The blind cavefish has a problem. In the absolute blackness where it lives, no light illuminates its world. Yet the small fish has traded its eyesight for a different way to perceive its environment: "touch at a distance."
As the species, also known as the Mexican tetra, found its way from the pools of the Rio Grande river to underwater caves, it evolved the ability to locate and track objects underwater without light, sound, or electric field—all methods used by animals in nature. The trick was an exquisitely sensitive lateral line along each side of its body to monitor water flow and pressure and sense a detailed pictures of the surroundings.
Now, engineers at Singapore’s Nanyang Technological University are borrowing this sensor strategy to develop a radically different approach to "seeing" underwater without cameras or sonar. Their technology, a set of tiny sensors, act as an artificial lateral line to detect minute changes in water pressure that paint a 3-D map of nearby objects. The design means that extremely small (less than an inch square) and low-power sensors could replace standard expensive, power-hungry sensor arrays on underwater craft.
"To mimic nature, our team created microscopic sensory pillars wrapped in hydrogel—a material which is similar to the natural neuromasts of the blind cave fish—into an array of two rows of five sensors," said Miao Jianmin of the School of Mechanical and Aerospace Engineering in a statement. "This array of micro-sensors will then allow AUVs to locate, identify, and classify obstacles and objects in water through water pressure and also to optimize its movement in water by sensing the water flow."
The Singapore team reports they will present the results of their research at the Institute of Electrical and Electronics Engineers conference later this year, and are already installing their sensors on small autonomous underwater vehicles built though the Singapore-MIT Alliance for Research and Technology.
This line of research is still gaining momentum. Biomimicry—raiding strategies found in nature to design new technologies—is moving ever closer to the sophistication of biology. Researchers are looking at infrared receptors of snakes and insects, the electroreceptors of fish, and magnetic sense organs of birds to find the next insights for the sensors in our machines.
[Hat tip: Dmass]