Ultrasonic induction circuit of intelligent door lock and intelligent door lock
By incorporating an interference absorption module into the ultrasonic sensing circuit of the smart door lock, the ultrasonic sensing module's human body sensing distance is enhanced by absorbing harmonic interference and spike interference, thus solving the problem of excessively short sensing distance and improving the user experience.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHENZHEN FENDA SMART HOME CO LTD
- Filing Date
- 2025-06-13
- Publication Date
- 2026-05-15
AI Technical Summary
Existing smart door locks using ultrasonic technology have a short sensing distance, which affects the user experience.
By incorporating an interference absorption module into the ultrasonic sensing circuit, the human body sensing distance of the ultrasonic sensing module can be enhanced by absorbing harmonic interference and spike interference.
The human body sensing distance of the ultrasonic sensing module has been increased, improving the user experience and solving the problem of insufficient sensing distance.
Smart Images
Figure CN224248147U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of ultrasonic sensing technology for smart door locks, and particularly to an ultrasonic sensing circuit for a smart door lock and a smart door lock. Background Technology
[0002] Current smart locks use radar sensing technology to detect human signals. However, radar sensing is costly, technically complex, and consumes a lot of power, generally limiting its application to high-precision ranging environments. Ultrasonic sensing technology, on the other hand, emits ultrasonic waves through an ultrasonic transmitter and calculates distance using the Doppler effect. Advantages of ultrasonic sensing include low cost, mature technology, and low power consumption. Although its detection range is limited and susceptible to environmental factors, this does not hinder its application in smart locks. Furthermore, ultrasonic technology is highly sensitive and consumes little power, making it ideal for detecting the presence of people at the door. In locks, it primarily activates the device upon detecting a person. In practical implementation, its ultra-low power consumption and wide-angle capability contribute to improved battery life in smart locks.
[0003] However, currently, the application of ultrasonic technology in smart locks is limited by the internal environment of the lock, and most smart locks on the market can only achieve a human body sensing distance of 0.5 to 1 meter. Utility Model Content
[0004] Existing smart door locks that use ultrasonic technology have the problem of insufficient sensing distance.
[0005] To address the aforementioned issues, an ultrasonic sensing circuit and smart lock for smart door lock are proposed. By incorporating an interference absorption module to absorb harmonic and spike interference, the ultrasonic sensing module's human body sensing distance is increased, improving the user experience and helping to solve the problem of excessively short sensing distance in existing smart door locks using ultrasonic technology.
[0006] In a first aspect, an ultrasonic sensing circuit for a smart door lock includes:
[0007] Ultrasonic sensing module;
[0008] MCU;
[0009] Interference absorption module;
[0010] The interference absorption module is electrically connected to the ultrasonic sensing module;
[0011] The ultrasonic sensing module is communicatively connected to the MCU and is used to sense human body signal data and transmit the human body signal data to the MCU.
[0012] The interference absorption module is used to absorb interference when the ultrasonic sensing module performs human body sensing.
[0013] In conjunction with the ultrasonic sensing circuit of the smart door lock described in the first aspect of this utility model, in a first possible embodiment, the ultrasonic sensing module includes:
[0014] Ultrasonic sensing chip;
[0015] The ultrasonic sensing chip includes a first power supply pin.
[0016] The input terminal of the interference absorption module is electrically connected to the first power input circuit and the second power input circuit, and the output terminal of the interference absorption module is electrically connected to the first power pin.
[0017] In conjunction with the first possible embodiment of the first aspect of this utility model, in the second possible embodiment, the interference absorption module includes:
[0018] Frequency doubling interference absorption capacitor and spike interference absorption resistor;
[0019] The first end of the spike interference absorption resistor is electrically connected to the first power input circuit, the second end of the spike interference absorption resistor is electrically connected to the second power input circuit and the first end of the frequency doubling interference absorption capacitor, and the second end of the frequency doubling interference absorption capacitor is grounded.
[0020] In conjunction with the second possible implementation of the first aspect of this utility model, in the third possible implementation, the capacitance value of the frequency doubling interference absorption capacitor is 40-50uF, and the resistance value of the spike interference absorption resistor is within 0-3Ω.
[0021] In conjunction with the second possible embodiment of the first aspect of this utility model, in the fourth possible embodiment, the ultrasonic sensing circuit further includes:
[0022] First filtering module;
[0023] The first filtering module is electrically connected to the first power supply pin, the interference absorption circuit, and the second power input circuit.
