Liquid level sensor, liquid level detection circuit, control system and intelligent bathtub

Abstract

The application discloses a liquid level sensor, a liquid level detection circuit, a control system and an intelligent bathtub, and relates to the technical field of liquid level sensors. The liquid level sensor comprises an inductive pad, a first voltage dividing resistor and a second voltage dividing resistor. One end of the first voltage dividing resistor and the second voltage dividing resistor is connected with an external pull-up resistor, the other end of the second voltage dividing resistor is grounded, and the external pull-up resistor is used to form a voltage dividing circuit to divide the input DC power supply. A switch tube is connected in series between the other end of the first voltage dividing resistor and the ground. An input end of a touch chip is electrically connected with the inductive pad. The application aims at solving the problem that the existing liquid level sensor can only be connected with the interface of a main control board one by one, and the main control board interface resources are occupied when a large number of liquid level sensors are used.

Description

Technical Field

[0001] This invention relates to the field of liquid level sensor technology, and in particular to a liquid level sensor, a liquid level detection circuit, a control system, and a smart bathtub. Background Technology

[0002] Existing capacitive level sensors on the market typically only allow for individual detection. Even in multi-point level detection applications, multiple single-point level sensors are simply connected one by one to the main control board, with the motherboard processing the detection information output by each sensor. This method of achieving multi-point level detection through multiple single-point level sensors requires each sensor to be connected to a separate interface on the main control board. This results in high requirements for the main control board's interface resources and interface design during the detection circuit design, as well as complex wiring. Summary of the Invention

[0003] The main objective of this invention is to propose a liquid level sensor, a liquid level detection circuit, a control system, and an intelligent bathtub, aiming to solve the problem that existing liquid level sensors can only be connected one-to-one with the interface of the main control board, which will occupy the interface resources of the main control board when a large number of liquid level sensors are used.

[0004] To achieve the above objectives, the present invention provides a liquid level sensor comprising: Induction pads are used to output corresponding capacitance values ​​based on the degree of water immersion. A first voltage divider resistor and a second voltage divider resistor, one end of which is connected to an externally connected pull-up resistor, and the other end of which is grounded, are used to form a voltage divider circuit with the externally connected pull-up resistor to divide the input DC power supply. A switching transistor, wherein the switching transistor is connected in series between the other end of the first voltage divider resistor and ground; The touch chip has its input terminal electrically connected to the sensing pad and its control terminal electrically connected to the controlled terminal of the switching transistor. The touch chip is used to control the switching transistor to open / close based on the capacitance value output by the sensing pad, so as to control the first voltage divider resistor and the second voltage divider resistor to work together and generate a liquid level detection signal with a corresponding voltage value.

[0005] Optionally, the liquid level sensor further includes: A connection terminal is electrically connected to the first voltage divider resistor and the second voltage divider resistor, and the connection terminal is used for detachable connection to an external controller; And / or, the connection terminal is used for detachable connection with an external level sensor to form a cascaded level sensor group with other level sensors.

[0006] Optionally, the liquid level sensor further includes: A sensitivity adjustment capacitor is connected in series between the reference capacitor pin of the touch chip and ground, and is used to adjust the threshold value of the touch chip for detecting the capacitance value of the sensing pad.

[0007] Optionally, the liquid level sensor further includes: An indicator light, wherein the controlled terminal of the indicator light is electrically connected to the touch chip; The touch chip is also used to control the indicator light to work when it is triggered.

[0008] The present invention also proposes a liquid level detection circuit, including an electronic control component and the liquid level sensor described above; The electronic control component is electrically connected to the liquid level sensor, and the electronic control component is used to determine the current liquid level based on the liquid level detection signal output by the liquid level sensor.

[0009] Optionally, there are multiple liquid level sensors, which are connected in series via connection terminals to form a cascaded liquid level sensor group. Each pair of adjacent liquid level sensors is detachably connected. When the cascaded liquid level sensor group is triggered by the liquid surface, it outputs a corresponding liquid level detection signal to the electronic control component.

