ggi-project.org]. It's a portable graphics layer with various targets implemented. e.g. there are kernel targets for various graphics cards, a Windows target, a VNC target, etc.

    What'll interest you is the display-tile target, which is a
    • There is a fellow running a computer recycling center in Oakland, California who brought to the May 2006 MakeFair in San Mateo a rolling wall with a 9 monitor display. The display was one image partitioned among all 9 displays.

      The base of his system was a 3 shelf display rack with casters. It is a common commercial shelving unit.

      On the cart he put 3 rows of 3 CRT monitors. Each row of 3 monitors was driven by a salvaged pentium class computer, and each computer had 3 video cards. The video cards pick up an
  • Oh wait... you said windows. Never mind.
  • I would definitely not try to tap into the video systems for the laptops; keep the whole machine, unhook the hinge, and get a long-enough interconnecting cable to let you flip the display and mount it face up over the keyboard. Yank the hard drives and let the machines boot off the network. Have them all running VNC so you can control them remotely. If they're old laptops you'll want a codec you can detune a bit so it plays the video you want well enough. You'll also need to adjust brightness and color
  • by a cluster computing group at the University of Kentucky called the Aggregate http://aggregate.org/ [aggregate.org]. They built a nine laptop display panel that is basically what you are trying to do. It is much more difficult than I thought it would be to do. Here is a video of the panel in action http://aggregate.org/IMG/mvi_5158.avi [aggregate.org]. And here is the software they created to do it http://aggregate.org/VWLib/ [aggregate.org].

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