Knock sensor circuit and household appliance

Abstract

The invention discloses a knocking sensor circuit and a household appliance. The knocking sensor circuit comprises a vibration mechanism, a precision rectification circuit and a controller. The vibration mechanism is used for outputting an AC voltage signal after receiving mechanical vibration. The precise rectification circuit is connected with the vibration mechanism and is used for converting the alternating-current voltage signal into a direct-current voltage signal; and the controller is connected with the precise rectifying circuit and is used for generating a pulse waveform signal based on the direct-current voltage signal and judging whether effective knocking occurs or not based on the pulse waveform signal. Through the above mode, the knocking sensor circuit rectifies an original AC voltage signal into a DC voltage signal suitable for being processed by a controller through additionally arranging the precision rectification circuit, thereby reducing the cost of the controller, and reducing the software development difficulty.

Description

Technical Field

[0001] This application relates to the field of home appliance technology, specifically to a tapping sensor circuit and a home appliance. Background Technology

[0002] In the field of home appliances, control is achieved by detecting user tapping behavior to receive control commands. Detecting user tapping behavior requires tapping sensors embedded in the appliance's panel. However, existing tapping sensors are either expensive or have low sensitivity. For example, piezoelectric film sensors are costly, and controllers struggle to differentiate between different panel materials and tapping methods, leading to misjudgments. Bone conduction vibration sensors offer high sensitivity but are also expensive. Accelerometers place high demands on the controller, and increased controller costs also raise the overall cost of the appliance. Using speakers as vibration sensors is susceptible to the influence of airborne sound waves, reducing sensitivity. Therefore, there is a pressing need in the home appliance industry for a low-cost, highly sensitive tapping sensor. Summary of the Invention

[0003] This application proposes a tapping sensor circuit and a household appliance, aiming to solve the above-mentioned problems.

[0004] To solve the above-mentioned technical problems, one technical solution adopted in this application is: to provide a knock sensor circuit, which includes a vibration mechanism, a precision rectifier circuit and a controller. The vibration mechanism is used to output an AC voltage signal after receiving mechanical vibration. The precision rectifier circuit is connected to the vibration mechanism and is used to convert the AC voltage signal into a DC voltage signal. The controller is connected to the precision rectifier circuit and is used to generate a pulse waveform signal based on the DC voltage signal and to determine whether a valid knock has been received based on the pulse waveform signal.

[0005] The precision rectifier circuit includes a first diode, a second diode, a first operational amplifier, a first resistor, and a second resistor. The first terminal of the first resistor receives an AC voltage signal, the second terminal of the first resistor is connected to the first input terminal of the first operational amplifier, the second input terminal of the first operational amplifier is grounded, the first terminal of the second resistor and the cathode of the first diode are both connected to the first input terminal of the first operational amplifier, the anode of the first diode is connected to the output terminal of the first operational amplifier, the output terminal of the first operational amplifier is also connected to the cathode of the second diode, the second terminal of the second resistor is connected to the anode of the second diode, and the connection point between the second terminal of the second resistor and the anode of the second diode serves as the output terminal of the precision rectifier circuit, outputting a DC voltage signal.

[0006] The impact sensor circuit also includes an amplifier circuit, which is connected between the vibration mechanism and the precision rectifier circuit to increase the amplitude of the AC voltage signal.

[0007] The amplifier circuit includes an instrumentation amplifier circuit.

[0008] The amplifier circuit includes a second operational amplifier, a third resistor, a fourth resistor, and a first capacitor. The first and second input terminals of the second operational amplifier receive AC voltage signals. The first terminal of the third resistor receives a preset voltage, and the second terminal of the third resistor is connected to the first input terminal of the second operational amplifier. The first terminal of the fourth resistor receives a preset voltage, and the second terminal of the fourth resistor is connected to the second input terminal of the second operational amplifier. The output terminal of the second operational amplifier is connected to the first terminal of the first capacitor, and the second terminal of the first capacitor serves as the output terminal to output an increased AC voltage signal.

[0009] The impact sensor circuit also includes a filter circuit, which is connected between the precision rectifier circuit and the controller to filter high-frequency interference in the DC voltage signal.

[0010] The filtering circuit includes a low-pass active filter circuit.

