New cheap seismic detector, low consumption and resistant to adverse conditions

With the idea of ​​perfecting earthquake monitoring systems and, therefore, improving information to the population and the competent authorities on the seismic risk to which they are subjected at a given time and place, some researchers have created a new seismic detector based on a sensor that uses the triboelectric effect to do its job and that works without batteries.

The innovation is the work of specialists from the Polytechnic University of Madrid (UPM) and IMDEA Materials, in collaboration with the National Geographic Institute (IGN) and the Center for Studies and Experimentation of Public Works (CEDEX), all of these entities in Spain.

The results obtained in tests with this new sensor show that, within a seismic network, the sensor can detect earthquakes thousands of kilometers from their epicenter with great sensitivity and precision. In addition to being resistant to extreme conditions, each sensor can communicate information on seismic activity over great distances, and this information can also be viewed on any device equipped with an Internet connection. In short, the new sensor ꟷthat has been patentedꟷ can be used to detect earthquakes and warn of danger through a very cheap system, with very low consumption and resistant to adverse conditions.

Specifically, in collaboration with the IGN’s Seismic Data Service, researchers ꟷled by José Sánchez del Río, from the UPM’s Advanced Structural Materials and Nanomaterials Research Groupꟷ tested at CEDEX the relationship between the vibration measurements obtained with the new sensor placed on the surface of a triaxial vibration table, in comparison with those obtained by the MEMS sensors (of English microelectromechanical systems) normally used in the national network of seismic sensors of the IGN. The results showed a great similarity between both signals, which demonstrates the usefulness of the new sensor.

Detecting seismic waves is vital to study their propagation and determine the epicenter of an earthquake, among other things. The image is an artistic recreation of the concept. (Illustration: Amazings/NCYT)

The new seismic sensor has as main elements triboelectric transducers. These transducers are manufactured in the IMDEA Materials laboratory led by researcher De-Yi Wang. They are made up of two layers of polymeric material that, through different chemical treatments, have opposite electronegativity. The moment these layers come into contact, high-voltage electrical power is generated, without the need for any external source. This fact makes these sensors also called triboelectric nanogenerators (TENGS) sensors (auto) nanogenerators.

The seismic sensor is also composed of an inertial mass that is positioned on the triboelectric transducer, allowing vibration to be detected in the Z axis of space. The Department of Industrial Mechanical Design of the ETS of Engineering and Industrial Design of the UPM (ETSIDI-UPM), led by Francisco Santos Olalla and Rafael Cascón Porres, is currently in charge of the mechanical design for 3D detection, together with the student Alba Lopez Laguna. In addition, the new seismic sensors are capable of detecting vibrations of very low amplitude (5 mg) and high frequency (300 Hz). José Sánchez del Río, together with David Patrizi and Álvaro Merodio, also a student at ETSIDI, verified that vibration signals could be transmitted over long distances and also be viewed on the Internet through the Internet of Things (IoT).

In summary, and in the opinion of the researcher José Sánchez del Río: “this new seismic sensor can be used to detect earthquakes and warn of danger through a very cheap system, with very low consumption and resistant to adverse conditions. Potential users range from large corporations, small and medium-sized companies or interested individuals, as well as those responsible for national earthquake detection systems.”

José Sánchez del Río and his colleagues present the technical details of their new seismic detector in the academic journal Nano Energy, under the title “High-resolution TENGS for earthquakes ground motion detection. (Source: UPM)