Handwriting device and drawing input method

Abstract

The application provides a handwriting device and a drawing input method. The handwriting device comprises a handwriting screen, a handwriting pen and a knob. The handwriting screen is internally provided with an antenna. The antenna can emit a first electromagnetic wave and obtain a first resonance signal, and can emit a second electromagnetic wave and obtain a second resonance signal. The handwriting pen is internally provided with a first resonance circuit. The first resonance circuit has a first resonance frequency. The first resonance circuit can receive the first electromagnetic wave and generate the first resonance signal. The knob comprises a base piece, a rotating piece rotatably connected with the base piece, an inductor arranged on the base piece and a plurality of first capacitors arranged on the rotating piece. Each first capacitor is electrically connected with the first capacitor one by one to form a second resonance circuit when the rotating piece rotates. The second resonance circuit has a second resonance frequency. The second resonance frequency is not equal to the first resonance frequency. The second resonance circuit can receive the second electromagnetic wave and generate the second resonance signal. The handwriting device provided by the application can simplify the circuit and structure and reduce the cost of the device.

Description

Technical Field

[0001] This invention relates to the field of handwriting input devices, and more particularly to a handwriting device and a drawing input method. Background Technology

[0002] A graphics tablet, also known as a digital tablet, drawing tablet, or sketching tablet, is an input device for computers, tablets, embedded systems, etc. It typically consists of a tablet and a pressure-sensitive stylus. Primarily designed for office workers, it's used for drawing and creative purposes, and is mainly geared towards design and art-related majors, advertising companies and design studios, and Flash vector animation production. The hardware of a graphics tablet uses electromagnetic induction; cursor positioning and movement are entirely accomplished through electromagnetic induction.

[0003] When using a graphics tablet for drawing and creation, rotating the drawn image or model is often involved. This operation is achieved through a knob. In existing designs, the knob integrates a battery, an optical sensor, and a Bluetooth module. The battery powers the optical sensor and Bluetooth module, the optical sensor detects the rotation direction and angle, and the Bluetooth module transmits this information to a control center (calculator). The control center then rotates the drawn image or model accordingly. This setup requires battery power, is relatively heavy, and, combined with the Bluetooth module and optical sensor, has a complex structure and high cost. Summary of the Invention

[0004] In order to solve the above-mentioned technical problems of heavy weight and high cost, the present invention provides a handwriting device and a drawing input method.

[0005] A handwriting device, comprising:

[0006] The handwriting screen has a built-in antenna, which can emit a first electromagnetic wave and acquire a first resonant signal, and can emit a second electromagnetic wave and acquire a second resonant signal;

[0007] The stylus has a built-in first resonant circuit with a first resonant frequency. The first resonant circuit can receive the first electromagnetic wave and generate the first resonant signal.

[0008] The knob includes a base, a rotating component rotatably connected to the base, an inductor disposed on the base, and a first capacitor disposed on the rotating component. The first capacitor has at least three capacitors arranged in parallel with the inductor. Among the plurality of first capacitors, at least three of the first capacitors have different capacitance values. Each first capacitor is electrically connected to the first capacitor one by one as the rotating component rotates to form a second resonant circuit. The second resonant circuit has a second resonant frequency, which is not equal to the first resonant frequency. The second resonant circuit is capable of receiving the second electromagnetic wave and generating the second resonant signal.

[0009] A drawing input method, the drawing input method being based on the aforementioned handwriting device, comprising:

[0010] The antenna transmits a first electromagnetic wave at a preset first frequency during a first transmission cycle and a second electromagnetic wave at a preset second frequency during a second transmission cycle.

[0011] The first resonant circuit receives the first electromagnetic wave and generates a first resonant signal;

[0012] The second resonant circuit receives the second electromagnetic wave and generates a second resonant signal;

[0013] The writing information of the stylus is determined based on the first resonant signal, and the rotation information of the knob is determined based on the second resonant signal.

[0014] A drawing input method, the drawing input method being based on the aforementioned handwriting device, comprising:

[0015] The antenna transmits a first electromagnetic wave at a preset first frequency in a first transmission cycle, transmits a second electromagnetic wave at a preset second frequency in a second transmission cycle, and transmits a third electromagnetic wave at a third frequency in a third transmission cycle.