[0011] The low-pass active filter circuit includes a third operational amplifier, a fifth resistor, a sixth resistor, a seventh resistor, and a second capacitor. The first terminal of the fifth resistor receives a DC voltage signal, and the second terminal of the fifth resistor is connected to the first input terminal of the third operational amplifier. The first terminal of the second capacitor is also connected to the first input terminal of the second operational amplifier. The second terminal of the second capacitor and the first terminal of the sixth resistor are both connected to the output terminal of the third operational amplifier. The second terminal of the sixth resistor is connected to the first terminal of the seventh resistor, and the second terminal of the seventh resistor is grounded. The second input terminal of the third operational amplifier is connected to the junction of the second terminal of the sixth resistor and the first terminal of the seventh resistor. The output terminal of the third operational amplifier serves as the output terminal of the filter circuit.

[0012] The controller includes an analog-to-digital conversion sampling circuit and a control module. The analog-to-digital conversion sampling circuit is used to sample DC voltage signals to generate pulse waveform signals. The control module is connected to the analog-to-digital conversion sampling circuit and is used to determine whether a valid impact has been received based on the pulse waveform signals.

[0013] The vibration mechanism includes a housing, permanent magnets, an iron core, a coil, and a vibration support. The iron core, permanent magnets, and vibration support are all fixedly connected to the housing, and the iron core is placed between the permanent magnets to form a magnetic field. The vibration support includes a pressing mechanism and a sleeve fixedly connected to the pressing mechanism. The sleeve is fitted onto the iron core, and the coil is fitted onto the sleeve. When the pressing mechanism is subjected to mechanical vibration, it will drive the sleeve to move relative to the iron core, thereby driving the coil to move in the magnetic field and generating an AC voltage signal.

[0014] To solve the above-mentioned technical problems, another technical solution adopted in this application is to provide a household appliance that includes the tapping sensor circuit of any one of the above-mentioned features.

[0015] The beneficial effects of this application are as follows: Unlike existing technologies, the impact sensor circuit of this application includes a vibration mechanism, a precision rectifier circuit, and a controller. The vibration mechanism outputs an AC voltage signal after receiving mechanical vibration. The precision rectifier circuit is connected to the vibration mechanism and converts the AC voltage signal into a DC voltage signal. The controller is connected to the precision rectifier circuit and generates a pulse waveform signal based on the DC voltage signal, and determines whether a valid impact has occurred based on the pulse waveform signal. Through this method, the impact sensor circuit of this application, by adding a precision rectifier circuit, rectifies the original AC voltage signal into a DC voltage signal suitable for the controller to process, thus reducing both the cost of the controller and the difficulty of software development. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with this application and, together with the specification, serve to explain the technical solutions of this application.

[0017] Figure 1 This is a schematic diagram of the structure of the first embodiment of the tapping sensor circuit provided in this application; Figure 2 This is a schematic diagram of the circuit structure of an embodiment of the precision rectifier circuit provided in this application; Figure 3 This is a schematic diagram of the second embodiment of the tapping sensor circuit provided in this application; Figure 4 This is a schematic diagram of the circuit structure of an embodiment of the amplifier circuit provided in this application; Figure 5 This is a schematic diagram of the actual circuit structure of an embodiment of the instrumentation amplifier circuit and precision rectifier circuit provided in this application; Figure 6 This is a schematic diagram of the third embodiment of the tapping sensor circuit provided in this application; Figure 7 This is a schematic diagram of the circuit structure of an embodiment of the filter circuit provided in this application; Figure 8 This is a schematic diagram of the actual circuit structure of an embodiment of the second-order low-pass active filter circuit provided in this application; Figure 9 This is a schematic diagram of the fourth embodiment of the tapping sensor circuit provided in this application; Figure 10 This is a schematic diagram of the structure of an embodiment of the vibration horn provided in this application; Figure 11 This is a schematic diagram of the structure of an embodiment of the home appliance provided in this application. Detailed Implementation

[0018] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0020] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0021] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0022] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0023] In the field of home appliances, control is achieved by detecting user tapping behavior to receive control commands. Detecting user tapping behavior requires tapping sensors embedded in the appliance's panel. However, existing tapping sensors are either expensive or have low sensitivity. For example, piezoelectric film sensors are costly, and controllers struggle to differentiate between different panel materials and tapping methods, leading to misjudgments. Bone conduction vibration sensors offer high sensitivity but are also expensive. Accelerometers place high demands on the controller, and increased controller costs also raise the overall cost of the appliance. Using speakers as vibration sensors is susceptible to the influence of airborne sound waves, reducing sensitivity. Therefore, there is a pressing need in the home appliance industry for a low-cost, highly sensitive tapping sensor.

