Sensor unit and system and method for detecting damage

Abstract

The invention relates to a sensor unit for acoustically detecting damage events on materials, to a system comprising a sensor unit of this type, and to a method for acoustically detecting damage events. The sensor unit (1) comprises: • a housing (7) having an end wall (7a) and a side wall (7b); • a circuit board (6) arranged in the housing (7); • a microphone (2) which is mounted on the assembly side of the circuit board (6) and comprises a wall (2', 2'') which, together with the circuit board, encloses an interior (3); • a sound transducer (4) arranged on the circuit board (6) in the interior (3) of the microphone (2); • a sound opening (8) in a wall region (2'') of the microphone (2); • a sound-permeable connecting layer (10) which covers the sound opening (8); and • a fastening means (9, 9') for fastening the sensor unit (1) on the material surface (11a).

Description

[0001] Sensor unit and system and method for

[0002] Damage detection

[0003] The present invention relates to a sensor unit for the acoustic detection of damage events on materials, in particular on vehicle glass panes, as well as to a system comprising such a sensor unit for the acoustic detection of damage events on materials. The invention further relates to a method for the acoustic detection of damage events on materials, in particular on

[0004] Vehicle glass panes.

[0005] Especially in motor vehicles, there is a need to automatically detect unexpected damage, for example to glass panes or the bodywork, as soon as it occurs. This makes it possible, for example, to send automatic emergency messages or

[0006] Detect vandalism or parking damage caused by third parties and initiate appropriate measures. This damage detection also makes it possible to save detailed information about detected damage for the purpose of preserving evidence. Sensor-based damage detection also enables the detection of damage that is difficult or impossible to detect through visual inspection.

[0007] EP 0657 330 A1 discloses an alarm system for pane breakage detection, in which an electrically conductive track is embedded or deposited in a pane of glass to be monitored. If the glass breaks, the electrically conductive track is interrupted, triggering an alarm. Applying the electrically conductive track is very complex, however. Another disadvantage is that this alarm system cannot distinguish between different types of damage (e.g., stone chips or cracks).

[0008] WO 2004 / 011311 A1 describes a breakage detector for a windshield. This detector is also based on the application of an electrically conductive material to the windshield. A disadvantage (in addition to the disadvantages already mentioned in EP 0 657 330 A1) is that the transparency of the windshield is impaired by the material applied there.

[0009] The object of the present invention is therefore to enable or improve automatic damage detection on materials, in particular on vehicle glass panes, while avoiding the disadvantages mentioned above.

[0010] This object is achieved by a sensor unit, a system comprising such a sensor unit, and a method according to the independent patent claims, as well as by the embodiments specified in the dependent claims and in the following description. Further advantages, effects, and possible applications emerge from the following description and the drawings.

[0011] The sensor unit according to the invention is a sensor unit for the acoustic detection of damage events on materials, in particular on vehicle glass panes. The sensor unit is intended for attachment to the surface of a material that is to be monitored for the occurrence of damage events; in particular, the sensor unit is intended for attachment to the surface of a glass pane. The side of the sensor unit that is intended for attachment to the surface of a material and that, after attachment of the sensor unit, is adjacent to the aforementioned surface of the material (i.e., rests against this surface) is referred to as the "attachment side."

[0012] The sensor unit has at least the following components and features:

[0013] - a housing with an end wall and a circumferential side wall connected thereto, which extends towards the fastening side and whose edge, when fastened to the surface, is at a distance from this surface;

[0014] - a circuit board arranged in the housing and connected thereto, with a distance being provided between the underside of the circuit board and the end wall of the housing opposite it;

[0015] - a microphone mounted on the component side of the circuit board with a wall which, together with the circuit board, encloses an interior space;

[0016] - at least one inside the microphone on the

[0017] Circuit board arranged sound transducer;

[0018] - a sound opening located in a wall area of ​​the microphone opposite the circuit board and facing the mounting side;

[0019] - a sound-permeable connecting layer which is arranged in the said wall area of ​​the microphone on its outer surface and covers the sound opening;

[0020] - At least one fastening means for attaching the sensor unit to the material surface, in particular to the surface of a glass pane. The fastening means is either attached to the edge of the side wall and extends to the fastening side, or the fastening means is attached to the component side of the circuit board, but outside the microphone and inside the housing, and extends to the fastening side.

[0021] The housing, usually made of plastic or metal, encloses the circuit board and microphone housed therein with its end wall and surrounding side wall. The wall area of ​​the housing, referred to as the "end wall," defines the sensor unit on the outside, opposite the mounting side. The side wall can, for example, be shaped like the shell of a cylinder, or have a rectangular or square contour. The housing, consisting of the end wall and surrounding side wall, is preferably manufactured as a single piece.

[0022] The housing is preferably open toward the fastening side if the fastening means—as mentioned above—is attached to the component side of the circuit board. The edge of the side wall extending toward the fastening side has a gap from the surface after attachment to the surface. This can be achieved, in particular, by selecting the height of the fastening means(s) such that the aforementioned gap is maintained. The gap is preferably 1 to 3 mm.

[0023] This avoids direct contact between the housing and the material surface when the sensor unit is mounted on such a surface as intended to detect damage events. Direct contact between the housing and the material surface could cause inherent noise from the housing, which could distort the acoustic signals of a damage event.

[0024] If the fastening means is attached to the edge of the side wall according to the above-mentioned alternative, the fastening means which is attached to this edge and the

[0025] material surface, direct contact of the housing with the material surface is avoided. In this case, the thickness (height) of the fastener determines the distance of the edge of the side wall to the material surface. This distance is also preferably 1 to 3 mm, but can also be less.

[0026] A circuit board connected to the housing is arranged in the housing, wherein it is preferred that there is a distance between the underside of the circuit board and the end wall of the housing opposite it, whereby an intermediate

[0027] cavity is formed.

[0028] Preferably, the circuit board is aligned parallel or approximately parallel to the front wall of the housing above it.

[0029] The top side of the board (component side) on which the

[0030] The microphone is arranged on the mounting side. After the sensor unit is mounted on the surface of a material to be monitored, the circuit board is generally aligned approximately parallel to this surface. A commercially available circuit board (printed circuit board) can be used. The circuit board preferably has a thickness in the range of 0.5 - 1.5 mm, in particular 0.8 - 1.2 mm.

[0031] At least one microphone is mounted on the component side of the circuit board, which has a wall (or "housing" or "capsule"; e.g. made of metal (particularly aluminum) or plastic) which, together with the circuit board, encloses an interior space. In this interior space is the microphone's sound transducer, or two or more such sound transducers, in order to convert the alternating sound pressure vibrations caused by a damage event into electrical signals (= microphone signal).