[0010] Optionally, the electronic control components include: The circuit board is equipped with a sensor interface; A control chip is mounted on the circuit board. The detection terminal of the control chip is electrically connected to the sensor interface. The control chip is used to receive the liquid level detection signal output by the cascaded liquid level sensor group through the sensor interface, and determine the current liquid level based on the received liquid level detection signal.

[0011] Optionally, the electronic control component further includes a pull-up resistor for connecting to a DC power supply; The cascaded liquid level sensor group is connected in series between the pull-up resistor and ground. Specifically, the cascaded liquid level sensor group is used to divide the DC power supply connected to the pull-up resistor according to the triggered state of each liquid level sensor, and output the corresponding current voltage division value to the control chip.

[0012] Optionally, the control chip has multiple preset voltage division values; The control chip is also used to identify the number of liquid level sensors connected in series in the cascaded liquid level sensor group based on the voltage value output by the cascaded liquid level sensor group.

[0013] The present invention also proposes a liquid level control system, including a water inlet module, a water valve device and the above-mentioned liquid level detection circuit; The water inlet module is connected to the water valve device via a pipe, and the controlled end of the water valve device is electrically connected to the liquid level detection circuit. The liquid level detection circuit is used to control the water valve device to open / close based on the detected liquid level information.

[0014] The present invention also proposes an intelligent bathtub, including the above-mentioned liquid level control system.

[0015] This invention's technical solution divides the DC power supply connected to the pull-up resistor by setting a first voltage divider resistor and a second voltage divider resistor, and uses a switching transistor to control the current loop of the first voltage divider resistor to be connected / disconnected. This liquid level sensor can control the first and second voltage divider resistors to generate liquid level detection signals of different voltage values ​​by switching the transistor on / off, achieving single-point liquid level detection. Simultaneously, it can be connected in series with other liquid level sensors to form a cascaded liquid level sensor group. By changing the number of disconnected first voltage divider resistors in the cascaded liquid level sensor group, the total resistance value of the voltage divider resistor group is changed, generating liquid level detection signals corresponding to different water levels, thus achieving multi-point liquid level detection. Furthermore, since the liquid level sensor is used in cascade with an external controller by connecting the first and last liquid level sensors, only the first liquid level sensor in the cascaded liquid level sensor group needs to be connected to the external controller. Therefore, when using multiple liquid level sensors to achieve multi-point liquid level detection, it does not occupy excessive main control board interface resources. Attached Figure Description

[0016] 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0017] Figure 1 A schematic diagram of an embodiment of the liquid level detection circuit of the present invention; Figure 2 A schematic diagram of another embodiment of the liquid level detection circuit of the present invention; Figure 3 This is a schematic diagram of the circuit structure of an embodiment of the liquid level sensor of the present invention; Figure 4 This is a schematic diagram of a cascaded liquid level sensor group according to an embodiment of the liquid level sensor of the present invention. Figure 5 This is a schematic diagram of an embodiment of the liquid level control system of the present invention.

[0018] Explanation of icon numbers:

[0019] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0022] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0023] This invention proposes a liquid level sensor.

[0024] Currently, existing capacitive level sensors on the market typically only perform individual detection. Even in multi-point level detection applications, multiple single-point level sensors are simply connected one by one to the main control board, with the motherboard processing the detection information output by each sensor. This method of achieving multi-point level detection through multiple single-point level sensors requires each sensor to be connected to a separate interface on the main control board. This results in high requirements for the main control board's interface resources and interface design during the detection circuit design, as well as complex wiring.

[0025] To solve the above problems, refer to Figure 3 and Figure 4 In one embodiment, the liquid level sensor includes: Induction pads are used to output corresponding capacitance values ​​based on the degree of water immersion. A first voltage divider resistor and a second voltage divider resistor, one end of which is connected to an externally connected pull-up resistor, and the other end of which is grounded, are used to form a voltage divider circuit with the externally connected pull-up resistor to divide the input DC power supply. A switching transistor, wherein the switching transistor is connected in series between the other end of the first voltage divider resistor and ground; The touch chip has its input terminal electrically connected to the sensing pad and its control terminal electrically connected to the controlled terminal of the switching transistor. The touch chip is used to control the switching transistor to open / close based on the capacitance value output by the sensing pad, so as to control the first voltage divider resistor and the second voltage divider resistor to work together and generate a liquid level detection signal with a corresponding voltage value.

