Small portable anti-eavesdropping device

Abstract

The utility model discloses a small portable anti-eavesdropping device, which comprises a shell with a sound transmission hole and a function board, the function board comprises a circuit board, a plurality of ultrasonic transducers installed on the circuit board and a power interface used for being inserted into a power supply device, and the circuit board and the ultrasonic transducers are located in the shell. At least part of the power interface extends out of the shell, the circuit board sends out ultrasonic interference signals to the ultrasonic transducers under the power supply effect of the power interface, and the ultrasonic transducers send out the ultrasonic interference signals through the sound transmission holes in the shell. The utility model provides a miniaturized and portable ultrasonic anti-eavesdropping device.

Description

Technical Field

[0001] The utility model relates to the technical field of anti-eavesdropping, in particular to a small and convenient anti-eavesdropping device. Background Art

[0002] Eavesdropping or recording refers to the use of certain technological means to obtain effective audio information such as conversations or other sounds in a covert manner. This may cause damage to the party being eavesdropped or recorded to a certain extent.

[0003] Currently, most manufacturers use electromagnetic interference technology to prevent eavesdropping and recording, but since electromagnetic interference can prevent other electronic devices from working properly, there are certain limitations in its use.

[0004] Because ultrasound cannot be heard by the human ear, it can be applied to counter eavesdropping and recording. Currently, there are devices that use ultrasound to prevent eavesdropping and recording. Commonly used ultrasonic anti-eavesdropping devices generally utilize piezoelectric ceramic ultrasonic transducers. By emitting high-power ultrasonic signals, they exploit the nonlinear characteristics of the eavesdropping device's amplifier, saturating it and preventing the recording of actual sound signals.

[0005] However, existing ultrasonic eavesdropping equipment is bulky and inconvenient to carry, so a new anti-eavesdropping device needs to be designed to solve these problems. Utility Model Content

[0006] The purpose of the utility model is to provide a miniaturized and convenient ultrasonic anti-eavesdropping device.

[0007] To achieve the above-mentioned purpose, the utility model proposes a small and portable anti-eavesdropping device, including a shell with a sound-transmitting hole and a functional board, the functional board including a circuit board and multiple ultrasonic transducers mounted on the circuit board and a power interface electrically connected to the circuit board and used to be plugged into a power supply device, the circuit board and the multiple ultrasonic transducers are located in the shell, the power interface at least partially extends out of the shell, the circuit board emits ultrasonic interference signals to the multiple ultrasonic transducers under the power supply of the power interface, and the ultrasonic interference signals are emitted by the multiple ultrasonic transducers through the sound-transmitting hole on the shell.

[0008] In a preferred embodiment, the ultrasonic interference signal is an ultrasonic signal of multiple frequencies greater than 20 KHz, or a plurality of ultrasonic signals of the same frequency greater than 20 KHz, or an ultrasonic signal in the frequency range of 20 KHz to 40 KHz.

[0009] In a preferred embodiment, the ultrasonic interference signal is a plurality of ultrasonic signals with different frequencies between 22KHz and 26KHz, or a plurality of ultrasonic signals with the same frequency between 22KHz and 26KHz, or an ultrasonic signal between the frequency range of 22KHz and 26KHz.

[0010] In a preferred embodiment, the circuit on the circuit board includes a microcontroller unit and a switching circuit, the microcontroller unit is connected to the power interface, and the switching circuit is connected to the microcontroller unit and the multiple ultrasonic transducers. The microcontroller unit emits the ultrasonic interference signal under the power supply of the power interface, and the ultrasonic interference signal is boosted by the switching circuit to a voltage matching the operating voltage of the ultrasonic transducer and then output to the ultrasonic transducer.

[0011] In a preferred embodiment, the ultrasonic interference signal emitted by the micro control unit is a square wave or a sine wave.

[0012] In a preferred embodiment, the switch circuit is a MOS switch circuit composed of a plurality of MOS transistors.

[0013] In a preferred embodiment, the circuit on the circuit board also includes a voltage conversion circuit, which includes a linear regulator and a boost circuit. The linear regulator is connected between the power interface and the micro control unit, and the boost circuit is connected between the power interface and the switching circuit.

[0014] In a preferred embodiment, the ultrasonic transducer is a piezoelectric ultrasonic transducer, and a plurality of the piezoelectric ultrasonic transducers are arranged in an array on the circuit board.

[0015] In a preferred embodiment, the power interface is any one of a USB interface, a Type-C interface, a DC interface, a Lightning interface, and a MagSafe interface, or a combination of any two or more interfaces.