[0032] The wall of the microphone has a wall region which is opposite the circuit board and faces the fastening side; preferably, this wall region has a flat outer surface which, when attached to the surface of a material, runs parallel or substantially parallel to this surface.

[0033] The aforementioned wall area has a sound opening which serves to create a connection between the interior of the microphone and the environment of the sensor unit. Preferably, the sound opening is not arranged above the sound transducer (i.e. opposite it), but laterally offset from it (i.e. outside the base area of ​​the sound transducer, in plan view), so that the sound entering through the sound opening strikes the sound transducer partly directly, partly indirectly - after reflection from various surfaces in the interior of the microphone. The sound opening is covered by a sound-permeable connecting layer which is attached to the outer surface of the aforementioned wall area of ​​the microphone.

[0034] When the sensor unit is attached to the surface of a material, this connecting layer is located between the aforementioned wall area of ​​the microphone and the material surface, thus establishing a preferably full-surface contact between the microphone and the material surface. Direct contact of the microphone (ie its

[0035] wall) with the material surface is thereby avoided.

[0036] This connecting layer enables the transmission of low-frequency vibrations in the infrasound range, which are caused by a damage event in the material to be monitored, e.g. a pane of glass, to the microphone so that these vibrations (infrasound signals) can be recorded by the microphone (i.e. its sound transducer). On the other hand, this connecting layer suppresses or reduces the background noise caused by vibrations. Such background noise would be caused by the natural movements of the material surface to be monitored during a damage event if the microphone were to rest directly, i.e. without a connecting layer, on this material surface, e.g. a pane of glass.

[0037] The material of this connecting layer is thus sound-permeable (i.e. permeable to airborne sound) and also enables the transmission of infrasound signals; on the other hand, this connecting layer prevents or suppresses inherent noise that could be caused by the vibration-related movement of the material to be monitored, to which the sensor unit is attached.

[0038] The following materials are particularly suitable for the connecting layer: rubber, elastomers, felt, soft PVC, also in combination (laminates). Due to the use of these materials, the connecting layer is elastic, particularly elastic under pressure. The thickness of the connecting layer is preferably 0.1 to 1 mm, in particular 0.2 to 0.6 mm.

[0039] To attach the sensor unit according to the invention to a material surface to be monitored, in particular to the surface of a glass pane, the sensor unit has at least one fastening means. This is either attached to the edge of the side wall and extends to the fastening side, or the fastening means is attached to the component side of the circuit board, outside the microphone and inside the housing, and extends to the fastening side. Consequently, when the sensor unit is attached as intended to a material surface to be monitored, it is connected to the material surface to be monitored by the fastening means(s).

[0040] If the fastening means, as described above, is attached to the component side of the circuit board, there is a free gap (air gap) between the edge of the side wall of the housing and the material surface when the sensor unit is fastened to a material surface. Contact between the housing and the material surface is thus excluded. The gap is preferably 1 to 3 mm. The fastening means extends, preferably in a ring shape, over the entire circumference of the sensor unit, or two or more individual fastening means, e.g. in the form of supports or segments, can be provided. The fastening means used is preferably a double-sided, preferably elastic adhesive tape with a thickness of 0.3 - 3 mm, in particular 1 to 2 mm. For example, a double-sided, elastic PVC adhesive tape with a thickness of 1 - 2 mm can be used.Instead of an adhesive tape, a preferably elastic adhesive layer created by applying an adhesive can also serve as a fastening means.

[0041] If the fastening means is attached to the edge of the side wall as mentioned above, it extends, preferably over the entire circumference of the edge of the side wall. The fastening means mentioned above can be used.

[0042] Due to the above-described features, the sensor unit according to the invention is advantageously suitable for the acoustic detection of damage events on materials, particularly on glass panes. The combination of the following two features is particularly advantageous:

[0043] - When the sensor unit is attached to a material surface, e.g. a glass pane, the housing has no direct contact with this material surface because - as described above - the edge of the side wall of the housing is at a distance from this surface when attached to a material surface.

[0044] - A connecting layer is arranged between the microphone and the material surface, which creates contact between the microphone and the material surface when the sensor unit is attached to a material surface.

[0045] These design features ensure that the

[0046] When properly attached to the surface of a material to be monitored, the sensor unit is only in contact with the material surface via the attachment(s) and the bonding layer. This allows the microphone to detect the resulting sound signals (airborne sound) and infrasound signals when a damage event occurs, for example, when a stone hits a pane of glass. At the same time, the microphone suppresses or reduces the detection of disruptive background noise.

[0047] The frequency range of sound signals is 0 to 30 kHz; it includes both sound waves that propagate in air (airborne sound) and sound waves that propagate in solids, especially glass.

[0048] The present invention is based, among other things, on the realization that, in order to detect different damage events as accurately as possible, it is essential to use a sensor unit that is capable of detecting, by means of the microphone arranged in the sensor unit, the sound signals generated by a damage event (i.e., airborne sound) and, in addition, the infrasound signals generated thereby. The special features of the sensor unit prevent the strong infrasound signals of a damage event from overlaying the airborne sound signals; at least the extent of such overlay is reduced. As a result, this sensor unit is generally capable of separating the infrasound signals and the airborne sound signals of a damage event and of detecting both signal types.

[0049] For example, glass damage is often caused by a stone being thrown against a window, which creates a clearly audible stone-chip noise. This airborne sound signal can be picked up, i.e., recorded, with all its properties and special characteristics, by the microphone of a sensor unit according to the invention, as described above.

[0050] However, the impact of a stone on a pane of glass, for example, creates a second important component: the impact causes the pane to vibrate locally, generating an infrasound signal in the frequency range of 1 to 50 Hz. This signal also propagates directly through the damaged material (glass pane) and reaches the microphone faster than the noise generated by the damage event (stonefall). The latter propagates only by air conduction, whereas the infrasound signal also propagates directly through the damaged material (structure-borne sound). Infrasound propagates much faster in glass and other solids than sound in air.

[0051] Due to its ability to record both the sound signals (airborne sound) generated by a damage event and the infrasound signals also generated in the process, the sensor unit according to the invention can be used advantageously to detect different damage events, in particular in the system according to the invention for the acoustic detection of damage events to materials, as described below.

[0052] According to a preferred embodiment, it is provided that the circuit board, when the sensor unit is mounted on a material to be monitored, bulges towards the end wall of the housing (i.e. away from the mounting side). This can be achieved, for example, by dimensioning the height of the mounting means or / and the height of the side wall of the housing such that the microphone (with the connecting layer located thereon) exerts pressure on the circuit board, whereby the circuit board is elastically deformed and bulges in the mentioned direction. In particular, the circuit board can bulge in the above-mentioned positions between the underside of the

[0053] Board and the cavity opposite the end wall.

