Abstract: A system in accordance with an embodiment of the present disclosure comprises at least two electrodes coupled to an electromagnetically sensitive bio-organism and control logic configured to predict an earthquake based upon signals produced by the electrodes in response to an electromagnetic signal.

Abstract: A system provides an in situ or non-invasive vibro-acoustic (VA) analysis of an arbitrary complex vibrating structure. The noise diagnostic system includes a plurality of first transducers for measuring acoustic pressure in a sound field near a noise source. At least one second transducer measures normal surface velocity on the noise source. A computer acquires acoustic pressure data from the plurality of first transducers and normal surface velocity data from the at least one second transducer. The computer generates a transfer matrix representing a correlation between normal surface velocity on the noise source and the acoustic pressure in the sound field.

Abstract: A vibration sensor includes a probe body with a vibration isolator operatively connected to the probe body for isolation of the probe body from vibrations of a structure to be monitored for vibration. A waveguide is operatively connected to the probe body to convey microwaves to and from a surface for sensing vibration of the structure to be monitored for vibration.

Abstract: The present invention relates to an ultrasound therapy system using high-intensity focused ultrasound. The present invention improves ultrasound and heat release characteristics and provides an ultrasound probe which easily performs manufacturing and maintenance processes. According to the present invention, a housing is recessed on the inward side around the upper-part edge. A plurality of mounting holes are uniformly formed from the outside at a constant radius to the edge in the center of the upper part. And a plurality of probe units are respectively installed to the plurality of mounting holes to form a sphere in the upper part of the housing wherein a first connection pin is protruded to the lower part of the housing in the lower part of a copper connection bar and a rear block, a piezoelectric wafer, and an acoustic matching layer are sequentially stacked on the upper part of the connection bar.

Abstract: An absorption target for measuring power of high-intensity focused ultrasound, comprising a container and a cone target cluster. The cone target cluster includes basic units with the same geometrical shape. The upper part of each basic unit is a pyramid, and the lower part of each basic unit is a prismatic base. The vertexes of respective side surfaces of the pyramid converge at a perpendicular bisector of the prismatic base to form a cone vertex and the cross sections of the pyramid and the base are squares, regular triangles or regular hexagons. The bases of the basic units are seamlessly and tightly arrayed at the bottom in the container. Sound waves of an incident cone target cluster to escape into space outside the cone target cluster only in case of at least two reflections or scatterings. Open micropores are densely distributed inside the basic units of the cone target cluster.

Abstract: An active ultrasonic room occupancy sensor with the output amplitude of the transmitter controlled by the amplitude of power applied to the transmitter to control the zone of coverage for a sensor. An adjustable voltage regulator under control of a microcontroller applies controlled amplitude voltage to the transmitter to adjust the output amplitude of the transmitter. The adjustable amplitude transmitter allows an occupancy sensor to have its total output energy adjusted to conform to the area to be covered. Lowering the total ultrasonic energy in the monitored space lowers the sensitivity of the receiver to inappropriate activations. Lowering the input power to the transmitter also lowers the total internal system noise and provides an improved signal to noise ratio in the receiver. Alternatively, the power applied to the receiver may also be controlled by an adjustable voltage regulator under control of the microcontroller to improve receiver efficiency.

Abstract: Provided is a measuring apparatus capable of measuring a vibration amount weighted with characteristics of vibration transmission to a human ear and capable of evaluating correctly an electronic device having a vibrator. A measuring apparatus 10 configured to evaluate an electronic device 100 that transmits vibration sound to a human ear by pressing a vibrator 102 held in a housing 101 thereto, including an ear simulator 50 that mimics a human ear, and a vibration detection unit 55 disposed on a periphery 52 of an artificial ear canal 53 formed in the ear simulator 50.

Abstract: An apparatus for inspecting an empty crate that is transported on a transport device includes an inspection device having a pulse generator, a processor, a sensor, and an uncoupling device. Prior to inspection, the uncoupling device uncouples the empty crate from the transport device. The pulse generator then excites vibrations in the empty crate, which the sensor receives and passes to a processor for analysis.

