Water meter

Abstract

The invention discloses a water meter which comprises a metering module used for detecting water flow and outputting a corresponding flow electric signal; the water flow calculation module is connected with the metering module and is used for receiving the flow electric signal and calculating to obtain water flow data; the voltage sampling circuit is used for monitoring the voltage of the power supply battery in real time; the display module is connected with the water flow calculation module and is used for displaying the base water quantity calculated by the water flow calculation module; the low-power-consumption switching circuit is respectively connected with the voltage sampling circuit and the display module; when the voltage sampling circuit detects that the battery voltage is lower than a preset threshold value, the water meter is controlled to enter a low-power-consumption mode, power supply to the unnecessary functional circuit is cut off or reduced, and meanwhile power supply to the display module is maintained so that the display module can be driven to accurately display the current water volume base number. The water meter solves the problem of display error or metering interruption caused by insufficient voltage of a traditional water meter.

Description

Technical Field

[0001] This invention relates to the field of water flow detection technology, and more specifically, to a water meter. Background Technology

[0002] Existing ultrasonic water meters typically use non-replaceable batteries as their power source. Due to the limited lifespan of these batteries, when the battery power drops to a certain level, the voltage becomes insufficient to support the meter's normal measurement and display functions, and the battery cannot be replaced to maintain operation. In this situation, traditional electronic water meters cannot display accurate water flow data. Therefore, it is necessary to solve the problem of how water meters can accurately display water volume data when the battery voltage is insufficient.

[0003] To address these issues, existing technologies typically combine traditional mechanical water meters with electronic display modules. These meters use conventional mechanical gears and a rotating disc to measure water flow. After mechanical measurement, the water flow is converted into a digital signal by the electronic module for display. The advantages of this type of water meter are its simple structure and low maintenance costs. However, its disadvantages include the fact that the mechanical parts rely on high voltage to drive the electronic display, which may prevent accurate water flow readings at low voltages; additionally, the mechanical components wear down over time, affecting measurement accuracy.

[0004] In summary, the inability of water meters to guarantee normal readings when they are out of power is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a water meter that can solve the problem of display errors or metering interruptions caused by insufficient voltage in traditional water meters in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A water meter, the water meter comprising:

[0008] The metering module is used to detect water flow and output the corresponding flow rate electrical signal;

[0009] A water flow calculation module, connected to the metering module, is used to receive the flow electrical signal and calculate the water flow data;

[0010] Voltage sampling circuit, used to monitor the voltage of the power supply battery in real time;

[0011] The display module is connected to the water flow calculation module and is used to display the baseline water volume calculated by the water flow calculation module.

[0012] A low-power switching circuit is connected to both the voltage sampling circuit and the display module.

[0013] The low-power switching circuit is configured to: when the voltage sampling circuit detects that the battery voltage is lower than a preset threshold, control the water meter to enter a low-power mode and cut off or reduce the power supply to non-essential functional circuits, while maintaining the power supply to the display module to drive it to accurately display the current water level.

[0014] In some embodiments, the metering module is an ultrasonic metering module, which includes a piezoelectric ceramic transducer for transmitting and receiving ultrasonic signals. In some embodiments, there are at least two piezoelectric ceramic transducers; the at least two piezoelectric ceramic transducers are spaced apart along the direction of water flow.

[0015] In some embodiments, the water flow calculation module includes an impedance matching circuit, and the flow electrical signal output by the metering module is transmitted to the metering chip of the water flow calculation module after passing through the impedance matching circuit.

[0016] In some embodiments, the piezoelectric ceramic transducer includes a first piezoelectric ceramic and a second piezoelectric ceramic spaced apart; the impedance matching circuit includes:

[0017] A first impedance matching circuit is used to connect the first piezoelectric ceramic to the metering chip.

[0018] The second impedance matching circuit connects the second piezoelectric ceramic and the metering chip.

[0019] In some embodiments, the impedance matching circuit includes:

[0020] A matching circuit is provided, one end of which is connected to the input terminal of the metering chip, and the other end of which is connected to the output terminal of the metering chip; a matching resistor R1 and a matching capacitor C are connected in series in the matching circuit.

[0021] A connection circuit is provided, one end of which is connected to the piezoelectric ceramic transducer, and the other end of which is connected to the circuit between the matching resistor R1 and the matching capacitor C.