[0054] The elastic deformation of the circuit board and the resulting spring tension (compressive stress) cause the microphone and its connecting layer to be pressed against the surface of the material when the sensor unit is attached. This ensures a reliable connection between the sensor unit and the material surface and improves the transmission of sound signals.

[0055] The combination of the following features is therefore particularly advantageous:

[0056] - When the sensor unit is attached to a material surface, e.g., a pane of glass, the housing has no direct contact with this material surface (as explained above). A connecting layer is arranged between the microphone and the material surface, which creates contact between the microphone and the material surface when the sensor unit is attached to a material surface. As explained above, the microphone is pressed against the surface of the material by contact pressure when the sensor unit is attached to such a material.

[0057] According to a further preferred embodiment of the sensor unit according to the invention, it is provided that an electronic

[0058] A circuit, in particular an integrated circuit, is arranged and electrically connected to the microphone, e.g. via conductor tracks in the circuit board. The electronic circuit is designed in particular to perform one or more of the following functions: preamplifier, analog-to-digital converter, audio filter, noise suppression. This makes it possible, among other things, to convert the analog signal from the sound transducer into a digital signal and to amplify it. Alternatively, these functions can also be performed by a separate circuit outside the sensor unit.

[0059] The sensor unit is preferably a miniaturized (micro-electromechanical system = MEMS) component implemented using SMD technology. Miniaturized microphones are preferably used as microphones, particularly microphones implemented using SMD technology, e.g.

[0060] B. electret microphones or MEMS microphones, the latter being particularly preferred. According to a further preferred embodiment, a MEMS transducer is used as the sound transducer, wherein a circuit board connected to the MEMS

[0061] An integrated circuit, particularly an ASIC, is electrically connected to the sound transducer. The integrated circuit or ASIC is preferably designed to perform one or more of the following functions: preamplifier, analog-to-digital converter, audio filter, noise suppression.

[0062] Commercially available "MEMS microphones" comprising a circuit board with sound transducer (MEMS transducer), ASIC and housing

[0063] (Wall) with a sound opening are suitable for use in a sensor unit according to the invention or for the construction of such a sensor unit and are preferred due to their small dimensions and high sensitivity. An example of a commercially available MEMS microphone is the MEMS

[0064] SMD component from the manufacturer Adafruit Industries (New York) with the type designation "SPW2430" (dimensions: approx. 16mm x 14mm x 3mm).

[0065] Particularly preferably, a MEMS microphone is equipped with a sound opening that is arranged laterally offset from the sound transducer (sound pickup), so that the sound entering through the sound opening strikes the sound transducer partly directly and partly indirectly (after reflection from surfaces inside the microphone). The surface of the encapsulation material ("molding", e.g., "glob top molding") with which the ASIC is encapsulated also serves as a sound-reflecting surface. The ASIC of the MEMS microphone is designed in particular to perform one or more of the following functions: preamplifier, analog-to-digital converter, audio filter, noise suppression. The MEMS microphone preferably has an integrated analog-to-digital converter so that a digital audio signal is output.If the MEMS microphone used outputs an analog audio signal, a downstream analog-to-digital converter is preferably used to generate a digital audio signal.

[0066] The microphone used in the sensor unit is preferably a microphone designed to detect sound in the frequency range from 50 Hz to 20 kHz (audible sound range), in particular from 50 to 15 kHz, and infrasound < 50 Hz, in particular in the

[0067] Range from 5 Hz to < 25 Hz. MEMS microphones are generally designed to record sound and infrasound in the specified frequency ranges. The characteristics of the various MEMS microphones can be found in the respective manufacturer's information. The sensitivity of such MEMS microphones is typically in the range of -45 to -35 dBV, with a signal-to-noise ratio in the range of 57 - 65 dB(A).

[0068] In addition, it may be advantageous if the used

[0069] Microphone is designed to record ultrasonic signals (> 20 kHz). Commercially available MEMS microphones, as described above, generally also record a proportion of sound signals in the ultrasonic range. Although this proportion is comparatively small, these ultrasonic signals can be used to specifically detect different damage patterns, e.g. stone chip patterns, i.e. they can be taken into account in the evaluation. The sensor unit is usually equipped with means for supplying current or voltage to the microphone and, if necessary, an electronic circuit, as well as for forwarding the analog or digital signal generated by the sensor unit; such means are known to the person skilled in the art (e.g. electrical connections, plug connections, electrical connecting cables).In order to enable uninterrupted microphone recording, the power supply of the sensor unit can comprise batteries, accumulators, solar cells, capacitors (preferably supercapacitors) or similar means known to the person skilled in the art.

[0070] The sensor unit according to the invention can be mounted on a variety of different materials to detect damage events occurring there. Examples and preferred materials and areas of application include:

[0071] Glass panes of (air / land / water) vehicles, especially motor vehicles (cars, trucks, buses, rail vehicles, cable cars, etc.); also glass panes on stationary facilities (architecture / buildings, industrial plants, etc.). The sensor unit is preferably mounted on the inside of a glass pane (e.g., a motor vehicle).

[0072] Other materials and areas of application include: metal structures and components, particularly the body and components of motor vehicles.

[0073] Structures and components made of plastics or composite materials (e.g., carbon fiber-reinforced plastic), in particular the body and components of motor vehicles, as well as lighting devices and exterior mirrors of motor vehicles. In particular, the sensor unit can be used to detect the following damage events:

[0074] Glass - stone chip damage, glass breakage damage, glass cracks; accident damage, especially dents, in sheet metal parts; scratches in

[0075] Sheet metal parts; scratches in plastic parts or composite parts; breakage in plastic parts or composite parts; impact or breakage damage to vehicle exterior mirrors; impact or breakage damage to lighting devices, particularly headlights and taillights. The preferred use is for recording damage to vehicles, particularly motor vehicles.

[0076] The present invention further comprises a system for the acoustic detection of damage events to materials, in particular to vehicle glass panes. "Detection" means that the nature (or type) of the damage event that has occurred is detected, preferably also its other properties (e.g., the strength or intensity of the damage event). "Acoustic" means that the detection is based on sound signals (including infrasound). For example, the following types of damage events to glass panes can be distinguished, among others: Scratches

[0077] (superficial only), stone chip damage, cracks or breaks, breakage, total destruction. The system according to the invention enables the detection and differentiation of such damage events. It can also be used to differentiate between non-damaging, noise-generating physical impacts (e.g. impact of a rubber ball on a pane of glass) and actual damage events. The system according to the invention for the acoustic detection of damage events is based on the knowledge that a specific damage event - depending, among other things, on the type and energy (strength) as well as on the type of material damaged - generates a specific acoustic pattern over its duration, which is characteristic of the respective type of damage event.According to the present invention, it is of essential importance that both airborne sound signals (particularly in the audible sound range) and infrasound signals of a damage event are recorded and evaluated.