[0016] In a preferred embodiment, the outer shell includes an upper shell and a lower shell fixedly connected to each other, the upper shell includes an upper shell and a mesh covering the upper shell, the upper shell and the mesh are both provided with the sound-transmitting holes, the sound-emitting surface of the ultrasonic transducer faces the sound-transmitting holes, and an accommodation space for accommodating the functional board is formed between the upper shell and the lower shell.

[0017] Compared with existing technologies, the present invention has the following advantages: The present invention innovatively designs an anti-eavesdropping device with a power port, allowing it to be plugged into any device with a power port, making it convenient to use and compact for portability. Furthermore, the present invention uses an ultrasonic interference signal of appropriate frequency to saturate recording devices (such as professional eavesdropping and recording equipment, voice recorders, and mobile phones), rendering the recording device unable to reproduce audio without the user noticing. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the three-dimensional structure of the small and convenient anti-eavesdropping device of the utility model;

[0019] Figure 2 This is a schematic diagram of the explosion structure of the small and convenient anti-eavesdropping device of the utility model;

[0020] Figure 3 This is a circuit principle block diagram of the utility model;

[0021] Figure 4 Schematic diagram of the circuit structure of a switch circuit in one embodiment of the present utility model;

[0022] Figure 5 Schematic diagram of the circuit structure of a switch circuit in another embodiment of the present invention.

[0023] The accompanying drawings are:

[0024] 1. Outer shell, 11. Upper shell, 111. Mesh, 112. Upper shell, 113. Sound-permeable hole, 12. Lower shell, 13. Screws, 2. Function board, 21. Power interface, 22. Circuit board, 221. Microcontroller unit, 222. Switching circuit, 223. Linear regulator, 224. Boost circuit, 23. Ultrasonic transducer. DETAILED DESCRIPTION

[0025] The specific implementation methods of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific implementation methods.

[0026] Unless expressly stated otherwise, throughout the specification and claims, the term "comprise" or variations such as "include" or "comprising", etc., will be understood to include the stated elements or components but not to exclude other elements or other components.

[0027] Combine Figure 1 and Figure 2As shown, the utility model discloses a small and portable anti-eavesdropping device, including a shell 1 and a function board 2. The function board 2 includes a power interface 21. When in use, the anti-eavesdropping device is plugged into a power supply device (not shown) through the power interface 21 to perform anti-eavesdropping and anti-recording work.

[0028] Specifically, in this embodiment, the housing 1 includes an upper shell 11 and a lower shell 12 that are fixedly connected. During implementation, they can be fixed by screws 13. The upper shell 11 includes a mesh 111 and an upper shell 112. The mesh 111 is sleeved outside the upper shell 112, and the mesh 111 is densely covered with sound-transmitting holes 113. The upper shell 112 is also provided with sound-transmitting holes 113. A storage space for accommodating the function board 2 is formed between the upper shell 11 and the lower shell 12.

[0029] Specifically, in this embodiment, the functional board 2 also includes a circuit board 22 and a plurality of ultrasonic transducers 23, wherein the power interface 21 is electrically connected to the circuit board and at least partially extends out of the housing 1. During implementation, it can be directly installed on the circuit board 22, or it can be electrically connected to the circuit board 22 through an electrical connection line, and is used to plug the anti-eavesdropping device into other power supply devices. During implementation, the power interface 21 can be, but is not limited to, any one of a USB interface, a Type-C interface, a DC interface, a Lightning interface, and a MagSafe interface, or a combination of any two or more interfaces; the power supply device is any device with an interface that matches these power interfaces, such as a laptop computer, a socket, etc.

[0030] The circuit board 22 is located in the accommodation space of the housing 1. In this embodiment, the circuit board 22 is located in the accommodation space of the housing 1. Figure 3 As shown, the circuit on the circuit board 22 specifically includes a voltage conversion circuit, a microcontroller unit (MCU) 221, and a switching circuit 222. The voltage conversion circuit specifically includes a linear regulator (LDO) 223 and a boost circuit (BOOST) 224. The linear regulator 223 is connected between the power interface 21 and the MCU 221 and is used to convert the voltage of the power signal into a power voltage that matches the operating voltage of the MCU 221, such as converting the 5V voltage input from the power interface 21 into a 3.3V voltage for the MCU 221; the boost circuit 224 is connected between the power interface 21 and the switching circuit 222 and is used to convert the voltage of the power signal into a voltage that matches the operating voltage of the ultrasonic transducer 23, such as converting the 5V voltage input from the power interface 21 into a 40V voltage for the switching circuit 222. Of course, if the voltage of the power interface 21 matches the operating voltage of the ultrasonic transducer 23, the voltage conversion circuit here can be omitted. In other words, the voltage conversion circuit here is not necessary.

