Low-cost and high-accuracy water level detection system

Abstract

The utility model provides a water level detection system with low cost and high accuracy, which comprises a kettle body for storing water, a signal sending unit and a signal reading unit, the signal sending unit and the signal reading unit are used for detecting the water level of the kettle body, the signal sending unit comprises a singlechip and a water level probe electrically connected with the singlechip, and the singlechip outputs a pulse signal to drive the water level probe. The water level probe is conducted with the kettle body connected with the ground wire by taking water as a medium to form an electric loop, the signal reading unit comprises a peripheral circuit for detecting the water level of the kettle body, the electric loop is electrically connected with the peripheral circuit, the electric loop and the peripheral circuit form a voltage division circuit, and the voltage division circuit is electrically connected with the single chip microcomputer. The single-chip microcomputer converts signals of the voltage division circuit into AD signals and reads the AD signals so as to obtain water level information in the kettle body. The stability of the water level detection system is improved, the requirement for accurately detecting different water qualities is met, the problems of probe polarization and scaling are solved through the mode of combining software and hardware, and the accuracy, stability and low cost of detection of the water level detection system are guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of detection, in particular to a low-cost and high-accuracy water level detection system. Background Technique

[0002] At present, there are mainly three water level detection methods for electric kettles. Method 1: Use a float switch for water level detection. The float switch is provided with a reed switch at a fixed position. When a hollow float with a ring magnet inside floats to the position of the reed switch due to the rising water level, the reed switch will be closed, generating a switch action, so that the float switch can play the function of controlling and detecting the water level. The cost is low and the signal is stable. Method 2: Use a touch spring for water level detection. The change in water volume will cause the capacitance value of the touch button to change. By using the change in capacitance value generated when the touch button is triggered, different frequency waveforms can be output according to the change in capacitance value. The main control chip realizes the purpose of water detection by receiving this waveform. Method 3: Water level probe water detection method. The kettle body is grounded, the probe outputs a level, and a loop is formed by means of the conductivity of water. The change in current value is generated by electrolyzing water, and then the current value is converted into a changing voltage value through a resistor. The main control chip then reads the changing voltage value in the form of an AD value to obtain the water level value.

[0003] The disadvantages of the above three methods are as follows:

[0004] Method 1: Although it can provide a stable water level signal, the float has a large volume, is restricted by the product structure, and is not beautiful.

[0005] Method 2: The water detection is realized by means of touch induction, which simplifies the water detection structure and reduces the cost. However, to read the frequency waveform converted from the change in capacitance value, a relatively high touch button detection frequency is required, resulting in a relatively high water level detection frequency. High-frequency detection is easily interfered by the external environment, leading to misjudgment of water detection and reducing the accuracy and stability of water level detection.

[0006] Method 3: By detecting the AD value to obtain the water level value, not only can the water level be accurately obtained, but also because the conductivity of different water qualities is different, accurate detection can be ensured for different water qualities. However, only a fixed level is output, and after a long time, the water detection is prone to polarization, making the water scale more likely to adhere to the surface of the probe. Moreover, electrolyzing water will generate a large current, and long-term detection will cause the probe to turn yellow and discolor, resulting in misjudgment or failure of the probe detection. In addition, for an ordinary water detection probe, one probe can only detect the water level at one position. When multiple water levels need to be detected, multiple probe detection heads need to be installed, which will make the inside of the kettle less beautiful and inconvenient to clean.

[0007] The reason is:

[0008] 1. Inside the kettle, by outputting a level signal and using water as a conductor to form a circuit, polarization occurs after a long time, resulting in the inability to detect the water level signal.

[0009] 2. After long-term use, the kettle is prone to scale formation. The scale adhering to the surface of the probe will affect the accuracy of water level detection.

[0010] 3. High-frequency detection is easily affected by external interference, leading to misjudgment.

[0011] 4. Affected by the kettle structure and market demand, the requirements for the sensor are precise.

[0012] Therefore, further improvement is needed. Summary of the Utility Model

[0013] Based on this, the purpose of the present utility model is to provide a low-cost and highly accurate water level detection system to overcome the deficiencies in the prior art. By means of an output waveform driving method, it is possible to avoid the formation of an electric field due to the long-term potential difference between the kettle body and the probe, resulting in polarization and loss of conductivity. Moreover, through the electric circuit formed among the probe, the kettle body, and water, an electrolytic reaction can be generated to make water molecules active, thus avoiding the problem of scale formation after long-term water deposition.