[0024] For example, a piezoelectric thin-film sensor consists of a piezoelectric thin film, a signal amplification circuit, a comparator circuit, and a controller. When the piezoelectric thin film senses vibration, it generates a corresponding voltage signal at its electrodes. This voltage signal is amplified by the signal amplifier and then transmitted to the comparator circuit. If the voltage signal exceeds a threshold voltage signal, the comparator circuit's output flips, outputting a series of pulse signals to the controller. The controller determines whether an impact has occurred based on the number of pulses in the pulse signal. As mentioned earlier, the disadvantages of piezoelectric thin-film sensors are their high cost and low sensitivity. Furthermore, because the controller processes the number of pulses, it struggles to flexibly distinguish between different panel materials and load waveforms generated by different impact methods, leading to false impact detections. A bone conduction vibration sensor consists of a bone conduction sensor, a signal amplifier, and a controller. When the bone conduction sensor senses vibration, it outputs a corresponding electrical signal. This signal is amplified and directly inputs to the controller, which analyzes the waveform characteristics to determine if an impact has occurred. As mentioned earlier, bone conduction vibration sensors are also very expensive. Although they have high sensitivity, if the controller directly processes the vibration waveform, it requires a high-speed analog-to-digital converter for sampling. This places very high demands on the controller's processing power and the software algorithm. Overall, the cost is high, and the algorithmic limitations make it difficult to implement. Accelerometers consist of an accelerometer sensor and a controller. The accelerometer sensor is mounted on the device panel. When the device panel is struck, the accelerometer sensor outputs corresponding acceleration data through a digital interface. After receiving the acceleration data, the controller analyzes the data characteristics to determine whether a strike has occurred. As mentioned earlier, accelerometer sensors are also very expensive. The controller directly processes the acceleration data, requiring high processing power, and controllers suitable for this solution are also quite expensive. Therefore, it can be seen that existing impact sensors are generally expensive, and the requirements for controllers and algorithm implementation are also quite high.

[0025] To address the aforementioned problems, this application first proposes a tapping sensor circuit, please refer to [link / reference needed]. Figure 1 , Figure 1 This is a schematic diagram of the structure of the first embodiment of the tapping sensor circuit provided in this application. Figure 1 As shown, the impact sensor circuit 100 of this embodiment includes a vibration mechanism 10, a precision rectifier circuit 20, and a controller 30. The vibration mechanism 10 is used to output an AC voltage signal after receiving mechanical vibration. The precision rectifier circuit 20 is connected to the vibration mechanism 10 and is used to convert the AC voltage signal into a DC voltage signal. The controller 30 is connected to the precision rectifier circuit 20 and is used to generate a pulse waveform signal based on the DC voltage signal and determine whether a valid impact has been received based on the pulse waveform signal.

[0026] In this embodiment, the vibration mechanism 10 includes a vibration horn. This embodiment utilizes the electrical characteristics of the vibration horn to apply an electro-acoustic conversion device to the field of vibration detection. When the vibration horn receives mechanical vibration from a tap on the panel, it outputs a small-amplitude AC voltage signal. Since the output signal is an AC voltage signal, it does not require processing by the subsequent controller 30. Therefore, in this embodiment, a precision rectifier circuit 20 is added. The function of the precision rectifier circuit 20 is to convert AC or bidirectional signals into unidirectional DC signals, while eliminating signal distortion caused by forward voltage drop in traditional diode rectifier circuits. Therefore, after the AC power signal is rectified by the precision rectifier circuit 20, it can be converted into a DC voltage signal without losing signal energy. At this time, the controller 30 can sample the DC voltage signal to obtain a pulse waveform signal and determine whether a valid tap has occurred based on the pulse waveform signal.

[0027] In addition, in this embodiment, a precision rectifier circuit 20 is added, which can condition the original vibration waveform into a single pulse waveform signal suitable for processing by the low-cost controller 30, thereby reducing the cost of the controller 30 and the difficulty of software development.

