hand holding a smartwatch, water in backgroundFor UW News, new member Stefan Milne writes about the first underwater 3D-positioning app for smartwatches and similar devices, recently developed at the university. Instead of GPS, whose signals do not transmit far underwater, the technology uses the microphones and speakers of the watches of three or more divers to triangulate everyone’s relative positions with sound — which travels farther in water than in air. Photo: University of Washington