Sensor device combining capacitive touch and ultrasonic waves

Abstract

The utility model relates to the technical field of sensors, and particularly discloses a sensor device combining capacitive touch and ultrasonic waves, which comprises a shell, an ultrasonic metal probe and a PCBA (printed circuit board assembly) electrically connected with the ultrasonic metal probe are mounted on the shell, the PCBA circuit board comprises an MCU control circuit, an ultrasonic signal processing circuit, a touch capacitance signal processing circuit, a power management circuit, a communication circuit and an external interface circuit, and the touch capacitance signal processing circuit is electrically connected with the ultrasonic metal probe and the MCU control circuit. The ultrasonic signal processing circuit, the power management circuit and the communication circuit are electrically connected with the MCU control circuit, and the external interface circuit is electrically connected with the power management circuit and the communication circuit. According to the utility model, the characteristics of the capacitive touch sensor and the ultrasonic sensor are combined, and the double functions of obstacle detection and hand touch identification are realized on the single metal probe.

Description

Technical Field

[0001] The utility model relates to the technical field of sensors, and in particular to a sensor device combining capacitive touch and ultrasonic waves. Background Art

[0002] At present, ordinary probes are commonly used in reversing radars. This probe only has the ability to detect the distance of surrounding obstacles and cannot realize other functions. Traditional capacitive human hand touch detection only has the ability to achieve touch detection through the change of capacitance generated by human hand touch. In some application scenarios, such as the application scenarios of door handles of certain models, both ultrasonic sensors and human hand touch detection sensors need to be arranged at the handle position. At this time, only two sets of sensors can be placed on the door handle, and the two sensors belong to two independent controller systems respectively. The human hand touch sensor belongs to the keyless entry system, and the ultrasonic sensor belongs to the door control system. This is not conducive to the systematic integration of body parts, increases system complexity, increases cost, and further reduces the degree of minimalist aesthetics.

[0003] Traditional touch sensors only detect the change in capacitance after human touch. When the change is greater than the preset value of the chip inside the sensor, the touch is determined to be valid. However, natural substances with strong dielectric constants such as water can also be determined to be effective. Based on the current single capacitance detection, it is impossible to completely solve the problem of false triggering in water spray or car washing scenarios, which will lead to the following defects: 1. For application scenarios with electric doors, if the door handle is triggered, the door will open automatically. During the car washing or raining process, the door may collide with surrounding obstacles after opening, and water may enter the car; 2. During the rain, the handle capacitance sensor is repeatedly triggered by mistake and the keyless entry system controller is repeatedly activated, which will cause the entire vehicle to be repeatedly awakened in a silent state and lose power; 3. During the rain, the surface of the handle capacitance sensor is covered with rain, and the capacitance value has changed. If a human hand continues to touch it, the chip inside the sensor may not be able to effectively determine that it is a human touch and cannot open the door. Utility Model Content

[0004] The technical problem to be solved by the present invention is that, in view of the above-mentioned defects of the prior art, a sensor device combining capacitive touch and ultrasonic wave is provided, aiming to combine the respective characteristics of the capacitive touch sensor and the ultrasonic sensor, and realize the dual functions of obstacle detection and human hand touch recognition on a single metal probe, which can effectively solve the misjudgment problem faced by traditional capacitive touch.

[0005] In order to solve the above technical problems, the technical solution of the utility model is:

[0006] A sensor device combining capacitive touch and ultrasound, comprising a shell, on which an ultrasonic metal probe and a PCBA circuit board electrically connected to the ultrasonic metal probe are installed, the PCBA circuit board comprising an MCU control circuit, an ultrasonic signal processing circuit, a touch capacitance signal processing circuit, a power management circuit, a communication circuit and an external interface circuit, the touch capacitance signal processing circuit is electrically connected to the ultrasonic metal probe and the MCU control circuit respectively, the ultrasonic signal processing circuit, the power management circuit and the communication circuit are all electrically connected to the MCU control circuit, and the external interface circuit is electrically connected to the power management circuit and the communication circuit respectively.

[0007] Preferably, the MCU control circuit includes an MCU main control chip U3, a capacitor C20 and a resistor R14, and the capacitor C20 and the resistor R14 are both connected to the MCU main control chip U3.

