A water immersion detection circuit with adaptive sensitivity

Abstract

The invention discloses a water immersion detection circuit with adaptive sensitivity, which belongs to the technical field of Internet of Things, and includes a data processing unit and a power supply circuit. The data processing unit includes a main control chip, a sampling module, and a A , Sampling module B , compensation capacitor group, matrix sensor group, storage module, temperature and humidity sensor, calibration sampling module, reference capacitor and wireless communication module, solve the technical problems of a water intrusion detection system based on an adjustable capacitor array and dynamic gain adjustment, performing a real-time sensitivity compensation mechanism, and realizing dynamic adjustment of the matrix sensor. The present invention ensures the internal sensitivity consistency of the sensor matrix, realizes fine-grained adjustment of the sensitivity of the capacitive sensor, adapts to changes in sensor characteristics under different temperature and humidity environments, reduces installation complexity, and realizes a higher level of protection and early warning functions.

Description

Technical Field

[0001] The invention belongs to the technical field of Internet of Things, and in particular relates to a water immersion detection circuit with adaptive sensitivity. Background Art

[0002] The water intrusion detection system is mainly used to monitor water leakage or water accumulation in the environment in real time. It is widely used in data centers, underground pipe corridors, computer rooms, smart homes, industrial equipment and other places that are extremely sensitive to water intrusion. The system usually detects the presence of moisture or liquid in the environment through a capacitive sensor array distributed in the target area. When water contacts the sensor surface, the capacitance value of the sensor will change significantly, thereby triggering an alarm or initiating protective measures.

[0003] In modern industrial and smart building environments, water intrusion may cause serious equipment damage, data loss or production interruption. Therefore, early detection and real-time monitoring of water intrusion are particularly important. Traditional water intrusion detection systems mainly rely on single-point sensors or simple detection lines, but these systems often have detection blind spots and it is difficult to accurately locate the water intrusion position or measure the direction of water flow.

[0004] The use of matrix capacitive sensors can cover a larger area, improve detection accuracy, and effectively distinguish water flow direction and leakage degree, becoming one of the core technologies of the new generation of water intrusion monitoring systems.

[0005] Matrix sensors arrange multiple capacitive detection units to form a two-dimensional or linear array structure, which is widely used in the following scenarios:

[0006] Data center and computer room waterproofing: laid under the floor or around key equipment, it can accurately detect the location and respond promptly in case of water intrusion.

[0007] Underground pipeline corridor monitoring: covers a wide range of underground facilities, provides early warning for pipeline leakage or water accumulation, and avoids the expansion of disasters.

[0008] Industrial production line monitoring: Dynamically monitor industrial scenarios of liquid leakage to prevent production accidents caused by leakage of equipment cooling water or chemical liquids.

[0009] Smart home waterproof detection: installed in the kitchen, bathroom or near the water pipe to prevent property damage caused by water leakage inside the home.

[0010] Agricultural irrigation management: By monitoring soil moisture and water flow, the irrigation system can be optimized to achieve efficient management of water resources.

[0011] Although the existing water intrusion detection system has achieved certain results, it still has the following problems and shortcomings:

[0012] Inconsistent sensitivity: Sensors vary during the manufacturing process. Even sensors from the same batch may have different sensitivities and response thresholds, leading to false alarms or missed alarms. In addition, when the sensor matrix is ​​deployed over a large area, sensors at different locations may also have different responses to water intrusion, especially in areas with complex environments.

[0013] Environmental interference and capacitance drift: Changes in temperature and humidity, equipment aging, and external interference factors can easily cause sensor capacitance drift, resulting in detection errors in fixed threshold systems and reducing the reliability of water intrusion detection.

[0014] Fixed threshold setting is rigid: Traditional systems use fixed capacitance thresholds to determine water intrusion, which is difficult to adapt to dynamic changes in long-term operating environments. For example, in high humidity in summer, the sensor capacitance value will naturally rise, which is easy to trigger false alarms; while in dry environments, the system may be insensitive to actual water intrusion, increasing the risk of missed alarms.

[0015] Complex installation and difficult maintenance: When the matrix sensor is first installed, each sensor needs to be debugged and calibrated one by one to eliminate errors caused by position and electrical differences. This process is time-consuming and labor-intensive. In addition, readjusting the sensitivity of the sensor during maintenance is also relatively complicated. Summary of the invention

[0016] The purpose of the present invention is to provide a water immersion detection circuit with adaptive sensitivity, which solves the technical problem of implementing a real-time sensitivity compensation mechanism and realizing dynamic adjustment of a matrix sensor based on a water intrusion detection system with an adjustable capacitor array and dynamic gain adjustment.