[0026] It is understood that this liquid level sensor can be specifically applied to water level detection in water storage containers such as water heaters and bathtubs. In this embodiment, the sensing pad K1 is disposed on the outer shell of the water storage container. When the sensing pad K1 is subjected to water, it will collect the charge, causing the capacitance value to change. The switching transistor can be implemented using an electronic switch with low on-resistance characteristics, such as a MOSFET, so that when the switching transistor is connected in series with the first voltage divider resistor, its internal resistance is negligible and will not affect the resistance values ​​of the first and second voltage divider resistors. The pull-up resistor connected to one end of the first and second voltage divider resistors R1 and R2 can be an independent device or a pull-up resistor of an external controller.

[0027] When implementing single-point detection, the output terminal of the liquid level sensor is directly connected to the detection terminal of the external controller. When the liquid level sensor is submerged, the touch chip U1 is triggered, and the output low level controls the switch Q1 to turn off, thus disconnecting the current loop of the first voltage divider resistor R1 connected in series with the switch Q1. At this time, only the second voltage divider resistor R2 divides the DC power supply connected to the pull-up resistor. The liquid level detection signal output by the liquid level sensor through the output terminal is the voltage division value across the second voltage divider resistor R2. When the liquid level sensor is not submerged, the touch chip U1 is not triggered, and the output high level controls the switch Q1 to turn on, thus conducting the current loop of the first voltage divider resistor R1 connected in series with the switch Q1. At this time, the first voltage divider resistor R1 and the second voltage divider resistor R2 are connected in parallel, and then divide the DC power supply connected to the pull-up resistor. The liquid level detection signal output by the liquid level sensor through the output terminal is the voltage division value across the first voltage divider resistor R1 and the second voltage divider resistor R2 connected in parallel.

[0028] In multi-point detection, the liquid level sensor is connected end-to-end with other liquid level sensors to form a cascaded liquid level sensor group. In this cascaded liquid level sensor group, the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2 in each liquid level sensor can be connected in parallel with other liquid level sensors to form a voltage-dividing resistor group. This voltage-dividing resistor group divides the DC power supply connected to the pull-up resistor. When the water level reaches a certain height, the triggered liquid level sensor will disconnect the current loop of its first voltage-dividing resistor R1, while the untriggered liquid level sensor will connect its first voltage-dividing resistor R1 and second voltage-dividing resistor R2 in parallel. Therefore, depending on the liquid level, the cascaded liquid level sensor group will change the total resistance value of the voltage-dividing resistor group by changing the number of first voltage-dividing resistors R1 disconnected, thereby generating different voltage divisions. These voltage divisions serve as liquid level detection signals characterizing different water levels, allowing the external controller to detect the current liquid level height based on the liquid level detection signals with different voltage divisions.

[0029] Since the entire cascaded level sensor group is connected to the detection terminal of the external controller through the output terminal of the first level sensor when the level sensor is used in cascade with an external controller, the output terminal of the first level sensor is the output terminal of the cascaded level sensor group. Therefore, when using multiple level sensors for detection, only the first level sensor in the cascaded level sensor group needs to be connected to the external controller, which will not occupy too many interface resources.

[0030] Compared to existing liquid level sensors that can only indicate whether the sensor is submerged by outputting high or low voltage levels, and where multiple existing liquid level sensors connected in series can only output binary high and low signals, failing to output corresponding detection information based on the current water level, this invention addresses the issue of single-point liquid level detection. This is achieved by setting a first voltage-dividing resistor R1 and a second voltage-dividing resistor R2 to divide the DC power supply connected to the pull-up resistor, and by using a switching transistor Q1 to control the current loop of the first voltage-dividing resistor to be connected / disconnected. This allows the first and second voltage-dividing resistors to jointly generate liquid level detection signals with different voltage values. Furthermore, the liquid level sensor of this invention can be connected in series with other liquid level sensors to form a cascaded liquid level sensor group. By changing the number of first voltage-dividing resistors R1 disconnected in the cascaded liquid level sensor group, the total resistance value of the voltage-dividing resistor group is changed, generating liquid level detection signals corresponding to different water levels. When the liquid level sensor of this invention is used in cascade with an external controller, it can be connected end-to-end with other liquid level sensors. With this configuration, only the first liquid level sensor in the cascaded liquid level sensor group needs to be connected to the external controller. When using multiple liquid level sensors to achieve multi-point liquid level detection, it will not occupy excessive main control board interface resources.