[0014] A low-cost and highly accurate water level detection system designed according to this purpose includes a kettle body for storing water, a signal sending unit, and a signal reading unit for detecting the water level of the kettle body. The signal sending unit includes a single-chip microcomputer and a water level probe electrically connected to the single-chip microcomputer. The single-chip microcomputer outputs a pulse signal to drive the water level probe. The water level probe forms an electric circuit with the kettle body connected to the ground wire through water as a medium. The signal reading unit includes a peripheral circuit for detecting the high and low water levels of the kettle body. The electric circuit is electrically connected to the peripheral circuit. The electric circuit and the peripheral circuit form a voltage dividing circuit. The voltage dividing circuit is electrically connected to the single-chip microcomputer. The single-chip microcomputer converts the signal of the voltage dividing circuit into an AD signal for reading to obtain the water level information inside the kettle body.

[0015] The single-chip microcomputer includes a main control chip U1, and the 24th pin of the main control chip U1 is electrically connected to the peripheral circuit.

[0016] The main control chip U1 has a control port and a resistor R28. The control port is connected to the peripheral circuit through the resistor R28 to read the electrically divided signal.

[0017] The peripheral circuit includes a resistor R27 and a capacitor C12. One end of the resistor R27 is connected to the +5V power supply. The other end of the resistor R27 is connected to the capacitor C12 and is connected to the water level probe through the capacitor C12.

[0018] The peripheral circuit further includes point A of the circuit, and the peripheral circuit is connected to the water level probe through point A of the circuit.

[0019] The water level probe includes resistor R21 and resistor R22. One end of resistor R21 is connected to the high water level detection point of the kettle body, and the other end of resistor R21 is connected to point A of the circuit.

[0020] One end of resistor R22 is connected to the low water level detection point of the kettle body, and the other end of resistor R22 is connected to point A of the circuit; when the water level in the kettle body reaches the high water level detection point or the low water level detection point, resistor R21 and resistor R22 will be connected and conduct to the ground with the kettle body with water as the medium, and resistor R21, resistor R22 and resistor R27 form a voltage dividing circuit.

[0021] The housing of the kettle body is connected to the ground wire to be grounded.

[0022] The model of the main control chip U1 is CBM7320A4S2D.

[0023] A low-cost and high-accuracy water level detection system of the above embodiment includes a kettle body for storing water, a signal sending unit and a signal reading unit for detecting the water level of the kettle body. The signal sending unit includes a single-chip microcomputer and a water level probe electrically connected to the single-chip microcomputer. The single-chip microcomputer outputs a pulse signal to drive the water level probe. The water level probe is connected and conducts with the kettle body connected to the ground wire with water as the medium to form an electric circuit. The signal reading unit includes a peripheral circuit for detecting the high and low water levels of the kettle body. The electric circuit is electrically connected to the peripheral circuit, the electric circuit and the peripheral circuit form a voltage dividing circuit, and the voltage dividing circuit is electrically connected to the single-chip microcomputer. The single-chip microcomputer converts the signal of the voltage dividing circuit into an AD signal for reading to obtain the water level information in the kettle body. The stability of the water level detection system is improved, the requirement of accurately detecting different water qualities is realized. This way of combining software and hardware avoids the problems of probe polarization and scaling, ensures the accuracy and stability of the water level detection system, and also realizes the customer's low-cost requirement. Description of the Drawings

[0024] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 This is the logic block diagram of the water level detection system in an embodiment of the present utility model.

[0027] Figure 2 This is the schematic diagram of the main control chip in an embodiment of the present utility model.

[0028] Figure 3 This is the peripheral circuit diagram in an embodiment of the present utility model.

[0029] Figure 4 This is the equivalent schematic diagram of the peripheral circuit and the water level probe in an embodiment of the present utility model. Detailed implementation manners

[0030] In order to make the above objects, features and advantages of the present utility model more obvious and understandable, the following will describe the detailed implementation manners of the present utility model with reference to the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present utility model. However, the present utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present utility model. Therefore, the present utility model is not limited by the specific embodiments disclosed below.

