A device for sensing a knock on an induction household appliance

Abstract

The utility model discloses a device of response home appliance knock, aims at solving the problem of piezoelectric ceramic sensor sensitivity being affected by installation, signal processing being complex and capacitive touch sensor being limited by shell material in the existing home appliance knock detection scheme. The device includes main control module, accelerometer module, level conversion module and power module. The main control module adopts microcontroller, the power module provides stable voltage through voltage stabilizing chip, and supplies power for the core module, the level conversion module realizes the bidirectional conversion of main control serial port 3.3V and 5V signal, and guarantees the stable communication. After the main control module is powered on, it enters the cycle waiting interruption. After detecting the knock interruption, the timer is started, if detecting the interruption again in the timer window, it is judged as double-click event, otherwise, it is judged as single-click event, and finally the event result is output through the serial port after level conversion. The device reduces the development cost of software and hardware by means of the knock detection function of accelerometer hardware.

Description

Technical Field

[0001] This utility model relates to the field of home appliances, specifically to a device for sensing the impact of home appliances. Background Technology

[0002] In the current home appliance industry, to achieve the function of controlling home appliances through tapping, existing tapping detection modules mostly adopt two technical solutions: piezoelectric ceramic sensors or capacitive touch sensors.

[0003] Piezoelectric ceramic sensors operate based on the piezoelectric effect, where specific materials generate an electric charge when subjected to mechanical stress and deform when an electric field is applied. This effect is used to sense and detect impacts on household appliances. However, the sensitivity of this solution is significantly affected by the installation method. The sensor needs to be tightly attached to the surface of the appliance being struck; improper installation can lead to a significant attenuation of the impact signal, directly affecting detection accuracy. Furthermore, the signal processing of this solution is relatively complex, requiring additional signal amplification circuitry and filtering algorithms to effectively distinguish between valid impact signals and environmental interference. This not only increases the complexity of the hardware circuitry but also raises the difficulty of software development and the overall cost.

[0004] Capacitive touch sensors detect impacts by measuring changes in capacitance between sensor electrodes. This approach is only suitable for appliances with conductive surfaces and cannot detect impacts on non-conductive appliance casings, significantly limiting its application. Furthermore, this method is susceptible to environmental interference; changes in humidity and temperature can cause abnormal fluctuations in sensor capacitance, leading to false triggers, reduced reliability, and difficulty in meeting stable detection requirements under varying usage environments.

[0005] In summary, existing mainstream home appliance impact detection solutions are insufficient to meet the practical application requirements of impact control modules in the home appliance industry, necessitating a new technical solution to address these issues. Utility Model Content

[0006] To address the aforementioned problems in the prior art, this utility model proposes a device for sensing tapping of household appliances, comprising a main control module, an accelerometer module, a level conversion module, and a power supply module; the power supply module is electrically connected to the main control module and the accelerometer module, providing a stable voltage to the main control module and the accelerometer module; the accelerometer module is communicatively connected to the main control module, and the interrupt pin of the accelerometer module is connected to the interrupt receiving pin of the main control module for sending a tapping interrupt signal to the main control module; the level conversion module is connected to the serial port of the main control module for realizing bidirectional level conversion of the serial port signal of the main control module.

[0007] Preferably, the accelerometer module includes an accelerometer chip, which is a three-axis linear accelerometer chip and has a built-in high-pass filter for filtering environmental vibration interference signals; the accelerometer module communicates with the main control module through an SPI interface, with its INT1 pin connected to the PA0 pin of the main control module and its INT2 pin connected to the PA1 pin of the main control module.

[0008] Preferably, the main control module includes an STM32C0 microcontroller.

[0009] Preferably, the accelerometer chip is a LIS2DW12 chip.

[0010] Preferably, the level conversion module includes a bidirectional conversion circuit built with a MOSFET; when the main control module's serial port outputs a high level, the MOSFET is turned off, and the external signal terminal is pulled up to a high level by a resistor; when the main control module's serial port outputs a low level, the MOSFET is turned on, and the external signal terminal is pulled down to a low level; during reverse transmission, the signal is turned on through the body diode of the MOSFET.

[0011] Preferably, the power supply module includes an L78L voltage regulator chip for converting externally input voltage into a stable voltage; the power supply module also includes a capacitor in the circuit for filtering out power supply noise.

[0012] This utility model has the following beneficial effects:

[0013] (1) The device adopts the hardware knock detection function built into the accelerometer chip, which can realize knock recognition without relying on complex software filtering algorithms and signal amplification circuits. This reduces the workload of algorithm design and debugging in the software development process, simplifies the hardware circuit structure, avoids the use of additional amplification and filtering components, reduces the overall development cost from both hardware and software aspects, and is more in line with the actual needs of cost control in the home appliance field.

[0014] (2) The accelerometer module is equipped with a hardware high-pass filter, which can effectively filter out interference signals such as environmental vibrations and reduce the impact of invalid signals on the detection results. The main control module uses a timer window design to accurately distinguish between single-click and double-click events, further reducing the probability of false triggering.

[0015] (3) This device is not limited by the material of the appliance casing. It can effectively detect knocking on appliance casings made of conductive or non-conductive materials and is compatible with a variety of types of appliances. At the same time, the device is minimally affected by changes in ambient temperature and humidity, avoiding detection failure or false triggering caused by environmental factors. It can maintain stable performance in different usage scenarios and has stronger applicability.