[0008] Preferably, the ultrasonic metal probe includes a first capacitive touch electrode P1 and a second capacitive touch electrode P2, the touch capacitance signal processing circuit includes a transistor T2, a resistor R11, a resistor R20, a resistor R24, a capacitor C25 and a capacitor C27, the transistor T2 is respectively connected to the resistor R11, the first capacitive touch electrode P1 and the twenty-fourth pin of the MCU main control chip U3, the resistor R20 is respectively connected to the resistor R11, the capacitor C25 and the seventh pin of the MCU main control chip U3, and the second capacitive touch electrode P2 is sequentially connected to the fourteenth pin of the MCU main control chip U3 via the resistor R24 ​​and the capacitor C27.

[0009] Preferably, the ultrasonic signal processing circuit includes an ultrasonic sensor chip U1, a transformer T1, a resistor R2, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5 and a capacitor C6. The transformer T1, the resistor R2, the capacitor C1, the capacitor C2, the capacitor C3, the capacitor C4, the capacitor C5 and the capacitor C6 are all connected to the ultrasonic sensor chip U1. The second pin of the ultrasonic sensor chip U1 is connected to the twenty-second pin of the MCU main control chip U3 via the resistor R14. The first capacitive touch electrode P1 is connected to the ultrasonic sensor chip U1 via the capacitor C5 and the resistor R3 in sequence.

[0010] Preferably, the communication circuit includes a CAN communication chip U4, an inductor CM1, a resistor R22, a resistor R23 and a capacitor C24, and the CAN communication chip U4 is connected to the MCU main control chip U3, the inductor CM1, the resistor R22, the resistor R23 and the capacitor C24 respectively.

[0011] Preferably, the power management circuit includes a power supply chip U2, a capacitor C11, a capacitor C15, a capacitor C16, a diode D1 and a voltage regulator D2. The power supply chip U2 is respectively connected to the MCU main control chip U3, the capacitor C11, the capacitor C15, the capacitor C16 and the diode D1, and the diode D1 is connected to the voltage regulator D2.

[0012] Preferably, the external interface circuit comprises an interface J1, a capacitor C14 and a capacitor C17, the interface J1 is connected to the capacitor C14, a diode D1 and an inductor CM1 respectively, and the capacitor C14 is grounded via the capacitor C17.

[0013] By adopting the above technical scheme, the utility model provides a sensor device combining capacitive touch and ultrasound, which has the following beneficial effects: the touch capacitance signal processing circuit in the sensor device is electrically connected to the ultrasonic metal probe and the MCU control circuit respectively, the ultrasonic signal processing circuit, the power management circuit and the communication circuit are all electrically connected to the MCU control circuit, and the external interface circuit is electrically connected to the power management circuit and the communication circuit respectively. By setting the ultrasonic signal processing circuit and the touch capacitance signal processing circuit to cooperate with the MCU control circuit, and combining the inherent characteristics of the ultrasonic metal probe that the echo characteristics will change after human hand contact occurs, because the echo characteristics changes caused by human hand contact and water flow are different, the misjudgment problem faced by traditional capacitive touch is effectively solved; the ultrasonic metal probe can play the role of capacitive touch, and can also play the role of ultrasonic mechanical vibration to generate ultrasonic waves and receive ultrasonic echoes. Combining the characteristics of the two, the time-sharing multiplexing mechanism can perfectly solve the false triggering problem caused by contact with objects such as water flow, and can complete the object distance detection function of the ultrasonic sensor and the touch detection function of the capacitive sensor, effectively enhancing the user's comprehensive use experience, reducing the number of components, and effectively reducing the overall cost of the entire body controller system. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the utility model;

[0015] Figure 2 It is a structural block diagram of the utility model;

[0016] Figure 3 It is the circuit principle diagram of the utility model;

[0017] In the figure, 1-housing, 2-ultrasonic metal probe, 3-PCBA circuit board, 4-MCU control circuit, 5-ultrasonic signal processing circuit, 6-touch capacitance signal processing circuit, 7-power management circuit, 8-communication circuit, 9-external interface circuit, 10-wire. DETAILED DESCRIPTION

