A “sixth sense” sensor has been created – people and machines will be able to sense objects at a distance without seeing them

The biofield, aura and other esotericism find real embodiment in weak electromagnetic fields. Fish of the beaked whale family (mormyrids) are able to identify food in turbid water and even in silt, sensing it by weak disturbances of the electromagnetic field. Scientists from Hong Kong have reproduced the sensory system of these fish in biocompatible pads and intend to equip humans and automation with it.

Image source: City University of Hong Kong

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One layer of the sensor acts as a transmitter, generating an electric field that extends far beyond its boundaries. The other layer acts as a receiver that is able to determine both the direction and distance to an object. This allows the sensory system to “feel” the location of an object in three-dimensional space.

The sensor’s electrode layers are made of biogel deposited on both sides of a dielectric substrate made of polydimethylsiloxane (PDMS), a silicon-based polymer popular in biomedicine. A pattern is created on the transmitting and receiving parts that forms and recognizes electromagnetic fields – in fact, antennas. All this is enclosed in a transparent biogel, flexible and compatible with human biology. A kind of patch can stretch and bend, for example, tightly fitting a person’s wrist.

When a foreign object appears in the sensor’s field of action, it is detected by the receiver. Thanks to an array of sensors, the direction to the object and, in general, its location in three-dimensional space are determined. The sensor prototype was able to recognize objects in the air within 10 cm, and under water – up to 1 m. Light barriers made of fabric or paper did not interfere with the recognition of “disturbers” of the peace, but the appearance of another person or massive objects within 40 cm of the sensor reduced the accuracy recognition

The developers have created a platform that is as energy efficient as possible. Ultimately, the sensor transmits situational data to the smartphone via Bluetooth. It is not raw data about the environment that is transmitted, but the already processed result, prepared for final processing. This saves energy and resource-intensive transmission is carried out only when necessary. A simple controller and data processing circuit are built into the patch and filled with biogel. The built-in lithium-ion battery is charged wirelessly through an electromagnetic coil.

The development promises to improve orientation in complex environments of people and robots, but so far it can only recognize objects of a certain size, in particular 8 mm in diameter. Smaller objects are detected with poor accuracy, and larger objects are detected too slowly. Now such a device can be used, for example, to recognize gestures shown with fingertips, but there is still a lot of work, and research will continue.