[0031] As Figures 1 - 4 shown, a low-cost and highly accurate water level detection system is provided, which includes a kettle body 1 for storing water, a signal sending unit 2 for detecting the water level of the kettle body 1, and a signal reading unit 3. The signal sending unit 2 includes a single-chip microcomputer 201 and a water level probe 202 electrically connected to the single-chip microcomputer 201. The single-chip microcomputer 201 outputs a pulse signal to drive the water level probe 202. The water level probe 202 forms an electrical circuit 4 in conduction with the kettle body 1 connected to the ground wire with water as the medium. The signal reading unit 3 includes a peripheral circuit 301 for detecting the high and low water levels of the kettle body 1. The electrical circuit 4 is electrically connected to the peripheral circuit 301. The electrical circuit 4 and the peripheral circuit 301 form a voltage dividing circuit 5. The voltage dividing circuit 5 is electrically connected to the single-chip microcomputer 201. The single-chip microcomputer 201 converts the signal of the voltage dividing circuit 5 into an AD signal for reading to obtain the water level information in the kettle body 1.

[0032] Specifically, in the way of output waveform driving by the single-chip microcomputer 201, the single-chip microcomputer 201 outputs a pulse signal through the water level probe 202 in a pulse control manner, avoiding the formation of an electric field due to the long-term potential difference between the kettle body 1 and the water level probe 202, which may lead to polarization phenomenon and loss of conductivity. And through the water level probe 202, with water as the medium, it conducts to the ground with the kettle body 1 to form an electric circuit 4. The electrolytic reaction can make water molecules active, avoiding the problem of scale formation after long-term water deposition, improving the stability of the control system, and ensuring the anti-interference ability of the entire water detection circuit. During this process, a current signal will be generated in the circuit, and this electric circuit 4 and the peripheral circuit 301 form a voltage dividing circuit 5. At this time, the single-chip microcomputer 201 converts the signal of the voltage dividing circuit 5 into an AD signal for reading to obtain the water level information in the kettle body 1. By connecting different resistors in series with the water level probe 202, when the water level reaches different detection positions, with water as a conductor, different resistors can be connected in series with the probe. Using the principle of resistor voltage division, different resistance values can collect different voltage values, so that the main control can distinguish different water levels, meeting the requirement of realizing multi-channel water level detection with one probe and reducing costs.

[0033] It should be noted that the conductivity of different water qualities is different, and the obtained voltage dividing signals will also be different, and the AD values read by the single-chip microcomputer 201 will also change accordingly. Therefore, by testing waters of different water qualities to obtain the AD values of different water qualities and then processing them through software, it can be ensured that even if users use waters of different water qualities, the kettle body 1 can accurately detect the water level, ensuring the accuracy of the water level detection system.

[0034] Furthermore, as Figure 2 and Figure 3 shown, the single-chip microcomputer 201 includes a main control chip U1, and the 24th pin of the main control chip U1 is electrically connected to the peripheral circuit 301.

[0035] Specifically, the main control chip U1 can receive the electrical signals of the voltage dividing circuit 5 from the peripheral circuit 301. These electrical signals are generated by the electric circuit 4 formed by the water level probe 202 conducting with the kettle body 1 through the water medium and are transmitted to the main control chip U1 after being processed by the peripheral circuit 301. The main control chip U1 can convert the electrical signals of the peripheral circuit 301 into AD signals, thereby reading and processing these signals. By reading the AD signals, the main control chip U1 can accurately judge the water level information in the kettle body 1 and distinguish different water level heights according to different voltage values, ensuring the efficient operation of the entire water level detection system, being able to adapt to changes in different water qualities, and providing accurate water level detection results.

[0036] Furthermore, the main control chip U1 has a control port and a resistor R28. The control port is connected to the peripheral circuit 301 through the resistor R28 to read the voltage-divided electrical signal.

[0037] Specifically, after the main control chip U1 outputs a pulse signal through the control port for a period of time, the software converts the control port into an AD input port. The main control chip U1 reads the electrical signal of the voltage division circuit 5, converts it into an AD signal, and obtains the water level information in the kettle body 1; through software processing, the control port outputs a pulse signal to the water level probe 202 regularly, so that the water level probe 202 forms an electrical circuit 4 with the kettle body 1 connected to the ground wire with water as the medium. After a period of pulse output, the control port will be converted into an AD input port again through software processing to read the water level detection data.