[0028] Unlike existing technologies, the impact sensor circuit 100 of this application includes a vibration mechanism 10, a precision rectifier circuit 20, and a controller 30. The vibration mechanism 10 outputs an AC voltage signal after receiving mechanical vibration. The precision rectifier circuit 20 is connected to the vibration mechanism 10 and converts the AC voltage signal into a DC voltage signal. The controller 30 is connected to the precision rectifier circuit 20 and generates a pulse waveform signal based on the DC voltage signal, and determines whether a valid impact has occurred based on the pulse waveform signal. Through this method, the impact sensor circuit 100 of this application, by adding the precision rectifier circuit 20, rectifies the original AC voltage signal into a DC voltage signal suitable for processing by the controller 30, thus reducing both the cost of the controller 30 and the difficulty of software development.

[0029] Optionally, based on the above embodiments, please refer to Figure 2 , Figure 2 This is a schematic diagram of the circuit structure of an embodiment of the precision rectifier circuit provided in this application. Figure 2 As shown, the precision rectifier circuit 20 in this embodiment includes a first diode D1, a second diode D2, a first operational amplifier U1, a first resistor R1, and a second resistor R2.

[0030] like Figure 2 As shown, in this embodiment, the first end of the first resistor R1 receives an AC voltage signal, the second end of the first resistor R1 is connected to the first input terminal of the first operational amplifier U1, the second input terminal of the first operational amplifier U1 is grounded, the first end of the second resistor R2 and the cathode of the first diode D1 are both connected to the first input terminal of the first operational amplifier U1, the anode of the first diode D1 is connected to the output terminal of the first operational amplifier U1, the output terminal of the first operational amplifier U1 is also connected to the cathode of the second diode D2, the second end of the second resistor R2 is connected to the anode of the second diode D2, and the connection point between the second end of the second resistor R2 and the anode of the second diode D2 serves as the output terminal of the precision rectifier circuit 20, outputting a DC voltage signal.

[0031] In this embodiment, the precision rectifier circuit 20 can improve the dynamic range of the DC voltage signal. Furthermore, in this embodiment, the voltage at the power input terminal of the first operational amplifier U1 is VCC, which can be set to 3.3V. In other embodiments, the precision rectifier circuit 20 can also be of other circuit forms, which are not limited here.

[0032] In this embodiment, the precision rectifier circuit 20 achieves full-wave rectification through the combination of the first operational amplifier U1, the first diode D1, and the second diode D2. When converting the AC voltage signal output by the vibration mechanism 10 into a DC signal, it avoids the voltage drop loss of traditional diode rectification, effectively preserving signal energy and thus improving the dynamic range of the input (approximately twice in this embodiment) and significantly enhancing the signal-to-noise ratio. This allows the impact sensor circuit 100 of this embodiment to reliably detect low-intensity impact signals, reducing the false alarm rate. Simultaneously, it supports signal processing using a low-cost controller 30, solving the problems of low sensitivity and high cost in the prior art and achieving a balance between high sensitivity and low cost.

[0033] Optionally, based on the above embodiments, please refer to Figure 3 , Figure 3 This is a schematic diagram of the second embodiment of the tapping sensor circuit provided in this application. Figure 3 As shown, the impact sensor circuit 100 in this embodiment also includes an amplifier circuit 40, wherein the amplifier circuit 40 is connected between the vibration mechanism 10 and the precision rectifier circuit 20, and is used to increase the amplitude of the AC voltage signal.

[0034] In this embodiment, since the vibration mechanism 10 is a vibration horn, the signal output by the vibration horn after receiving mechanical vibration is a small-amplitude voltage signal. Therefore, in order to facilitate the subsequent processing by the controller, an amplifier circuit 40 needs to be set up. Only after being amplified by the amplifier circuit 40 can a sufficiently large AC voltage signal be obtained.

[0035] Optionally, based on the above embodiments, please refer to Figure 4 , Figure 4 This is a schematic diagram of the circuit structure of an embodiment of the amplifier circuit provided in this application. Figure 4 As shown, the amplifier circuit 40 includes a second operational amplifier U2, a third resistor R3, a fourth resistor R4, and a first capacitor C1. The first and second input terminals of the second operational amplifier U2 receive AC voltage signals. The first terminal of the third resistor R3 receives a preset voltage, and the second terminal of the third resistor R3 is connected to the first input terminal of the second operational amplifier U2. The first terminal of the fourth resistor R4 receives a preset voltage, and the second terminal of the fourth resistor R4 is connected to the second input terminal of the second operational amplifier U2. The output terminal of the second operational amplifier U2 is connected to the first terminal of the first capacitor C1, and the second terminal of the first capacitor C1 serves as the output terminal, outputting an increased AC voltage signal.

