The Col.legi Oficial d'Arquitectes de Catalunya in Barcelona
Versión en español | More articles here.
The Col.legi Oficial d'Arquitectes de Catalunya in Barcelona
This project, whose title in Spanish was Emociones de creación compartida, de lo virtual versus lo físico (Shared creative emotions, the virtual verses the physical in English) was created for the 8th Mostra Internazionale d'Architettura (Biennale di Venezia) which took place between 6th September and 3rd November 2002.
The general concept (in my mind) was a study with two objectives. Firstly, how a group of people from different creative fields (see the credits below) could come together and produce a result which seamlessly melded these diverse backgrounds and abilities together to produce a contiguous whole; and secondly, how the concept of what is virtual and what is physical could be explored.
At the centre of this project was a rectangular block made up of various different materials (stone, metal, plastic, etc.) that would be suspended from the ceiling in the main reception of the Col.legi Oficial d'Arquitectes de Catalunya (Official College of Catalan Architects) in the centre of Barcelona. This block, the piece, would contain electronic gadgetry that would emit various sounds, light and smells when brought into contact with external stimuli. The stimuli would be people passing underneath the piece, whose passage would be detected by motion sensors installed within the block itself. Images and sounds from the block would be transmitted via the Internet to be displayed on a large (42") plasma screen as part of the exhibition in Venice.
To complement the piece itself and to complete the story of the construction of multi-sensorial artifacts, accompanying animations and graphics were to be produced that would be shown both on the web site and also played via a DVD in Venice. There would be a computer in Venice which would intersperse parts of the DVD with the sounds and images coming from the piece in Barcelona.
I was approached in August 2002 and asked to provide a solution as to how the piece could been seen and heard in Venice over the Internet. At this point, the piece was already under construction and a great deal of work was being put into the circuitry that would be installed within it. In addition, the graphics and animation were also being created, but there was a distinct need for somebody that could actually get the link between Barcelona and Venice working. The Internet connexion was in the process of being installed and there were two high-quality web cameras on order.
The piece suspended from the ceiling in COAC.
The Internet connexion was provided by two 2Mb/s ADSL lines from Telefónica (Spain's national telecommunications monopology). These lines, whilst having a maximum of 2Mb/s downstream, actually only have an upstream of 300Kb/s. However, this was sufficient for the requirements of the project. Each line had an Efficient Networks SpeedStream 5660 ADSL router connected to it. The two ADSL routers were given IP addresses on the local network of 192.168.0.1 and 192.168.0.2 and NAT was enabled so that port forwarding could be used to direct requests coming from the Internet to the web server, web cameras and audio stream.
Telefónica had provided two rather low-end 10Mb/s Ethernet hubs with their ADSL routers, which, although of poor quality, proved to be sufficient for our needs. In the end, we only used one of the hubs and all five ports on this hub were employed, two for each of the two ADSL lines, two for each of the cameras and one for the audio and web PC.
ADSL routers and hub |
The hub |
A high-quality, ultra-sensitive microphone was mounted inside the piece in order to capture the ambient sounds of the main foyer of the COAC building. A quality audio cable was run to where the ADSL lines were and this was connected to a small mixer to control input volume. The output from the mixer was fed into the sound card of a standard PC running Windows XP*.
The Shoutcast streaming server software for Windows was installed on this PC and also WinAmp and the Shoutcast plug-in for WinAmp. Audio was captured on the sound card's line-in and then streamed locally to the Shoutcast server running on the same machine. The default Shoutcast ports of 8000 and 8001 were used and connexions to this port on the ADSL router were forwarded to the PC.
We were originally planning to use our own server, based in London, and running Debian GNU/Linux with the GPL'd IceCast streaming server. However, due to some recent hosting agreement changes, our current international bandwidth allowance was insufficient to handle additional services such as a streaming server, so this idea was abandoned.
This caused some problems as the streaming server had to be run locally under Windows and port forwarding relied on. As I am not that familiar with Shoutcast, this initially caused a few difficulties when trying to connect from outside to listen to the output. However, in the end, and after some tweaking of the router configuration, it all worked successfully.