[0016] The first resonant circuit receives the first electromagnetic wave and generates a first resonant signal;

[0017] The second resonant circuit receives the second electromagnetic wave and generates a second resonant signal;

[0018] The third resonant circuit receives the third electromagnetic wave and generates a third resonant signal;

[0019] The writing information of the stylus is determined based on the first resonant signal, the rotation information of the knob is determined based on the second resonant signal, and the pressing information of the knob is determined based on the third resonant signal.

[0020] Compared to existing technologies, the handwriting device provided by this invention uses electromagnetic induction to input the rotation signal of the knob. Since both the stylus and the writing screen use electromagnetic induction for handwriting input, the knob and stylus can share the writing screen's antenna, simplifying the circuitry and structure. It also eliminates the need for batteries, thus reducing device costs. The first resonant circuit built into the stylus and the second resonant circuit built into the knob are differentiated by their resonant frequencies to prevent interference and ensure simultaneous use. The coordinated arrangement of multiple first capacitors and inductors allows the knob to have multiple adjustable angle settings, improving the precision of rotational operation. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the handwriting device disclosed in this invention;

[0022] Figure 2 This is a schematic diagram illustrating the relationship between the antenna and the control unit in the handwriting device disclosed in this invention;

[0023] Figure 3 yes Figure 1 A schematic diagram of the first arrangement of the first capacitor and inductor on the central knob;

[0024] Figure 4 This invention discloses the detection procedure flow for handwriting devices;

[0025] Figure 5 yes Figure 1 A schematic diagram of a second arrangement of the first capacitor and inductor on the central knob. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Example 1

[0028] Please see Figure 1 This is a schematic diagram of the structure of the handwriting device disclosed in this invention. The handwriting device includes a handwriting screen (not shown), a knob 20, and a stylus 30.

[0029] The handwriting screen includes an antenna 11, which is capable of emitting a first electromagnetic wave and acquiring a first resonant signal, and emitting a second electromagnetic wave and acquiring a second resonant signal.

[0030] The stylus 30 includes a first resonant circuit, which has a first resonant frequency and is capable of receiving the first electromagnetic wave and generating the first resonant signal.

[0031] The knob 20 includes a second resonant circuit, which has a second resonant frequency and receives the second electromagnetic wave and generates the second resonant signal.

[0032] In this embodiment, the antenna 11 is constructed from a ring-shaped copper foil trace. The width and shape of the copper foil determine the electrical performance characteristics of the antenna 11. The copper foil can be distributed in the X and Y directions, and the shape of the antenna 11 in both directions is consistent, both being "U"-shaped. The antenna 11 has a transmitting state for emitting the first electromagnetic wave and the second electromagnetic wave, and a receiving state for receiving the corresponding first resonant signal and the second resonant signal.

[0033] It is understood that the first electromagnetic wave and the second electromagnetic wave emitted by the antenna have preset frequencies, and can have multiple different frequencies and be emitted in different transmission cycles. For example, the antenna 11 transmits the first electromagnetic wave at a preset first frequency in the first transmission cycle, and the first electromagnetic wave is a preset electromagnetic wave that can resonate with the first resonant circuit. The antenna 11 transmits the second electromagnetic wave at a preset second frequency in the second transmission cycle, and the second electromagnetic wave is an electromagnetic wave that can resonate with the second resonant circuit. The first transmission cycle is different from the second transmission cycle, and the first frequency is different from the second frequency.

[0034] The stylus 30 incorporates the first resonant circuit, which, together with the antenna 11, constitutes a first electromagnetic induction module. Specifically, the antenna 11 transmits the first electromagnetic wave at a preset first frequency during a first transmission cycle. When the first resonant circuit is within the coverage area of ​​the first electromagnetic wave, it resonates with the first electromagnetic wave to generate the first resonant signal. This first resonant signal is fed back to the antenna 11, and the control unit MCU displays the handwriting corresponding to the writing operation of the stylus 30 on the handwriting screen based on the first resonant signal. The control unit MCU is a data processing chip, typically located in a laptop or in the cloud, but it is possible that it is integrated into the handwriting screen.