[0018] The specific implementation methods of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the description of these implementation methods is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in each implementation method of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0019] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0020] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0021] like Figure 1-3As shown, the sensor device combining capacitive touch and ultrasonic wave comprises a housing 1, on which an ultrasonic metal probe 2 and a PCBA circuit board 3 electrically connected to the ultrasonic metal probe 2 are mounted, and the PCBA circuit board 3 comprises an MCU control circuit 4, an ultrasonic signal processing circuit 5, a touch capacitance signal processing circuit 6, a power management circuit 7, a communication circuit 8 and an external interface circuit 9, wherein the touch capacitance signal processing circuit 6 is electrically connected to the ultrasonic metal probe 2 and the MCU control circuit 4 respectively, and the ultrasonic signal processing circuit 5, the power management circuit 7 and the communication circuit 8 are all electrically connected to the MCU control circuit 4, and the external interface circuit 9 is electrically connected to the power management circuit 7 and the communication circuit 8 respectively. It can be understood that in actual application, the sensor device can be directly applied to the main body of a car door handle, a car exterior panel, and a car tailgate panel, and can realize both a capacitive touch unlocking function and an external obstacle recognition function. The wiring harness and wiring harness terminals are connected to the PCBA circuit board through welding, riveting, etc., and assembled with the casing. The components must meet at least IP67 waterproof and dustproof requirements. The components and other auxiliary body parts include but are not limited to being in a complete separate form or directly assembling the ultrasonic metal probe and PCBA in the auxiliary body parts to form a community.

[0022] Specifically, the MCU control circuit 4 includes an MCU main control chip U3, a capacitor C20 and a resistor R14, and the capacitor C20 and the resistor R14 are both connected to the MCU main control chip U3; the ultrasonic metal probe 2 includes a first capacitive touch electrode P1 and a second capacitive touch electrode P2, and the touch capacitance signal processing circuit 6 includes a transistor T2, a resistor R11, a resistor R20, a resistor R24, a capacitor C25 and a capacitor C27, and the transistor T2 is respectively connected to the resistor R11, the first capacitive touch electrode P1 and the twenty-fourth pin of the MCU main control chip U3, the resistor R20 is respectively connected to the resistor R11, the capacitor C25 and the seventh pin of the MCU main control chip U3, and the second capacitive touch electrode P2 is sequentially connected to the fourteenth pin of the MCU main control chip U3 via the resistor R24 ​​and the capacitor C27. The MCU main control chip U3 can be an 80C51 single-chip microcomputer chip, etc.; the touch capacitance signal processing circuit 6 captures the change in capacitance on the ultrasonic metal probe through the capacitance signal channel, and then determines whether a human touch occurs, and comprehensively calculates the capacitance signal change and the distance change detected by the ultrasound, so as to effectively and accurately identify the external touch and obstacle status of the door.

[0023] Specifically, the ultrasonic signal processing circuit 5 includes an ultrasonic sensor chip U1, a transformer T1, a resistor R2, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5 and a capacitor C6. The transformer T1, the resistor R2, the capacitor C1, the capacitor C2, the capacitor C3, the capacitor C4, the capacitor C5 and the capacitor C6 are all connected to the ultrasonic sensor chip U1. The second pin of the ultrasonic sensor chip U1 is connected to the twenty-second pin of the MCU main control chip U3 via the resistor R14, and the first capacitive touch electrode P1 is connected to the ultrasonic sensor chip U1 via the capacitor C5 and the resistor R3 in sequence. It can be understood that the ultrasonic sensor chip U1 can be a TDC1000QPWRQ1 chip, etc. The ultrasonic signal processing circuit 5 generates a pressure-dependent oscillation signal of a certain frequency and transmits it to the ultrasonic metal probe through an ultrasonic signal channel, causing the ultrasonic metal probe to generate mechanical vibrations and radiate ultrasonic signals into space. The ultrasonic wave will be reflected when it encounters an obstacle in space, and the reflected ultrasonic signal of a certain frequency will also cause the ultrasonic metal probe to generate mechanical vibrations. The mechanical vibration causes the piezoelectric ceramic piece inside the probe to generate a changing piezoelectric signal due to the piezoelectric effect. The piezoelectric signal is transmitted to the signal generation and processing unit through the ultrasonic signal channel to determine the time period from ultrasonic emission to return transmission. The distance of the detected obstacle can be calculated by combining the speed of sound and the transmission period.

