Household appliance water shortage detection circuit, household appliance and water shortage detection method

Abstract

The invention particularly relates to a household appliance water shortage detection circuit, a household appliance and a water shortage detection method, and the circuit comprises an electrode sensor circuit which is composed of a first electrode E1 and a second electrode E2 which are insulated from each other, and is used for collecting a first AD turn-off value and a second AD turn-on value; the MCU chip is used for being connected to the electrode sensor module and used for calculating the difference value between the first AD turn-off value and the second AD turn-on value, comparing the difference value with a preset threshold value and outputting a water shortage state signal according to a comparison result; and the water pump control circuit is connected with the MCU chip and controls the working state of the water pump M1 according to the electric signal output by the MCU chip. Compared with a traditional detection scheme, the circuit has the advantages that the cost is reduced and the structure is extremely simple; besides, difference judgment between water outlet detection and non-water outlet detection is more reliable than fixed AD value judgment, and the fixed value judgment may cause misjudgment due to different water quality AD values, so that the detection stability can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of water dispensers or ice makers, in particular to a household appliance water shortage detection circuit, a household appliance and a water shortage detection method. Background Art

[0002] As global technology continues to advance and innovate at an unprecedented speed, the importance of water shortage detection technology in the field of household appliances has become increasingly prominent and has been widely studied and applied by academia and industry. From traditional water dispensers or ice makers, water shortage detection functions are key factors in ensuring the normal operation of equipment, extending service life, and ensuring user safety and convenience.

[0003] At present, there are many water shortage detection technologies on the market. These technologies have met the needs of some household appliances to a certain extent, but there are still many problems to be solved in terms of cost and stability. For example, although some high-end optical detection technologies can provide relatively accurate detection results, they require the use of high-precision optical components and complex signal processing circuits, resulting in high costs, making the product expensive, limiting its promotion and application in the mid- and low-end household appliance market. Although the traditional electrode detection method has a relatively low cost, the electrode is immersed in water for a long time, which is easily affected by the corrosion and electrochemical effects of impurities and ions in the water, resulting in a reduction in electrode life, poor detection stability, frequent misjudgments or failures, which brings many inconveniences to users and affects the brand image and market competitiveness of household appliances. Specific problems of the existing technology: 1. Cost problem: In the existing water shortage detection technology, some technologies use expensive sensors, chips or special materials, which greatly increases the cost of the entire detection system. Taking the water shortage detection technology based on the ultrasonic detection principle as an example, the ultrasonic sensor itself is relatively expensive, and in order to ensure the accuracy of the detection, it is also necessary to be equipped with a high-precision signal processing module and a complex algorithm, which further increases the cost of the system. For some price-sensitive household appliances, the high detection cost makes the products lack price competitiveness in the market and difficult to popularize on a large scale. In addition, the second stability problem: the traditional detection method has obvious deficiencies in stability. In addition to the problem of short electrode life in the electrode detection method mentioned above, some detection methods based on mechanical principles are also easily affected by external environmental factors. For example, during the use of the float type water level detection device, the float may be stuck by impurities in the water, resulting in inaccurate detection results; and as the use time increases, the wear of mechanical parts will also affect the stability of the detection. In addition, some technologies that use capacitive detection principles are easily affected by factors such as ambient humidity and temperature, resulting in large fluctuations in the detection signal, affecting the accuracy and reliability of the detection. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the present invention is to provide a household appliance water shortage detection circuit, a household appliance and a household appliance water shortage detection method, which can provide a low-cost and high-stability detection solution to meet the fiercely competitive market demand for household appliances.

[0005] The household appliance water shortage detection circuit of the present invention includes the following.

[0006] The electrode sensor circuit is composed of a first electrode E1 and a second electrode E2 insulated from each other, and is used to collect a first AD closing value when the water pump M1 is closed and a second AD opening value when the water pump is opened.

[0007] The MCU chip is connected to the electrode sensor module to calculate the difference between the first AD closing value and the second AD opening value and compare it with a preset threshold value, and output a water shortage state signal according to the comparison result.

[0008] The water pump control circuit is connected to the MCU chip and controls the working state of the water pump M1 according to the electrical signal output by the MCU chip.