[0024] In conjunction with the ultrasonic sensing circuit of the smart door lock described in the first aspect of this utility model, in a fifth possible embodiment, the MCU and the ultrasonic sensing module communicate via an SPI module;
[0025] The SPI module includes:
[0026] MOSI and MISO data cables;
[0027] The MOSI data line and MISO data line are used to connect the MCU and the ultrasonic sensing module, respectively.
[0028] In conjunction with the fifth possible embodiment of the first aspect of this utility model, in the sixth possible embodiment, the ultrasonic sensing circuit further includes:
[0029] Second filtering module;
[0030] The second filter is electrically connected to the MOSI data line and the MISO data line, respectively.
[0031] In conjunction with the fourth possible implementation of the first aspect of this utility model, and in the seventh possible implementation, the first filtering module includes:
[0032] First filter capacitor and second filter capacitor;
[0033] The first terminal of the first filter capacitor and the second filter capacitor are electrically connected to the first power supply pin, the interference absorption circuit and the second power supply input circuit, and the second terminal of the first filter capacitor and the second filter capacitor are respectively grounded.
[0034] In conjunction with the seventh possible implementation of the first aspect of this utility model, and in the eighth possible implementation, the second filtering module includes:
[0035] The third and fourth filter capacitors;
[0036] The first terminals of the third and fourth filter capacitors are electrically connected to the MOSI data line and the MISO data line, respectively, and the second terminals of the third and fourth filter capacitors are grounded.
[0037] In a second aspect, there is a smart door lock, including the ultrasonic sensing circuit of the smart door lock described in the first aspect.
[0038] The ultrasonic sensing circuit and smart lock of this utility model absorb interference from harmonic and spike interference by setting an interference absorption module, which helps to increase the human body sensing distance of the ultrasonic sensing module, improve the user experience, and help solve the problem of excessively short sensing distance in existing smart locks using ultrasonic technology. Attached Figure Description
[0039] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0040] Figure 1 This is a logic circuit diagram of the ultrasonic sensing circuit of the smart door lock in this utility model.
[0041] Figure 2 This is a circuit diagram showing the connection between the ultrasonic sensing module and the MCU in the ultrasonic sensing circuit of the smart door lock of this utility model.
[0042] Figure 3 This is a circuit diagram of the ultrasonic sensing module in the ultrasonic sensing circuit of the smart door lock of this utility model.
[0043] Figure 4 This is a schematic diagram of the interface circuit of the ultrasonic sensing module in the ultrasonic sensing circuit of the smart door lock of this utility model.
[0044] Figure 5 This is a schematic diagram of the ultrasonic sensing module in the ultrasonic sensing circuit of the smart door lock of this utility model, illustrating the ultrasonic effect.
[0045] Components and their serial numbers:
[0046] 100 – Ultrasonic sensing module, 200 – MCU, 300 – Interference absorption module. Detailed Implementation
[0047] The technical solutions of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, other embodiments obtained by those skilled in the art without creative effort are all within the scope of protection of this utility model.
[0048] 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 invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0049] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.
[0050] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.
[0051] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.
[0052] Existing smart door locks that use ultrasonic technology have the problem of insufficient sensing distance.
[0053] To address the above problems, an ultrasonic sensing circuit for a smart door lock and a smart door lock are proposed.
[0054] Firstly, an ultrasonic sensing circuit for a smart door lock, such as... Figure 1 , Figure 1 This is a logic circuit diagram of the ultrasonic sensing circuit of the smart door lock of this utility model; it includes an ultrasonic sensing module 100, an MCU 200, and an interference absorption module 300; the interference absorption module 300 is electrically connected to the ultrasonic sensing module 100; the ultrasonic sensing module 100 is communicatively connected to the MCU 200 and is used to sense human body signal data and transmit the human body signal data to the MCU 200; the interference absorption module 300 is used to absorb interference when the ultrasonic sensing module 100 is sensing human body.
[0055] In this embodiment, by setting an interference absorption module 300 to absorb harmonic interference and spike interference, it is beneficial to increase the human body sensing distance of the ultrasonic sensing module 100, improve the user experience, and help solve the problem of excessively short sensing distance in existing smart door locks using ultrasonic technology.
[0056] In one specific implementation, such as Figure 3 , Figure 3This is a circuit diagram of the ultrasonic sensing module 100 in the ultrasonic sensing circuit of the smart door lock of this utility model; the ultrasonic sensing module 100 includes an ultrasonic sensing chip (ICU_20201); the ultrasonic sensing chip includes a first power supply pin (VDD); the input terminal of the interference absorption module 300 is electrically connected to the first power input circuit (VCC_3V3) and the second power input circuit (VCC_3V3_CONST), and the output terminal of the interference absorption module 300 is electrically connected to the first power supply pin (VDD).