[0017] To achieve the above object, the present invention adopts the following technical solution:

[0018] A water immersion detection circuit with adaptive sensitivity includes a data processing unit and a power supply circuit. The data processing unit includes a main control chip and a sampling module. A , Sampling module B , compensation capacitor group, matrix sensor group, storage module, temperature and humidity sensor, calibration sampling module, reference capacitor and wireless communication module, the matrix sensor group includes 8 water intrusion sensors, the compensation capacitor group includes 8 compensation capacitor chips, and each water intrusion sensor is connected in series with a compensation capacitor chip;

[0019] Sampling Module A The 4 sampling input interfaces are connected to 4 compensation capacitor chips respectively, and are used to sample the water intrusion sensors behind the 4 series compensation capacitor chips; the sampling module B The 4 sampling input interfaces are respectively connected to the other 4 compensation capacitor chips, so as to sample the capacitive sensors behind the other 4 series compensation capacitor chips;

[0020] The calibration sampling module is connected to the reference capacitor and is used to sample the reference capacitor;

[0021] Compensation capacitor group, sampling module A , Sampling module B , storage module, temperature and humidity sensor, calibration sampling module and wireless communication module are all connected to the main control chip; the input end of the power circuit is connected to the external 12 V Power supply, the output end supplies power to the data processing unit;

[0022] The matrix sensor group consists of 4×2 matrix water intrusion sensors. The main control chip uses the sampling module A and sampling modules B The capacitance measurement sampling of the 4×2 matrix water intrusion sensor is carried out, and the deviation between the capacitance change of each water intrusion sensor and the overall level of the matrix is ​​calculated through the differential compensation model. When the sensitivity of a water intrusion sensor is too high or too low, the capacitance value of the compensation capacitor chip connected in series with the water intrusion sensor is adjusted, and then the compensation capacitor is adjusted. At the same time, the sampling module for sampling the water intrusion sensor is adjusted. A or sampling module B The gain is adjusted to adjust the sensitivity adaptively.

[0023] Preferably, the matrix sensor group specifically includes two groups of capacitive sensors, one group includes sensors C 1. Sensor C 2. Sensors C 3 and sensor C 4. Another group includes sensors C 12. Sensors C 13. Sensors C 14 and sensor C 15;

[0024] The compensation capacitor group includes a compensation capacitor CP 1. Compensation capacitor CP 2. Compensation capacitor CP 3. Compensation capacitor CP 4. Compensation capacitor CP 5. Compensation capacitor CP 6. Compensation capacitor CP 7 and compensation capacitor CP 8;

[0025] sensor C 1. Connect one end to the ground wire and the other end to the compensation capacitor. CP 1 of CP Terminal, compensation capacitor CP 1 of CN Terminal connection sampling module A of CIN 1 terminal, compensation capacitorCP 1Through the road I 2 C bus I 2 C 5. Communicate with the main control chip;

[0026] sensor C 2. Connect one end to the ground wire and the other end to the compensation capacitor. CP 2 of CP Terminal, compensation capacitor CP 2 of CN Terminal connection sampling module A of CIN 2-terminal, compensation capacitor CP 2Through the road I 2 C bus I 2 C 5. Communicate with the main control chip;

[0027] sensor C 3. Connect one end to the ground wire and the other end to the compensation capacitor. CP 3 of CP Terminal, compensation capacitor CP 3 of CN Terminal connection sampling module A of CIN 3-terminal, compensation capacitor CP 3Through the road I 2 C bus I 2 C 5. Communicate with the main control chip;

[0028] sensor C 4. Connect one end to the ground wire and the other end to the compensation capacitor. CP 4 of CP Terminal, compensation capacitor CP 4 of CN Terminal connection sampling module A of CIN 4-terminal, compensation capacitor CP 4Through the road I 2 C bus I 2 C 5. Communicate with the main control chip;

[0029] sensor C 12 Connect one end to the ground wire and the other end to the compensation capacitor CP 5 of CP Terminal, compensation capacitor CP 5 of CN Terminal connection sampling module B of CIN 1 terminal, compensation capacitor CP 5Through the roadI 2 C bus I 2 C 4. Communicate with the main control chip;

[0030] sensor C 13 Connect one end to the ground wire and the other end to the compensation capacitor CP 6 of CP Terminal, compensation capacitor CP 6 of CN Terminal connection sampling module B of CIN 2-terminal, compensation capacitor CP 6Through the road I 2 C bus I 2 C 4. Communicate with the main control chip;

[0031] sensor C 14 Connect one end to the ground wire and the other end to the compensation capacitor CP 7 of CP Terminal, compensation capacitor CP 7 of CN Terminal connection sampling module B of CIN 3-terminal, compensation capacitor CP 7Through the road I 2 C bus I 2 C 4. Communicate with the main control chip;

[0032] sensor C 15 Connect one end to the ground wire and the other end to the compensation capacitor CP 8 of CP Terminal, compensation capacitor CP 8 of CN Terminal connection sampling module B of CIN 4-terminal, compensation capacitor CP 8Through the road I 2 C bus I 2 C 4. Communicate with the main control chip;

[0033] Sampling Module A and sampling modules B All passed I 2 C bus I 2 C 2. Communicate with the main control chip.

[0034] Preferably, the sampling module A and sampling modules BCapacitance measurement chip IC 1 and capacitance measurement chip IC 2. Capacitance measurement chip IC 1 and capacitance measurement chip IC 2 models are FDC 1004 DSCT ;

[0035] The compensation capacitor CP 1. Compensation capacitor CP 2. Compensation capacitor CP 3. Compensation capacitor CP 4. Compensation capacitor CP 5. Compensation capacitor CP 6. Compensation capacitor CP 7 and compensation capacitor CP 8 models are NCD 2400 M ;

[0036] The model of the main control chip is STM 32 L 072.