Abstract: A vibration detector suitable for field use and associated systems and methods are disclosed. A representative apparatus includes a vibration sensor in contact with the vibrating structure. The vibration sensor can be in contact with the vibration isolators to eliminate the frequencies of the operator's hand. In some embodiments, a contact force between the vibration sensor and the vibrating structure can be measured using, for example, contact resistors. Since the sensitivity of the vibration sensor can be a function of the contact force, the vibration amplitude measurements can be adjusted for a known contact force to improve the precision of the vibration amplitude measurement.

Abstract: A radar wave sensing apparatus including a rotation element, a nanosecond pulse near-field sensor and a control unit is provided. The nanosecond pulse near-field sensor emits an incident radar wave and receives a reflection radar wave of the incident radar wave hitting on a surface of the rotation element to obtain a repetition frequency variation of the reflection radar wave corresponding to the incident radar wave. The control unit calculates a vibration of the rotation element according to the repetition frequency variation.

Abstract: An apparatus for detecting defects in a railway rail mounted on a test vehicle. The apparatus includes a transducer assembly with one or more arrays of ultrasonic transducers directed toward the running surface of the rail. Beams transmitted by the one or more arrays of ultrasonic transducers may be dynamically adjusted to compensate for the varying profile of the rail head and running surface. A laser profiler mounted on the test vehicle in combination with a linear encoder provide profile data, which is communicated to a system controller to dynamically adjust the focal laws for the one or more arrays of transducers to steer the transmitted beams to produce the ideal inspection beam sets while the test vehicle is in motion.

Abstract: A combined driver and pick-off sensor component (200, 300) for a vibrating meter is provided. The combined driver and pick-off sensor component (200, 300) includes a magnet portion (104B) with at least a first magnet (211). The combined driver and pick-off sensor component (200, 300) further includes a coil portion (204A, 304A) receiving at least a portion of the first magnet (211). The coil portion (204A, 304A) includes a coil bobbin (220), a driver wire (221) wound around the coil bobbin (220), and a pick-off wire (222) wound around the coil bobbin (220).

Abstract: A portable monitoring device includes a hand-held housing, a processing circuit disposed within the housing, and a primary sensor extending outwardly from the housing, coupled with the processing circuit, and configured to transmit input to the processing circuit. A rechargeable battery is disposed within the housing and is configured to provide electric power to at least the processing circuit. A connector is coupled with the processing circuit and configured to operatively couple the battery with a battery charger and to alternatively couple the processing circuit with at least one of a secondary sensor and a calibration device. Preferably, a temperature sensor is disposed proximal to the primary sensor and configured to transmit temperature input to the processing circuit, and a switch disposed within the housing is electrically connected with the processing circuit, the connector and the primary sensor and couples the connector with the battery charger or the processing circuit.

Abstract: A method for accurately and speedy analyzing vibration property of head suspension including a piezoelectric element that moves a head according to voltage application. The method comprises a displacement obtaining step obtaining displacement of each node point of the piezoelectric element by voltage application to the piezoelectric element, a reaction force obtaining step eliminating the voltage application and applying the obtained displacement to each node point, a reaction force applying step eliminating the applied displacement and applying obtained reaction force to each node point, and an analyzing step performing the frequency response analysis by using mode superposition method.

Abstract: An ultrasonic sensor of the present invention is attached to the back face of a bumper 4, and provided with a matching member 3 that is in intimate contact with the ultrasonic wave transmitting surface of the ultrasonic sensor and the opposing face of the bumper 4 and that has an acoustic impedance smaller than each of the impedances of the sensor and the bumper.

Abstract: To restrict a bowing amount of a piezoelectric actuator, provided is a switching apparatus comprising a contact point section including a first contact point; and an actuator that moves a second contact point to contact or move away from the first contact point. The actuator includes a first piezoelectric film that expands and contracts according to a drive voltage to change a bowing amount of the actuator, and a second piezoelectric film that is provided in parallel with the first piezoelectric film and restricts bowing of the actuator when the drive voltage is not being supplied to the first piezoelectric film.

Abstract: An apparatus and method for a monitoring system for operating equipment is provided. The monitoring system includes a first sensor having first operating parameters. A first printed circuit board includes an electrical circuit and signal processing hardware. A first sensor is in electrical communication with a second printed circuit board and the second printed circuit board includes signal processing hardware configured to process the signal. The second printed circuit board is in electrical communication with the first printed circuit board through a connector. The connector is configured to permit insertion and removal of a third printed circuit board to operate a second sensor having second operating parameters that differ from the first operating parameters of the first sensor. In another aspect, the first printed circuit board includes no processing circuit, the first printed circuit board includes an analog-to-digital hardware circuit, processor, controller or microprocessor and an output circuit.

