The earth's magnetic field surrounds us all, but for the most part humans cannot feel it. Now, scientists at a German research lab have created an electronic skin (e-skin) with magnetosensitive capabilities.
Wearing this e-skin is, according to the researchers at Helmholtz-Zentrum Dresden-Rossendorf (HZDR) lab, a "bionic analog of a compass." Using only a silver polymer a thousandth of a millimeter thick and the earth's magnetic fields, researchers were able to control a virtual panda on a screen in a demonstration.
"The foil is equipped with magnetic field sensors that can pick up geomagnetic fields,” says lead author Gilbert Santiago Cañón Bermúdez, speaking in a . “We are talking about 40 to 60 microtesla—that is 1,000 times weaker than a magnetic field of a typical fridge magnet.”
Previous models of the e-skin required external magnets. This time, Cañón Bermúdez says, “Our sensors enable the wearer to continuously ascertain his orientation with respect to the earth’s magnetic field. Therefore, if he or the body part hosting the sensor changes orientation, the sensor captures the motion, which is then transferred and digitized to operate in the virtual world.”
The ultra-thin strips work on what's known as the anisotropic magneto-resistive (AMR) effect. “It means that the electric resistance of these layers changes depending on their orientation in relation to an outer magnetic field," Bermúdez says. The researchers performed their virtual test outdoors to show that the e-skin could work in a practical setting.
For the outdoor tests, researchers attached electric sensors to the e-skin, meant to put out higher voltages to the north and lower to the south. With a sensor attached to his finger, a tester started off at a northern position, then walked west, then south, and then back again. Monitoring the voltages, the tester found they corresponded to the directions like they were attached to a compass.
"This shows that we were able to develop the first soft and ultrathin portable sensor which can reproduce the functionality of a conventional compass and prospectively grant artificial magnetoception to humans,” Bermúdez says.
The wearable compass skin could have a number of uses, particularly in health-related fields. A sense of direction could help those suffering from disorientation issues, like Alzheimer's patients. "Psychologists," Bermúdez says, "could study the effects of magnetoception in humans more precisely." While humans don't have a magnetic sense, an e-skin like Bermúdez's could offer the next best thing.