[0078] The system for acoustic detection of damage events shall include at least the following:

[0079] - at least one sensor unit containing a microphone for

[0080] Attachment to a surface of a material to be monitored, wherein the sensor unit is designed to detect the sound signals caused by a damage event (ie airborne sound, in particular in the audible sound range) and

[0081] To detect infrasound signals and convert them into electrical signals;

[0082] - at least one electronic circuit conductively connected to the microphone, which is designed to perform one or more of the following functions: preamplifier, analog-to-digital converter, audio filter, noise suppression; wherein the circuit is preferably arranged in the sensor unit;

[0083] - at least one evaluation unit, which is connected to the aforementioned circuit of the sensor unit and is designed to evaluate the signals transmitted by the circuit and to detect the damage event based on the result of the evaluation. The advantages of using a microphone suitable for recording both the sound signals caused by a damage event (i.e. airborne sound, particularly in the audible sound range) and the infrasound signals caused by this damage event have already been explained above. In order to increase the sensitivity and / or accuracy in detecting damage events, it can be advantageous if the system is equipped with two or more of the aforementioned sensor units, which can be attached to the material to be monitored.

[0084] The system according to the invention advantageously enables the detection of damage in actual time, since the respective damage event and at the same time the type of damage are detected at the time in which the damage event takes place (in contrast to a subsequent assessment of damage).

[0085] Preferably, the sensor unit of the system is a sensor unit according to the invention, although multiple sensor units can also be used in combination. Due to the special properties and advantages explained above, the sensor unit according to the invention is particularly suitable for use as a component of the system.

[0086] The electronic circuit, which can perform the functions of a preamplifier, analog-digital converter, etc., can, for example, form a unit together with the microphone, as described above.

[0087] The evaluation unit is preferably a computer that is designed, using appropriate software, to evaluate the signals received from the sensor unit and to detect the damage event, as described in more detail below.

[0088] For example, if two or more sensor units are installed in a vehicle (e.g. at different

[0089] locations on the windscreen or on different panes), each sensor unit can be connected to a respective evaluation unit, or a common evaluation unit can be installed which is set up to receive and evaluate data from two or more sensor units.

[0090] Microcontrollers are preferably used as the hardware for the evaluation unit. These generally contain a processor (CPU), RAM, program memory, interfaces (e.g., network, USB), and input and output ports (I / O ports). Furthermore, the evaluation unit can contain an analog-to-digital converter if the sensor unit used does not have one.

[0091] A preferred example of a microcontroller is the

[0092] The "RP2040" is a 32-bit microcontroller from the Raspberry Pi Foundation (Cambridge, UK). The technical specifications of this microcontroller are as follows: CPU: 32-bit RP2040 dual-core processor with 133 MHz clock frequency.

[0093] RAM: 264 kByte SRAM;

[0094] Program memory: 2Mbyte Q-SPI flash;

[0095] I / O ports: 26 multifunctional general-purpose inputs and outputs (GPIO), 3.3V compatible. The microcontroller can also be equipped with a suitable radio module, e.g., Bluetooth or WiFi, to enable, among other things, the transmission of evaluation data via a wireless

[0096] to enable connection.

[0097] The microcontroller's software is preferably designed for pattern recognition of sound signals, with the data provided by the aforementioned sensor unit being evaluated across all frequency ranges. The evaluation software can preferably be created based on Raspberry Libraries.

[0098] In particular, the evaluation unit is designed to carry out an evaluation of the temporal course of infrasound signals and the temporal course of sound signals (airborne sound).

[0099] The evaluation of the temporal progression of the signals generally takes place continuously. To enable the most uninterrupted evaluation possible, the power supply of the evaluation unit can comprise batteries, accumulators, solar cells, capacitors (preferably supercapacitors), or similar means known to those skilled in the art.

[0100] Preferably, the data or signals supplied by the sensor unit(s) are evaluated by the evaluation unit at specific intervals, with these intervals preferably being 1 second or less. The detection of sound signals by the sensor unit(s) is usually continuous. The temporal progression of the infrasound or airborne sound signals, in particular the amplitudes or frequencies, during the duration of the respective damage event results in a characteristic pattern that can be used by the evaluation unit to identify the type of damage event. In addition, this pattern can be characterized using further parameters, as described below.

[0101] The evaluation unit is preferably designed to perform the above-mentioned evaluation of the temporal progression of the infrasound and airborne sound signals based on one or more of the following parameters: frequency range, frequency spectrum, gaps in the frequency spectrum, change in frequency over time, minimum / maximum amplitude, amplitude (sound energy or intensity) over time, level decrease at the end, total duration of the damage event. These functions can be realized by suitable software or implemented in an ASIC.

[0102] Furthermore, the evaluation unit is preferably designed to use one or more of the following programs or methods when evaluating the signals and / or to detect a damage event: audio filters, Fourier transformations, wavelet transformations, pattern

[0103] Recognition, statistical methods. Such methods and suitable programs or software are known to those skilled in the art.

[0104] The evaluation of the signals using software is fundamentally based on the fact that during a damage event (e.g. stone impact on a glass pane) a signal pattern is created which consists of different sound components (audible noise, infrasound, possibly ultrasound) and changes over time. It is particularly important that the propagation of the infrasound signals in the material occurs faster than the propagation of the audible sound component (noise) in the air, so that the infrasound signals reach the microphone faster than the audible sound signals. The temporal course of the signal pattern can, for example, have an initial phase with a strong infrasound signal, followed by a phase with a strong sound signal in the audible range (e.g. impact noise), followed by a decay phase due to reverberation reflections.For signal evaluation, it is therefore preferable to use software that works with adjustable parameters that characterize the aforementioned phases or sections. For example, these could be parameters that determine the

[0105] Describe signal strength (amplitude; minimum / maximum), the frequency range of the signals and / or the duration of the respective phase.

[0106] According to a preferred embodiment, the evaluation unit is designed to take various adjustable thresholds into account during pattern recognition, so that if a threshold is exceeded, the occurrence of damage is detected or the severity of the damage can be classified. The thresholds can be determined using practical tests and thus continuously developed to improve damage detection or adapt it to specific conditions.