Abstract: Devices usable as sensors, as transducers, or as both sensors and transducers include one or more nanotubes or nanowires. In some embodiments, the devices may each include a plurality of sensor/transducer devices carried by a common substrate. The sensor/transducer devices may be individually operable, and may exhibit a plurality of resonant frequencies to enhance the operable frequency bandwidth of the devices. Sensor/transducer devices include one or more elements configured to alter a resonant frequency of a nanotube. Such elements may be selectively and individually actuable. Methods for sensing mechanical displacements and vibrations include monitoring an electrical characteristic of a nanotube. Methods for generating mechanical displacements and vibrations include using an electrical signal to induce mechanical displacements or vibrations in one or more nanotubes.

Abstract: A reader for mechanical actuation of fluids within a test cartridge. The instrument interface including multiple independently-controlled plungers aligned to respective fluidic pouches on a test cartridge that is inserted into a testing apparatus embodying the instrument interface. The plungers include tips for applying mechanical force to the respective fluidic pouches.

Abstract: The positional displacement detector includes a contact member, a prohibition member, and a vibration detector. The contact member is configured to make contact with the object and deform with a positional displacement of the object. The prohibition member is configured to make contact with the deformed contact member to prohibit a deformation of a magnitude equal to or more than a predetermined magnitude from being caused to the contact member. The vibration detector is configured to detect a vibration generated when the contact member has made contact with the prohibition member.

Abstract: The present invention relates to a method of non-destructive inspection of mechanical structures (2) by using vibratory waves in order to detect local defects and/or changes of state. According to the invention, the method comprises: a first training stage in which a transient vibratory excitation is injected into an inspection zone (Z) and the received signals are picked up and time reversed in order to constitute reference excitation signals; a second training stage in which the reference excitation signals are emitted simultaneously and the resulting diverging signals are picked up in order to constitute reference response signals; and a stage of inspecting the mechanical structure (2), in which the reference excitation signals are emitted, the resulting diverging signals are picked up, and the diverging signals are compared with the reference response signals.

Abstract: A device includes a substrate 5, an emission source 1 emitting an acoustic beam from the first surface 7 of the substrate 5 towards the second surface 6 of the substrate 5, first reflection element 11 arranged so that, after reflection, the beam has a propagation direction substantially parallel to the second surface 6 and through a study area 3, and second reflection element 12 for reflecting the beam after crossing the study area 3 in the direction of the first surface, towards a receiver 10. The device is useful in the field of bioMEMS and labs-on-a-chip, and in particular makes it possible to leave one of the surfaces of the substrate free, for example for observation of the study area in parallel by element of an optical microscope. Moreover, the device facilitates the production of elements for the focussing or divergence (lenses) or reflection (mirror) of the acoustic beam.

Abstract: An approach for detecting rotor anomalies is disclosed. An on-site monitoring unit monitors vibration measurements obtained from a rotor during a transient speed operation. In one aspect, the on-site monitoring unit classifies the vibration measurements into predetermined ranges of rotor speed during the transient speed operation, determines maximum vibration data for each of the predetermined ranges of rotor speed during the transient speed operation and compiles the maximum vibration data into a snapshot of the vibration measurements obtained during the transient speed operation. A remote monitoring unit detects a rotor anomaly from the snapshot of vibration measurements generated by the on-site monitoring unit.

Abstract: A standing wave amplification device for vibration signal collection includes a sensing rod (11) acting as standing wave transmission medium. A standing wave formation device includes two fixing support devices (12) distributed along the axial direction and connecting the sensing rod (11) to an operating arm (14). The two fixing support devices (12) respectively collect vibration waves and transmit them to the sensing rod (11) from two different locations of the operating arm (14). The vibration waves are superimposed to form a standing wave on the sensing rod (11). A vibration sensor (13) is connected to the sensing rod (11) and the vibration sensor (13) is between the two fixing support devices (12). A wave detected by the vibration sensor (13) is the standing wave. Compared with transverse wave or longitudinal wave transmitted in the transmission medium of prior art, the standing wave has advantages of larger amplitude and more obvious vibration effect.