[0036] In this embodiment, the preset voltage received by the third resistor R3 and the fourth resistor R4 can be set to 1.8V. In other embodiments, the preset voltage can be set based on the actual situation.

[0037] In this embodiment, the amplifier circuit 40 includes an instrumentation amplifier circuit. Compared to the prior art, in this embodiment, using an instrumentation amplifier as the analog front end enhances the anti-interference capability of the impact sensor circuit 100. In other embodiments, the amplifier circuit 40 can also be configured as a general-purpose amplifier, which is not limited here.

[0038] Based on the above embodiments, in one application scenario, please refer to Figure 5 , Figure 5 This is a schematic diagram of the actual circuit structure of an embodiment of the instrumentation amplifier circuit and precision rectifier circuit provided in this application. Figure 5 The circuit in the lower left corner is the power supply circuit for the instrumentation amplifier circuit. Figure 5 The circuit in the upper left corner is the amplifier circuit of the instrumentation amplifier circuit; Figure 5 The right half of the circuit is a precision rectifier circuit 20. The specific structure and connections of the above circuit are as follows: Figure 5 As shown, it will not be described in detail here.

[0039] Optionally, based on the above embodiments, please refer to Figure 6 , Figure 6 This is a schematic diagram of the third embodiment of the tapping sensor circuit provided in this application. Figure 6 As shown, the impact sensor circuit 100 in this embodiment also includes a filter circuit 50, which is connected between the precision rectifier circuit 20 and the controller 30 and is used to filter high-frequency interference in the DC voltage signal.

[0040] In this embodiment, the filter circuit 50 includes a low-pass active filter circuit. Using a low-pass active filter circuit can further improve the signal-to-noise ratio of the impact sensor circuit 100, and compared to the prior art, can make the impact sensor circuit 100 more sensitive.

[0041] Optionally, based on Figure 6 For an example, please refer to the following: Figure 7 , Figure 7 This is a schematic diagram of the circuit structure of one embodiment of the filter circuit provided in this application. Figure 7As shown, the low-pass active filter circuit of this embodiment includes a third operational amplifier U3, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and a second capacitor C2. The first terminal of the fifth resistor R5 receives a DC voltage signal, and the second terminal of the fifth resistor R5 is connected to the first input terminal of the third operational amplifier U3. The first terminal of the second capacitor C2 is connected to the first input terminal of the third operational amplifier U3. The second terminal of the second capacitor C2 and the first terminal of the sixth resistor R6 are both connected to the output terminal of the third operational amplifier U3. The second terminal of the sixth resistor R6 is connected to the first terminal of the seventh resistor R7. The second terminal of the seventh resistor R7 is grounded. The second input terminal of the third operational amplifier U3 is connected at the junction of the second terminal of the sixth resistor R6 and the first terminal of the seventh resistor R7. The output terminal of the third operational amplifier U3 serves as the output terminal of the low-pass active filter circuit.

[0042] In this embodiment, the low-pass active filter circuit is a first-order low-pass active filter circuit. In other embodiments, to improve signal quality, a second-order low-pass active filter circuit can be used, that is, two such circuits... Figure 7 The first-order low-pass active filter circuit shown is used in series. Please refer to [link / reference]. Figure 8 , Figure 8 This is a schematic diagram of the actual circuit structure of an embodiment of the second-order low-pass active filter circuit provided in this application. The specific structure and connection relationships of the second-order low-pass active filter circuit are as follows: Figure 8 As shown, it will not be described in detail here.

[0043] Optionally, based on the above embodiments, please refer to Figure 9 , Figure 9 This is a schematic diagram of the fourth embodiment of the tapping sensor circuit provided in this application. Figure 9 As shown, the controller 30 in this embodiment includes an analog-to-digital conversion sampling circuit 31 and a control module 32. The analog-to-digital conversion sampling circuit 31 is used to sample DC voltage signals to generate pulse waveform signals. The control module 32 is connected to the analog-to-digital conversion sampling circuit 31 and is used to determine whether a valid impact has been received based on the pulse waveform signal.

[0044] In this embodiment, the analog-to-digital conversion sampling circuit 31 is integrated into the controller 30; in other embodiments, this application may also use a separate analog-to-digital conversion sampling circuit 31, which is not limited here.

