If you hear reports of giant, glowing blocks falling from the top of the French National Library in Paris this week, don't be alarmed: it's just Berlin's Chaos Computer Club (CCC) at play.
The tumbling blocks are part of a 3,370 square meter game of Tetris pieced together by 10 CCC members and projected -- from the inside -- onto the facade of one of the library's four glass towers for a night-long festival of the arts.
Here in the 18th-floor Chaos Control Center, the team has been ready to roll since Sept. 25, but the festival proper, Nuit Blanche, doesn't start until dusk on Oct. 5, running throughout Paris till dawn on Oct. 6.
The Blinkenlights project, as it is jokingly referred to by its creators, was first dreamed up to celebrate CCC's 20th anniversary with an illuminated display stretching across the upper eight floors of an office block on Berlin's Alexanderplatz. There, passers-by could play the arcade game Pong on the display via their mobile phone, or watch animated messages and graphics scroll across its surface.
"Nuit Blanche called us (to ask) if we would be interested in doing a similar installation to the one in Berlin. We said 'Yes, if you have an interesting building for us,' and they came up with the National Library," Tim Pritlove, one of the Blinkenlights team, said.
As it turned out, creating the Blinkenlights display for Nuit Blanche wasn't as simple as unplugging the one in Berlin and shipping it to Paris. For a start, the office building in Berlin was empty, so CCC could run cables directly from the central controlling computer to each of the 144 lamps without anyone tripping over them.
The library, on the other hand, is in constant use, and has strict rules about fire security to avoid damage to its collection of 10 million books, so running temporary power cables from one floor to another was out of the question. Besides, the number of cables necessary would have been prohibitive: the library display consists of 20 rows of 26 pixels, each illuminated from inside the building by two halogen spotlamps projecting onto a fire-retardant plastic sheet hanging by the window.
There's remarkably little cabling chaos here in the control center. A dozen or so computers are scattered around the room, linked by cables and an Apple Computer Inc. AirPort wireless LAN hub. To one side lies a table full of sandwiches, and to the other a cluttered workbench on the corner of which perches an unassuming little box, one of 20 custom-built lighting controllers the team created for this installation.
The controllers are embedded PCs running the RTAI realtime application interface for Linux on Advanced Micro Devices Inc. 486 processors. They use silicon relays to control the lamps, each setting up to 48 pixels independently to one of eight levels of illumination, Thomas Fiedler, another team member, explained.
The library authorities made available some redundant networking cables running between the floors, which the Blinkenlights team used to connect the controllers, one per floor, to a central computer.
It took two to three weeks to assemble and test all the new equipment in Berlin, and another two days just to pack it, Fiedler said. On arrival in Paris, it took another two weeks to set it all up.
The lighting controllers aren't the only thing that's modular about the system: the controlling software is too. CCC has published the code that drives the system, and the interface to it too, allowing others to create modules that display messages, a slideshow, and arcade games including the giant Tetris. If you want to play, all you need is your mobile phone (you'll find the number to dial on the Blinkenlights Web site at http://www.blinkenlights.de/arcade/) -- and a clear line of site to the tower: Try the East end of the Pont de Tolbiac, in the 13th Arrondissement.
Now, if you'll excuse me, it's nearly dusk, and I have an important phone call to make.