Abstract: A sensor arrangement (10) has a vibration sensor (11), which includes a cable (13) and is free of a metal housing, and a holding device (12), which is joined detachably to the vibration sensor (11) and is configured and arranged to protect mechanically and fix in place the vibration sensor (11).

Abstract: A system for making available information which represents a vibration state for the operation of vibration-emitting machines, in particular construction machines, comprising at least one measuring station (12, 12?, 12?) having at least one sensor (20) for detecting at least one variable which relates to the vibration state and having a radio-transmitting unit (24) for outputting a radio output signal which relates to the variable, or at least one reception station (16, 16?, 16?) for picking up the radio output signal of the at least one measuring station (12, 12?, 12?), is characterized in that the at least one measuring station (12, 12?, 12?) comprises an evaluation unit (22) which picks up a sensor signal from the at least one sensor (20) and has the purpose of making available an evaluation signal, representing the vibration state, on the basis of the sensor signal, wherein the radio-transmitting unit (24) generates the radio output signal on the basis of the evaluation signal.

Abstract: An apparatus (500) for fatigue testing elongate test articles (404) including wind turbine blades through forced or resonant excitation of the base (406) of the test articles (404). The apparatus (500) includes a testing platform or foundation (402). A blade support (410) is provided for retaining or supporting a base (406) of an elongate test article (404), and the blade support (410) is pivotally mounted on the testing platform (402) with at least two degrees of freedom of motion relative to the testing platform (402). An excitation input assembly (540) is interconnected with the blade support (410) and includes first and second actuators (444, 446, 541) that act to concurrently apply forces or loads to the blade support (410). The actuator forces are cyclically applied in first and second transverse directions. The test article (404) responds to shaking of its base (406) by oscillating in two, transverse directions (505, 507).

Abstract: A method of and an apparatus for measuring the strength of ultrasonic waves are provided. They are capable of measuring the strength of ultrasonic waves easily and at low cost without using a sound pressure meter. The ultrasonic wave strength measuring apparatus has a particle source soaked in a cleaning liquid, an oscillator to generate the ultrasonic waves whose strength is going to be measured to vibrate the particle source so that particles are eluted from the particle source into the cleaning liquid, a counter to count the number of particles in the cleaning liquid, and an operation unit to find the strength of the applied ultrasonic waves based on the counted number of particles.

Abstract: Temperature compensation for ultrasonic sensors can have a significant error that is highly undesirable because temperature of ultrasonic sensors and the temperature of the medium through which they sense objects affect signal strength calibrations (e.g., echo thresholds) applied when detecting an object. In order to increase the detection capabilities and reported distance of an object, ultrasonic sensors need to adjust their detection criteria and distance calculations as the temperature of air surrounding a vehicle (i.e., outside air temperature) changes and also as the temperature of the sensor changes. Embodiments of the inventive subject matter provide for a simple, effective and consistent approach for determining a temperature upon which such detection criteria and distance calculation adjustments can be based.

Abstract: An ultrasonic sensor is described having a housing which has a circumferential side wall and a base surface. A transducer element for generating ultrasonic vibrations is mounted on the base surface. The side wall includes a lower side wall section, in which the side wall has an essentially rotationally asymmetrical profile in a plane parallel to the base surface, and an upper side wall section in which the side wall changes to an essentially rotationally symmetrical profile toward an upper edge of the side wall. In other respects, the present system provides a parking assistance system for a vehicle, having a control unit and such an ultrasonic sensor, as well as a method for manufacturing an ultrasonic sensor.

Abstract: A windscreen is configured for measuring outdoor infrasonic sound. The windscreen includes a container and a microphone. The container defines a chamber. The microphone is disposed in the chamber and can be operatively supported by the floor. The microphone is configured for detecting infrasonic sound. The container is advantageously formed from material that exhibits an acoustic impedance of between 0 and approximately 3150 times the acoustic impedance of air. A reflector plate may be disposed in the container. The reflector plate operatively can support the microphone and provides a doubling effect of infrasonic pressure at the microphone.

Abstract: An exemplary analyzer, such as a circuit breaker analyzer, method, and system are provided for use in determining the mechanical condition of a device, such as a circuit breaker, appliance, machine, equipment, or other mechanical system. In one embodiment the analyzer is implemented using a smartphone or other smart device to couple to the device being analyzed to measure mechanical vibrations generated at a surface of the device during an operational event using a force detector, such as an accelerometer, and then comparing such measured values to a known, good signature of mechanical vibrations for the same type of operational event for same type of equipment.