[0045] Optionally, please refer to Figure 10 , Figure 10 This is a schematic diagram of a structural embodiment of the vibration horn provided in this application. Based on the above embodiment, as follows... Figure 10As shown, the vibrating horn of this embodiment includes a housing 11, a permanent magnet 12, an iron core 13, a coil 14, and a vibration bracket 15. The iron core 13, the permanent magnet 12, and the vibration bracket 15 are all fixedly connected to the housing 11, and the iron core 13 is disposed between the permanent magnets 12 to form a magnetic field. The vibration bracket 15 includes a pressing mechanism 151 and a sleeve 152 fixedly connected to the pressing mechanism 151. The sleeve 152 is sleeved on the iron core 13, and the coil 14 is sleeved on the sleeve 152. When the pressing mechanism 151 is subjected to mechanical vibration, it will drive the sleeve 152 to move relative to the iron core 13, thereby driving the coil 14 to move in the magnetic field, thereby generating an AC voltage signal.

[0046] In this embodiment, the pressing mechanism 151 is an elastic mechanism. When subjected to mechanical vibration, it drives the sleeve 152 to move back and forth in the magnetic gap between the iron core 13 and the permanent magnet 12, thereby driving the coil 14 to cut the magnetic field lines and generate the AC voltage signal mentioned above. In this embodiment, the vibration bracket 15 may also include a dust cover 153, which is used to prevent dust and impurities from falling into the magnetic gap between the iron core 13 and the permanent magnet 12, and to avoid the coil 14 getting stuck or generating noise.

[0047] Furthermore, the vibrating horn of this embodiment, also known as a conductive horn, is a type of loudspeaker without a diaphragm. Its original working principle involves energizing the internal coil 14 to vibrate the vibrating support 15, converting the electrical signal into mechanical vibration, and transmitting it to the connected diaphragm. This makes the diaphragm a temporary sound source, propagating sound into the surrounding space. Specifically, when current flows, the change in current drives the coil 14 to cause the vibrating support 15 to vibrate mechanically. This vibration causes the diaphragm connected to the vibrating support 15 to vibrate as well, thus producing sound. Because the sound source becomes the diaphragm, the sound characteristics vary depending on the diaphragm material. For example, a wooden diaphragm produces a warm sound, a glass diaphragm produces a crisp sound, and a metal diaphragm produces a brighter and more transparent sound.

[0048] In this embodiment, a vibrating horn is used as a vibration sensor, and the diaphragm connected to the vibration bracket 15 is discarded. Therefore, the coil 14, which is sleeved on the sleeve 152, will only move when the vibration bracket 15 is subjected to mechanical vibration. The coil 14 will then cut magnetic lines of force in the magnetic field, and this relative motion will generate an induced electromotive force at both ends of the coil 14, thereby outputting a small-amplitude AC voltage signal. When sound waves vibrate in the air, because the diaphragm is discarded, the sound wave vibration is insufficient to cause the vibration bracket 15 to vibrate, thus reducing the interference of sound waves on the impact sensor circuit 100 and reducing the possibility of misjudgment.

[0049] Therefore, compared to existing technologies such as piezoelectric films, bone conduction sensors, and accelerometers, this embodiment uses a vibrating horn as the vibration mechanism 10, which is inexpensive and thus reduces the cost of the impact sensor circuit 100 in this embodiment. Furthermore, compared to using a loudspeaker as the vibration mechanism 10, which is susceptible to interference from airborne sound waves (generating an AC voltage signal upon receiving sound waves, leading to false impacts), this application uses a vibrating horn and eliminates the diaphragm, further reducing costs and filtering out airborne sound wave interference, thereby reducing the possibility of false impacts.

[0050] Optionally, this application further proposes a household appliance; please refer to [link / reference]. Figure 11 , Figure 11 This is a schematic diagram of the structure of an embodiment of the home appliance provided in this application, as shown below. Figure 11 As shown, the home appliance 200 in this embodiment includes the tapping sensor circuit 100 of any of the above embodiments.

[0051] In this embodiment, the home appliance 200 can be a speaker, an air conditioner, a cleaning robot, or other similar device, and is not limited thereto. In other embodiments, the tap sensor circuit 100 of this application can also be applied to electronic devices such as headphones, and is not limited thereto.