[0107] Furthermore, it is planned that pattern recognition will be optimized using AI (artificial intelligence) methods. This means, in particular, that the system (i.e., the software of the evaluation unit) continuously learns using new data from subsequent damage events. Neural networks or deep learning functions can be used in particular. The use of these methods is particularly advantageous for improving pattern recognition of particularly difficult-to-detect damage events.

[0108] According to a preferred embodiment, the evaluation unit is designed to store the data generated during the evaluation and / or transmit it to another device, preferably via a wireless data connection or a radio network, in particular via Bluetooth, WLAN, or a wireless internet connection. An "other device" could be, for example, a smartphone, a computer / server, or an on-board diagnostic system or infotainment system of a motor vehicle.

[0109] According to a particularly preferred embodiment, the evaluation unit is designed to send a message, e.g. via WLAN, WiFi or Bluetooth, to a mobile device (mobile phone, smartphone, notebook, tablet, etc.), if a damage pattern is detected. The mobile device is preferably equipped with an app designed for this purpose. In addition to the information about the damage event that has occurred, the sent message can also contain the data generated by the evaluation by the evaluation unit. In addition, the mobile device or the app installed on it can be set up to forward this message, preferably together with the data of the damage pattern, to a server (e.g. of a service provider). This sending of data from the mobile device to a server preferably takes place automatically, i.e. without human intervention (programmatically).Typically, the mobile device mentioned is the mobile phone or smartphone of the driver of a vehicle in which a damage event has been detected by the evaluation unit.

[0110] According to a preferred embodiment, it is provided that the evaluation unit is designed to assign the pattern of the sound and infrasound signals of a damage event obtained by the evaluation to one of several damage pattern types, wherein the damage pattern types include in particular the following: glass stone chip damage, glass breakage damage, glass cracks; accident damage, in particular dents, in

[0111] Sheet metal parts; scratches in sheet metal parts; scratches in plastic parts or composite parts; breakages in plastic

[0112] Fabric parts or composite parts; impact or breakage damage to vehicle exterior mirrors; impact or breakage damage to lighting equipment, particularly headlights and taillights of motor vehicles. The aforementioned damage pattern types can be stored in the evaluation unit.

[0113] According to a further embodiment, the evaluation unit is designed to detect vandalism damage or parking damage caused by a third party to a vehicle depending on the pattern obtained for the respective damage event.

[0114] Particularly when using the system in a motor vehicle, it is advantageous if the evaluation unit is designed to generate an alarm or emergency signal depending on the damage event detected, or to transmit an emergency call to a rescue control center.

[0115] According to a further advantageous embodiment, the system comprises at least one camera which is suitable for continuously recording and optionally storing video recordings. In particular, it is provided that such a camera is mounted in a vehicle which is equipped with a system according to the invention for the acoustic detection of damage events. Preferably, the camera is mounted in such a way that its viewing angle covers the front area of ​​the vehicle. Such a camera can also be mounted to monitor the rear area. In this way, the damage progression can be detected visually in addition to acoustic detection. Since the camera continuously

[0116] Operation, it also detects and documents the damage progression shortly before the occurrence of a damage event, in particular a frontal collision.

[0117] The present invention further extends to a vehicle, in particular a motor vehicle, which is equipped with at least one sensor unit or a system according to the above description.

[0118] Furthermore, the present invention provides a method for the acoustic detection of damage events to materials, in particular to glass panes of vehicles, wherein the method comprises at least the following steps: a) Recording sound signals generated by a damage event in the frequency range from 50 Hz to 20 kHz (= airborne sound range), preferably 50 to 15 kHz, and additionally infrasound signals in the frequency range < 50 Hz, in particular in the range from 5 Hz to < 25 Hz, by means of at least one sensor unit which contains at least one microphone and is attached to a surface of a material to be monitored; b) Evaluating the temporal course of the airborne sound signals and the temporal course of the infrasound signals, whereby a pattern of the airborne sound and infrasound signals of the damage event on the material to be monitored is obtained.

[0119] Suitable means and methods for carrying out these process steps have been described above. In general, the process is carried out software- or program-controlled, using suitable computers, particularly microcontrollers.

[0120] The recording of the temporal course of the signals is generally carried out continuously, i.e. without interruption.

[0121] Preferably, the airborne sound and infrasound signals are evaluated at specific intervals, whereby these intervals are preferably 1 second or less.

[0122] Preferably, the evaluation of the temporal course of the signals is carried out on the basis of one or more of the following parameters: frequency range, frequency spectrum, gaps in the frequency spectrum, change in frequency over time, minimum / maximum amplitude, amplitude (sound energy or intensity) over time, level decrease at the end, total duration of the damage event.

[0123] According to a preferred embodiment, the method comprises a subsequent step in which the pattern of airborne sound and infrasound obtained by the evaluation

[0124] Signals of a damage event are assigned to one of several damage pattern types, whereby these damage pattern types include in particular the following: glass stone chip damage, glass breakage damage, glass cracks; hail damage to glass or sheet metal, accident damage, in particular dents, in sheet metal parts;

[0125] Scratches in sheet metal parts; scratches in plastic parts or in

[0126] Composite parts; breakage in plastic parts or composite parts; impact or breakage damage to vehicle exterior mirrors; impact or breakage damage to lighting devices, in particular headlights and taillights of motor vehicles.

[0127] When recording the temporal course of the signals and when evaluating the signals, one or more of the following programs or methods are preferably used: audio filters, Fourier transforms, wavelet transforms, pattern recognition, statistical methods.

[0128] According to a preferred embodiment, the evaluation is carried out in such a way that various adjustable threshold values ​​are taken into account during pattern recognition, so that if a threshold value is exceeded, the occurrence of a

[0129] Damage is detected or the severity of the damage can be classified. The method preferably comprises a further step in which the data generated during the evaluation are transmitted to another device, preferably by means of a wireless data connection or a radio network, in particular by means of Bluetooth, WLAN or a wireless Internet connection.

[0130] According to a particularly preferred embodiment, the method is designed so that, if a damage pattern is detected, a message is sent from the evaluation unit, e.g. via WLAN, WiFi or Bluetooth, to a mobile device (mobile phone, smartphone, notebook, tablet, etc.), which is preferably equipped with an app designed for this purpose. In addition to the information about the damage event that has occurred, the sent message can also contain the data generated by the evaluation of the evaluation unit. In addition, the mobile device or the app installed on it can be set up to forward this message, preferably together with the data of the damage pattern, to a server (e.g. of a service provider). This sending of data from the mobile device to a server preferably takes place automatically, i.e. without human intervention (program-controlled).

