The SafePassage Automatic Identification System monitors the real-time data that commercial ships broadcast-including name, position, course and speed-for boats in a 30-mile radius. The system comes loaded with differential GPS, two data receivers, and ports for running information to a laptop or plotter, which will alert you if you're on a collision course. $1,250
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.