[0037] Preferably, the reference capacitor is a tantalum capacitor CRF 2. The calibration sampling module consists of a capacitance measurement chip IC 12 and its peripheral circuit composition, capacitance measurement chip IC 12's CIN 1 end and EXC 1 terminal to tantalum capacitor CRF 2. Take samples;

[0038] Capacitance measurement chip IC The model number of 12 is AD 7150.

[0039] Preferably, the temperature and humidity sensor is a temperature transmitter IC 13. Temperature transmitter IC The model number of 13 is SHT 30, wireless communication module is LoRa RF chip, its model is SX 1262; the memory module is FLASH Memory IC 11, its model is AT 45 DB 642.

[0040] Preferably, the power supply circuit includes 12 V Power interface, power module and lithium battery pack, 12 V The power interface is the interface J 4. Lithium battery pack is a battery pack B1. The power module includes a battery management chip IC 14, 5 V Voltage Regulator IC 15 and 3.3 V Voltage Regulator IC 16. Battery pack B 1With battery management chip IC 14 connections, interfaces J 4 and battery management chip IC 14 input connection, interface J 4Connect external 12 V Power supply, battery management chip IC The output terminal of 14 is connected to 5 V Voltage Regulator IC 15 input, 5 V Voltage Regulator IC 15 output terminal connected to 3.3 V Voltage Regulator IC 16 input, 3.3 V Voltage Regulator IC 16 output ports VCC power supply, VCC The power supply provides power to the data processing unit.

[0041] Preferably, the battery management chip IC The model number of 14 is BQ 24032,5 V Voltage Regulator IC The model of 15 is TPS 7 A 02,3.3 V Voltage Regulator IC The model number of 16 is PW 6566 A 33.

[0042] The invention discloses a water immersion detection circuit with adaptive sensitivity, which solves the technical problem of implementing a real-time sensitivity compensation mechanism and realizing dynamic adjustment of a matrix sensor in a water intrusion detection system based on an adjustable capacitor array and dynamic gain adjustment. The invention adopts a digital adjustable capacitor in series with a sensor, and can dynamically adjust the compensation capacitance value, so that the initial state of each sensor tends to be consistent, collects capacitance change data in real time, calculates the actual capacitance change of the sensor, and dynamically adjusts the compensation capacitance according to the difference with the adjacent sensor, so as to ensure the consistency of sensitivity within the sensor matrix, adopts differential capacitance to calculate the deviation between a single sensor and the overall average sensitivity of the matrix, automatically compensates for capacitance drift, and significantly reduces the false alarm rate, and makes the response curves of each sensor to capacitance change consistent by adjusting the gain, so as to realize fine-grained adjustment of the sensitivity of the capacitance sensor, and dynamically adjusts the water intrusion threshold value in combination with the environmental data collected by the temperature and humidity sensor to adapt to the change of sensor characteristics under different temperature and humidity environments, and in the process of initial installation or maintenance of the sensor matrix, the system can automatically detect the capacitance difference of each sensor, automatically perform sensitivity compensation, reduce the manual adjustment time, and reduce the installation complexity, analyze the water flow direction by the capacitance change sequence of the sensors in the matrix, and evaluate the severity of water intrusion by measuring the capacitance change amplitude, so as to realize a higher level of protection and early warning function. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic block diagram of the present invention;

[0044] Figure 2 The sampling module of the present invention A , Sampling module B , circuit diagram of compensation capacitor group and matrix sensor group;

[0045] Figure 3 It is a circuit diagram of the temperature and humidity sensor and the calibration sampling module of the present invention;

[0046] Figure 4 is a circuit diagram of a storage module of the present invention;

[0047] Figure 5 is a circuit diagram of a power supply circuit of the present invention. DETAILED DESCRIPTION

[0048] Depend on Figures 1 - 5 The water immersion detection circuit with adaptive sensitivity shown in the figure includes a data processing unit and a power supply circuit. The data processing unit includes a main control chip, a sampling module A , Sampling module B , compensation capacitor group, matrix sensor group, storage module, temperature and humidity sensor, calibration sampling module, reference capacitor and wireless communication module.

[0049] The temperature and humidity sensor is a temperature transmitterIC 13. Temperature transmitter IC The model number of 13 is SHT 30, wireless communication module is LoRa RF chip, its model is SX 1262; the memory module is FLASH Memory IC 11, its model is AT 45 DB 642.

[0050] The matrix sensor group includes 8 water intrusion sensors, the compensation capacitor group includes 8 compensation capacitor chips, and each water intrusion sensor is connected in series with a compensation capacitor chip;

[0051] The matrix sensor group consists of 4×2 matrix water intrusion sensors. The main control chip uses the sampling module A and sampling modules B The capacitance measurement sampling of the 4×2 matrix water intrusion sensor is carried out, and the deviation between the capacitance change of each water intrusion sensor and the overall level of the matrix is ​​calculated through the differential compensation model. When the sensitivity of a water intrusion sensor is too high or too low, the capacitance value of the compensation capacitor chip connected in series with the water intrusion sensor is adjusted, and then the compensation capacitor is adjusted. At the same time, the sampling module for sampling the water intrusion sensor is adjusted. A or sampling module B The gain is adjusted to adjust the sensitivity adaptively.