[0035] The knob 20 incorporates the second resonant circuit, which, together with the antenna 11, constitutes the second electromagnetic induction module. Specifically, the antenna 11 transmits the second electromagnetic wave at a preset second frequency during the second transmission cycle. When the second resonant circuit is placed within the coverage area of ​​the second electromagnetic wave, it resonates with the second electromagnetic wave to generate the second resonant signal. This second resonant signal is fed back to the antenna 11, and the control unit MCU performs a corresponding rotation operation on the image on the handwriting screen based on the second resonant signal. It should be noted that the image (including two-dimensional or three-dimensional images) is composed of handwriting. Handwriting is the most basic element in drawing an image. The rotation operation can be performed on the entire image drawn on the handwriting screen, a part of the image, or individual handwriting strokes. The specific operation can be limited according to the software design.

[0036] Please refer to Figure 2 The handwriting screen also includes an analog switch, a transmitting / receiving circuit, and a control unit, which are electrically connected in sequence. The analog switch is electrically connected to the antenna 11, and the transmitting / receiving circuit is electrically connected to the analog switch and the control unit.

[0037] The transmitting and receiving circuit includes an amplifier and a detector. The amplifier is electrically connected to the analog switch. The control unit includes an analog-to-digital converter (ADC). During operation, the control unit (MCU) controls the analog switch to transmit either the first electromagnetic wave or the second electromagnetic wave through the antenna 11. The first resonant circuit receives the first electromagnetic wave and generates the first resonant signal, and the second resonant circuit receives the second electromagnetic wave and generates the second resonant signal. The control unit (MCU) controls the antenna 11 to be in a signal receiving state. The antenna 11 receives either the first resonant signal or the second resonant signal. The first resonant signal or the second resonant signal is transmitted sequentially through the analog switch, the amplifier, and the detector to the ADC. The control unit determines the writing information of the stylus 30 based on the first resonant signal, or determines the rotation position, rotation angle, and rotation speed of the knob 20 based on the second resonant signal.

[0038] In this embodiment, the first resonant frequency of the first resonant circuit is different from the second resonant frequency of the second resonant circuit. This setting ensures that the operation of the stylus 30 and the operation of the knob 20 will not interfere with each other.

[0039] Please refer to Figure 3In this embodiment, the second resonant circuit is optimized to obtain information about the rotation direction and angle of the knob 20. Specifically, the knob 20 includes a base, a rotating component rotatably connected to the base, an inductor 21 disposed on the base, and a first capacitor 22 disposed on the rotating component. At least three of the first capacitors 22 are arranged in parallel with the inductor 21. At least three of the first capacitors 22 have different capacitance values. Each first capacitor 22 is electrically connected to the inductor 21 one by one as the rotating component rotates, forming the second resonant circuit. The second resonant circuit has a second resonant frequency, which is not equal to the first resonant frequency. The second resonant circuit can receive the second electromagnetic wave and generate the second resonant signal.

[0040] Please refer to Figure 3 The knob 20 has a magnetic core and a coil at its center to form the inductor 21. Multiple first capacitors 22 are arranged around the inductor 21, and at least three of the first capacitors 22 have different capacitance values. Only one first capacitor 22 is connected to the coil at any given time, forming the second resonant circuit (LC oscillation circuit). When first capacitors 22 with different capacitance values ​​are connected to the circuit, the resonant frequency of the second resonant circuit is different.

[0041] According to f=1 / (2π√LC), the first capacitors 22 with different first capacitance values ​​are electrically connected to the inductor 21, corresponding to different frequencies. For ease of description, the three first capacitors 22 arranged clockwise are denoted as C1, C2, and C3, and their corresponding first resonant frequencies are denoted as f1, f2, and f3. The first resonant signals are F1, F2, and F3. Referring to Table 1, by comparing the resonant frequencies before and after rotation when the knob 20 is rotated, it can be determined whether the knob 20 is rotating clockwise or counterclockwise.

[0042] Table 1: Knob Operation Events

[0043]

[0044] When the control unit MCU obtains that the first resonant signal changes from F1 to F2, from F2 to F3, or from F3 to F1, it can be determined that the knob 20 is rotating clockwise. Conversely, if the first resonant signal changes from F2 to F1, from F3 to F2, or from F1 to F3, it can be determined that the knob 20 is rotating counterclockwise.