[0024] It can be understood that the ultrasonic metal probe 2 plays the following two roles in the sensor device: 1. The MCU control circuit 4 generates a pressure-dependent oscillation signal of a certain frequency and transmits it to the ultrasonic metal probe 2 through the ultrasonic signal channel, causing the ultrasonic metal probe 2 to generate mechanical vibrations and radiate ultrasonic signals into space. When the ultrasonic wave encounters an obstacle in space, it will be reflected. The ultrasonic signal of a certain frequency reflected back will also cause the ultrasonic metal probe 2 to generate mechanical vibrations. The mechanical vibration causes the piezoelectric ceramic piece inside the probe to generate a changing piezoelectric signal due to the piezoelectric effect. The piezoelectric signal is transmitted to the signal generation and processing unit through the ultrasonic signal channel, and the distance between the probe and the obstacle can be calculated according to the law of sound propagation. In addition, since the ultrasonic wave itself is generated by the mechanical vibration of the ultrasonic metal probe, when an external object contacts the ultrasonic metal probe, it will directly affect the mechanical vibration of the ultrasonic metal probe, causing the ultrasonic echo characteristics to change. The change in the signal can also be indirectly used as a basis for judging whether there is contact with an external object. 2. Since the ultrasonic metal probe itself is made of metal and is a good conductor of electrical signals, it can be understood as a capacitive sensing plane. The MCU control circuit 4 will charge and discharge it repeatedly, and judge the capacitance on the capacitive sensing plane by the charge and discharge time variable. When the human hand does not come into contact with it, the medium between the capacitive sensing plane (ultrasonic metal probe) and the earth is air. The relative capacitance of the current ultrasonic metal probe can be obtained by calculating the charge and discharge time through the internal circuit. By continuously capturing and calculating the capacitance, combined with the actual test data of different objects (including fluid media such as water), it can be used as an effective detection method for human hand contact. Based on the above two effects, in some application scenarios, such as intermittent or continuous rainy weather, because the dielectric constant of water is close to that of the human body, a single capacitive detection may be misjudged at this time, thinking that there is a human hand touching outside. In order to solve this problem, it is necessary to combine the inherent characteristics of the ultrasonic metal probe that the echo characteristics will change after the human hand touches, because the echo characteristics caused by the human hand contact and the water flow are different, and then this solution can effectively solve the misjudgment problem faced by traditional capacitive touch.

[0025] Specifically, the communication circuit 8 includes a CAN communication chip U4, an inductor CM1, a resistor R22, a resistor R23 and a capacitor C24, and the CAN communication chip U4 is connected to the MCU main control chip U3, the inductor CM1, the resistor R22, the resistor R23 and the capacitor C24 respectively. It can be understood that the communication circuit 8 generates communication behavior with the external controller as a physical bridge, and the communication methods include but are not limited to UART, USB, Internet, LIN, CAN, etc. The CAN communication chip U4 can be a TLE6251DS chip, etc.

[0026] Specifically, the power management circuit 7 includes a power supply chip U2, a capacitor C11, a capacitor C15, a capacitor C16, a diode D1 and a voltage regulator D2. The power supply chip U2 is connected to the MCU main control chip U3, the capacitor C11, the capacitor C15, the capacitor C16 and the diode D1 respectively. The diode D1 is connected to the voltage regulator D2. The external interface circuit 9 includes an interface J1, a capacitor C14 and a capacitor C17. The interface J1 is connected to the capacitor C14, the diode D1 and the inductor CM1 respectively. The capacitor C14 is grounded via the capacitor C17. It can be understood that the power management circuit 7 is used to convert the external vehicle body power supply voltage (usually greater than 9V) into a voltage value (usually 5V or 3.3V) suitable for the communication circuit and the MCU control circuit 4 for use by the communication unit and the MCU control circuit 4.