[0052] Sampling Module A The 4 sampling input interfaces are connected to 4 compensation capacitor chips respectively, and are used to sample the water intrusion sensors behind the 4 series compensation capacitor chips; the sampling module B The 4 sampling input interfaces are respectively connected to the other 4 compensation capacitor chips, so as to sample the capacitive sensors behind the other 4 series compensation capacitor chips;

[0053] The matrix sensor group specifically includes two groups of capacitive sensors, one group includes sensors C 1. Sensor C 2. Sensors C 3 and sensor C 4. Another group includes sensors C 12. Sensors C 13. Sensors C 14 and sensor C 15;

[0054] The compensation capacitor group includes a compensation capacitor CP 1. Compensation capacitor CP 2. Compensation capacitor CP 3. Compensation capacitor CP 4. Compensation capacitorCP 5. Compensation capacitor CP 6. Compensation capacitor CP 7 and compensation capacitor CP 8;

[0055] sensor C 1. Connect one end to the ground wire and the other end to the compensation capacitor. CP 1 of CP Terminal, compensation capacitor CP 1 of CN Terminal connection sampling module A of CIN 1 terminal, compensation capacitor CP 1Through the road I 2 C bus I 2 C 5. Communicate with the main control chip;

[0056] In this embodiment, the sensor C 1Connect to the compensation capacitor via a shielded cable CP 1 of CP Terminal, compensation capacitor CP 1 of CN Connect the capacitance measurement chip IC 1 (Sampling module A )of CIN 1 terminal, compensation capacitor CP 1 of SDA Duanhe SCL End through I 2 C bus I 2 C 4 and a set of main control chips IO Port connection, to achieve I 2 C Bus communication;

[0057] Capacitance measurement chip IC 1 of SHLD 1 end is also connected to the sensor C 1. Shield connection of shielded cable;

[0058] Capacitance measurement chip IC 1 of SDA Duanhe SCL End through I 2 C bus I 2 C 2 and a set of main control chips IO Port connection, to achieve I 2 C Bus communication.

[0059] In this embodiment, the circuit principles of sampling and measurement of other sensors in the matrix sensor group are the same as those of the sensor C 1, other sensors are sensors C 2. Sensors C 3 and sensor C 4. Sensors C 12. Sensors C 13. Sensors C 14 and sensor C 15.

[0060] sensor C 2. Connect one end to the ground wire and the other end to the compensation capacitor. CP 2 of CP Terminal, compensation capacitor CP 2 of CN Terminal connection sampling module A of CIN 2-terminal, compensation capacitor CP 2Through the road I 2 C bus I 2 C 5. Communicate with the main control chip;

[0061] sensor C 3. Connect one end to the ground wire and the other end to the compensation capacitor. CP 3 of CP Terminal, compensation capacitor CP 3 of CN Terminal connection sampling module A of CIN 3-terminal, compensation capacitor CP 3Through the road I 2 C bus I 2 C 5. Communicate with the main control chip;

[0062] sensor C 4. Connect one end to the ground wire and the other end to the compensation capacitor. CP 4 of CP Terminal, compensation capacitor CP 4 of CN Terminal connection sampling module A of CIN 4-terminal, compensation capacitor CP 4Through the road I 2 C bus I 2 C 5. Communicate with the main control chip;

[0063] sensor C 12 Connect one end to the ground wire and the other end to the compensation capacitor CP 5 ofCP Terminal, compensation capacitor CP 5 of CN Terminal connection sampling module B of CIN 1 terminal, compensation capacitor CP 5Through the road I 2 C bus I 2 C 4. Communicate with the main control chip;

[0064] sensor C 13 Connect one end to the ground wire and the other end to the compensation capacitor CP 6 of CP Terminal, compensation capacitor CP 6 of CN Terminal connection sampling module B of CIN 2-terminal, compensation capacitor CP 6Through the road I 2 C bus I 2 C 4. Communicate with the main control chip;

[0065] sensor C 14 Connect one end to the ground wire and the other end to the compensation capacitor CP 7 of CP Terminal, compensation capacitor CP 7 of CN Terminal connection sampling module B of CIN 3-terminal, compensation capacitor CP 7Through the road I 2 C bus I 2 C 4. Communicate with the main control chip;

[0066] sensor C 15 Connect one end to the ground wire and the other end to the compensation capacitor CP 8 of CP Terminal, compensation capacitor CP 8 of CN Terminal connection sampling module B of CIN 4-terminal, compensation capacitor CP 8Through the road I 2 C bus I 2 C 4. Communicate with the main control chip;

[0067] Sampling Module A and sampling modules B All passed I 2 C busI 2 C 2. Communicate with the main control chip.

[0068] The sampling module A and sampling modules B Capacitance measurement chip IC 1 and capacitance measurement chip IC 2. Capacitance measurement chip IC 1 and capacitance measurement chip IC 2 models are FDC 1004 DSCT ;

[0069] The compensation capacitor CP 1. Compensation capacitor CP 2. Compensation capacitor CP 3. Compensation capacitor CP 4. Compensation capacitor CP 5. Compensation capacitor CP 6. Compensation capacitor CP 7 and compensation capacitor CP 8 models are NCD 2400 M ;

[0070] The model of the main control chip is STM 32 L 072.

[0071] In this embodiment, two capacitance measurement chips are used to sample 8 capacitive sensors. When installed, these 8 capacitive sensors can form a capacitive water intrusion sensor matrix to measure water intrusion events.