Abstract: The invention relates to an ultrasound inspection device for the inspection of tubular workpieces, where the ultrasound inspection device can be coupled to the workpiece by means of a fluid medium, so that sound emitted from a transducer unit hits an insonification point on the lateral surface of the workpiece, the workpiece and the ultrasound inspection device can be moved relative to each other, and where the transducer unit is pivotable on a pivoting line which corresponds to an arc of a circle whose center is formed by the insonification point.

Abstract: A gas turbine combustor vibration sensing system includes a non-contact reflective optical vibration sensor adapted for reflecting photons off of a component within the combustor with a photon source and receiving reflected photons with a photon detector. Exemplary combustor internal components include the combustor basket or transition. A vibration analyzer is coupled to the vibration sensor, for correlating photons received by the detector with vibration characteristics of the component. Vibration characteristics in turn can be correlated with combustion characteristics, including by way of example flame front position and flameout conditions. Vibration characteristic information may be used as an operational parameter by a turbine monitoring system to modify operation of a gas turbine.

Abstract: An imaging apparatus for generating photoacoustic images and ultrasound images that is capable of generating both types of images with high resolution is provided. An ultrasound probe includes a plurality of probe elements. A first phase matching adding section reads out photoacoustic signals from a photoacoustic element data memory, and administers phase matching addition within a first phase matching range. An image processing section generates a photoacoustic image based on phase matched and added data. A second phase matching adding section administers phase matching addition on reflected acoustic signals sampled by a signal obtaining section within a second phase matching range. An image processing section generates an ultrasound image based on phase matched and added data. The first phase matching range is greater than the second phase matching range.

Abstract: A seismic sensor node comprising an annular body (2) with an annular cutting edge (3) at one end. One or more seismic sensors (8, 9) are coupled to the annular body (2). The annular body (2) surrounds a duct (5) which is open at either end to permit liquid to flow through the duct, and which increases in cross-sectional area as it extends towards the cutting edge (3). The compression of the seabed material squeezes out water from the material, making it more dense so that it transmit seismic vibrations more efficiently. The shape of the duct (5) also means that the centre of gravity of the node is lower than it would be for a cylindrical node—thus increasing the stability of the node compared with a cylindrical one.

Abstract: An apparatus and system for sensing vibration in rotary or reciprocating machinery, such as motors, pumps, fans, gearboxes, compressors, turbo-machinery or high-speed spindles, which comprises a mechanical isolation member (14) interposed between a sensor base (15) and a main sensor body (11). In one aspect, the mechanical isolation member comprises a coaxial cylinder of plastic, rubber or polyurethane which is compressed between the sensor base and main sensor body.

Abstract: An acoustic sensor system includes a first plurality of acoustic sensors, and an acoustic transmitter structured to generate acoustic noise to mimic acoustic noise induced by an electrical conductivity fault. A smaller second number of acoustic sensors of the first plurality of acoustic sensors are structured to identify a plurality of locations in an electrical distribution system having a plurality of electrical joints, in order that the smaller second number of acoustic sensors can monitor the plurality of electrical joints of the electrical distribution system.

Abstract: A disclosed airfoil health monitoring system and method obtains a signal comprising a waveform indicative of an airfoil path with a sensor. Features of the waveform are determined and compared waveform characteristics indicative of a vibrational mode. A vibrational mode of the airfoil may then be determined based on the comparison between the predetermined waveform characteristics and the obtained waveform indicative of the airfoil path.

Abstract: In an ultrasonic inspection method or ultrasonic inspection system in which an ultrasonic wave is propagated to an test object via a medium such as a liquid or a gas, an incident position of the ultrasonic wave is accurately and reliably identified. In an ultrasonic inspection method based on an immersion technique, an optical irradiator is mounted on an ultrasonic wave transmitting/receiving unit, an optical marker is irradiated from the optical irradiator to the test object, and an irradiated position of the optical marker is imaged using imaging equipment in order to perform inspection.

Abstract: An apparatus for lifting an aircraft may include a plurality of lifting mechanisms mounted on a supporting surface. Each lifting mechanism may be configured to impart an upward force on a component of the aircraft for lifting the aircraft off the supporting surface. The apparatus may include a beam structure configured to be mounted to the lifting mechanisms. The apparatus may also include a lifting beam suspended from the beam structure. A measurement device may be mounted to the lifting beam and may be configured to engage a jack point associated with the component to determine a weight of the aircraft when the aircraft is lifted off the supporting surface.