[0031] Reference Figure 3 and Figure 4 In one embodiment, the liquid level sensor further includes: A connection terminal is electrically connected to the first voltage divider resistor R1 and the second voltage divider resistor R2, and the connection terminal is used for detachable connection to an external controller; And / or, the connection terminal is used for detachable connection with an external level sensor to form a cascaded level sensor group with other level sensors.

[0032] In this embodiment, there are two connection terminals, including an input plug CN1 and an output interface P1. Since the liquid level sensor can perform single-point detection or multi-point detection, multiple liquid level sensors can be connected in series through the connection terminals, or the liquid level sensor can be connected to an external sensor through the connection terminals.

[0033] Specifically, when implementing single-point detection, the liquid level sensor is directly connected to the external controller through the input plug CN1 and the output interface P1. That is, the input plug CN1 of the liquid level sensor is connected to the detection terminal of the external controller, and the output interface P1 of the liquid level sensor is connected to the ground terminal of the external controller, thereby forming a detection loop between the liquid level sensor and the external controller.

[0034] When implementing multi-point detection, the liquid level sensor can be connected to an external liquid level sensor in sequence through the input plug CN1 and the output interface P1 to form a cascaded liquid level sensor group 100. The cascaded liquid level sensor group 100 includes a first-end liquid level sensor and a last-end liquid level sensor. The input plug CN1 of the first-end liquid level sensor is connected to the detection terminal of the external controller, and the output interface P1 of the last-end liquid level sensor is connected to the ground terminal of the external controller, so that multiple liquid level sensors are connected to the external controller as a detection unit to form a detection loop.

[0035] Reference Figure 3 and Figure 4 In one embodiment, the liquid level sensor further includes: A sensitivity adjustment capacitor is connected in series between the reference capacitor pin of the touch chip U1 and ground, and is used to adjust the threshold value of the touch chip U1 for detecting the capacitance value of the sensing pad K1.

[0036] In this embodiment, the sensitivity adjustment capacitor can specifically be... Figure 3 The capacitors are CDC1 or C2.

[0037] The sensitivity adjustment capacitor provides a reference capacitance value to the touch chip U1. The trigger condition is that the capacitance value output by the sensing pad K1 reaches the reference capacitance value. Specifically, during water level detection, the comparator integrated within the touch chip U1 compares the capacitance value output by the sensing pad K1 with the reference capacitance value. The touch chip U1 is only triggered when the capacitance value output by the sensing pad K1 reaches the reference capacitance value. Therefore, a larger capacitance value results in lower sensitivity of the touch chip U1; the capacitance value output by the sensing pad K1 may only reach the reference capacitance value when the liquid level sensor is completely submerged. Conversely, a smaller capacitance value results in higher sensitivity of the touch chip U1; the capacitance value output by the sensing pad K1 may reach the reference capacitance value even when the liquid level sensor is merely in contact with the liquid surface. Thus, adjusting the capacitance value of the sensitivity adjustment capacitor adjusts the sensitivity of the touch chip U1 during water level detection.

[0038] Reference Figure 3 and Figure 4 In one embodiment, the liquid level sensor further includes: Indicator LED1, the controlled terminal of which is electrically connected to the touch chip U1; The touch chip U1 is also used to control the indicator LED1 to work when it is triggered.

[0039] In this embodiment, the indicator LED1 is used to light up when the liquid level sensor is triggered, so that the user can determine whether the liquid level in the water storage container has reached the set position by the on / off state of the indicator LED1.