[0022] In some embodiments, the voltage sampling circuit includes a resistor divider sampling circuit, which includes a first sampling resistor R2 and a second sampling resistor R3 connected in series between the positive and negative terminals of the power supply battery, and the common connection point of the first sampling resistor R2 and the second sampling resistor R3 serves as the sampling voltage output terminal.

[0023] In some embodiments, the voltage sampling circuit is configured to reduce its detection frequency when it detects that the battery voltage is lower than a preset threshold. In some embodiments, the display module includes a character wheel display device, which includes:

[0024] A digital panel, which is rotatably configured to change the displayed water level.

[0025] An electromagnet control structure is provided, which is signal-connected to the water flow calculation module. By outputting an electrical signal to the electromagnet control structure, the electromagnet control structure is made to engage or disengage, thereby controlling the rotation of the digital disk.

[0026] In some embodiments, the electromagnet control structure includes:

[0027] The first electromagnet is signal-connected to the water flow calculation module.

[0028] A pawl mechanism is provided, which is connected to the first electromagnet and the character wheel shaft. When the first electromagnet is attracted, it drives the pawl mechanism to release the character wheel shaft. When the first electromagnet is released, the pawl mechanism resets, thereby pushing the character wheel shaft to rotate by a step angle.

[0029] The second electromagnet is connected to the water flow calculation module; when the pawl mechanism is reset, the second electromagnet is attracted to ensure that the pawl mechanism is reset accurately. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0031] Figure 1 A schematic diagram of the metering module of the water meter according to the present invention is shown;

[0032] Figure 2 A top view of the metering module of the water meter of the present invention is shown;

[0033] Figure 3 A schematic diagram of the impedance matching circuit of the water meter of the present invention is shown;

[0034] Figure 4 A schematic diagram of the voltage sampling circuit of the water meter of the present invention is shown;

[0035] Figure 5 A schematic diagram of the piezoelectric ceramic transducer of the water meter of the present invention is shown.

[0036] Figures 1-5 middle:

[0037] 1. First piezoelectric ceramic; 2. Second piezoelectric ceramic; 3. First impedance matching circuit; 4. Second impedance matching circuit; 5. Matching loop; 6. Connection circuit; 7. Voltage sampling circuit;

[0038] 1-1. Vibration source piezoelectric ceramic; 1-2. Piezoelectric ceramic limiting step; 1-3. Adhesive; 1-4. Matching layer; 1-6. Electrical signal transmission line. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0040] The core of this invention is to provide a water meter.

[0041] Despite significant progress in existing technologies for electronic water meters and ultrasonic metering, several major drawbacks remain:

[0042] Low-voltage reading display and measurement issues: Existing ultrasonic electronic water meters typically rely on battery power. When the battery charge decreases, the display of some water meters will be affected. If the battery voltage is unstable, the display results of ultrasonic water meters may be inaccurate, while mechanical water meters may result in inaccurate measurements. Therefore, under low-power conditions, disputes may arise between users and water companies due to reading discrepancies.

[0043] Errors caused by wear and tear of mechanical parts: Although some water meters combine mechanical metering systems with electronic display modules, these meters are still affected by wear and tear of mechanical parts. Over time, components such as mechanical gears and turntables may wear out or jam, leading to errors in the metering results and affecting metering accuracy.

[0044] Poor battery replaceability: To ensure the dustproof and waterproof requirements of the structure, most ultrasonic water meters usually do not have replaceable batteries or require disassembly of complex outer shells or mechanical parts, which increases the difficulty and time cost of maintenance.

[0045] See Figures 1 to 5The water meter in this embodiment includes: a metering module for detecting water flow and outputting a corresponding flow rate electrical signal; a water flow rate calculation module connected to the metering module for receiving the flow rate electrical signal and calculating water flow rate data; a voltage sampling circuit for real-time monitoring of the voltage of the power supply battery; a display module connected to the water flow rate calculation module for displaying the water volume calculated by the water flow rate calculation module; and a low-power switching circuit connected to both the voltage sampling circuit and the display module. The low-power switching circuit is configured to: when the voltage sampling circuit detects that the battery voltage is lower than a preset threshold, control the water meter to enter a low-power mode and cut off or reduce the power supply to non-essential functional circuits, while maintaining the power supply to the display module to drive it to accurately display the current water volume.

