When you think about it, fish can do some pretty remarkable things. They can find prey in murky water, travel in tightly-packed schools without colliding, they always know what depth they’re at, and they manage to avoid being swept away by invisible underwater currents. They’re able to do all of these things and more thanks to their lateral lines - rows of tiny hair cell clusters that run down each side of their bodies. These clusters, known as neuromasts, pick up on changes in water pressure and transmit that information to the brain. Now, researchers in Illinois have created an artificial lateral line, that could someday be used to keep man-made submersibles out of harm’s way.

Douglas Jones, from the University of Illinois, along with Chang Liu from Northwestern University, developed the device. They created artificial neuromasts out of 500-micrometer-long lengths of silicon fiber, wired to a computer. The fibers acted as resistors, whose resistance would change as they bent in response to water pressure. Several of these sensors were placed in a line on a section of plastic pipe, which was then submerged in a pool of water.

Sure enough, the lateral sensor array was able to detect movement. When a wriggling live crayfish was placed in the pool, the array was able to detect not only that it was there, but also where it was in relation to the plastic pipe. This was possible thanks to the placement of the sensors in relation to one another, as different ones would register the crayfish’s movements at different times - of course, we’re talking fractions of a second, here.

“A man-made lateral-line system can be indispensable for underwater vehicles and robots, enabling new methods of exploration, interaction and communication,” say Jones and Liu in their paper on the project. This is not their first foray into artificial sensing devices, either. In 2005, they created an array of polymer-based tactile sensors that could someday allow robots to detect different textures - essentially, giving them a sense of touch.

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