[0031] The microcontrol unit 221 is used to emit an ultrasonic interference signal under the power supply of the power interface 21. During implementation, the ultrasonic interference signal is preferably an ultrasonic signal of multiple frequencies greater than 20KHz, or a plurality of ultrasonic signals of the same frequency greater than 20KHz, or an ultrasonic signal between the frequency range of 20KHz and 40KHz. More preferably, the ultrasonic interference signal is a plurality of ultrasonic signals of different frequencies between 22KHz and 26KHz, or a plurality of ultrasonic signals of the same frequency between 22KHz and 26KHz, or an ultrasonic signal between the frequency range of 22KHz and 26KHz. For example, in a specific embodiment, the microcontrol unit 221 emits ultrasonic signals of four different frequencies, such as ultrasonic signals of 24.8KHz, 25KHz, 25.1KHz, and 25.3KHz. For example, in another specific embodiment, the microcontroller unit emits four ultrasonic signals of the same frequency, such as four ultrasonic signals of a single frequency of 25 kHz. For example, in yet another embodiment, the microcontroller unit 221 emits an ultrasonic signal varying in frequency from 22 kHz to 26 kHz. In these embodiments, the preferred frequency is around 25 kHz because the high-frequency resonance peaks of most MEMS microphones are near this frequency, which can better saturate them. In this embodiment, the ultrasonic interference signal emitted by the microcontroller unit 221 is specifically a square wave. By setting different periods T of the square wave, the corresponding frequency of the ultrasonic signal is obtained. Of course, in other embodiments, the ultrasonic interference signal emitted by the microcontroller unit 221 can also be replaced by a sine wave, and the present invention is not limited to this.

[0032] The switch circuit 222 is connected to the micro control unit 221 and the plurality of ultrasonic transducers 23, and is used to boost the ultrasonic interference signal emitted by the micro control unit 221 to a voltage that matches the operating voltage of the ultrasonic transducer 23 and then output it to the ultrasonic transducer 23. In this embodiment, the switch circuit 222 adopts a MOS switch circuit composed of multiple MOS transistors. For example, in a specific embodiment, Figure 4 As shown, the switch circuit 222 includes four MOS transistors, namely three NMOS transistors Q1, Q3, and Q4 and one PMOS transistor Q2, wherein the gate of the NMOS transistor Q3 is connected to the micro control unit 21, and the drain is connected to the gate of the NMOS transistor Q4. The drain of the NMOS transistor Q4 is connected to the gate of the NMOS transistor Q1 and the gate of the PMOS transistor Q2. The drain of the NMOS transistor Q1 is connected to the boost circuit 224, and its source is connected to the source of the PMOS transistor Q2 and is connected to the ultrasonic transducer 23. The sources of the NMOS transistors Q1, Q3, and Q4 and the drain of the PMOS transistor Q2 are all grounded. Alternatively, in another specific embodiment, as Figure 5As shown, the switch circuit 222 includes three MOS transistors, namely three NMOS transistors Q5, Q6, and Q7. The gate of NMOS transistor Q5 is connected to the microcontroller unit 221, the drain is connected to the gate of NMOS transistor Q6, the drain of NMOS transistor Q6 is connected to the gate of NMOS transistor Q7, the drain of NMOS transistor Q7 is connected to the boost circuit 224 and the ultrasonic transducer 23, and the sources of NMOS transistors Q5, Q6, and Q7 are all grounded. Similar to the voltage conversion circuit described above, if the voltage of the power interface 21 matches the operating voltage of the ultrasonic transducer 23, the switch circuit 222 here can be omitted. In other words, the switch circuit 222 here is not necessary. The implementation is not limited to the two switch circuits described here. Other switch circuits that can boost the ultrasonic interference signal emitted by the microcontroller unit 221 to a voltage that matches the operating voltage of the ultrasonic transducer 23 are also applicable to the present invention.