[0046] By employing the above configuration, and through the coordination of the low-power switching circuit and the voltage sampling circuit, when the battery voltage is detected to be lower than a preset threshold, the system automatically enters a low-power mode, cutting off or reducing power supply to non-essential functional circuits (such as the background communication module) while maintaining power supply to the display module. This ensures that the water meter can still accurately display the water level even when the battery is low, avoiding display errors or metering interruptions caused by insufficient voltage in traditional water meters.

[0047] In the water meter of this embodiment, see Figure 5 The metering module is an ultrasonic metering module, which includes a piezoelectric ceramic transducer for transmitting and receiving ultrasonic signals.

[0048] Ultrasonic metering technology avoids the use of mechanical parts, fundamentally eliminating metering errors caused by mechanical wear and improving the long-term accuracy and reliability of water meters. Piezoelectric ceramic transducers detect water flow through sound waves, reducing reliance on traditional mechanical gears. (Reference) Figure 1 and Figure 2 , Figure 1 The installation location of the piezoelectric ceramic transducer in the water meter is shown, while Figure 2 The top view further illustrates the transducer layout, ensuring the stability of signal transmission.

[0049] See Figure 2 In the water meter of this embodiment, there are at least two piezoelectric ceramic transducers; the at least two piezoelectric ceramic transducers are distributed at intervals along the direction of water flow.

[0050] By employing the above configuration and through the coordinated operation of multiple transducers, the detection accuracy and anti-interference capability of ultrasonic signals are enhanced, and measurement errors caused by water flow fluctuations or pipeline noise are reduced. The spaced distribution design optimizes the signal reflection path and improves data reliability.

[0051] See Figure 3 In the water meter of this embodiment, the water flow calculation module includes an impedance matching circuit, and the flow electrical signal output by the metering module is transmitted to the metering chip of the water flow calculation module after passing through the impedance matching circuit.

[0052] Through the above configuration, the impedance matching circuit optimizes signal transmission between the piezoelectric ceramic transducer and the metering chip, reducing signal reflection and energy loss, thereby improving the accuracy of water flow calculation. This solves the signal distortion problem caused by impedance mismatch in traditional circuits. (Refer to...) Figure 3 This demonstrates the structure of an impedance matching circuit, where the matching loop and connection circuit ensure efficient signal transmission.

[0053] Specifically, when the low-power switching circuit issues an interrupt signal, it provides a level to allow the system to enter low-power mode. This mode has fewer functions than the normal state, including LCD display, reduced NB reporting frequency, and changed sampling frequency.

[0054] In the water meter of this embodiment, see Figure 3 The piezoelectric ceramic transducer includes a first piezoelectric ceramic 1 and a second piezoelectric ceramic 2 arranged at intervals; the impedance matching circuit includes: a first impedance matching circuit 3, through which the first piezoelectric ceramic 1 and the metering chip are connected; and a second impedance matching circuit 4, through which the second piezoelectric ceramic 2 and the metering chip are connected.

[0055] With the above setup, this discrete design allows for independent impedance optimization for each transducer, avoiding signal crosstalk and further improving metering accuracy. (Refer to...) Figure 3 The figure shows the connection of the first impedance matching circuit 3 and the second impedance matching circuit 4, which ensures the independent processing of each piezoelectric ceramic signal.

[0056] See Figure 3 In the water meter of this embodiment, the impedance matching circuit includes: a matching loop 5, one end of which is connected to the input terminal of the metering chip, and the other end of which is connected to the output terminal of the metering chip; a matching resistor R1 and a matching capacitor C are connected in series on the matching loop 5; and a connection circuit 6, one end of which is connected to the piezoelectric ceramic transducer, and the other end of which is connected to the circuit between the matching resistor R1 and the matching capacitor C.

[0057] The above structure, through series matching resistors and capacitors, achieves more flexible impedance adjustment, adapting to piezoelectric ceramic transducers of different specifications, and enhancing the circuit's versatility and reliability. (Refer to...) Figure 3The design of matching circuit 5 and connecting circuit 6 simplifies the circuit layout and reduces production costs.