[0131] Furthermore, the method preferably comprises a further step in which an alarm or emergency signal is generated or an emergency call is transmitted to a rescue control center, depending on the pattern obtained during the evaluation for the respective damage event. According to a further embodiment of the method, if a damage event caused by vandalism or parking damage caused by a third party is detected on a vehicle, a notification is transmitted to the driver and / or owner of the vehicle, and optionally the damage pattern of the detected damage event, the detected damage pattern type, as well as information on the vehicle part(s) affected by the damage event and information on the time and location of the damage occurrence are stored for the purpose of preserving evidence, whereby the transmission of the notification and the storage are triggered automatically when damage occurs.

[0132] Description of the drawings and examples

[0133] The invention is illustrated by way of example and explained below with reference to drawings (Figs. 1 to 3; Figs. 4A, 4B, 4C, 4D, 4E, 4F). The drawings are schematic representations and not to scale.

[0134] FIG. 1 is a sectional view showing an embodiment of the sensor unit according to the invention in the state of attachment to a material.

[0135] FIG. 2 shows (in plan view) a sensor unit according to the invention (as shown in FIG. 1) in the state of attachment to a material.

[0136] FIG. 3 is a sectional view showing a modification of the embodiment of the sensor unit according to the invention shown in FIG. 1 in the state of being attached to a material.

[0137] Fig. 1:

[0138] The sensor unit (1) is attached to the surface (11a) of a material (11) to be monitored (e.g. glass pane).

[0139] The housing (7) of the sensor unit consists of a front wall

[0140] (7a) and a circumferential side wall connected to it

[0141] (7b). This side wall extends toward the mounting side (A); the edge (7c) of the side wall (7b) does not touch the surface (11a) of the material (11), but maintains a distance (d) from this surface, creating an air gap. This leaves the housing open on one side, namely toward the mounting side (A).

[0142] A circuit board (6) is arranged in the housing (7) and connected to the housing, as shown in the drawing. The circuit board is aligned approximately parallel to the end wall (7a) of the housing and to the surface (11a) to which the sensor unit (1) is attached. A distance (e) exists between the underside (6a) of the circuit board (6) and the opposite end wall (7a) of the housing (7), so that a cavity is formed therebetween.

[0143] On the component side of the board (6) (opposite the bottom side (6a)) there is a microphone (2) with a wall

[0144] (2 ', 2 '') which, together with the circuit board, encloses an interior space (3). In this interior space (3) on the

[0145] A sound transducer (4) is arranged on the component side of the circuit board (6). The microphone (2) has a sound opening (8) which is arranged in a wall area (2") of the microphone (2), which is opposite the circuit board (6) and faces the fastening side (A). The wall area (2") is essentially flat and runs approximately parallel to the surface (11a) on which the sensor unit (1) is fastened.

[0146] The sound opening (8) is not located opposite the sound transducer (4), but at a laterally offset position.

[0147] Also arranged in the wall area (2") of the microphone (2) is a sound-permeable connecting layer (10) with a thickness (a), which is applied to the outer surface in the aforementioned area and covers the sound opening (8). When the sensor unit is attached to the surface (11a), the connecting layer (10) is located between this surface and the outer surface of the wall area (2") of the microphone, connecting these two surfaces.

[0148] On the component side of the circuit board (6), fastening means (9, 9') for fastening the sensor unit (1) to the material surface (11a) are provided; these are located outside the area of ​​the microphone (2) but inside the housing (7) and extend to the fastening side (A) or to the surface (11a) of the material (in the illustrated state of fastening the sensor unit to the surface of a material, the plane of the fastening side of the sensor unit, designated by the dashed line (A), is identical to the surface (11a) of the material). An elastic, double-sided PVC adhesive tape with a thickness of 1-2 mm can be used as the material for the fastening means(s).

[0149] As can be seen from the drawing, the height (c) of the fastening means (9, 9 ') is selected so that the edge (7c) of the side wall (7b) has the mentioned distance (d) to the surface

[0150] (11a) of the material. The housing therefore has no

[0151] Contact with the material surface (11a) .

[0152] Also arranged on the component side of the circuit board (6) and in the interior (3) of the microphone (2) is an electronic circuit (5), e.g. an ASIC, which includes, for example, a preamplifier and an analog-to-digital converter.

[0153] The circuit is encapsulated in an encapsulating material (5a).

[0154] As can be seen from the drawing, the sensor unit, in the state of attachment to a material (11), is only connected to the surface (11a) of the material (11) via the fastening means (9, 9') and the connecting layer (10).

[0155] The arrow (12) indicates that the circuit board

[0156] (6) in the state of fastening the sensor unit to the material (11) bulges towards the front wall (7a) of the housing (7)

[0157] (12) , as provided according to a preferred embodiment (the curvature of the circuit board is not shown in Fig. 1, but is merely indicated by the arrow (12)). This can be achieved - as shown in Fig. 1 - by choosing the height (c) of the fastening means (9, 9 ') such that it is shorter than the sum of the height (b) of the microphone and the thickness (a) of the connecting layer (10). Due to its elastic properties, the circuit board which is curved in the direction of the arrow (12) exerts pressure (by spring force) on the microphone and the connecting layer (10) located thereon in the direction of the material 11.

[0158] This improves the contact between the microphone (2, 2 ' ') and the connecting layer (10) to the surface (11a) of the material (11).

[0159] Fig. 2 :

[0160] The sensor unit (1) is mounted on a material to be monitored

[0161] (11). The circuit board (6) is located inside the housing, which is shown transparent here and whose peripheral edge (7b) is shown by a thick line. The position of the microphone (2) on the circuit board is indicated by a dashed line, as are the positions of the sound transducer (4) and the circuit (5). Both elements are located together in the interior of the microphone (2) (as in Fig. 1). The sound opening (8) is located above the circuit (5) and laterally offset (distance (f) from the sound transducer (4).

[0162] The fastening means (9, 9 ') are mounted opposite each other in the outer area of ​​the circuit board (6).

[0163] Fig. 3 :

[0164] The sensor unit (1) shown in this drawing is a modification of the sensor unit according to Fig. 1 and differs from it as follows: The fastening means (9, 9') is not attached to the circuit board (6), but rather to the edge (7c) of the side wall (7b) of the housing (7). The edge (7c) can be bent or folded inwards (ie, directed towards the microphone (2)), as shown in Fig. 3. The edge (7c) has no direct contact with the material surface (11a), but is connected to it via the fastening means (9, 9').

[0165] Fastening means, e.g. a double-sided adhesive tape, preferably extends over the entire circumference of the edge (7c) (not shown).