[0009] The device further comprises an alarm and a digital display tube, wherein the alarm and the digital display tube are respectively connected to the MCU chip.

[0010] Furthermore, the electrode sensor circuit is also provided with a first resistor R1, a second resistor R2, a first capacitor C1 and a +5V terminal. The first resistor R1 is connected to the first electrode E1, and the common terminal between the first resistor R1 and the first electrode E1 is respectively connected to the second resistor R2 and the first capacitor C1, the first capacitor C1 is connected to the second electrode E2, and the second resistor R2 is connected to the +5V terminal.

[0011] Furthermore, the AD detection circuit also includes a field effect tube Q1, a third resistor R3 and a fourth resistor R4, the water pump M1 is connected to the D pole of the field effect tube Q1, the G pole of the field effect tube Q1 is connected to the third resistor R3, the common end between the G pole of the field effect tube Q1 and the third resistor R3 is connected to one end of the fourth resistor R4, and the other end of the fourth resistor R4 is connected to the S pole of the field effect tube Q1.

[0012] Furthermore, one end of the water pump M1 is connected to a 12V terminal.

[0013] The present invention discloses a household appliance using the household appliance water shortage detection circuit, comprising a first water tank, a second water tank, a water pump M1, a delivery pipe and the household appliance water shortage detection circuit. The household appliance water shortage detection circuit is fixed to one side of the first water tank, the second water tank or the delivery pipe, two ends of the delivery pipe are respectively placed in the first water tank and the second water tank, and the water pump M1 is installed on the delivery pipe.

[0014] Furthermore, the first electrode E1 and the second electrode E2 on the electrode sensor circuit are made of food-grade stainless steel and are in contact with water only at the water outlet stage of the delivery pipe.

[0015] Furthermore, one end of the delivery pipe passes through the inner wall of the first water tank, and one end of the delivery pipe is connected to the inner wall of the first water tank via a sealing ring.

[0016] The present invention also discloses a water shortage detection method using the household appliance water shortage detection circuit, which comprises the following steps.

[0017] Step 1: Detection when the water pump is turned off: The water pump M1 is controlled to be turned off through the MCU chip. At this time, the electrode sensor circuit collects the first AD closing value, and the collected AD value needs to be filtered.

[0018] Detection when the water pump is turned on: After the MCU chip controls the water pump M1 to discharge water, the electrode sensor circuit collects the second AD turn-on value.

[0019] Step 2: Difference calculation: During the water discharge stage of the water pump M1, the difference between the first AD closing value and the second AD opening value is calculated by the MCU chip.

[0020] Water shortage judgment: Compare the calculated difference with the preset threshold.

[0021] Status feedback: When it is judged that there is a water shortage, the MCU chip outputs a water shortage status signal. The water pump control circuit controls the water pump M1 to stop working according to the signal. At the same time, the alarm connected to the MCU chip sounds an alarm, and the digital display tube shows the water shortage status, reminding the user to deal with it in time.

[0022] Furthermore, in step 2, if the difference is greater than the threshold, it is determined that there is water and the water pump is working normally; if the difference is lower than the threshold, it is determined that there is no water.

[0023] The beneficial effects of the present invention are as follows: compared with traditional detection schemes, the present circuit reduces costs and has an extremely simple structure; in addition, the present structure makes full use of the water-adding characteristics of household appliances to place the electrodes at the water outlet, which greatly reduces the proportion of the time of contact with water and increases the service life of the first electrode E1 and the second electrode E2; furthermore, the difference judgment between water outlet detection and no water outlet detection is more reliable than the fixed AD value judgment, which may be misjudged due to different AD values ​​of different water qualities, and can improve the detection stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments with reference to the following drawings.

[0025] Figure 1It is a circuit diagram of the present invention.

[0026] Figure 2 The invention discloses a connection diagram of an MCU chip, an alarm and a digital display tube.

[0027] Figure 3 It is a structural diagram of the present invention.

[0028] Figure 4 It is a flow chart of the detection process of the present invention. DETAILED DESCRIPTION

[0029] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0030] Reference below Figure 1 to Figure 2 A water shortage detection circuit for household appliances according to an embodiment of the present invention is described, including the following.