[0058] In the water meter of this embodiment, see Figure 4 The voltage sampling circuit includes a resistor divider sampling circuit, which includes a first sampling resistor R2 and a second sampling resistor R3 connected in series between the positive and negative terminals of the power supply battery. The common connection point of the first sampling resistor R2 and the second sampling resistor R3 serves as the sampling voltage output terminal.

[0059] The above setup results in a simple and low-cost circuit that reliably monitors battery voltage in real time and provides accurate sampling values ​​through voltage divider principles, thus providing a basis for low-power switching decisions. (Refer to...) Figure 4 , Figure 4 The series voltage divider structure of the first sampling resistor R2 and the second sampling resistor R3 is shown. The sampling voltage is output at the common connection point, which ensures the stability of the monitoring.

[0060] Specifically, in this embodiment, the ratio of the first sampling resistor R2 to the second sampling resistor R3 is 3:1.

[0061] In the water meter of this embodiment, the voltage sampling circuit is configured to reduce the detection frequency of the voltage sampling circuit when the voltage sampling circuit detects that the battery voltage is lower than a preset threshold.

[0062] By reducing the frequency of voltage detection, the circuit's power consumption is lowered, extending battery life in a low-charge state while still ensuring voltage monitoring at critical points. This achieves low-power optimization. (See reference) Figure 4 This circuit can dynamically adjust the detection frequency by controlling the MCU.

[0063] In the water meter of this embodiment, the display module includes a digit display device, which includes: a digital disk rotatably configured to change the displayed water volume baseline; and an electromagnet control structure signal-connected to the water flow calculation module. By outputting an electrical signal to the electromagnet control structure, the electromagnet control structure is engaged or disengaged, thereby controlling the rotation of the digital disk.

[0064] The digital display uses a mechanical digital disc, which is low in power consumption and highly reliable. Even when the battery is low, it can still accurately update the water level using electromagnet control, avoiding the display malfunctions of electronic displays under low voltage. The electromagnet control structure ensures the precise rotation of the digital disc.

[0065] In this embodiment of the water meter, the electromagnet control structure includes: a first electromagnet, which is signal-connected to the water flow calculation module; a pawl mechanism, which is connected to the first electromagnet and to the digit wheel shaft; when the first electromagnet is engaged, it drives the pawl mechanism to release the digit wheel shaft; when the first electromagnet is released, the pawl mechanism resets, thereby pushing the digit wheel shaft to rotate by a step angle; and a second electromagnet, which is signal-connected to the water flow calculation module; when the pawl mechanism resets, the second electromagnet is engaged to ensure accurate reset of the pawl mechanism.

[0066] By employing the above configuration, a step-by-step rotation and locking of the digital disk is achieved through a combination of dual electromagnets and a ratchet mechanism, ensuring the accuracy and stability of the displayed data. The second electromagnet plays an auxiliary positioning role during the reset process, preventing carry errors.

[0067] Example 1

[0068] The ultrasonic electronic water meter of this embodiment employs ultrasonic metering technology, a low-power switching circuit, a digital display with feedback, and a convenient battery replacement design. All units work closely together to ensure accurate metering even under low-voltage conditions, while also facilitating battery replacement.

[0069] Example 2

[0070] The ultrasonic metering electronic water meter of this embodiment includes an ultrasonic metering module: this module mainly consists of an ultrasonic transducer, used to detect the water flow through the water meter. The ultrasonic transducer transmits and receives ultrasonic signals and converts them into electrical signal data, which is then transmitted to the metering chip. After this data is processed by the computing unit, including the metering chip, an accurate water flow measurement result is obtained.

[0071] The ultrasonic metrology section uses a piezoelectric ceramic transducer. To avoid mechanical loss and enhance stability, an integrated metrology design is adopted. The overall design is shown below. Figure 1 , Figure 2 :

[0072] The piezoelectric ceramics (first piezoelectric ceramic 1 and second piezoelectric ceramic 2) are connected to the pipe wall by a special adhesive. Similar to the vibration of a crystal oscillator, they emit ultrasonic signals, which are reflected by the support inside the pipe and reach the other end to obtain a basic metering signal. For details, see [link to specific structure]. Figure 5 :

[0073] Among them, 1-1 is the piezoelectric ceramic vibration source, which provides the signal; 1-2 is the piezoelectric ceramic limiting step, which ensures the reserved position for the adhesive; 1-3 is the adhesive; 1-4 is the matching layer, which is a PPM pipe of a special thickness calculated according to acoustic principles; 1-6 is the electrical signal transmission line. All of the above parts are combined to form the ultrasonic metering module.