[0027] It is understandable that the utility model has a reasonable design and unique structure. The chip generates ultrasonic waves by controlling the piezoelectric ceramic inside the metal probe to oscillate at a certain frequency. After the ultrasonic waves encounter surrounding obstacles in space, the ultrasonic waves are transmitted back to the metal probe. The metal probe resonates and drives the internal ceramic piece to generate piezoelectric signals. The chip connected to the metal probe will automatically detect the time difference between ultrasonic emission and return, and the distance between the surrounding obstacles and the probe can be calculated based on the speed of sound propagation in the air; at the same time, the user can touch the metal probe, and the metal probe will effectively detect whether a human touch action is generated based on the principle of capacitance change. The utility model can reuse the traditional ultrasonic probe as a capacitive human hand touch detection, which can effectively reduce the number of sensor components on the car and effectively reduce the overall cost of the entire body controller system.

[0028] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and variations of these embodiments are made without departing from the principles and spirit of the present invention, and still fall within the scope of protection of the present invention.

Claims

1. A sensor device combining capacitive touch and ultrasonic wave, comprising a housing, an ultrasonic metal probe and a PCBA circuit board electrically connected to the ultrasonic metal probe mounted on the housing, characterized in that: The PCBA circuit board includes an MCU control circuit, an ultrasonic signal processing circuit, a touch capacitance signal processing circuit, a power management circuit, a communication circuit and an external interface circuit. The touch capacitance signal processing circuit is electrically connected to the ultrasonic metal probe and the MCU control circuit, respectively. The ultrasonic signal processing circuit, the power management circuit and the communication circuit are all electrically connected to the MCU control circuit. The external interface circuit is electrically connected to the power management circuit and the communication circuit, respectively.

2. The sensor device combining capacitive touch and ultrasonic wave according to claim 1, characterized in that: The MCU control circuit includes an MCU main control chip U3, a capacitor C20 and a resistor R14, and the capacitor C20 and the resistor R14 are both connected to the MCU main control chip U3.

3. The sensor device combining capacitive touch and ultrasonic wave according to claim 2, characterized in that: The ultrasonic metal probe includes a first capacitive touch electrode P1 and a second capacitive touch electrode P2, and the touch capacitance signal processing circuit includes a transistor T2, a resistor R11, a resistor R20, a resistor R24, a capacitor C25 and a capacitor C27. The transistor T2 is respectively connected to the resistor R11, the first capacitive touch electrode P1 and the twenty-fourth pin of the MCU main control chip U3, the resistor R20 is respectively connected to the resistor R11, the capacitor C25 and the seventh pin of the MCU main control chip U3, and the second capacitive touch electrode P2 is sequentially connected to the fourteenth pin of the MCU main control chip U3 via the resistor R24 ​​and the capacitor C27.

4. The sensor device combining capacitive touch and ultrasonic wave according to claim 3, characterized in that: The ultrasonic signal processing circuit includes an ultrasonic sensor chip U1, a transformer T1, a resistor R2, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5 and a capacitor C6. The transformer T1, the resistor R2, the capacitor C1, the capacitor C2, the capacitor C3, the capacitor C4, the capacitor C5 and the capacitor C6 are all connected to the ultrasonic sensor chip U1. The second pin of the ultrasonic sensor chip U1 is connected to the twenty-second pin of the MCU main control chip U3 via the resistor R14. The first capacitive touch electrode P1 is connected to the ultrasonic sensor chip U1 via the capacitor C5 and the resistor R3 in sequence.

5. The sensor device combining capacitive touch and ultrasonic wave according to claim 2, characterized in that: The communication circuit includes a CAN communication chip U4, an inductor CM1, a resistor R22, a resistor R23 and a capacitor C24. The CAN communication chip U4 is connected to the MCU main control chip U3, the inductor CM1, the resistor R22, the resistor R23 and the capacitor C24 respectively.

6. The sensor device combining capacitive touch and ultrasonic wave according to claim 5, characterized in that: The power management circuit includes a power supply chip U2, a capacitor C11, a capacitor C15, a capacitor C16, a diode D1 and a voltage regulator D2. The power supply chip U2 is respectively connected to the MCU main control chip U3, the capacitor C11, the capacitor C15, the capacitor C16 and the diode D1, and the diode D1 is connected to the voltage regulator D2.

7. The sensor device combining capacitive touch and ultrasonic wave according to claim 6, characterized in that: The external interface circuit includes an interface J1, a capacitor C14 and a capacitor C17. The interface J1 is connected to the capacitor C14, a diode D1 and an inductor CM1 respectively. The capacitor C14 is grounded via the capacitor C17.

Images