[0031] The electrode sensor circuit is composed of a first electrode E1 and a second electrode E2 insulated from each other, and is used to collect a first AD closing value when the water pump M1 is closed and a second AD opening value when the water pump is opened.

[0032] The MCU chip is connected to the electrode sensor module to calculate the difference between the first AD closing value and the second AD opening value and compare it with a preset threshold value, and output a water shortage state signal according to the comparison result.

[0033] The water pump control circuit is connected to the MCU chip and controls the working state of the water pump M1 according to the electrical signal output by the MCU chip.

[0034] Compared with traditional detection schemes, this circuit reduces costs and has an extremely simple structure. In addition, the difference judgment between water outflow detection and no water outflow detection is more reliable than fixed AD value judgment. Fixed value judgment may be misjudged due to different AD values ​​of different water qualities, which can improve detection stability.

[0035] This circuit also includes an alarm and a digital display tube, which are respectively connected to the MCU chip. The electrode sensor circuit described in this circuit is also provided with a first resistor R1, a second resistor R2, a first capacitor C1 and a +5V terminal, the first resistor R1 is connected to the first electrode E1, the common terminal between the first resistor R1 and the first electrode E1 is respectively connected to the second resistor R2 and the first capacitor C1, the first capacitor C1 is connected to the second electrode E2, and the second resistor R2 is connected to the +5V terminal. The AD detection circuit described in this circuit also includes a field effect tube Q1, a third resistor R3 and a fourth resistor R4, the water pump M1 is connected to the D pole of the field effect tube Q1, the G pole of the field effect tube Q1 is connected to the third resistor R3, the common terminal between the G pole of the field effect tube Q1 and the third resistor R3 is connected to one end of the fourth resistor R4, and the other end of the fourth resistor R4 is connected to the S pole of the field effect tube Q1. One end of the water pump M1 described in this circuit is connected to a 12V terminal.

[0036] This circuit is designed to detect the working status of the water pump M1, collect AD values ​​through the electrode sensor circuit, and combine the logic judgment of the MCU chip to realize the water pump control and water shortage detection and alarm. The following is its working principle and detailed description.

[0037] Working principle of electrode sensor circuit.

[0038] The electrode sensor circuit is composed of a first electrode E1 and a second electrode E2 which are insulated from each other, and collects AD values ​​by detecting the conductivity change in water. The specific process is as follows.

[0039] First AD closing value collection: When the water pump M1 is turned off, the electrode sensor circuit detects the water flow state (no water flow) and collects the first AD closing value.

[0040] Second AD opening value collection: When the water pump M1 is turned on, the electrode sensor circuit detects the water flow state and collects the second AD opening value.

[0041] Difference calculation: The MCU chip calculates the difference between the first AD off value and the second AD on value, and compares it with the preset threshold. The change in the difference reflects the change in the water flow state, avoiding the problem of misjudgment of fixed AD values ​​due to different water quality.

[0042] The electrode sensor circuit is also provided with a first resistor R1, a second resistor R2, a first capacitor C1 and a +5V terminal, which are used to stabilize the circuit operating voltage and improve the detection accuracy.

[0043] The MCU chip is the core control unit of the circuit. Its main functions include: Difference comparison: compare the calculated AD difference (second AD on value - first AD off value) with the preset threshold. Water shortage status judgment: if the difference is less than the preset threshold, it indicates that the water pump M1 may be in a water shortage state, and the MCU chip outputs a water shortage status signal. Control signal output: according to the judgment result, the MCU chip outputs the corresponding control signal to the water pump control circuit to adjust the working state of the water pump M1.

[0044] Working principle of the water pump control circuit: The water pump control circuit is connected to the MCU chip, and controls the opening or closing of the water pump M1 according to the output signal of the MCU chip. The specific process is as follows: Control of the field effect tube Q1: The G pole of the field effect tube Q1 is connected to the MCU chip through the third resistor R3 and the fourth resistor R4. When the MCU chip outputs a high-level signal, the field effect tube Q1 is turned on and the water pump M1 is turned on; when the MCU chip outputs a low-level signal, the field effect tube Q1 is turned off and the water pump M1 is turned off. In addition, 12V power supply: one end of the water pump M1 is connected to the 12V end to provide a stable working voltage.