[0074] Example 3

[0075] The ultrasonic metering electronic water meter in this embodiment includes a water flow calculation module, which is responsible for receiving and processing data from the ultrasonic metering module. The receiving circuit first performs an impedance matching circuit calculated based on the parameters of the piezoelectric ceramic and the metering chip, such as... Figure 3 The electrical signal passes through an impedance matching circuit and enters the metering chip, where a predetermined algorithm calculates the water flow rate and converts it into a digital display signal for use by subsequent display modules.

[0076] The calculation module also includes a voltage metering circuit for monitoring the voltage status of the water meter battery, such as... Figure 4 The switch is controlled by controlling the output state of the CTR pin, and sampling is performed using a 3:1 voltage divider.

[0077] Example 4

[0078] The ultrasonic metering electronic water meter of this embodiment includes a digital display module: the digital display module displays the metering results by rotating the digital disk.

[0079] The digit counting machine adopts a traditional dual-electromagnet control structure. Its signal comes from the high and low levels output from the GPIO port after the chip processes the metering signal. The signal processed by the algorithm and its carry logic work together to ensure the accuracy of the mechanical counting part. The working process of the digit counting machine from the current digit N to the digit N+1 is as follows:

[0080] Initial state: The control line is in the (0, 0) state, the number wheel is locked, and the number N is displayed.

[0081] Release the character wheel shaft: The main control chip switches the control line output to the (1, 0) state. The first electromagnet (S1) engages, and the pawl mechanism releases the character wheel shaft.

[0082] Carry-in drive: The main control chip switches the control line output to the (0, 1) state. The first electromagnet (S1) is released, and the pawl mechanism pushes the character wheel shaft to rotate by one step angle during the reset process; at the same time, the second electromagnet (S2) is attracted, but its action sequence is designed to coordinate with the pawl's return or only play an auxiliary positioning role to ensure accurate carry-in.

[0083] Re-locking: After the carry operation is completed, the main control chip restores the control line output to the (0, 0) state. All electromagnets are de-energized, and the digit wheel shaft is re-locked at the new digit position (N+1), resulting in stable display.

[0084] For multi-digit digit wheels (such as ones, tens, and hundreds digits), the main control chip executes the above carry process cyclically and controls the transmission of carry signals (for example, when the ones digit returns from 9 to 0, a carry pulse signal is sent to the tens digit), thereby realizing continuous carry and display of all digits.

[0085] Example 5

[0086] The ultrasonic electronic water meter in this embodiment includes a low-power switching circuit, which ensures stable operation of the water meter even under low voltage conditions. When the battery voltage drops to a set threshold, the circuit activates a low-voltage protection mechanism, adjusting the water meter's operating mode to extend its lifespan. This is primarily achieved through the aforementioned voltage sampling circuit and the main control MCU. When the voltage sampled by the sampling circuit is lower than the set value, the chip sends an interrupt signal to enter low-power mode and notifies the user to replace the battery via a low-voltage symbol displayed on the screen. Simultaneously, in this state, only the digit display is shown, further increasing power supply lifespan while ensuring normal digit display under low power conditions.

[0087] Example 6

[0088] The ultrasonic electronic water meter of this embodiment includes a battery and a battery replacement module: the water meter is powered by a replaceable battery, and the user can easily replace the battery using the battery replacement module. The battery replacement module is simple in design and can be operated by the user without tools. Furthermore, the water meter will issue a prompt to replace the battery when the battery power is low.

[0089] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0090] This solution ensures that the water meter can still accurately display metering data even under low voltage: through low-power design and digital feedback control system, it can ensure that the water meter can still accurately display metering data through low-power LCD or digital display even when the battery power is low, thus solving the problem of inaccurate display in traditional water meters when the battery power is insufficient.

[0091] This water meter solution eliminates the problem of mechanical wear: it adopts ultrasonic metering technology and a digit feedback display system, completely avoiding the wear and tear issues of mechanical parts in traditional water meters. The metering accuracy is unaffected by mechanical wear and maintains stable performance and accuracy even after long-term use.