[0040] Specifically, in practical applications, multiple liquid level sensors are cascaded on the outer wall of the bathtub. When the user fills the bathtub with water, the water level submerges the liquid level sensors from bottom to top. The touch chip U1 in the submerged sensor is triggered and outputs a lighting control signal to the indicator LED1 to control the indicator LED1 to light up. This allows the user to determine the current water level based on the position of the lit indicator LED1 on the outer wall of the bathtub.

[0041] Reference Figures 1 to 4 The present invention also proposes a liquid level detection circuit, including an electronic control component 200 and the liquid level sensor described above; The electronic control component 200 is electrically connected to the liquid level sensor, and the electronic control component 200 is used to determine the current liquid level based on the liquid level detection signal output by the liquid level sensor.

[0042] In this embodiment, the electronic control component 200 can be installed at the bottom of the bathtub. The input plug CN1 of the liquid level sensor is connected via the detection terminal, and the output interface P1 of the liquid level sensor is connected via the grounding terminal, thus forming a detection loop between the liquid level sensor and the electronic control component 200. When the liquid level sensor is connected to the electronic control component 200, the DC power supply connected to its pull-up resistor 230 is divided by the first voltage divider resistor R1 and the second voltage divider resistor R2 inside the liquid level sensor. The voltage division value is the liquid level detection signal of the liquid level sensor. When the liquid in the water storage container submerges the level sensor, the level sensor is triggered, and the internal first voltage divider resistor R1 is disconnected, causing a change in the voltage divider output by the level sensor. When the liquid in the water storage container does not submerge the level sensor, the level sensor is not triggered, the internal first voltage divider resistor R1 remains connected and connected in parallel with the second voltage divider resistor R2, and the voltage divider output by the level sensor does not change. This allows the electronic control component 200 to detect the current water level based on the received voltage divider and stop water injection in time or take other countermeasures.

[0043] Reference Figures 1 to 4 In one embodiment, there are multiple liquid level sensors connected in series to form a cascaded liquid level sensor group 100, wherein each pair of adjacent liquid level sensors is detachably connected; when the cascaded liquid level sensor group 100 is triggered by the liquid surface, it outputs a corresponding liquid level detection signal to the electronic control component 200.

[0044] In this embodiment, the cascaded liquid level sensor group 100 includes at least two liquid level sensors.

[0045] In a cascaded liquid level sensor group 100, multiple liquid level sensors connected in series can be detachably connected. For example, the input terminal of a new liquid level sensor can be connected to the cascaded liquid level sensor group 100 to increase the number of cascaded liquid level sensors in the cascaded liquid level sensor group 100. Alternatively, the number of cascaded liquid level sensors in the cascaded liquid level sensor group 100 can be reduced by removing existing liquid level sensors, thereby flexibly adjusting the number of cascaded liquid level sensors.

[0046] Specifically, when the cascaded liquid level sensor group 100 is installed on the outer wall of the bathtub, the liquid level sensor directly connected to the electronic control component 200 can be used as the lowest detected water level of the water level detection module, or the liquid level sensor directly connected to the electronic control component 200 can be used as the highest detected water level of the water level detection module.

[0047] In practical applications, when the cascaded liquid level sensor group 100 performs multi-point water level detection, the water level will sequentially submerge the corresponding number of liquid level sensors from bottom to top. This triggers the liquid level sensors below the liquid surface, breaking the current loop of the internal first voltage divider resistor R1. The liquid level sensors above the liquid surface are not triggered, and the current loop of their internal first voltage divider resistor R1 is connected. Since the number of liquid level sensors with the first voltage divider resistor R1 disconnected increases or decreases with the rise and fall of the liquid level, the total resistance value of the multiple liquid level sensors connected in parallel also changes with the rise and fall of the liquid level. Because the cascaded liquid level sensor group 100 is also electrically connected to the pull-up resistor 230 of the electronic control component 200 when connected to the electronic control component 200, it divides the DC power supply connected to the pull-up resistor 230. Therefore, when the current loop of the first voltage divider resistor R1 in the liquid level sensor is connected or disconnected, the voltage value of the cascaded liquid level sensor group 100 will also change accordingly. Since the voltage values ​​generated by these liquid level sensors change with the liquid level, the current liquid level height can be determined based on the voltage values, given a fixed number of cascaded liquid level sensor groups 100.