The audio mixer |
The streaming PC |
Two high-quality web cameras were employed. These were Pixord model NC-100P (PIXORD-100) cameras which feature a quality detachable lens, an integrated web server and web-based configuration system, and an RJ45 Ethernet port. To get the camera working, it was neccesary to access it via telnet or http and give it an IP address suitable for the local network. The web interface provides password-protected configuration of the image size, contrast, brightness, hue and saturation, as well as a host of other parameters, including the frame rate. For Internet purposes, as we were likely to obtain a physical rate of only around 2 frames per second over an Internet connexion, this was set to a happy medium, between quality of image and speed, of 8 frames per second.
The configuration was relatively straight-forward, but a certain amount of customisation was required to ensure that the output would be suitable to integrate into the final web pages. This was done by the use of FTP to download the contents of the camera's web interface and by modifying the home page so it would display as desired. As a web server was also to be used, the TCP ports for the cameras were changed from 80 to 8888.
The two cameras were connected to the hub and given IP addresses on the local network (192.168.0.30 and 192.168.0.40 for cameras 1 and 2 respectively). On each of the two ADSL routers, port forwarding was enabled so that port 8888 on the router went to the same port on the camera. This meant that the images came from two separate ADSL lines and the load wass split.
The two cameras were mounted in place, camera 1 in the ceiling, directed at the piece, and camera 2 mounted inside the piece, directed at people passing underneath. RJ45 cable was run through the ceiling from each camera to the hub. Both cameras were fitted with high quality wide-angled lenses that were better suited to the application.
Auvidea IPcam-10 web camera |
Camera 1 in situ |
Camera 2 in situ |
We had originally planned to run the web server directly from the same PC used for the audio stream. However, this meant more dependency on Windows and for this reason the web serving was moved to a machine at a remote location that was connected via a cable connexion, giving a downstream of 256Kb/s. The software used was the Apache web server running on Debian GNU/Linux. Links from the web site content to the URLs of the cameras and audio stream pulled the whole content together into a contiguous site.
On 24th October, there was a formal presentation of the project at the COAC and for this we needed to simulate what the people in Venice were seeing. pHila set-up a laptop and a video projector to reproduce the short sequences that were shown from the DVD. The presentation took place on the floor above where the piece was hung, and the idea was to have a large 42" plasma screen laying horizontally on the floor, alligned with where the piece was situated below. The screen was to show the image of the camera located inside the piece and the audio from the microphone was also to be heard, thus giving the impression of looking through the floor and the piece - seeing the physical through the virtual in this instance.
The solution I chose to achieve this was to use a wireless network to get the signal up to the floor above without using a lot of Ethernet cabling that would have been impractical. I installed a modified Apple Airport Base Station, which had an extended quarter wavelength omni-directional antenna fitted to it to boost the signal from the standard integrated antenna. The images and sound were to be played from my laptop (an Apple PowerBook G4). To achieve good reception (as it is well known that the Titanium's internal Airport card does not have a strong signal, which appears to be due to the metal case acting as an insulator), I installed a Buffalo WaveLan wireless card and used the wireless drivers for Mac OS X (see project page), and then connected a Buffalo extended range sector antenna to the external connector on the card. This meant we achieved a reliable signal strength of between 40 and 50 dB, which was sufficient to guarantee a fast enough network to transmit the audio and video. An interesting interactive effect caused by the use of wirless was that when people moved in between the signal path, the signal strength was reduced and this is turn affected the network speed, therefore changing (only slightly) what was seen and heard on the plasma screen.
The 42" plasma screen worked under OS X without the need to install any additional drivers or reconfigure the laptop. For a while, we used the sound-to-light animations from iTunes to display colourful images reacting to the sound of the room below. This was particularly interesting and, in some ways, the patterns generated were better than those for continuous music. The connexion to the audio stream was made using iTunes and the site was viewed using Internet Explorer for OS X.
The presentation was a success and the visitors were extremely impressed (as I was myself) with the work put in and the end result acheived.
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| View from camera (enlarge) | Animation by pHila (enlarge) | iTunes (more) |
* Author's note: it is not usually my principal to use Microsoft's Windows operating system in technology solutions. I avoid it where possible at all times. However, in this application the equipment came as supplied and, due to a couple of technical considerations and timing constraints, it was necessary to use Windows for the solution. It did make life harder not having decent Internet services for remote administration, nor proper network monitoring and logging tools, but it did work and BSODs were not produced.
Versión en español | More articles here.
Author: Mike Harris, Psand.net
Copyright (c) 2002 Psand Limited. Permission is granted to copy, distributed and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License".