[0092] This solution simplifies the battery replacement process for water meters: the side-mounted replaceable battery module offers a longer service life and higher reliability compared to traditional ultrasonic water meters with non-replaceable batteries.

[0093] In addition, it should be noted that the orientation or positional relationship indicated by "horizontal", "vertical", etc. in this application is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the purpose of simplifying the description and making it easier to understand, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0094] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. Any combination of all embodiments provided by this invention is within the scope of protection of this invention and will not be elaborated upon here.

[0095] The water meter provided by this invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this invention.

Claims

1. A water meter, characterized in that, The water meter includes: The metering module is used to detect water flow and output the corresponding flow rate electrical signal; A water flow calculation module, connected to the metering module, is used to receive the flow electrical signal and calculate the water flow data; Voltage sampling circuit, used to monitor the voltage of the power supply battery in real time; The display module is connected to the water flow calculation module and is used to display the baseline water volume calculated by the water flow calculation module. A low-power switching circuit is connected to both the voltage sampling circuit and the display module. The low-power switching circuit is configured to: when the voltage sampling circuit detects that the battery voltage is lower than a preset threshold, control the water meter to enter a low-power mode, maintain the power supply to the display module, and cut off or reduce the power supply to circuits other than the display module, so as to drive the water meter to accurately display the current water level.

2. The water meter as described in claim 1, characterized in that, The metering module is an ultrasonic metering module, which includes a piezoelectric ceramic transducer for transmitting and receiving ultrasonic signals.

3. The water meter as described in claim 2, characterized in that, The piezoelectric ceramic transducer comprises at least two; the at least two piezoelectric ceramic transducers are distributed at intervals along the direction of water flow.

4. The water meter as described in claim 2, characterized in that, The water flow calculation module includes an impedance matching circuit, and the flow electrical signal output by the metering module is transmitted to the metering chip of the water flow calculation module after passing through the impedance matching circuit.

5. The water meter as described in claim 4, characterized in that, The piezoelectric ceramic transducer includes a first piezoelectric ceramic (1) and a second piezoelectric ceramic (2) arranged at intervals; the impedance matching circuit includes: The first impedance matching circuit (3) is used to connect the first piezoelectric ceramic (1) to the metering chip. The second impedance matching circuit (4) connects the second piezoelectric ceramic (2) and the metering chip.

6. The water meter as described in claim 4, characterized in that, The impedance matching circuit includes: Matching circuit (5), one end of the matching circuit (5) is connected to the input terminal of the metering chip, and the other end of the matching circuit (5) is connected to the output terminal of the metering chip; a matching resistor R1 and a matching capacitor C are connected in series on the matching circuit (5); A connection circuit (6) is provided, one end of which is connected to the piezoelectric ceramic transducer, and the other end of which is connected to the circuit between the matching resistor R1 and the matching capacitor C.

7. The water meter as described in claim 4, characterized in that, The voltage sampling circuit includes a resistor divider sampling circuit, which includes a first sampling resistor R2 and a second sampling resistor R3 connected in series between the positive and negative terminals of the power supply battery. The common connection point of the first sampling resistor R2 and the second sampling resistor R3 serves as the sampling voltage output terminal.

8. The water meter as described in claim 1, characterized in that, The voltage sampling circuit is configured to reduce its detection frequency when it detects that the battery voltage is lower than a preset threshold.

9. The water meter as described in claim 1, characterized in that, The display module includes a character wheel display device, and the character wheel display device includes: A digital panel, which is rotatably configured to change the displayed water level. An electromagnet control structure is provided, which is signal-connected to the water flow calculation module. By outputting an electrical signal to the electromagnet control structure, the electromagnet control structure is made to engage or disengage, thereby controlling the rotation of the digital disk.

10. The water meter as described in claim 9, characterized in that, The electromagnet control structure includes: The first electromagnet is signal-connected to the water flow calculation module. A pawl mechanism is provided, which is connected to the first electromagnet and the character wheel shaft. When the first electromagnet is attracted, it drives the pawl mechanism to release the character wheel shaft. When the first electromagnet is released, the pawl mechanism resets, thereby pushing the character wheel shaft to rotate by a step angle. The second electromagnet is connected to the water flow calculation module; when the pawl mechanism is reset, the second electromagnet is attracted to ensure that the pawl mechanism is reset accurately.

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