Researchers in China and Japan developed a tactile sensor that demonstrated minimum loading, or sensitivity, of 50 micronewtons (1.25 pascals), which is less than the sensitivity threshold of human skin. The features of the tactile sensor show potential for application in smart prosthetic limbs that may function more like replaced natural limbs. According to the study, published online September 19 in Science Robotics, the bionic tactile-perception system is based on giant magneto-impedance (GMI) material embedded with an air gap.
The Daily Mail describes the skin as a hollow polymer membrane encasing a magnetic sensor; the skin has magnetic particles on its top surface. When pressure is applied to the magnetic particles, the membrane inverts, causing the particles to move toward the sensor. The resulting resistance is transmitted as signals using an electrical circuit, which are converted as pulses that increased with greater pressure. The newspaper reports that an artificial finger equipped with the skin was able to detect and pulse in response to wind, various volumes of drops of water, and a moving trail of ants.