[0166] When the sensor unit (1) - as shown in Fig. 3 - is attached to the surface (11a) of a material (11) to be monitored, for example a glass pane, the fastening means (9, 9') connects the housing (7) of the sensor unit to the material (11). The height of the fastening means (9, 9') in this case corresponds to the distance (d) between the material surface (11a) and the edge (7c) of the side wall (7b) of the housing (7). The housing has no direct contact with the surface (11a), but is only connected by the

[0167] Fasteners connected to it.

[0168] As shown in Fig. 1, the arrow (12) indicates that the circuit board (6) bulges (12) toward the end wall (7a) of the housing (7) when the sensor unit is mounted on the material (11). This can be achieved by appropriately dimensioning the side wall (7b) and the height / thickness (d) of the fastening means in relation to the height (b) of the microphone (2) and the thickness (a) of the connecting layer (10). Examples

[0169] Fig. 4A to 4F show the temporal course (pattern) of the infrasound signals or airborne sound signals in the case of different damage events on a glass pane (stone impact, glass breakage).

[0170] The experimental setup used to obtain the sound signals shown is as follows:

[0171] A production vehicle (car) was equipped with a windshield to which a sensor unit according to the invention was adhesively attached, as described above. The position of the sensor unit on the windshield was varied during the tests (e.g., top left or bottom center).

[0172] The tests were conducted at an ambient temperature of 26 °C; the test room was open to the outside, so that a background noise caused by road traffic was present.

[0173] To simulate damage events (e.g. stone impact), a metal pin was used, which was equipped with adjustable

[0174] The force of impact strikes a particular spot on the respective pane. 96 impacts were generated on a windscreen in this way, with the conditions varied as follows:

[0175] 1) 700 g force applied on an area of ​​0.3 mm 2 .

[0176] 2) 1200 g force applied on an area of ​​0.3 mm 2 .

[0177] 3) 1700 g force applied on an area of ​​0.3 mm 2 .

[0178] 4) 2200 g force applied on an area of ​​0.3 mm 2 After each test run, the window was removed from the vehicle and replaced with a new window, which was fitted with a new sensor unit (adhesive bond).

[0179] The sound signals generated during the experiments were recorded using audio recording software ("Audacity"; free software). Figures 4A to 4F show screenshots of the sound signal patterns recorded with this software.

[0180] From the temporal course of the recorded signals (from left to right) it can be seen that when the

[0181] A very strong infrasound signal is generated during the damage event ("infrasound phase"). These infrasound ranges are characterized by strong signal overload and usually exhibit only a few zero crossings on the x-axis. Signals in the airborne sound range are usually not overloaded (due to lower energy or lower volume) and are characterized by a large number of zero crossings.

[0182] This infrasound phase transitions seamlessly into a characteristic signal pattern in the audible sound range ("beat pattern phase"). Finally, a "fade-out" occurs due to reverberation reflections. Infrasound and (airborne) sound signals can overlap, although in this case, the (airborne) sound signals can be identified by their signal profile ("fast" oscillations, superimposed sine curves). List of reference symbols

[0183] (1) Sensor unit

[0184] (2) Microphone

[0185] (2 ' ) Microphone wall

[0186] (2 * ' ) Wall area

[0187] (3) Interior of the microphone

[0188] (4) Transducer

[0189] (5) Electrical circuit

[0190] (5a) Encapsulation material

[0191] (6) Circuit board

[0192] (6a) Bottom of the circuit board

[0193] (7) Housing

[0194] (7a) Front wall of the housing

[0195] (7b) Side wall of the housing

[0196] (7c) Edge of the side wall

[0197] (8) Sound opening

[0198] (9) Fasteners

[0199] (9 ' ) Fasteners

[0200] (10) Connection layer

[0201] (11) Material (material to be monitored)

[0202] (11a) Surface of the material

[0203] (12) Direction of the bulge of the plate

[0204] (A) Mounting side; level

[0205] (a) Thickness of the bonding layer

[0206] (b) Height of the microphone

[0207] (c) Height of the fasteners

[0208] (d) Distance of the edge (7c) to the surface (11a)

[0209] (e) Distance between bottom (6a) and front wall (7a)

[0210] (f) lateral distance between sound opening (8) and sound transducer (4).

Claims

CLAIMS 1. Sensor unit (1) for the acoustic detection of damage events on materials, in particular on glass panes of vehicles, for attachment to a surface (11a) of a material (11), in particular on the surface of a Glass pane, wherein the sensor unit comprises: - a housing (7) with an end wall (7a) and a peripheral side wall (7b) connected thereto, which extends to the fastening side (A) and whose edge (7c) in the state after fastening on the surface (11a) has a distance (d) from this surface; wherein the "fastening side (A) is that side of the sensor unit (1) which is adjacent to the surface (11a) in the state after fastening on the surface; - a housing (7) arranged in and connected to the housing circuit board (6); - a mounted on the component side of the board (6) Microphone (2) with a wall (2 ', 2 '') which, together with the circuit board, encloses an interior space (3); - at least one in the interior (3) of the microphone (2) on the circuit board (6) arranged sound transducer (4); - a sound opening (8) which is arranged in a wall area (2 ' ') of the microphone (2) which is opposite the circuit board (6) and faces the fastening side (A); - a sound-permeable connecting layer (10) which is applied in the said region (2 '' ) of the microphone (2) on its outer surface and covers the sound opening (8); - at least one fastening means (9, 9') for fastening the sensor unit (1) to the material surface (11a), in particular to the surface of a glass pane, wherein the fastening means is either attached to the edge (7c) of the side wall (7b) and extends to the fastening side (A), or on the component side of the circuit board (6), outside the microphone (2) and inside the housing (7) and extends to the fastening side (A).

2. Sensor unit according to claim 1, characterized in that the height (c, d) of the fastening means or means (9, 9 ') is dimensioned such that the circuit board (6) bulges (12) towards the end wall (7a) of the housing (7) when the sensor unit is fastened to the material (11) due to the pressure generated by the microphone (2) and the connecting layer (10) located thereon.

3. Sensor unit according to claim 1 or 2, characterized in that an electronic circuit (5), in particular an integrated circuit, is further arranged on the circuit board (6) in the interior (3) of the microphone (2); wherein the electronic circuit is designed in particular to carry out one or more of the following functions: preamplifier, analog-digital converter, audio filter, noise suppression.

4. Sensor unit according to one of the preceding claims, characterized in that it is a miniaturized (micro-electromechanical system = MEMS) component implemented using SMD technology.