[0072] Each of the two capacitance measurement chips samples four capacitive sensors. When communicating with the main controller, the compensation capacitor corresponding to each capacitive sensor is connected through the same two channels. I 2 C bus( I 2 C 4 and I 2 C 5) Realize communication with the main control chip, while the two capacitance measurement chips communicate through another I 2 C bus( I 2 C 2) Communicate with the main control chip and achieve communication isolation on the communication channel. In the direction of the sensor matrix, each capacitance measurement chip is responsible for the sampling of a column or a row of sensors, while the compensation capacitors of the sensors in each row or column communicate with the main control chip through the same bus, which greatly facilitates software design and facilitates the expansion of the sensor array.

[0073] The calibration sampling module is connected to the reference capacitor and is used to sample the reference capacitor;

[0074] The reference capacitor is a tantalum capacitor CRF 2. The calibration sampling module consists of a capacitance measurement chip IC 12 and its peripheral circuit composition, capacitance measurement chip IC 12's CIN 1 end and EXC 1 terminal to tantalum capacitor CRF 2. Take samples;

[0075] Capacitance measurement chip IC The model number of 12 is AD 7150.

[0076] In this embodiment, a reference capacitor measurement circuit is added, and the capacitance measurement chip IC 12Realized the tantalum capacitor CRF 2 precision measurement provides reliable reference data for adjusting sensitivity, greatly improving the adjustment accuracy.

[0077] Capacitance measurement chip IC 12. It can also expand an external independent capacitive water intrusion sensor CRF 1. Users can measure external environmental capacitance according to their own needs to adapt to special environmental requirements.

[0078] Compensation capacitor group, sampling module A , Sampling module B , storage module, temperature and humidity sensor, calibration sampling module and wireless communication module are all connected to the main control chip; the input end of the power circuit is connected to the external 12 V Power supply, the output end supplies power to the data processing unit;

[0079] The power supply circuit includes 12 V Power interface, power module and lithium battery pack, 12 V The power interface is the interface J 4. Lithium battery pack is a battery pack B 1. The power module includes a battery management chip IC 14, 5 V Voltage Regulator IC 15 and 3.3 V Voltage Regulator IC 16. Battery pack B 1With battery management chip IC 14 connections, interfaces J 4 and battery management chip IC 14 input connection, interface J 4Connect external 12 V Power supply, battery management chipIC The output terminal of 14 is connected to 5 V Voltage Regulator IC 15 input, 5 V Voltage Regulator IC 15 output terminal connected to 3.3 V Voltage Regulator IC 16 input, 3.3 V Voltage Regulator IC 16 output ports VCC power supply, VCC The power supply provides power to the data processing unit.

[0080] The battery management chip IC The model number of 14 is BQ 24032,5 V Voltage Regulator IC The model of 15 is TPS 7 A 02,3.3 V Voltage Regulator IC The model number of 16 is PW 6566 A 33.

[0081] In this embodiment, the battery management chip IC 14 is used to connect the external 12 V Power conversion to 4.4 V Power output, and through 5 V Voltage Regulator IC 15 boost to 5 V Then, from 3.3 V Voltage Regulator IC 16 output 3.3 V Supply voltage VCC The power supply greatly improves the reliability of the power supply. This embodiment adopts a lithium battery for power supply, which improves the applicability.

[0082] This embodiment can dynamically adjust the sensor sensitivity, reduce the difference between sensors, optimize the performance of each sensor in the matrix, and dynamically adjust the gain in real time. NCD 2400 compensation capacitor and FDC 1004 gain registers enable precise detection. The water intrusion detection threshold can be dynamically set to ensure accurate water intrusion judgment and reduce false alarm rate. The initial installation calibration mechanism reduces sensor inconsistency problems after installation and improves system reliability.

[0083] In terms of circuit principle, this embodiment adopts 4 x 2 sensor matrix, a total of 8 sensors, each sensor is connected in series NCD 2400, passed I 2C Interface control dynamic adjustment capacitor, 2 FDC 1004 is used to measure the capacitance change of 8 sensors and monitor water intrusion. The reference capacitor uses a fixed capacitor for calibration reference. The adaptive sensitivity adjustment is achieved through capacitance compensation algorithm and gain dynamic adjustment calculation.

[0084] In specific use, the circuit of this embodiment can be used to achieve adaptive sensitivity adjustment according to the following application process:

[0085] step S 1: System startup and initialization phase (first installation and calibration), including:

[0086] step S 1-1: After the main control chip is started, detect FDC 1004 and NCD 2400 working status, realize startup self-check;

[0087] step S 1-2: NCD The initial compensation capacitor value of 2400 is set to the minimum value (refer to 1.7 pF ), to initialize the capacitance matrix;

[0088] step S 1-3: Pass AD 7150 Measurement Reference Capacitance CRF 2. Record its capacitance, i.e. C base value, to achieve reference capacitance measurement;

[0089] step S 1-4: Scan the 8 sensors in the matrix in turn and record the initial capacitance value C raw [ i ], realize sensor matrix scanning, i is the number of the sensor in the matrix;

[0090] step S 1-5: Calculate the capacitance of each sensor in the matrix and the reference capacitance C base The difference between:

[0091] ΔC i = C raw [ i ] − C base ;

[0092] step S 1-6: Differential compensation capacitance calculation:

[0093] C comp [ i ] = ΔC i ;

[0094] Controlled by the main control chip NCD 2400, Dynamically set compensation capacitor C comp [ i ], so that the initial capacitance value of each sensor is as close as possible C base , to achieve the purpose of initial calibration, in practical application, taking into account NCD 2400 threshold adjustment features (512 levels), according to C comp [ i ] value, select a higher grade as the adjustment value for adjustment;

[0095] step S 1-6: FDC 1004 Gain registers are set to default values.