[0038] Furthermore, as Figure 3 and Figure 4 shown, the peripheral circuit 301 includes a resistor R27 and a capacitor C12. One end of the resistor R27 is connected to the +5V power supply, and the other end of the resistor R27 is connected to the capacitor C12 and connected to the water level probe 202 through the capacitor C12.

[0039] Specifically, the control port is connected to the peripheral detection circuit 301 through a resistor R28. One end of the resistor R27 is connected to the +5V power supply, and the other end of the resistor R27 is connected to the capacitor C12 and connected to the water level probe 202 through the capacitor C12 to form a voltage division circuit 5. The control port reads the voltage signal after voltage division through the resistor R28;

[0040] It should be noted that the resistor R28 is a 1K current-limiting resistor; the resistor R27 is a precision resistor with a resistance value of 200K; the capacitor C12 is an energy storage capacitor.

[0041] Furthermore, as Figure 4 shown, the peripheral circuit 301 also includes point A of the circuit. The peripheral circuit 301 is connected to the water level probe 202 through point A of the circuit.

[0042] Specifically, the peripheral circuit 301 is connected to the water level probe 202 through point A of the circuit to ensure the stability and accuracy of signal transmission.

[0043] Furthermore, as Figure 4 shown, the water level probe 202 includes a resistor R21 and a resistor R22. One end of the resistor R21 is connected to the high water level detection point of the kettle body 1, and the other end of the resistor R21 is connected to point A of the circuit.

[0044] Specifically, the water level probe 202 includes a resistor R21 and a resistor R22. One end of the resistor R21 is connected to the high water level detection point of the kettle body 1 and the other end is connected to point A of the circuit, and one end of the resistor R22 is connected to the low water level detection point of the kettle body 1 and the other end is connected to point A of the circuit. When the water level reaches different detection points, voltage division circuits with different resistance values generate different voltage values, and the main control chip U1 reads these voltage values to identify different water level heights.

[0045] Furthermore, as Figure 4 shown, one end of the resistor R22 is connected to the low water level detection point of the kettle body 1, and the other end of the resistor R22 is connected to point A of the circuit; when the water level in the kettle body 1 reaches the high water level detection point or the low water level detection point, the resistors R21 and R22 will be connected and conduct to the ground through water as a medium, and the resistors R21, R22 and the resistor R27 form a voltage dividing circuit 5.

[0046] Specifically, by the way of connecting different resistors in series with the water level probe 202, when the water level reaches different detection positions, by using water as a conductor, the probe can be connected in series with different resistors. According to the principle of resistor voltage division, different resistance values can collect different voltage values, so that the main control can distinguish different water levels, meeting the requirement of realizing multi-channel water level detection with one probe and reducing costs; on the premise of achieving accurate detection for different water qualities, the problem of scale formation that is prone to occur during long-term use of the kettle body 1 is solved by combining software and hardware adjustments, improving the stability of the control system to ensure the anti-interference ability of the entire water detection circuit; and directly based on the principle of series resistance, the detection circuit can be changed from multi-channel to one-channel, achieving low cost.

[0047] Furthermore, the shell of the kettle body 1 is connected to the ground wire to be grounded.

[0048] Furthermore, as Figure 2 shown, the model of the main control chip U1 is CBM7320A4S2D.

[0049] Furthermore, as Figure 4 shown, for the implementation of the control port output program, the reason why the water level probe 202 can detect the water level is by virtue of the conductivity of water. The probe outputs a high level, and the kettle body 1 is grounded through the ground wire, so that an electric circuit 4 is formed between the water level probe 202 and the kettle body 1. However, the long-term potential difference will cause an electric field to be formed between the water level probe 202 and the kettle body 1, resulting in polarization and loss of conductivity. Therefore, through software adjustment, controlling the frequency of waveform output and turning off the pulse output in the non-working state to reduce the detection frequency can avoid the polarization phenomenon in water level detection. And after the kettle is used for a long time, it is easy to scale. The output pulse will make the water ions become active to a certain extent, which can reduce the scaling situation of the probe to a certain extent. Therefore, in the control mode of regular pulse output, it can not only solve the problem of easy scaling of the kettle probe, but also avoid the problem of loss of conductivity caused by polarization reaction, ensuring the sensitivity and stability of the detection probe.