[0057] In this embodiment, the ultrasound chip ICU_20201 and its peripheral circuits are connected to the MCU200 via J1 to form a minimum ultrasound detection system circuit. In this circuit, ICU_20201 communicates with the MCU200 via SPI: MOSI, MISO, SCLK, and CS_B. MOSI and MISO are data lines, SCLK is the clock line, and CS_B is the chip select signal. The INT port within ICU_20201 is an open-drain input, externally pulled up to 3.3V. When the ultrasound chip senses a human body, it pulls INT low, generating a falling-edge pulse interrupt signal transmitted to the MCU200 to wake up the device and start operation. MUTCLK and LFCLK are external clock input signals; MUTCLK is the main high-frequency clock input, and LFCLK is the low-frequency clock input.
[0058] In one specific implementation, such as Figure 3 The interference absorption module 300 includes a frequency doubling interference absorption capacitor C5 and a spike interference absorption resistor R3; the first end of the spike interference absorption resistor R3 is electrically connected to the first power input circuit, the second end of the spike interference absorption resistor R3 is electrically connected to the second power input circuit and the first end of the frequency doubling interference absorption capacitor C5, and the second end of the frequency doubling interference absorption capacitor C5 is grounded.
[0059] In one specific implementation, such as Figure 3 The capacitance of the frequency doubling interference absorption capacitor C5 is 40-50uF, and the resistance of the spike interference absorption resistor R3 is 0-3Ω.
[0060] In the circuit of this embodiment, the ultrasonic sensing value is highly sensitive to power supply fluctuations, so the ripple requirements for the 3.3V power supply are relatively high, needing to be controlled within 50mV to achieve a relatively ideal detection effect. Besides the ripple effect, a more significant factor is the presence of harmonic interference (harmonics: 1 / 4 frequency, 1 / 2 frequency, 2 times frequency, 4 times frequency, etc.), since the ultrasonic operating frequency is 85kHz. Therefore, in this circuit, this embodiment adjusts the parameters of two key components: C5 and R3. C5 is selected as 47uF / 16V, and R3 is selected as a 2R precision resistor. When harmonic interference occurs in the 3.3V power supply, C5 can effectively mitigate this interference. C5 acts as a large capacitor, and charging C5 smooths out the fluctuations. The R3 resistor cannot be too large, nor can it be zero; a 2R resistance can effectively absorb some of the spike interference in the circuit. C5 and R3 form a good RC absorption circuit, making the circuit operate stably and reliably. Furthermore, by combining this circuit with software algorithms, our ultrasonic sensing detection can be stably controlled at a distance of over 2 meters, with an angle controlled within ±60 degrees. The actual chip angle can reach 180 degrees, and the chip power consumption is maintained at the microamplitude level. Figure 5 , Figure 5 This is a schematic diagram of the ultrasonic sensing module 100 in the ultrasonic sensing circuit of the smart door lock of this utility model, showing the ultrasonic action.
[0061] In one specific implementation, such as Figure 3 The ultrasonic sensing circuit also includes a first filtering module; the first filtering module is electrically connected to the first power supply pin VDD, the interference absorption circuit and the second power input circuit (VCC_3V3_CONST).
[0062] In one specific implementation, such as Figure 3 The MCU200 and the ultrasonic sensing module 100 communicate via an SPI module; the SPI module includes a MOSI data line and a MISO data line; the MOSI data line and the MISO data line are used to connect the MCU200 and the ultrasonic sensing module 100 respectively.
[0063] In one specific implementation, such as Figure 3 The ultrasonic sensing circuit also includes a second filtering module; the second filter is electrically connected to the MOSI data line and the MISO data line respectively.
[0064] In one specific implementation, such as Figure 3 The first filtering module includes a first filtering capacitor C3 and a second filtering capacitor C4; the first terminals of the first filtering capacitor C3 and the second filtering capacitor C4 are electrically connected to the first power supply pin, the interference absorption circuit and the second power supply input circuit, and the second terminals of the first filtering capacitor C3 and the second filtering capacitor C4 are grounded respectively.