[0033] Multiple ultrasonic transducers 23 are mounted on the circuit board 22, with their sound-emitting surfaces all facing the sound-transmitting holes 113 on the upper shell 11, and are used to transmit the ultrasonic interference signal output by the microcontroller unit 221 through the sound-transmitting holes 113 on the outer shell 1. In this embodiment, the ultrasonic transducers 23 are piezoelectric ultrasonic transducers, and there are four of them. The four ultrasonic transducers 23 emit four ultrasonic signals of different frequencies, such as the four ultrasonic signals of 24.8 kHz, 25 kHz, 25.1 kHz, and 25.3 kHz mentioned above, or four ultrasonic signals of the same frequency, such as the four ultrasonic signals of a single frequency of 25 kHz mentioned above, or each ultrasonic transducer 23 emits an ultrasonic signal varying in frequency from 22 kHz to 26 kHz. The four piezoelectric ultrasonic transducers are arranged linearly and evenly on the circuit board 22. Of course, other numbers and other array arrangements (such as circular or square arrays, etc.) are also applicable to the present invention.

[0034] The advantages of this utility model are that it innovatively designs the anti-eavesdropping device with a power interface, allowing it to be plugged into any device with a power interface, making it convenient to use and compact, making it easy to carry. In addition, by selecting an ultrasonic interference signal of appropriate frequency, this utility model can saturate recording devices (such as professional eavesdropping and recording equipment, voice recorders, mobile phones, etc.), making it impossible for the recording device to restore the audio without the user noticing.

[0035] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the present invention to the precise forms disclosed, and it is apparent that many modifications and variations are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the present invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the present invention and various options and variations. The scope of the present invention is intended to be defined by the claims and their equivalents.

Claims

1. A small and portable anti-eavesdropping device, characterized in that: The device includes a shell with a sound-transmitting hole and a functional board. The functional board includes a circuit board and multiple ultrasonic transducers mounted on the circuit board, and a power interface electrically connected to the circuit board and used to be plugged into a power supply device. The circuit board and multiple ultrasonic transducers are located in the shell, and the power interface at least partially extends out of the shell. Under the power supply of the power interface, the circuit board emits ultrasonic interference signals to the multiple ultrasonic transducers, which are emitted by the multiple ultrasonic transducers through the sound-transmitting hole on the shell.

2. A small and portable anti-eavesdropping device as claimed in claim 1, characterized in that: The ultrasonic interference signal is an ultrasonic signal with multiple frequencies greater than 20KHz, or a plurality of ultrasonic signals with the same frequency greater than 20KHz, or an ultrasonic signal with a frequency range between 20KHz and 40KHz.

3. A small and portable anti-eavesdropping device as claimed in claim 2, characterized in that: The ultrasonic interference signal is a plurality of ultrasonic signals with different frequencies between 22KHz and 26KHz, or a plurality of ultrasonic signals with the same frequency between 22KHz and 26KHz, or an ultrasonic signal in the frequency range of 22KHz to 26KHz.

4. A small and portable anti-eavesdropping device as claimed in claim 1, characterized in that: The circuit on the circuit board includes a microcontroller unit and a switching circuit. The microcontroller unit is connected to the power interface. The switching circuit is connected to both the microcontroller unit and the multiple ultrasonic transducers. The microcontroller unit emits the ultrasonic interference signal under the power supply of the power interface. The ultrasonic interference signal is boosted by the switching circuit to a voltage matching the operating voltage of the ultrasonic transducer and then output to the ultrasonic transducer.

5. A small and portable anti-eavesdropping device as claimed in claim 4, characterized in that: The ultrasonic interference signal emitted by the micro control unit is a square wave or a sine wave.

6. A small and portable anti-eavesdropping device as claimed in claim 4, characterized in that: The switch circuit is a MOS switch circuit composed of multiple MOS transistors.

7. A small and portable anti-eavesdropping device as claimed in claim 4, characterized in that: The circuit on the circuit board also includes a voltage conversion circuit, which includes a linear regulator and a boost circuit. The linear regulator is connected between the power interface and the micro control unit, and the boost circuit is connected between the power interface and the switching circuit.

8. A small and portable anti-eavesdropping device as claimed in claim 1, characterized in that: The ultrasonic transducer is a piezoelectric ultrasonic transducer, and a plurality of the piezoelectric ultrasonic transducers are arranged in an array on the circuit board.

9. A small and portable anti-eavesdropping device as claimed in claim 1, characterized in that: The power interface is any one of a USB interface, a Type-C interface, a DC interface, a Lightning interface, and a MagSafe interface, or a combination of any two or more interfaces.

10. A small and portable anti-eavesdropping device as claimed in claim 1, characterized in that: The outer shell includes an upper shell and a lower shell fixedly connected to each other, the upper shell includes an upper shell and a mesh covering the upper shell, the upper shell and the mesh are both provided with the sound-transmitting holes, the sound-emitting surface of the ultrasonic transducer faces the sound-transmitting holes, and an accommodating space for accommodating the functional board is formed between the upper shell and the lower shell.

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