[0096] step S 2: Real-time water intrusion detection stage (operation stage), the specific steps are as follows:

[0097] step S 2-1: Sensor data collection and real-time differential compensation, as follows:

[0098] step S 2-1-1: FDC 1004 Scan at a fixed frequency C 1 to C 4 and C 12 to C 15 sensor capacitance value, record real-time capacitance data C sense [ i ]; in the matrix, C 1 to C 4 and C 12 to C 15 is numbered according to i To record, from small to large, they are 1, 2, 3, ..., 8.

[0099] step S 2-1-2: Perform differential calculation on adjacent sensors to obtain differential capacitance ΔC avg :

[0100] ;

[0101] step S 2-1-3: Compensation condition judgment: If the difference between the sensor capacitance and the reference is greater than the set threshold, compensation adjustment is performed:

[0102] ΔC i > ΔC threshold ;

[0103] step S 2-1-4: Dynamically set compensation capacitance based on capacitance offset C compx [ i ]:

[0104] C compx [ i ] = C comp [ i ] + k × ( ΔC i − ΔC avg );

[0105] in, k is the compensation coefficient;

[0106] In the sensor matrix, each sensor may have different sensitivity or initial capacitance value due to factors such as manufacturing process, installation location, and environmental differences. This difference may cause false alarms or missed alarms in water intrusion detection.

[0107] formula ΔC i − ΔC avg It is mainly used to dynamically compensate for differences between sensors to make the overall sensitivity of the matrix more uniform, thereby improving detection accuracy and reliability.

[0108] ΔC i definition:

[0109] ΔC i It's a sensor i The capacitance change measured in real-time detection is compared with the reference capacitance C base The difference.

[0110] Essentially represents the sensor's response to water intrusion, the unit is pF .

[0111] ΔCi = C raw [ i ] − C base .

[0112] ΔC avg definition:

[0113] ΔC avg To calculate the average capacitance change of all sensors in the matrix;

[0114] Represents the average response of the matrix as a whole to the current environment or water intrusion situation, as a reference value:

[0115] ;

[0116] in N is the total number of sensors.

[0117] ΔC i - ΔC avg meaning:

[0118] ΔC i - ΔC avg The difference reflects the sensor i The degree of deviation from the overall level of the matrix:

[0119] like ΔC i > ΔC avg , indicating that the sensor response is too strong and the sensitivity needs to be reduced (compensation capacitance increased or gain reduced).

[0120] like ΔC i < ΔC avg , indicating that the sensor response is weak and the sensitivity needs to be improved (compensation capacitance is reduced or gain is increased).

[0121] The differences between sensors are sometimes systematic, and environmental noise or other external factors may affect the entire matrix. This embodiment uses the average capacitance change value to effectively smooth the deviation of the entire matrix and prevent individual sensors from over-responding or malfunctioning. This embodiment establishes a dynamic self-balancing mechanism, that is, in water intrusion detection, each sensor does not work independently, but achieves consistency through mutual reference, which helps to reduce errors and improve detection consistency.

[0122] In a minor water intrusion scenario, at the early stage of water intrusion, some sensors may detect water flow earlier than other sensors (such as the lowest sensor). ΔC i and ΔC avg The differential calculation can be used to adjust the compensation capacitor in time to avoid false alarms or ignore the initial signals.

[0123] In an uneven water flow scenario, if the water flow produces capacitance changes of different intensities in different areas of the matrix, differential calculation can dynamically level the matrix sensitivity, making the water flow direction detection more accurate.

[0124] step S 2-1-5: Main control chip passed I 2 C Bus NCD 2400Send I 2 C Instructions to dynamically adjust the capacitance of each channel.

[0125] step S 2-2: Dynamic gain adjustment, the specific steps are as follows:

[0126] step S 2-2-1: Perform gain calculation to obtain the gain value G i and through FDC 1004 gain register adjusts channel sensitivity:

[0127] G i = G base + α × ( ΔC i − ΔC avg );

[0128] in, G base is the initial gain value, α is the gain adjustment coefficient, which can be set between 0.1-0.5;

[0129] step S 2-2-2: According to the gain value G i Adjustment FDC The gain value of the gain register 1004 can be adjusted in stages in this embodiment, that is, when the gain value G i When a predetermined threshold is reached, the gain value of the first-stage gain register is adjusted, thereby achieving rapid adjustment.