[0065] In one specific implementation, such as Figure 3 The second filtering module includes a third filtering capacitor C6 and a fourth filtering capacitor C7; the first terminals of the third filtering capacitor C6 and the fourth filtering capacitor C7 are electrically connected to the MOSI data line and the MISO data line, respectively, and the second terminals of the third filtering capacitor C6 and the fourth filtering capacitor C7 are grounded.
[0066] In this embodiment of the application, as in this embodiment, Figure 2 and Figure 4 , Figure 2 This is a circuit diagram showing the connection between the ultrasonic sensing module 100 and the MCU 200 in the ultrasonic sensing circuit of the smart door lock of this utility model.
[0067] Figure 4 This is a schematic diagram of the interface circuit of the ultrasonic sensing module 100 in the ultrasonic sensing circuit of the smart door lock of this utility model.
[0068] As shown in other supporting documents, in the embodiments of this application, there was harmonic interference before the implementation of the embodiments of this application, and the harmonic interference disappeared after the implementation of the embodiments of this application.
[0069] Secondly, a smart door lock includes the ultrasonic sensing circuit of the smart door lock of the first aspect.
[0070] The present invention relates to an ultrasonic sensing circuit and a smart door lock. By setting an interference absorption module 300 to absorb harmonic interference and spike interference, the ultrasonic sensing module 100 can increase the human body sensing distance, improve the user experience, and help solve the problem of excessively short sensing distance in existing smart door locks using ultrasonic technology.
[0071] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.
Claims
1. An ultrasonic sensing circuit for a smart door lock, characterized in that, include: Ultrasonic sensing module; MCU; Interference absorption module; The interference absorption module is electrically connected to the ultrasonic sensing module; The ultrasonic sensing module is communicatively connected to the MCU and is used to sense human body signal data and transmit the human body signal data to the MCU. The interference absorption module is used to absorb interference when the ultrasonic sensing module performs human body sensing.
2. The ultrasonic sensing circuit of the smart door lock according to claim 1, characterized in that, The ultrasonic sensing module includes: Ultrasonic sensing chip; The ultrasonic sensing chip includes a first power supply pin. The input terminal of the interference absorption module is electrically connected to the first power input circuit and the second power input circuit, and the output terminal of the interference absorption module is electrically connected to the first power pin.
3. The ultrasonic sensing circuit of the smart door lock according to claim 2, characterized in that, The interference absorption module includes: Frequency doubling interference absorption capacitor and spike interference absorption resistor; The first end of the spike interference absorption resistor is electrically connected to the first power input circuit, the second end of the spike interference absorption resistor is electrically connected to the second power input circuit and the first end of the frequency doubling interference absorption capacitor, and the second end of the frequency doubling interference absorption capacitor is grounded.
4. The ultrasonic sensing circuit of the smart door lock according to claim 3, characterized in that, The capacitance of the frequency doubling interference absorption capacitor is in the range of 40-50 uF, and the resistance of the spike interference absorption resistor is in the range of 0-3Ω.
5. The ultrasonic sensing circuit of the smart door lock according to any one of claims 2-4, characterized in that, The ultrasonic sensing circuit also includes: First filtering module; The first filtering module is electrically connected to the first power supply pin, the interference absorption circuit, and the second power input circuit.
6. The ultrasonic sensing circuit of the smart door lock according to any one of claims 1-4, characterized in that, The MCU communicates with the ultrasonic sensing module via an SPI module; The SPI module includes: MOSI and MISO data cables; The MOSI data line and MISO data line are used to connect the MCU and the ultrasonic sensing module, respectively.
7. The ultrasonic sensing circuit of the smart door lock according to claim 6, characterized in that, The ultrasonic sensing circuit also includes: Second filtering module; The second filter is electrically connected to the MOSI data line and the MISO data line, respectively.
8. The ultrasonic sensing circuit of the smart door lock according to claim 5, characterized in that, The first filtering module includes: First filter capacitor and second filter capacitor; The first terminal of the first filter capacitor and the second filter capacitor are electrically connected to the first power supply pin, the interference absorption circuit and the second power supply input circuit, and the second terminal of the first filter capacitor and the second filter capacitor are respectively grounded.
9. The ultrasonic sensing circuit of the smart door lock according to claim 7, characterized in that, The second filtering module includes: The third and fourth filter capacitors; The first terminals of the third and fourth filter capacitors are electrically connected to the MOSI data line and the MISO data line, respectively, and the second terminals of the third and fourth filter capacitors are grounded.
10. A smart door lock, characterized in that, The ultrasonic sensing circuit of the smart door lock as described in any one of claims 1-9 is included.