Abstract: Two or more sound sensors are placed in a space of interest. Each sensor has a light-emitting output. Each sensor can be positioned at a specific location, such as at an ear location for a seated listener. An excitation source can provide a specified acoustical energy stimulus to the space. A user can obtain a visual impression of acoustical response of the space corresponding to the sound sensors' positions. An image acquisition system can acquire an image of the sound sensors responding to a stimulus. Acquired images can be analyzed to determine response characteristics. A presentation system can provide a display of response characteristics.

Abstract: The transparent photodetector includes a substrate; a waveguide on the substrate; a displaceable structure that can be displaced with respect to the substrate, the displaceable structure in proximity to the waveguide; and a silicon nanowire array suspended with respect to the substrate and mechanically linked to the displaceable structure, the silicon nanowire array comprising a plurality of silicon nanowires having piezoresistance. In operation, a light source propagating through the waveguide results in an optical force on the displaceable structure which further results in a strain on the nanowires to cause a change in electrical resistance of the nanowires. The substrate may be a semiconductor on insulator substrate.

Abstract: A vibration sensor arrangement (1) includes a vibrating mass (5) in permanent mechanical contact with a first side (3) of a piezoelectric element (2). The vibrating mass (5) includes a water-proof capsule (6) in which the piezoelectric element (2) is fixed. A dead weight (7) is in permanent mechanical contact with a second side (4) of the piezoelectric element (2) and is arranged in the water-proof capsule (6). A spring (8) is arranged between the dead weight (7) and the vibrating mass (5) and ensures permanent mechanical contact of the two masses (5,7) with the two sides (3,4) of the piezoelectric element (2). The vibration sensor arrangement (1) further includes first and second electric contacts (9,10) for picking up electric signals which are generated by the piezoelectric element (2) and for forwarding the signals to a recording device (11).

Abstract: An apparatus for monitoring a machine element (02), which moves with respect to a base and rotates about its own axis, having a sensor (06) and evaluation electronics (09). According to the invention, the sensor (06) and the evaluation electronics (09) and also a power supply unit and a transmitter unit (12) are arranged on the moving machine element (02).

Abstract: A multi-function detection liner is applied to a non-cured composite material at the point of manufacturing for building a composite part. The detection liner includes a first insulative layer and a first conductive layer. The detection liner is configured to be detectable from a plurality of non-destructive inspection tests. The first insulative layer is detectable by ultrasound and radiograph within the composite part. The first conductive layer is configured to provide an eddy current signal and to enhance ultrasound attenuation of the detection liner within the composite part. Alternatively, the detection liner may include an integrated layer that combines the functions of an insulative layer and a conductive layer. The detection liner is releasably bonded to a surface of the non-cured composite material.

Abstract: A method of monitoring a sequence of documents passing along a transport path is described. The method including: operating a radiation transmitter with a control signal at a first, working, level to cause radiation at a first intensity to impinge on one side of a document as it passes an inspection position in the transport path; receiving at a radiation receiver, radiation from the transmitter that has passed through the document, the radiation receiver generating an output signal with a level related to the intensity of the received radiation; and monitoring the output signal to detect the presence and/or a characteristic of the document.

Abstract: A compact vibration meter has at least two vibration sensors which sense vibrations at regions of a support element, the detected vibrations being adjusted to the frequency range to be sensed by the respective sensor.

Abstract: A vibration device includes: a semiconductor substrate; a first electrode provided on a first surface of the semiconductor substrate; a protective layer provided on the first surface and covering an end section of the first surface; and a vibration element having a vibration section, a mass adjusting section located on the vibration section and a second electrode. The vibration element is mounted on the first surface with the first electrode and the second electrode connected together, in a manner that the mass adjusting section is located in an area that overlaps the protective layer in a plan view, and a part of the vibration element is disposed at a position that does not overlap the first surface in a plan view.

Abstract: A device (D) for measuring the vibrations generated in a material, includes at least two separate modules, namely: a first module including a sensor provided with a membrane stretched over a rigid part, and a second module including a stressing device capable of generating vibrations by friction inside the material.