[0045] As described above, in the handwriting device provided in this embodiment, the rotation signal input of the knob 20 is achieved through electromagnetic induction. Since the stylus 30 and the handwriting screen also use electromagnetic induction to input handwriting, the knob 20 and the stylus 30 can share the antenna 11 of the handwriting screen, which simplifies the circuit and structure and eliminates the need for batteries or other power sources, thereby reducing device costs. The first resonant circuit built into the stylus 30 and the second resonant circuit built into the knob 20 are distinguished by their resonant frequencies to avoid interference and ensure that they can be used simultaneously. The setting of at least three first capacitors with different capacitance values ​​allows the control unit MCU to determine the rotation direction of the knob 20 based on the change in the second resonant frequency before and after rotation. Through the coordinated arrangement of multiple first capacitors 22 and the inductor 21, the knob 20 has multiple adjustment angle levels, improving the accuracy of rotation operation.

[0046] In other embodiments, the control unit MCU can also determine the rotation direction of the knob 20 based on the positions of the two adjacent first capacitors 22 before and after rotation. Compared with position recognition, it is simpler and more effective to identify the rotation angle by different resonant frequencies.

[0047] In this embodiment, adjusting the number and position of the first capacitors 22 changes the rotational precision of the knob 20. Figure 3 In the structure shown, there are 8 first capacitors 22, corresponding to 8 rotation positions. If the 8 first capacitors 22 are equally spaced, the accuracy of rotating one position is 45°. If the number of first capacitors 22 is 30, and each first capacitor 22 is equally spaced with its ring inductor 21, the knob 20 has 30 positions, and the accuracy of rotating one position is 12 degrees. Those skilled in the art can adjust the number and arrangement of the first capacitors 22 according to actual needs, and no unique limitation is made here. In this embodiment, the antenna 11 can also emit a third electromagnetic wave and acquire a third resonant signal; the knob 20 also includes the second capacitor. When the knob 20 is pressed, the inductor 21 is electrically connected to the second capacitor to form a third resonant circuit. The third resonant circuit has a third resonant frequency, and the third resonant circuit can receive the third electromagnetic wave and generate a third resonant signal.

[0048] The third resonant circuit and the antenna 11 constitute the third electromagnetic induction module. Specifically, the antenna 11 transmits a third electromagnetic wave at a preset third frequency during the third transmission cycle. The third resonant circuit, placed within the coverage area of ​​the third electromagnetic wave, resonates with the third electromagnetic wave to generate a third resonant signal. This third resonant signal is fed back to the antenna 11, and the control unit MCU determines the operator's pressing operation based on the third resonant signal. According to the software settings, combined with the rotation and pressing operations of the knob 20, various painting operations can be realized, such as scaling and rotating the canvas, adjusting brush size and density, and controlling volume.

[0049] It is understood that the capacitance value of the second capacitor is not equal to the capacitance value of each of the first capacitors 22. The third resonant circuit is triggered by pressing the knob 20, so that a pressing signal can be output regardless of the knob 20's position. For ease of distinction, the second capacitor is named C4, the corresponding third frequency is f4, and the corresponding third resonant signal is F4. Based on Table 1, the operation of the knob 20 is summarized as follows:

[0050] Table 2: Knob Operation Events

[0051]

[0052] When knob 20 is in the C1 position, pressing knob 20 changes the frequency from f1 to f4. Correspondingly, the resonant signal acquired by the control unit MCU changes from F1 to F4, indicating that the operator is pressing knob 20. When the operator releases knob 20, the resonant frequency changes from f4 to f1, and the resonant signal acquired by the control unit MCU changes from F4 to F1, indicating that the pressing operation of knob 20 has ended. Similarly, when knob 20 is in the C2 / C3 position, pressing knob 20 changes the frequency from f2 / f3 to f4. Correspondingly, the resonant signal acquired by the control unit MCU changes from F2 / F3 to F4, indicating that the operator is pressing knob 20. When the operator releases knob 20, the resonant frequency changes from f4 to f2 / f3, and the resonant signal acquired by the control unit MCU changes from F4 to F2 / F3, indicating that the pressing operation of knob 20 has ended.

