Roland Piquepaille writes "It's not always easy to explore small buildings in dangerous areas and even more difficult to see what might be hidden in a cave or a tunnel. In a short article, the MIT Technology Review describes the results obtained by Swiss researchers with a small robotic aircraft. It only weighs 30 grams for a 80-centimeter wingspan and can be flow inside a building for about 4 minutes. With its two 1-gram cameras, a gyroscope, and a small microcontroller onboard, it can detect walls and automatically avoid collisions. The team is now working on even smaller versions of these flying robots which will be used for search-and-rescue, reconnaissance, and inspection applications." For more details see Roland's latest blog entry. The article is based on research presented in the recently published paper, Toward 30-gram Autonomous Indoor Aircraft: Vision-based Obstacle Avoidance and Altitude Control (PDF format) by researchers at the EPFL Autonomous Systems Lab. The robot uses Optical Flow to understand the motion it sees. This is an under-utilized biologically inspired vision processing method that's always been a favorite of mine for robotics applications.