5. Sensor unit according to one of the preceding claims, characterized in that the sound transducer (4) is a MEMS Transducer, and that on the circuit board (6) Furthermore, an integrated circuit, in particular an ASIC, is arranged which is electrically connected to the MEMS sound transducer; wherein the integrated circuit or ASIC is designed in particular to carry out one or more of the following functions: preamplifier, analog-to-digital converter, audio filter, noise suppression.

6. Sensor unit according to claim 5, characterized in that the sound opening (8) is arranged laterally offset from the sound transducer (4) (f).

7. Sensor unit according to one of the preceding claims, characterized in that the microphone is designed to detect airborne sound in the frequency range from 50 Hz to 20 kHz, preferably 50 to 15 kHz, and infrasound < 50 Hz, in particular in the Range from 5 Hz to < 25 Hz.

8. A system for the acoustic detection of damage events to materials, in particular to vehicle glass panes, the system comprising: - at least one sensor unit containing a microphone for Attachment to a surface of a material to be monitored, wherein the sensor unit is designed to detect the airborne sound signals and infrasound signals caused by a damage event and to convert them into electrical signals; - at least one electronic circuit conductively connected to the microphone, which is designed to perform one or more of the following functions: preamplifier, analog-to-digital converter, audio filter, noise suppression; wherein the circuit is preferably arranged in the sensor unit; - at least one evaluation unit which is connected to the aforementioned circuit of the sensor unit and is designed to evaluate the signals transmitted by the circuit and to detect the damage event based on the result of the evaluation.

9. System according to claim 8, characterized in that the evaluation unit is designed to carry out an evaluation of the temporal course of the infrasound signals and the temporal course of the sound signals (airborne sound).

10. System according to claim 8 or 9, characterized in that the evaluation unit is designed to carry out the evaluation of the temporal course of the airborne sound signals and the temporal course of the infrasound signals on the basis of one or more of the following parameters: frequency range, frequency spectrum, gaps in the frequency spectrum, change in frequency over time, minimum / maximum amplitude, amplitude (sound energy or intensity) over time, level decrease at the end, total duration of the damage event.

11. System according to one of claims 8 to 10, characterized in that the evaluation unit is designed to use one or more of the following programs or methods when evaluating the signals and / or for detecting a damage event: audio filters, Fourier transformations, wavelet transformations, pattern recognition, statistical methods.

12. System according to one of claims 8 to 11, characterized in that the sensor unit is a sensor unit according to one of claims 1 to 7.

13. System according to one of claims 8 to 12, characterized in that the evaluation unit is designed to store the data generated during the evaluation and / or to transmit it to another device, preferably by means of a wireless data connection or a radio network, in particular by means of Bluetooth, WLAN, WiFi, or a wireless Internet connection.

14. System according to one of claims 8 to 13, characterized in that the evaluation unit is designed to assign the pattern of the sound and infrasound signals of a damage event obtained by the evaluation to one of several damage pattern types, the damage pattern types comprising in particular the following: glass stone chip damage, glass breakage damage, glass cracks; accident damage, in particular dents, in sheet metal parts; scratches in sheet metal parts; scratches in plastic parts or in composite parts; Breakage in plastic or composite parts; impact or breakage damage to vehicle exterior mirrors; Impact or breakage damage to lighting equipment, particularly headlights and taillights of motor vehicles.

15. System according to one of claims 8 to 14, characterized in that the evaluation unit is designed to generate an alarm or emergency signal depending on the pattern received for the respective damage event, or to transmit an emergency call to a rescue control center.

16. System according to one of claims 8 to 15, characterized in that the evaluation unit is designed to detect vandalism damage or parking damage caused by a third party to a vehicle depending on the pattern obtained for the respective damage event.

17. Vehicle, in particular a motor vehicle, which is equipped with at least one sensor unit according to one of claims 1 to 7 or a system according to one of claims 8 to 16.

18. A method for the acoustic detection of damage events to materials, in particular to glass panes of vehicles, the method comprising at least the following steps: a) recording airborne sound signals generated by a damage event in the frequency range from 50 Hz to 20 kHz (= audible sound range), preferably 50 to 15 kHz, and additionally infrasound signals in the frequency range < 50 Hz, in particular in the range from 5 Hz to < 25 Hz, by means of at least one sensor unit which contains at least one microphone and is attached to a surface of a material to be monitored; b) evaluating the temporal course of the airborne sound signals and the temporal course of the infrasound signals, whereby a damage pattern of the damage event on the material to be monitored is obtained.

19. Method according to claim 18, characterized in that the evaluation of the temporal course of the signals is carried out on the basis of one or more of the following parameters: Frequency range, frequency spectrum, gaps in the frequency spectrum, change in frequency over time, minimum / maximum amplitude, amplitude (sound energy or intensity) over time, level decrease at the end, total duration of the damage event.

20. The method according to claim 18 or 19, characterized in that in a subsequent step (c) the pattern obtained for the respective damage event is assigned to one of several predetermined, known damage pattern types, these damage pattern types comprising in particular the following: glass stone chip damage, glass breakage damage, glass cracks; hail damage to glass or sheet metal, accident damage, in particular dents, in sheet metal parts; scratches in sheet metal parts; scratches in plastic parts or in composite material parts; Breakage damage to plastic or composite parts; impact or breakage damage to vehicle exterior mirrors; Impact or breakage damage to lighting equipment, particularly headlights and taillights of motor vehicles.

21. Method according to one of claims 18 to 20, characterized in that a sensor unit according to one of claims 1 to 7 or a system according to one of claims 8 to 16 is used for implementation.

22. Method according to one of claims 18 to 21, characterized in that one or more of the following programs or methods are used when evaluating the signals: audio filters, Fourier transformations, wavelet transformations, pattern recognition, statistical methods.

23. Method according to one of claims 18 to 22, characterized in that it comprises a further step in which the data generated during the evaluation (step b) are transmitted to another device, preferably by means of a wireless data connection or a radio network, in particular by means of Bluetooth, WLAN, Wi-Fi or a wireless Internet connection.

24. Method according to one of claims 18 to 23, characterized in that it comprises a further step in which an alarm or hot fall signal is generated or an emergency call is transmitted to a rescue control center, depending on the pattern obtained in step (b) for the respective damage event.

25. Method according to one of claims 18 to 24, characterized in that upon detection of a damage event caused to a vehicle by vandalism or parking damage caused by a third party, a notification is sent to the driver and / or owner of the vehicle, and optionally the damage pattern of the detected damage event, the detected damage pattern type as well as details of the vehicle part(s) affected by the damage event and details of the time and place of the damage occurrence are stored for the purpose of preserving evidence, wherein the transmission of the notification and the storage are triggered automatically when the damage occurs.

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