[0016] In summary, the device of this utility model, while taking into account both high detection accuracy and wide applicability, achieves effective control of development costs and improved operational stability, and can better meet the actual application needs of the home appliance industry for tapping control modules. Attached Figure Description

[0017] Figure 1 This is a structural block diagram of an embodiment of the present utility model;

[0018] Figure 2 This is a circuit diagram of an embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram illustrating the working principle of an embodiment of this utility model. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] Example 1

[0022] The device in this embodiment that senses the tapping of home appliances is as follows: Figure 1 , Figure 2 As shown, it mainly consists of a main control module, an accelerometer module, a level conversion module, and a power supply module. These modules work together to achieve accurate identification and signal output of household appliance impact events.

[0023] The main control module uses an STM32C011F6P6 microcontroller, which features low power consumption and high integration, enabling it to efficiently process signals transmitted from the accelerometer and execute control logic. As the core of the entire device, the main control module is responsible for coordinating the working sequence of all modules, including key operations such as initialization configuration, interrupt response, timer management, and event judgment.

[0024] The accelerometer module uses the LIS2DW12 chip, an ultra-low-power triaxial linear accelerometer capable of sensing the mechanical vibrations generated when household appliances are struck, converting the vibrations into corresponding electrical signals of acceleration changes. The chip incorporates a high-pass filter, enabling the capture of basic striking signals without relying on complex additional software algorithms. It can filter out invalid signals such as environmental vibrations, minor shaking during appliance operation, and irrelevant external collisions, retaining only the high-frequency signal matching the striking action, reducing the probability of false detection. The accelerometer communicates with the main control module via an SPI interface, with its INT1 and INT2 pins connected to the PA0 and PA1 pins of the main control module, respectively, to send striking interrupt signals. The high-pass filter's configuration parameters can be adjusted according to the actual application scenario, effectively filtering out interference signals such as environmental vibrations and improving the accuracy of striking detection.

[0025] The level conversion module uses a bidirectional conversion circuit built with MOSFETs to convert the main control serial port output signal from 3.3V to 5V. When SDA1 outputs a high level, the MOSFET is off, and SDA2 is pulled up to 5V by a resistor; when SDA1 outputs a low level, the MOSFET is on, and SDA2 is pulled low. In reverse transmission, the signal is turned on through the body diode of the MOSFET, ensuring the communication stability between the main control and the external home appliance control system and adapting to the level requirements of different home appliances.

[0026] The power supply module uses an L78L33ABUTR voltage regulator chip to convert the externally input 5V voltage into a stable 3.3V voltage to power the main control module and the accelerometer module. A 4.7uF and a 0.1uF capacitor are configured in the power supply circuit to filter out power supply noise, ensure power supply stability, and prevent voltage fluctuations from affecting the device's detection accuracy.

[0027] The working process of the device is as follows Figure 3 As shown, the process is explained below: After power-on, the main control module first initializes the accelerometer, setting its output data rate and high-pass filter parameters. Then, it enables the hardware impact detection function and configures the interrupt trigger conditions. After initialization, the main control module enters the main loop, waiting for an impact interrupt signal from the accelerometer.

[0028] When a tapping interruption is detected, the main control module immediately starts a timer and sets a time window. If another tapping interruption is detected during the timer's operation, it is determined to be a double-click event; if no second interruption is detected after the timer ends, it is determined to be a single-click event. After the event determination is completed, the main control module outputs the event result to the main control system of the home appliance via a serial port with level conversion, enabling corresponding operation control of the home appliance.

[0029] The device in this embodiment, through hardware integration and simple control logic, effectively reduces software and hardware development costs while ensuring a tap recognition accuracy rate of over 90%. It is also unaffected by the material of the appliance casing and the ambient temperature and humidity, making it compatible with various types of home appliances.

[0030] It should be noted that the functions described in this embodiment require the cooperation of software and other related programs to be fully realized; the aforementioned software and other related programs are not the technical solutions claimed by this utility model and are not within the protection scope of this utility model.

[0031] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A device for sensing the impact of household appliances, characterized in that, It includes a main control module, an accelerometer module, a level conversion module, and a power supply module. The power supply module is electrically connected to the main control module and the accelerometer module, providing a stable voltage to them. The accelerometer module is communicatively connected to the main control module, and its interrupt pin is connected to the interrupt receive pin of the main control module to send a knock interrupt signal to the main control module. The level conversion module is connected to the serial port of the main control module to realize bidirectional level conversion of the serial port signals of the main control module.

2. The device for sensing the tapping of household appliances according to claim 1, characterized in that, The accelerometer module includes an accelerometer chip, which is a three-axis linear accelerometer chip and has a built-in high-pass filter for filtering environmental vibration interference signals. The accelerometer module communicates with the main control module through an SPI interface, with its INT1 pin connected to the PA0 pin of the main control module and its INT2 pin connected to the PA1 pin of the main control module.

3. The device for sensing the tapping of household appliances according to claim 1, characterized in that, The main control module includes an STM32C0 microcontroller.

4. The device for sensing the impact of household appliances according to claim 2, characterized in that, The accelerometer chip is a LIS2DW12 chip.

5. The device for sensing the tapping of household appliances according to claim 1, characterized in that, The level conversion module includes a bidirectional conversion circuit built with a MOSFET; when the main control module's serial port outputs a high level, the MOSFET is turned off, and the external signal terminal is pulled up to a high level by a resistor; when the main control module's serial port outputs a low level, the MOSFET is turned on, and the external signal terminal is pulled down to a low level; during reverse transmission, the signal is turned on through the body diode of the MOSFET.

6. The device for sensing the tapping of household appliances according to claim 1, characterized in that, The power supply module includes an L78L voltage regulator chip for converting externally input voltage into a stable voltage; the power supply module also includes capacitors in the circuit for filtering out power supply noise.

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