[0048] It should be noted that during the entire detection process, only one liquid level sensor is structurally directly connected to the external control unit. It is not necessary to connect each liquid level sensor to a corresponding interface of the external control unit. Therefore, the external control unit can save interface resources while connecting multiple sensors to achieve multi-point detection.

[0049] Reference Figures 1 to 4 In one embodiment, the electronic control component 200 includes: The circuit board is equipped with a sensor interface 210; A control chip 220 is disposed on the circuit board. The detection end of the control chip 220 is electrically connected to the sensor interface 210. The control chip 220 is used to receive the liquid level detection signal output by the cascaded liquid level sensor group 100 through the sensor interface 210, and determine the current liquid level based on the received liquid level detection signal.

[0050] In this embodiment, the sensor interface 210 includes an input interface and a grounding port. When the cascaded liquid level sensor group 100, formed by multiple cascaded liquid level sensors, is connected to the electronic control component 200, the output terminals of the cascaded liquid level sensors are connected to the detection terminals of the control chip 220 through the input interface, and the ground terminals of the cascaded liquid level sensors are connected to the ground terminals of the control chip 220 through the grounding port, so that the cascaded liquid level sensors and the control chip 220 form a detection loop. During water level detection, the cascaded liquid level sensor group 100 outputs the liquid level detection signal to the control chip 220 through the sensor interface 210 according to the detection status of each sensor, so that the control chip 220 can determine the current liquid level information based on the received liquid level detection signal.

[0051] Reference Figures 1 to 4 In one embodiment, the electronic control component 200 further includes a pull-up resistor 230 for connecting to a DC power supply; The cascaded liquid level sensor group 100 is connected in series between the pull-up resistor 230 and ground. Specifically, the cascaded liquid level sensor group 100 is used to divide the DC power supply connected to the pull-up resistor 230 according to the triggered state of each liquid level sensor, and output the corresponding current voltage division value to the control chip 220.

[0052] In this embodiment, when the liquid level sensor is connected to an external control unit, it divides the voltage of the connected DC power supply by connecting an external resistor. The external resistor can be a pull-up resistor 230 connected to the output terminal of the control chip 220. Thus, when the liquid level sensor performs multi-point water level detection, the water level will sequentially submerge the corresponding number of liquid level sensors from bottom to top. When different numbers of sensors detect the liquid surface, the total resistance value of the cascaded liquid level sensor group 100 will also change accordingly, thereby adjusting the voltage division value across the cascaded liquid level sensor group 100, so that the control chip 220 can determine the current liquid level based on the connected voltage division value.

[0053] For example, utilizing the low on-resistance of the switching transistor Q1, it can be used as a voltage divider resistor connected to the control switch. In a single-point water level detection scenario, when the sensing point is triggered, the voltage divider resistor value is the resistance R2 of the second voltage divider resistor; when the sensing point is not triggered, the voltage divider resistor value is the resistance R2 of the second voltage divider resistor and the first voltage divider resistor connected in parallel. R1 / (R2+R1). When used in a two-point water level detection scenario, and neither sensing point 1 nor 2 is triggered, the voltage divider resistor value is R2². R1² / (2 R2+2 R1); When sensing point 1 is triggered and sensing point 2 is not triggered, the voltage divider resistor value is R2². R1 / (2 R2+R1); When both sensing points 1 and 2 are triggered, the voltage divider resistor value is R2² / (2 R2). Similarly, the voltage divider resistor values ​​will vary depending on the number of water level sensors connected and the sensing state, resulting in different output voltage divider values.

[0054] This allows the liquid level sensor to record the current partial pressure value output when detecting different levels of liquid level under different total quantities, and preset it in the control chip 220. This enables the liquid level detection circuit to determine the number of sensors that detect the water surface under the current total quantity based on the current partial pressure value of the cascaded liquid level sensor group 100 when it is used in actual applications.