[0053] Please refer to Figure 4 , Figure 4The flowchart of the handwriting device detection procedure is shown. After the MCU is powered on, the ADC, USB and other modules are initialized. First, the stylus 30 is detected. All antennas 11 are scanned in a time-division manner, and each frequency point of the stylus 30 is detected one by one. If the stylus 30 is close to antenna 11, the resonant signal of the stylus (first resonant signal) can be obtained. The position, pressure and key value of the stylus 30 are calculated. After a series of data processing such as anti-shake and filtering, the final data of the stylus 30 is obtained. Then the knob 20 is detected. The principle is similar, but the frequency detected each time needs to be recorded and compared with the frequency detected last time to determine the change in the state of the knob 20, whether there is a rotation or pressing change. After one cycle is completed, the data is reported to the host computer operating system in the correct format. After the detection is completed, the specific drawing operation can be performed.

[0054] In this embodiment, the base component has a connecting shaft, the rotating component is sleeved on the connecting shaft and can rotate around the connecting shaft, and an elastic element is provided between the rotating component and the base component, allowing the rotating component to move up and down relative to the base component. The surface of the rotating component facing away from the base component is a pressing operation surface. The elastic element undergoes elastic deformation when the pressing operation surface is pressed and resets after the external force is removed. The second capacitor is electrically connected to the inductor 21 when the pressing operation surface is pressed, forming the third resonant circuit.

[0055] The surface of the rotating component facing away from the base is the pressing surface. When a hand applies pressure to the pressing surface, the rotating component is pressed and moves towards the base, causing the second capacitor and the inductor 21 to become electrically connected, forming a third resonant circuit. After the external force is released, the rotating component moves away from the base under the elastic restoring force of the elastic element, thus disconnecting the second capacitor from the inductor 21.

[0056] It should be noted that the second capacitor can be located on the rotating component, and its contact with and separation from the inductor 21 are achieved by the movement of the rotating component relative to the base component, thereby realizing the connection and disconnection of the third resonant circuit. In other embodiments, the second capacitor can also be located on the base component and electrically connected to a touch switch. When the pressing operation surface is pressed, the touch switch, the second capacitor, and the inductor 21 are electrically connected to form the third resonant circuit. The touch switch can be a micro switch. When the rotating component moves towards the base component, the micro switch opens to connect the third resonant circuit, and when the rotating component moves away from the base component, the micro switch closes to disconnect the third resonant circuit.

[0057] In this embodiment, the knob 20 is a separate component, meaning it is independently configured with respect to the handwriting screen. In other embodiments, the knob 20 may be fixedly connected to the handwriting screen or detachably connected. Relatively speaking, the independent configuration of the knob 20 allows the operator to move its position relative to the handwriting screen as needed, thereby improving the convenience of drawing operations. Furthermore, as a separate component, the knob 20 eliminates the need for a separate connecting structure between it and the handwriting screen, reducing the overall footprint of the handwriting screen while maintaining a fixed display size, thus improving aesthetics.

[0058] In this embodiment, a protective adhesive layer is attached to the surface of the knob 20 facing the handwriting screen. Rubber is preferred. The rubber layer has a high static friction force, which reduces unintentional movement of the knob 20 when placed on the handwriting screen or a table.

[0059] Example 2

[0060] The handwriting device provided in this embodiment differs from that in Embodiment 1 in the specific configuration of the first capacitor 22 within the knob 20. For Embodiment 1, please refer to... Figure 3 The capacitance values ​​of the first capacitors 22 within the knob 20 are different. By setting the first capacitors 22 with different capacitance values, the resonant frequency of the second resonant circuit corresponding to any position of the knob 20 is different. The rotation direction of the knob 20 is determined based on the change in the resonant frequency. In this embodiment, please refer to... Figure 5 The multiple first capacitors 22 are divided into multiple capacitor groups, and the multiple capacitor groups are arranged in a ring array around the inductor 21. Each capacitor group includes at least three first capacitors 22, and the capacitance values ​​of each first capacitor 22 in the capacitor group are different. Figure 5 In the structure shown, three adjacent first capacitors 22 form a capacitor group, and multiple capacitor groups are arranged in a ring array around the inductor 21. The capacitance values ​​of the three first capacitors 22 in each capacitor group are different. Taking 10 capacitor groups as an example, that is, there are 30 first capacitors 22. With 30 first capacitors 22, only three capacitance values ​​are needed to complete the 30 rotation settings. Compared with 30 different first capacitor values, the resonant frequency range of the first resonant circuit can be effectively shortened. Those skilled in the art can set the number of first capacitors 22 in each capacitor group to three, four, five, six, etc., as needed, and no unique limitation is made here.

