Everyone learns in school that humans have five basic senses: touch, sight, hearing, taste, and smell. There are actually several more, but one that humans don’t inherently have is magnetoception, the ability to perceive magnetic fields. This sense can be found in certain bacteria, migratory birds, fish, and invertebrates, and provides a better sense of navigation and orientation. A new paper published in Nature Communications by lead author Michael Melzer of the Leibniz Institute for Solid State and Materials Research in Dresden, Germany describes a new electronic skin, which provides a “sense” of magnetic fields that will have a wealth of implications when it is developed further.
"We have demonstrated an on-skin touch-less human-machine interaction platform, motion and displacement sensorics applicable for soft robots or functional medical implants as well as magnetic functionalities for electronics on the skin," Melzer said in a press release.
The electronic skin contains an array of magnetoresistive sensor foils which sense both static and dynamic magnetic fields. The sensors are made from layers of cobalt and copper, with polyethylene terephthalate (PET) film. Information about the sensor’s proximity to a magnetic field is transmitted wirelessly to an external device that has LED indicators, giving a visual representation of the distance.
The skin is only about two micrometers thick, which is about one-fifth as wide as a single human hair. A square meter of the material only weighs three grams, which makes it light enough to rest on a soap bubble, as can be seen above. It is also incredibly elastic, as it is able to stretch over 270% in multiple directions over 1,000 times before wearing out. Conversely, the sensors are still able to function properly if the skin is crumpled up. These features make them well-suited for use on the skin.
The electronic skin is resilient enough to be functional, even after it has been crumpled. Credit: IFW Dresden
"These ultrathin magnetic sensors with extraordinary mechanical robustness are ideally suited to be wearable, yet unobtrusive and imperceptible for orientation and manipulation aids," senior author Oliver Schmidt explained.
In the future, this technology could be used with biomedical implants such as artificial muscles or joints to detect anomalous behavior, and could also be used to improve the fine motor skills of soft robotics.
“The integration of magnetoelectronics with ultrathin functional elements such as solar cells, light-emitting diodes, transistors, as well as temperature and tactile sensor arrays, will enable autonomous and versatile smart systems with a multitude of sensing and actuation features,” the authors wrote in the paper.