[0055] Reference Figures 1 to 4 In one embodiment, the control chip 220 has multiple preset voltage division values; The control chip is also used to identify the number of liquid level sensors connected in series in the cascaded liquid level sensor group 100 based on the voltage value output by the cascaded liquid level sensor group 100.

[0056] In this embodiment, each level sensor in the cascaded level sensor group 100 has the same voltage divider resistance value under the same detection state. Therefore, by filling or emptying the water storage container, the first voltage divider resistance R1 inside each level sensor can be set to an open circuit, so that the voltage divider resistance value of the level sensor reaches its maximum. When the number of cascaded level sensors increases, it is equivalent to connecting a resistor in parallel in the cascaded level sensor group 100. Therefore, the maximum voltage divider value of the cascaded level sensor group 100 will decrease accordingly. When the number of level sensors is reduced, it is equivalent to removing one of the multiple parallel voltage divider resistors in the cascaded level sensor group 100. Therefore, the maximum voltage divider value of the cascaded level sensor group 100 will increase accordingly. This allows the maximum voltage divider value output by the cascaded level sensor group 100 when connected to different numbers of level sensors to be recorded and preset in the control chip 220. This enables the level detection circuit to determine the current number of sensors connected to the cascaded level sensor group 100 based on the detected maximum voltage divider value in actual applications.

[0057] For example, when three sensors are connected, the maximum voltage division value of the cascaded liquid level sensor group 100 is 5V; when four sensors are connected, the maximum voltage division value is 3V; and when five sensors are connected, the maximum voltage division value is 2V. Therefore, the first voltage dividing resistor R1 inside each liquid level sensor is set to be open-circuited, and the maximum voltage division value output by the cascaded liquid level sensor group 100 at this time is detected. If it is 3V, it means that four liquid level sensors are connected to the cascaded liquid level sensor group 100 at this time.

[0058] Furthermore, since the multiple level sensors connected in series are always triggered sequentially from bottom to top during detection in the cascaded level sensor group 100, the number of level sensors triggered actually refers to how many sensors detect the water surface from bottom to top. Thus, based on the output voltage divider value, the control chip 220 can accurately identify the detection status.

[0059] Reference Figures 1 to 5 The present invention also proposes a liquid level control system, including a water inlet module 300, a water valve device and the liquid level detection circuit described above. The water inlet module 300 is connected to the water valve device via a pipe, and the controlled end of the water valve device is electrically connected to the liquid level detection circuit. The liquid level detection circuit is used to control the water valve device to open / close based on the detected liquid level information.

[0060] In this embodiment, the water inlet module 300 includes a water inlet shower head and / or a water inlet handwheel.

[0061] The liquid level detection circuit includes a control chip 220. After the user outputs water level selection information to the control chip 220 through interactive components such as a touch screen, the control chip 220 outputs an open control signal to the water valve device to open the water valve device, allowing the water output from the water valve device to be transported through the pipe to the water inlet module 300, and then water is injected into the water tank through the water inlet module 300. During this process, the cascaded liquid level sensor group 100 in the liquid level detection circuit starts to detect the current water level in the bathtub in real time and outputs the corresponding current detection parameters. When the control chip 220 detects that the water level in the bathtub has not reached the water level set by the user through the water level selection information, it continues to output the open control signal to the water valve device. When the control chip 220 detects that the water level in the bathtub has reached the water level set by the user through the water level selection information, it outputs the close control signal to the water valve device to stop the transportation of water to the water inlet module 300.