[0061] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A handwriting device comprising a handwriting screen and a handwriting pen, the handwriting screen having an antenna built therein, the antenna being capable of emitting a first electromagnetic wave and acquiring a first resonance signal, and capable of emitting a second electromagnetic wave and acquiring a second resonance signal, the handwriting pen having a first resonance circuit built therein, the first resonance circuit having a first resonance frequency, the first resonance circuit being capable of receiving the first electromagnetic wave and generating the first resonance signal, characterized in that, The knob further comprises a base, a rotating member connected with the base, an inductor arranged on the base, and a first capacitor arranged on the rotating member, the first capacitor has at least three and is arranged around the inductor, among the plurality of first capacitors, at least three first capacitors have different capacitance values, each first capacitor is electrically connected with the inductor one by one to form a second resonant circuit when the rotating member rotates, the second resonant circuit has a second resonant frequency, the second resonant frequency is not equal to the first resonant frequency, and the second resonant circuit can receive the second electromagnetic wave and generate the second resonant signal; the plurality of first capacitors are divided into a plurality of capacitor groups, the plurality of capacitor groups are distributed around the inductor in an annular array, and each capacitor group comprises at least three first capacitors, and the first capacitors in the capacitor group have different capacitance values.

2. The handwriting device of claim 1, wherein: The first capacitors have different capacitance values.

3. The handwriting device of claim 1, wherein: The first capacitors are arranged at equal intervals around the inductor.

4. The handwriting device of claim 1, wherein: The knob is independently arranged from the handwriting screen.

5. The handwriting device of claim 1, wherein: The antenna can further emit a third electromagnetic wave and obtain a third resonant signal; the knob further comprises a second capacitor, the second capacitor is electrically connected with the inductor and forms a third resonant circuit when the knob is pressed, the third resonant circuit has a third resonant frequency, the third resonant circuit receives the third electromagnetic wave and generates the third resonant signal.

6. The handwriting device of claim 5, wherein: A surface of the rotating member away from the base is a pressing operation surface, an elastic member is arranged between the rotating member and the base, the elastic member elastically deforms when the pressing operation surface is pressed, and returns to the original position after the external force is removed, and the second capacitor is electrically connected with the inductor and forms the third resonant circuit when the pressing operation surface is pressed.

7. The handwriting device of claim 6, wherein: The second capacitor is arranged on the base and is electrically connected with a touch switch, the touch switch, the second capacitor and the inductor are electrically connected and form the third resonant circuit when the pressing operation surface is pressed.

8. A drawing input method characterized by, The drawing input method is based on the handwriting device of any one of claims 1 to 4, comprising: The antenna emits a first electromagnetic wave at a preset first frequency in a first emission period and emits a second electromagnetic wave at a preset second frequency in a second emission period; The first resonant circuit receives the first electromagnetic wave and generates a first resonant signal; The second resonant circuit receives the second electromagnetic wave and generates a second resonant signal; The writing information of the handwriting pen is determined according to the first resonant signal, and the rotation information of the knob is determined according to the second resonant signal.

9. A drawing input method characterized by, The drawing input method is based on the handwriting device of any one of claims 5 to 7, comprising: The antenna emits a first electromagnetic wave at a preset first frequency in a first emission period, emits a second electromagnetic wave at a preset second frequency in a second emission period, and emits a third electromagnetic wave at a third frequency in a third emission period; The first resonant circuit receives the first electromagnetic wave and generates a first resonant signal; The second resonant circuit receives the second electromagnetic wave and generates a second resonant signal; The third resonant circuit receives the third electromagnetic wave and generates a third resonant signal; The writing information of the stylus is determined according to the first resonance signal, the rotation information of the knob is determined according to the second resonance signal, and the pressing information of the knob is determined according to the third resonance signal.

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