[0130] step S 3: Water intrusion detection and threshold judgment mechanism, the specific steps are as follows:

[0131] step S 3-1: Considering the influence of temperature and humidity, the water intrusion judgment threshold is set. The specific formula is as follows:

[0132] C threshold = C base + k 1 × ( Tenv − T ref ) + k 2 × ( H env − H ref );

[0133] in, C threshold The capacitance threshold for water intrusion detection. If the sensor capacitance exceeds this value, it is determined that water intrusion has occurred;

[0134] C base is the reference capacitance value, that is, in the absence of water intrusion, the reference capacitance CRF 2 Measured fixed capacitance value;

[0135] T env is the current ambient temperature, SHT 30 measured.

[0136] T ref is the reference temperature, which is the ambient temperature recorded when the system is first installed or calibrated. SHT 30 measured.

[0137] H env is the current ambient humidity, SHT 30 measured.

[0138] H ref is the reference humidity, which is the ambient humidity recorded when the system is first installed or calibrated. SHT 30 measured.

[0139] k 1 is the temperature compensation coefficient, which indicates the influence of temperature on the capacitance change.

[0140] k 2 is the humidity compensation coefficient, which indicates the influence of humidity on the capacitance change.

[0141] step S 3-2: The water intrusion determination process is as follows:

[0142] like C sense [ i ]> C threshold , determined to be water intrusion;

[0143] like C sense [ i ]< C threshold , maintain normal status;

[0144] step S 3-3: Using the matrix multi-point consistency method, at least two adjacent sensors are required to alarm to reduce false alarms. The specific formula is as follows:

[0145] .

[0146] The invention discloses a water immersion detection circuit with adaptive sensitivity, which solves the technical problem of implementing a real-time sensitivity compensation mechanism and realizing dynamic adjustment of a matrix sensor in a water intrusion detection system based on an adjustable capacitor array and dynamic gain adjustment. The invention adopts a digital adjustable capacitor in series with a sensor, and can dynamically adjust the compensation capacitance value, so that the initial state of each sensor tends to be consistent, collects capacitance change data in real time, calculates the actual capacitance change of the sensor, and dynamically adjusts the compensation capacitance according to the difference with the adjacent sensor, so as to ensure the consistency of sensitivity within the sensor matrix, adopts differential capacitance to calculate the deviation between a single sensor and the overall average sensitivity of the matrix, automatically compensates for capacitance drift, and significantly reduces the false alarm rate, and makes the response curves of each sensor to capacitance change consistent by adjusting the gain, so as to realize fine-grained adjustment of the sensitivity of the capacitance sensor, and dynamically adjusts the water intrusion threshold value in combination with the environmental data collected by the temperature and humidity sensor to adapt to the change of sensor characteristics under different temperature and humidity environments, and in the process of initial installation or maintenance of the sensor matrix, the system can automatically detect the capacitance difference of each sensor, automatically perform sensitivity compensation, reduce the manual adjustment time, and reduce the installation complexity, analyze the water flow direction by the capacitance change sequence of the sensors in the matrix, and evaluate the severity of water intrusion by measuring the capacitance change amplitude, so as to realize a higher level of protection and early warning function.

Claims

1. A water immersion detection circuit with adaptive sensitivity, characterized in that: It includes a data processing unit and a power supply circuit. The data processing unit includes a main control chip and a sampling module. A , Sampling module B , compensation capacitor group, matrix sensor group, storage module, temperature and humidity sensor, calibration sampling module, reference capacitor and wireless communication module, the matrix sensor group includes 8 water intrusion sensors, the compensation capacitor group includes 8 compensation capacitor chips, and each water intrusion sensor is connected in series with a compensation capacitor chip; Sampling Module A The 4 sampling input interfaces are connected to 4 compensation capacitor chips respectively, and are used to sample the water intrusion sensors behind the 4 series compensation capacitor chips; Sampling Module B The 4 sampling input interfaces are respectively connected to the other 4 compensation capacitor chips, so as to sample the capacitive sensors behind the other 4 series compensation capacitor chips; The calibration sampling module is connected to the reference capacitor and is used to sample the reference capacitor; Compensation capacitor group, sampling module A , Sampling module B , storage module, temperature and humidity sensor, calibration sampling module and wireless communication module are all connected to the main control chip; the input end of the power circuit is connected to the external 12 V Power supply, the output end supplies power to the data processing unit; The matrix sensor group consists of 4×2 matrix water intrusion sensors. The main control chip uses the sampling module A and sampling modules B The capacitance measurement sampling of the 4×2 matrix water intrusion sensor is carried out, and the deviation between the capacitance change of each water intrusion sensor and the overall level of the matrix is ​​calculated through the differential compensation model. When the sensitivity of a water intrusion sensor is too high or too low, the capacitance value of the compensation capacitor chip connected in series with the water intrusion sensor is adjusted, and then the compensation capacitor is adjusted. At the same time, the sampling module for sampling the water intrusion sensor is adjusted. A or sampling module B The gain is adjusted to adjust the sensitivity adaptively.