[0045] Alarm and display function: This circuit also includes an alarm and a digital display tube, which are connected to the MCU chip respectively: Alarm: When the MCU chip detects a water shortage, it triggers the alarm to send an alarm signal to remind the user to deal with it in time. Digital display tube: Real-time display of the working status of the water pump M1 (such as normal, water shortage, etc.) for user monitoring.

[0046] like Figure 3 As shown, the present invention discloses a household appliance using the above-mentioned household appliance water shortage detection circuit, including a first water tank 1 and a second water tank 3, a water pump M1, a delivery pipe 2 and a household appliance water shortage detection circuit, the household appliance water shortage detection circuit is fixed to the first water tank 1, the second water tank 3 or one side of the delivery pipe 2, the two ends of the delivery pipe 2 are respectively placed in the first water tank 1 and the second water tank 3, and the water pump M1 is installed on the delivery pipe 2.

[0047] This structure makes full use of the water-adding characteristics of household appliances and places the electrodes at the water outlet, which greatly reduces the time of contact with water and increases the service life of the first electrode E1 and the second electrode E2. In addition, the first water tank 1 and the second water tank 3 are plastic water tanks or metal water tanks. The delivery pipe 2 is a plastic delivery pipe or a metal delivery pipe, which can be freely selected by the user.

[0048] The first electrode E1 and the second electrode E2 on the electrode sensor circuit of this structure are made of food-grade stainless steel and are in contact with water only at the water outlet stage of the delivery pipe 2. One end of the delivery pipe 2 of this structure passes through the inner wall of the first water tank 1, and one end of the delivery pipe 2 is connected to the inner wall of the first water tank 1 through a sealing ring.

[0049] The first electrode E1 is an M3 stainless steel screw with a diameter of 0.5 mm, and the second electrode E2 is formed into a three-ring ring structure by a spiral winding process. The spacing between the first electrode E1 and the second electrode E2 is designed to be 2 mm ± 0.1 mm, and the contact area ratio is 1:3, satisfying the linear response relationship of R = ρ·d / (S·k) (k = 0.95).

[0050] The resistance of the first resistor R1 in the water pump control circuit is 1MΩ, the resistance of the second resistor R2 is 470kΩ, and the capacity of the first capacitor C1 is 0.1μF. The first resistor R1, the second resistor R2 and the first capacitor C1 constitute a second-order low-pass filter, which converts the conductivity change of 0.1-10μS between the first electrode E1 and the second electrode E2 into a 0-5V measurable signal to eliminate high-frequency interference errors.

[0051] Dynamic difference algorithm: A dual sampling mechanism is used to obtain the reference value AD_off (theoretical value 4095) when the pump body M1 is closed, and the AD_on value is obtained when the pump body is working. The ambient temperature drift is eliminated through ΔAD=|AD_off-AD_on| (temperature coefficient ≤±0.05% / ℃).

[0052] The adaptive threshold model uses the forgetting factor α=0.85 to weight historical data, and combines the sliding standard deviation σ(n) to establish a dynamic correction equation of T(n)=0.85T(n-1)+0.15[ΔAD(n)-σ(n)] to effectively track the slow changes in water quality.

[0053] In addition, the working mode of the combination of the first electrode E1 and the second electrode E2 is innovative: 1. Contact time control: By installing the electrode 5mm downstream of the water outlet solenoid valve, the average daily contact time of the electrode is reduced from 100% of the traditional solution to 8.3% (calculated based on 5 minutes of water outlet per hour), and the theoretical life is increased by 12 times. 2. Material compatibility design: 316L food-grade stainless steel is selected, and the corrosion rate in the pH6-8 water environment is ≤0.002mm / year. With the epoxy resin sealing structure, it reaches the IP67 protection level.

[0054] Open circuit detection of fault diagnosis mechanism: When AD_off < 3800, the electrode failure alarm is triggered (corresponding resistance > 50MΩ). Short circuit detection: When ΔAD continues < 50, it is judged as an electrode adhesion fault (threshold corresponding resistance < 100Ω).

[0055] like Figure 4 As shown, the present invention discloses a water shortage detection method using the above household appliance water shortage detection circuit, including the following steps.

[0056] Step 1: Detection when the water pump is turned off: The water pump M1 is controlled to be turned off through the MCU chip. At this time, the electrode sensor circuit collects the first AD closing value, and the collected AD value needs to be filtered.

