A National Science Foundation story describes a new type of audio sensor based on the human cochlea. The sensor is being developed by Karl Grosh and Robert D. White at the University of Michigan for use in underwater sound wave detection. They sensor may also be suitable as a lower-cost replacement for microphones and cochlear implants. The sensor is a MEMS device and uses hydromechanical components to detect sound. It currently works in the range of 4,200 and 35,000 hertz but could potentially measure sound in frequencies far beyond human hearing. Several diagrams accompanying the NSF article, compare the sensor to the human cochlea. For the technical details, see the researcher's paper, Microengineered Hydromechanical Cochlear Model (PDF format)