[0062] The present invention also proposes an intelligent bathtub, including the above-mentioned liquid level control system. The specific structure of the liquid level control system is as described in the above embodiments. Since the intelligent bathtub adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0063] The above description is merely an optional embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made under the concept of the present invention using the description and drawings of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A liquid level sensor, characterized by, The liquid level sensor includes: Induction pads are used to output corresponding capacitance values ​​based on the degree of water immersion. A first voltage divider resistor and a second voltage divider resistor, one end of which is connected to an externally connected pull-up resistor, and the other end of which is grounded, are used to form a voltage divider circuit with the externally connected pull-up resistor to divide the input DC power supply. A switching transistor, wherein the switching transistor is connected in series between the other end of the first voltage divider resistor and ground; The touch chip has its input terminal electrically connected to the sensing pad and its control terminal electrically connected to the controlled terminal of the switching transistor. The touch chip is used to control the switching transistor to open / close based on the capacitance value output by the sensing pad, so as to control the first voltage divider resistor and the second voltage divider resistor to work together and generate a liquid level detection signal with a corresponding voltage value. When using multiple liquid level sensors for multi-point detection, the liquid level sensors are connected end to end with other liquid level sensors to form a cascaded liquid level sensor group. The first voltage divider resistor and the second voltage divider resistor in each liquid level sensor are connected in parallel with other liquid level sensors to form a voltage divider resistor group. The cascaded liquid level sensor group is used to change the total resistance value of the voltage divider resistor group in the cascaded liquid level sensor group by changing the number of disconnected first voltage divider resistors in the voltage divider resistor group, and to generate liquid level detection signals corresponding to different water levels, so as to realize multi-point liquid level detection. The output terminal of the liquid level sensor at the first end of the cascaded liquid level sensor group is the output terminal of the cascaded liquid level sensor group, and the liquid level sensor at the first end of the cascaded liquid level sensor group is used to connect to an external controller. The liquid level sensor also includes: A connection terminal is electrically connected to the first voltage divider resistor and the second voltage divider resistor, and the connection terminal is used for detachable connection to an external controller; And / or, the connection terminal is used for detachable connection with an external level sensor to form a cascaded level sensor group with other level sensors.

2. The liquid level sensor as described in claim 1, characterized in that, The liquid level sensor also includes: A sensitivity adjustment capacitor is connected in series between the reference capacitor pin of the touch chip and ground, and is used to adjust the threshold value of the touch chip for detecting the capacitance value of the sensing pad.

3. The liquid level sensor as described in claim 1, characterized in that, The liquid level sensor also includes: An indicator light, wherein the controlled terminal of the indicator light is electrically connected to the touch chip; The touch chip is also used to control the indicator light to work when it is triggered.

4. A liquid level detection circuit, characterized in that, Includes electronic control components and a liquid level sensor as described in any one of claims 1-3; The electronic control component is electrically connected to the liquid level sensor, and the electronic control component is used to determine the current liquid level based on the liquid level detection signal output by the liquid level sensor.

5. The liquid level detection circuit as described in claim 4, characterized in that, The liquid level sensor is a plurality of liquid level sensors, which are connected in series to form a cascaded liquid level sensor group. Each pair of adjacent liquid level sensors is detachably connected through a connection terminal. When the cascaded liquid level sensor group is triggered by the liquid surface, it outputs a corresponding liquid level detection signal to the electronic control component.

6. The liquid level detection circuit as described in claim 5, characterized in that, The electronic control components include: The circuit board is equipped with a sensor interface; A control chip is mounted on the circuit board. The detection terminal of the control chip is electrically connected to the sensor interface. The control chip is used to receive the liquid level detection signal output by the cascaded liquid level sensor group through the sensor interface, and determine the current liquid level based on the received liquid level detection signal.

7. The liquid level detection circuit as described in claim 6, characterized in that, The electronic control component also includes a pull-up resistor for connecting to a DC power supply; The cascaded liquid level sensor group is connected in series between the pull-up resistor and ground. Specifically, the cascaded liquid level sensor group is used to divide the DC power supply connected to the pull-up resistor according to the triggered state of each liquid level sensor, and output the corresponding current voltage division value to the control chip.

8. A liquid level control system, characterized in that, Includes a water inlet module, a water valve device, and a liquid level detection circuit as described in any one of claims 4-7; The water inlet module is connected to the water valve device via a pipe, and the controlled end of the water valve device is electrically connected to the liquid level detection circuit. The liquid level detection circuit is used to control the water valve device to open / close based on the detected liquid level information.

9. A smart bathtub, characterized in that, Including the liquid level control system as described in claim 8.

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