[0057] Detection when the water pump is turned on: After the MCU chip controls the water pump M1 to discharge water, the electrode sensor circuit collects the second AD turn-on value.

[0058] Step 2: Difference calculation: During the water discharge stage of the water pump M1, the difference between the first AD closing value and the second AD opening value is calculated by the MCU chip.

[0059] Water shortage judgment: Compare the calculated difference with the preset threshold.

[0060] Status feedback: When it is judged that there is a water shortage, the MCU chip outputs a water shortage status signal. The water pump control circuit controls the water pump M1 to stop working according to the signal. At the same time, the alarm connected to the MCU chip sounds an alarm, and the digital display tube shows the water shortage status, reminding the user to deal with it in time.

[0061] Specifically, in step 2, if the difference is greater than the threshold, it is determined that there is water and the water pump is working normally; if the difference is lower than the threshold, it is determined that there is no water.

[0062] Electrode material and position: The first electrode E1 and the second electrode E2 on the electrode sensor circuit must be made of food-grade stainless steel and only contact water during the water discharge stage of the delivery pipe 2. Install the electrodes to ensure that the water flow can contact the two electrodes at the same time when the water pump discharges water. At the same time, the household appliance water shortage detection circuit must be fixed to the first water tank 1, the second water tank 3 or one side of the delivery pipe 2. The two ends of the delivery pipe 2 are respectively placed in the first water tank 1 and the second water tank 3, one end of which passes through the inner wall of the first water tank 1, and the end is connected to the inner wall of the first water tank 1 through a sealing ring. A double sampling mechanism is used for connection, and the water pump M1 is installed on the delivery pipe 2.

[0063] Circuit connection check: Check the connection between the electrode sensor circuit and the MCU chip to ensure that the first AD closed value and the second AD open value can be collected normally. At the same time, check the connection between the water pump control circuit and the MCU chip to ensure that the working state of the water pump M1 can be controlled according to the MCU output electrical signal. Also confirm whether the connection between the alarm and the digital display tube and the MCU chip is normal.

[0064] The working mechanism of the electrode is as follows.

[0065] When water flows through the electrode, it forms an equivalent resistance R as a conductive medium. According to Maxwell's electromagnetic field theory, the electrode spacing d and the contact area S satisfy: R = ρ·d / (S·k), where ρ is the water conductivity and k is the electrode material coefficient. When stainless steel is used, k=0.93-0.97 to ensure linear response.

[0066] The AD detection logic is as follows.

[0067] When there is no water, the resistance between the electrodes →∞, AD(off)≈Vcc; when there is water, a voltage divider circuit is formed, AD(on)=Vcc·R1 / (R1+R2), where R1 is a fixed sampling resistor and R2 is the water resistance. The difference ΔAD eliminates the influence of temperature drift.

[0068] The dynamic threshold algorithm is as follows.

[0069] An adaptive model was established: T(n) = α·T(n-1) + (1-α)·[ΔAD(n) - σ(n)], where α=0.85 is the forgetting factor and σ(n) is the standard deviation of the most recent m samplings, to track the slow changes in water quality.

[0070] The embodiment takes a water dispenser as an example.

[0071] An M3 stainless steel screw was used as the first electrode E1, and a 0.5 mm diameter stainless steel wire was wound with 3 turns of spiral as the second electrode E2, which was installed 5 mm downstream of the water outlet solenoid valve.

[0072] Circuit parameters: sampling frequency 10Hz, filter window 20 cycles, the initial value of the water shortage judgment threshold is set to 300 (corresponding to 12-bit AD value).

[0073] In addition, the implementation examples and parameter configurations take the water dispenser application as an example.

[0074] 1. Installation parameters: The distance between the first electrode E1 and the delivery pipe 2 is 5 mm ± 0.5 mm from the water outlet, and a stable liquid film contact is formed when the water flow velocity is 1.2 m / s.

[0075] 2. Circuit parameters: Sampling frequency: 10Hz (satisfying the liquid film formation time constant τ=0.1s); Filter window: 20-cycle moving average (corresponding to 2 seconds of effective sampling); Initial threshold: 300 (corresponding to conductivity 150μS / cm); Calibration process: Perform dry / wet cycle detection when powered on for the first time, and automatically calculate the benchmark ΔAD range.

