The Graffiti Research Lab, creators of the LED throwie and inspiration for the mooninite signs that destroyed the city of Boston in January, went to Barcelona with their amazing laser guided graffiti project system. Here's a video of the event, which has a good shot of the pedal-powered projection system. Link
Previously on Boing Boing:
• Graffiti Research Labs high-power projection system
• Graffiti Research Lab's video of Maker Faire
• Mind blowing video of laser-guided graffiti system
• LED ad campaign ignites terrorism scare in Boston
• Make cheap magnetic LEDs for fun graffiti projects