[0052] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A tapping sensor circuit, characterized in that, include: A vibration mechanism, wherein the vibration mechanism is used to output an AC voltage signal after receiving mechanical vibration; A precision rectifier circuit, connected to the vibration mechanism, is used to convert the AC voltage signal into a DC voltage signal; A controller, connected to the precision rectifier circuit, is used to generate a pulse waveform signal based on the DC voltage signal and to determine whether a valid impact has been received based on the pulse waveform signal.

2. The tapping sensor circuit according to claim 1, characterized in that, The precision rectifier circuit includes a first diode, a second diode, a first operational amplifier, a first resistor, and a second resistor; In this circuit, the first end of the first resistor receives the AC voltage signal, the second end of the first resistor is connected to the first input terminal of the first operational amplifier, the second input terminal of the first operational amplifier is grounded, the first end of the second resistor and the cathode of the first diode are both connected to the first input terminal of the first operational amplifier, the anode of the first diode is connected to the output terminal of the first operational amplifier, the output terminal of the first operational amplifier is also connected to the cathode of the second diode, the second end of the second resistor is connected to the anode of the second diode, and the connection point between the second end of the second resistor and the anode of the second diode serves as the output terminal of the precision rectifier circuit, outputting the DC voltage signal.

3. The tapping sensor circuit according to claim 1, characterized in that, The impact sensor circuit also includes: An amplifier circuit is connected between the vibration mechanism and the precision rectifier circuit to increase the amplitude of the AC voltage signal.

4. The tapping sensor circuit according to claim 3, characterized in that, The amplifier circuit includes an instrumentation amplifier circuit.

5. The tapping sensor circuit according to claim 3, characterized in that, The amplifier circuit includes a second operational amplifier, a third resistor, a fourth resistor, and a first capacitor; The first and second input terminals of the second operational amplifier receive the AC voltage signal. The first terminal of the third resistor receives a preset voltage. The second terminal of the third resistor is connected to the first input terminal of the second operational amplifier. The first terminal of the fourth resistor receives the preset voltage. The second terminal of the fourth resistor is connected to the second input terminal of the second operational amplifier. The output terminal of the second operational amplifier is connected to the first terminal of the first capacitor. The second terminal of the first capacitor serves as the output terminal to output the increased AC voltage signal.

6. The tapping sensor circuit according to claim 1, characterized in that, The impact sensor circuit also includes: A filtering circuit is connected between the precision rectifier circuit and the controller to filter high-frequency interference in the DC voltage signal.

7. The tapping sensor circuit according to claim 6, characterized in that, The filtering circuit includes a low-pass active filter circuit.

8. The tapping sensor circuit according to claim 7, characterized in that, The low-pass active filter circuit includes a third operational amplifier, a fifth resistor, a sixth resistor, a seventh resistor, and a second capacitor; Wherein, the first end of the fifth resistor receives the DC voltage signal, the second end of the fifth resistor is connected to the first input terminal of the third operational amplifier, the first end of the second capacitor is connected to the first input terminal of the third operational amplifier, the second end of the second capacitor and the first end of the sixth resistor are both connected to the output terminal of the third operational amplifier, the second end of the sixth resistor is connected to the first end of the seventh resistor, the second end of the seventh resistor is grounded, the second input terminal of the third operational amplifier is connected at the junction of the second end of the sixth resistor and the first end of the seventh resistor; the output terminal of the third operational amplifier serves as the output terminal of the filter circuit.

9. The tapping sensor circuit according to claim 1, characterized in that, The controller includes an analog-to-digital conversion sampling circuit and a control module. The analog-to-digital conversion sampling circuit is used to sample the DC voltage signal to generate the pulse waveform signal. The control module is connected to the analog-to-digital conversion sampling circuit and is used to determine whether a valid impact has been received based on the pulse waveform signal.

10. The tapping sensor circuit according to claim 1, characterized in that, The vibration mechanism includes a housing, permanent magnets, an iron core, a coil, and a vibration support. The iron core, the permanent magnets, and the vibration support are all fixedly connected to the housing, and the iron core is disposed between the permanent magnets to form a magnetic field. The vibration support includes a pressing mechanism and a sleeve fixedly connected to the pressing mechanism. The sleeve is fitted onto the iron core, and the coil is fitted onto the sleeve. When the pressing mechanism is subjected to the mechanical vibration, it will drive the sleeve to move relative to the iron core, thereby driving the coil to move in the magnetic field and generating the AC voltage signal.

11. A household appliance, characterized in that, Includes the tapping sensor circuit as described in any one of claims 1-10.

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