[0076] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A water shortage detection circuit for household appliances, characterized in that: include: The electrode sensor circuit is composed of a first electrode E1 and a second electrode E2 insulated from each other, and is used to collect a first AD closing value when the water pump M1 is closed and a second AD opening value when the water pump is opened; The MCU chip is connected to the electrode sensor module to calculate the difference between the first AD closing value and the second AD opening value and compare it with a preset threshold value, and output a water shortage state signal according to the comparison result; The water pump control circuit is connected to the MCU chip and controls the working state of the water pump M1 according to the electrical signal output by the MCU chip.

2. The household appliance water shortage detection circuit according to claim 1, characterized in that: The utility model also comprises an alarm and a digital display tube, and the alarm and the digital display tube are respectively connected to the MCU chip.

3. The water shortage detection circuit for household appliances according to claim 1, characterized in that: The electrode sensor circuit is also provided with a first resistor R1, a second resistor R2, a first capacitor C1 and a +5V terminal. The first resistor R1 is connected to the first electrode E1, and the common terminal between the first resistor R1 and the first electrode E1 is respectively connected to the second resistor R2 and the first capacitor C1, the first capacitor C1 is connected to the second electrode E2, and the second resistor R2 is connected to the +5V terminal.

4. The household appliance water shortage detection circuit according to claim 1, characterized in that: The AD detection circuit also includes a field effect tube Q1, a third resistor R3 and a fourth resistor R4. The water pump M1 is connected to the D pole of the field effect tube Q1, the G pole of the field effect tube Q1 is connected to the third resistor R3, the common end between the G pole of the field effect tube Q1 and the third resistor R3 is connected to one end of the fourth resistor R4, and the other end of the fourth resistor R4 is connected to the S pole of the field effect tube Q1.

5. The water shortage detection circuit for household appliances according to claim 4, characterized in that: One end of the water pump M1 is connected to a 12V terminal.

6. A household appliance using the household appliance water shortage detection circuit according to any one of claims 1 to 5, characterized in that: The invention comprises a first water tank (1), a second water tank (3), a water pump M1, a delivery pipe (2) and a household appliance water shortage detection circuit. The household appliance water shortage detection circuit is fixed to one side of the first water tank (1), the second water tank (3) or the delivery pipe (2). Both ends of the delivery pipe (2) are respectively placed in the first water tank (1) and the second water tank (3). The water pump M1 is installed on the delivery pipe (2).

7. The household appliance according to claim 6, characterized in that: The first electrode E1 and the second electrode E2 on the electrode sensor circuit are made of food-grade stainless steel and are in contact with water only at the water outlet stage of the delivery pipe (2).

8. The household appliance according to claim 6, characterized in that: One end of the delivery pipe (2) passes through the inner wall of the first water tank (1), and one end of the delivery pipe (2) is connected to the inner wall of the first water tank (1) via a sealing ring.

9. A water shortage detection method using the water shortage detection circuit for household appliances according to any one of claims 1 to 5, characterized in that: The steps include: Step 1: Detection when the water pump is turned off: The water pump M1 is controlled to be turned off through the MCU chip. At this time, the electrode sensor circuit collects the first AD closing value, and the collected AD value needs to be filtered; Detection when the water pump is turned on: After the MCU chip controls the water pump M1 to discharge water, the electrode sensor circuit collects the second AD turn-on value; Step 2: Difference calculation: During the water discharge phase of the water pump M1, the difference between the first AD closing value and the second AD opening value is calculated by the MCU chip; Water shortage judgment: compare the calculated difference with the preset threshold; Status feedback: When it is judged that there is a water shortage, the MCU chip outputs a water shortage status signal. The water pump control circuit controls the water pump M1 to stop working according to the signal. At the same time, the alarm connected to the MCU chip sounds an alarm, and the digital display tube shows the water shortage status, reminding the user to deal with it in time.

10. The water shortage detection method according to claim 9, characterized in that: In the step 2, if the difference is greater than the threshold, it is determined that there is water and the water pump works normally; if the difference is lower than the threshold, it is determined that there is no water.

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