Innovation of the week

A new battery-free underwater navigation system could “transform ocean exploration,” said Darrell Etherington in TechCrunch .com. Researchers for years have been looking for a way to re-create GPS for underwater navigation that doesn’t rely on radio waves. The likeliest alternatives—sonar and other acoustic-signaling methods—“are power-hungry,” requiring “large, quick-to-deplete battery packs.” But researchers at MIT found a way to plot location information without any battery. The system uses piezoelectric materials, which “generate an electric charge when hit with” sound waves. Researchers already use such sensors to measure temperature and salinity in the ocean. The new technique translates the electric charges into strings of information, and could let “future robotic submarine explorers better map the ocean floor.”