Electronic Magnetic Sensor to Advance Virtual Reality

Many people became acquainted with the idea of "augmented reality" and computer-generated perception blends into both the virtual and real worlds, after the recent success of apps like Pokémon GO.

Controlling virtual light bulbs without touching them - HZDR's ultrathin electronic magnetic sensor makes it possible. Depending on the fields of a permanent magnet, the movement and the position of the hand, on which the sensor is attached like a second skin, are translated onto a virtual scale that then controls light intensity. (Image credit: D. Makarov)

So far, these apps have mostly used optical approaches for motion detection. Physicists at the German Helmholtz-Zentrum Dresden-Rossendorf (HZDR) working along with colleagues at the Leibniz Institute for Solid State and Materials Research (IFW) and the Johannes Kepler University Linz (JKU) in Austria, have created an ultrathin electronic magnetic sensor that can be worn on skin. Simply by interacting with magnetic fields, the device enables a touchless control of virtual and physical objects. Details of the research have been published in the journal “Science Advances” (DOI: 10.1126/sciadv.aao2623).

At first look, the gold elements look like a contemporary tattoo. But on this very thin, almost invisible foil that adheres to the palm of the hand like a second skin, there are sensors which offer a “sixth sense” to people regarding magnetic fields. These sensors will enable people to control everyday objects or regulate appliances both in the physical world and in augmented or virtual reality with simple gestures, similar to how one currently uses a smartphone. This is the vision supported by Dr. Denys Makarov of the Institute of Ion Beam Physics and Materials Research at HZDR.

For the first time, the physicist and his team – along with the groups of Prof. Oliver G. Schmidt at IFW Dresden and Prof. Martin Kaltenbrunner in the Soft Electronics Laboratory at JKU Linz – have currently showed that the ultrathin, compliant magnetic field sensors together with a permanent magnet are adept at sensing and processing body motion in a room.

"Our electronic skin traces the movement of a hand, for example, by changing its position with respect to the external magnetic field of a permanent magnet,” explains Cañón Bermúdez of HZDR, the study’s lead author. “This not only means that we can digitize its rotations and translate them to the virtual world but also even influence objects there.” Using this method, the researchers succeeded in regulating a virtual light bulb on a computer screen in a touchless way.

A Virtual Lamp

To attain this result, they fixed a permanent magnet in a ring-shaped plastic structure emulating a dial. Then, they connected the angle between the wearable sensor and the magnetic source with a control parameter, which moderated the intensity of the light bulb.

By coding the angles between 0 and 180 degrees so that they corresponded to a typical hand movement when adjusting a lamp, we created a dimmer – and controlled it just with a hand movement over the permanent magnet,” says Makarov, explaining one of the experiments. The team was also able to use a virtual dial in the same manner. The physicists at Dresden visualize that their method offers a unique alternative for interfacing the virtual and the physical world that goes far beyond what is possible with existing technologies.

To manipulate virtual objects, current systems essentially capture a moving body by optical means. This requires, on one hand, a load of cameras and accelerometers and, on the other hand, fast image data processing. However, usually the resolution is not sufficient to reconstruct fine movements of the fingers. Moreover, because they are so bulky, the standard gloves and glasses hamper the experience of virtual reality.

Dr. Denys Makarov

The skin-like sensors could be a superior way of connecting human and machine, according to Martin Kaltenbrunner: “As our polymer foils are not even three micrometers thick, you can easily wear them on your body. Just by way of comparison: a normal human hair is roughly 50 micrometers thick.”

As further experiments have revealed, the sensors can also endure bending, folding, and stretching without losing their functionality. They are therefore ideal for the integration into soft, shapeable materials like textiles, to manufacture wearable electronics. Makarov sees an extra benefit to the new method in contrast to optical systems: no direct line of sight between the object and the sensors is needed. This could pave the way for potential applications in the security industry, as well. Buttons or control panels in rooms which cannot be entered in dangerous situations, for instance, could be worked by remote control via the sensors.

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