2. The water immersion detection circuit with adaptive sensitivity as claimed in claim 1, characterized in that: The matrix sensor group specifically includes two groups of capacitive sensors, one group includes sensors C 1. Sensor C 2. Sensors C 3 and sensor C 4. Another group includes sensors C 12. Sensors C 13. Sensors C 14 and sensor C 15; The compensation capacitor group includes a compensation capacitor CP 1. Compensation capacitor CP 2. Compensation capacitor CP 3. Compensation capacitor CP 4. Compensation capacitor CP 5. Compensation capacitor CP 6. Compensation capacitor CP 7 and compensation capacitor CP 8; sensor C 1. Connect one end to the ground wire and the other end to the compensation capacitor. CP 1 of CP Terminal, compensation capacitor CP 1 of CN Terminal connection sampling module A of CIN 1 terminal, compensation capacitor CP 1Through the road I 2 C bus I 2 C 5. Communicate with the main control chip; sensor C 2. Connect one end to the ground wire and the other end to the compensation capacitor. CP 2 of CP Terminal, compensation capacitor CP 2 of CN Terminal connection sampling module A of CIN 2-terminal, compensation capacitor CP 2Through the road I 2 C bus I 2 C 5. Communicate with the main control chip; sensor C 3. Connect one end to the ground wire and the other end to the compensation capacitor. CP 3 of CP Terminal, compensation capacitor CP 3 of CN Terminal connection sampling module A of CIN 3-terminal, compensation capacitor CP 3Through the road I 2 C bus I 2 C 5. Communicate with the main control chip; sensor C 4. Connect one end to the ground wire and the other end to the compensation capacitor. CP 4 of CP Terminal, compensation capacitor CP 4 of CN Terminal connection sampling module A of CIN 4-terminal, compensation capacitor CP 4Through the road I 2 C bus I 2 C 5. Communicate with the main control chip; sensor C 12 Connect one end to the ground wire and the other end to the compensation capacitor CP 5 of CP Terminal, compensation capacitor CP 5 of CN Terminal connection sampling module B of CIN 1 terminal, compensation capacitor CP 5Through the road I 2 C bus I 2 C 4. Communicate with the main control chip; sensor C 13 Connect one end to the ground wire and the other end to the compensation capacitor CP 6 of CP Terminal, compensation capacitor CP 6 of CN Terminal connection sampling module B of CIN 2-terminal, compensation capacitor CP 6Through the road I 2 C bus I 2 C 4. Communicate with the main control chip; sensor C 14 Connect one end to the ground wire and the other end to the compensation capacitor CP 7 of CP Terminal, compensation capacitor CP 7 of CN Terminal connection sampling module B of CIN 3-terminal, compensation capacitor CP 7Through the road I 2 C bus I 2 C 4. Communicate with the main control chip; sensor C 15 Connect one end to the ground wire and the other end to the compensation capacitor CP 8 of CP Terminal, compensation capacitor CP 8 of CN Terminal connection sampling module B of CIN 4-terminal, compensation capacitor CP 8Through the road I 2 C bus I 2 C 4. Communicate with the main control chip; Sampling Module A and sampling modules B All passed I 2 C bus I 2 C 2. Communicate with the main control chip.

3. The water immersion detection circuit with adaptive sensitivity as claimed in claim 2, characterized in that: The sampling module A and sampling modules B Capacitance measurement chip IC 1 and capacitance measurement chip IC 2. Capacitance measurement chip IC 1 and capacitance measurement chip IC 2 models are FDC 1004 DSCT ; The compensation capacitor CP 1. Compensation capacitor CP 2. Compensation capacitor CP 3. Compensation capacitor CP 4. Compensation capacitor CP 5. Compensation capacitor CP 6. Compensation capacitor CP 7 and compensation capacitor CP 8 models are NCD 2400 M ; The model of the main control chip is STM 32 L 072.

4. The water immersion detection circuit with adaptive sensitivity as claimed in claim 1, characterized in that: The reference capacitor is a tantalum capacitor CRF 2. The calibration sampling module consists of a capacitance measurement chip IC 12 and its peripheral circuit composition, capacitance measurement chip IC 12's CIN 1 end and EXC 1 terminal to tantalum capacitor CRF 2. Take samples; Capacitance measurement chip IC The model number of 12 is AD 7150.

5. The water immersion detection circuit with adaptive sensitivity as claimed in claim 1, characterized in that: The temperature and humidity sensor is a temperature transmitter IC 13. Temperature transmitter IC The model number of 13 is SHT 30, wireless communication module is LoRa RF chip, its model is SX 1262; the storage module is FLASH Memory IC 11, its model is AT 45 DB 642.

6. The water immersion detection circuit with adaptive sensitivity as claimed in claim 1, characterized in that: The power supply circuit includes 12 V Power interface, power module and lithium battery pack, 12 V The power interface is the interface J 4. Lithium battery pack is a battery pack B 1. The power module includes a battery management chip IC 14, 5 V Voltage Regulator IC 15 and 3.3 V Voltage Regulator IC 16. Battery pack B 1With battery management chip IC 14 connections, interfaces J 4 and battery management chip IC 14 input connection, interface J 4Connect external 12 V Power supply, battery management chip IC The output terminal of 14 is connected to 5 V Voltage Regulator IC 15 input, 5 V Voltage Regulator IC 15 output terminal connected to 3.3 V Voltage Regulator IC 16 input, 3.3 V Voltage Regulator IC 16 output ports VCC power supply, VCC The power supply provides power to the data processing unit.

7. The water immersion detection circuit with adaptive sensitivity as claimed in claim 6, characterized in that: The battery management chip IC The model number of 14 is BQ 24032,5 V Voltage Regulator IC The model of 15 is TPS 7 A 02,3.3 V Voltage Regulator IC The model number of 16 is PW 6566 A 33.

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