[0050] Furthermore, after the control port finishes pulse output, it is converted into an input port to read the water level AD value through program control. After completing the pulse output control, the control port needs to be converted into an AD detection input port to read the water level state after electrolysis. However, after converting to the AD port, a certain time delay is required to wait for the port state to stabilize before data can be read, to avoid incorrect data reading caused by unstable state when just converted to the input port. When reading data, the program also performs multiple filtering processes to prevent incorrect judgment caused by data interference, so as to ensure the accuracy of signal acquisition.

[0051] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention.

[0052] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0053] In the present invention, unless otherwise clearly specified and limited, the terms "mounted", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0054] In the present utility model, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the horizontal height of the first feature is less than that of the second feature.

[0055] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or there can also be an intermediate element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are only for the purpose of illustration and do not represent the only implementation.

[0056] It should also be understood that when interpreting the connection relationship or positional relationship of elements, although not explicitly described, the connection relationship and positional relationship are interpreted to include an error range, and this error range should be within the acceptable deviation range of a specific value determined by those skilled in the art. For example, "about", "approximate" or "substantially" can mean within one or more standard deviations, which are not defined herein.

[0057] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as falling within the scope described in this specification.

[0058] The above embodiments only represent several implementation manners of the present utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the utility model patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present utility model, several deformations and improvements can still be made, and these all belong to the protection scope of the present utility model. Therefore, the protection scope of the utility model patent should be subject to the appended claims.

Claims

1. A low-cost and high-accuracy water level detection system, characterized by: The invention comprises a kettle body (1) for storing water, a signal sending unit (2) and a signal reading unit (3) for detecting the water level of the kettle body (1), wherein the signal sending unit (2) comprises a single chip computer (201) and a water level probe (202) electrically connected to the single chip computer (201), the single chip computer (201) outputs a pulse signal to drive the water level probe (202), and the water level probe (202) is connected to the kettle body (1) connected to a ground wire with water as a medium to form an electrical circuit (4). The signal reading unit (3) comprises a peripheral circuit (301) for detecting the high and low water levels of the kettle body (1); the electric circuit (4) is electrically connected to the peripheral circuit (301); the electric circuit (4) and the peripheral circuit (301) form a voltage divider circuit (5); the voltage divider circuit (5) is electrically connected to the single-chip computer (201); the single-chip computer (201) converts the signal of the voltage divider circuit (5) into an AD signal for reading to obtain the water level information in the kettle body (1).

2. The low-cost and high-accuracy water level detection system according to claim 1 is characterized in that: The single chip computer (201) comprises a main control chip U1, and pin 24 of the main control chip U1 is electrically connected to the peripheral circuit (301).

3. The low-cost and high-accuracy water level detection system according to claim 2 is characterized in that: The main control chip U1 has a control port and a resistor R28, and the control port is connected to the peripheral circuit (301) through the resistor R28 to read the divided electrical signal.

4. The low-cost and high-accuracy water level detection system according to claim 1 is characterized by: The peripheral circuit (301) comprises a resistor R27 and a capacitor C12, one end of the resistor R27 is connected to a +5V power supply, and the other end of the resistor R27 is connected to the capacitor C12 and connected to the water level probe (202) via the capacitor C12.

5. The low-cost and high-accuracy water level detection system according to claim 4 is characterized in that: The peripheral circuit (301) further comprises a circuit point A, and the peripheral circuit (301) is connected to the water level probe (202) via the circuit point A.

6. The low-cost and high-accuracy water level detection system according to claim 5 is characterized by: The water level probe (202) comprises a resistor R21 and a resistor R22, one end of the resistor R21 is connected to the high water level detection point of the kettle body (1), and the other end of the resistor R21 is connected to point A of the circuit.

7. The low-cost and high-accuracy water level detection system according to claim 6 is characterized by: One end of the resistor R22 is connected to the low water level detection point of the kettle body (1), and the other end of the resistor R22 is connected to point A of the circuit; when the water level of the kettle body (1) reaches the high water level detection point or the low water level detection point, the resistor R21 and the resistor R22 are connected to the kettle body (1) with water as the medium and are connected to the ground, and the resistor R21, the resistor R22 and the resistor R27 form a voltage divider circuit (5).

8. The low-cost and high-accuracy water level detection system according to claim 7 is characterized by: The shell of the kettle body (1) is connected to a ground wire for grounding.

9. The low-cost and high-accuracy water level detection system according to claim 2 is characterized by: The model of the main control chip U1 is CBM7320A4S2D.

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