A circuit arrangement for water detection

Abstract

The utility model discloses a circuit device for water detection, including printed circuit board, microcontrol unit and metal quality fixed screw. The fixed screw passes through equipment shell and is fixed with its machinery, and the one end exposed to the outside environment is directly used as water contact sensing element, and the inner end is directly connected to microcontrol unit input pin through the electrical connection point of printed circuit board. When water contacts the exposed part of screw, the capacitance or resistance characteristic produces change, and microcontrol unit detects the change in real time and exports water detection signal. The utility model reuses fixed screw as mechanical fastener and sensing element, and independent sensor module and signal processing circuit are saved, which simplifies structure and significantly reduces production and assembly cost. Further scheme contains anti -oxidation insulating layer, reference ground copper foil and alternative metal fixing piece (such as rivet, buckle), and improves detection stability and applicability. It has the advantages of high reliability and wide adaptation scene.

Description

Technical Field

[0001] This utility model relates to a circuit device based on a fixture reuse design, and more particularly to a circuit device for water detection. Background Technology

[0002] Existing water detection devices often rely on dedicated sensor modules (such as touch ICs, electrodes, or large copper foils) for signal sensing, and then transmit the signals to the main control unit via external processing circuitry. This design requires additional sensor components and supporting circuitry, resulting in a large number of components, cumbersome assembly processes, and high production costs. Furthermore, the complex peripheral circuitry is prone to introducing electromagnetic interference, reducing detection reliability and hindering miniaturization and integrated applications. Therefore, there is an urgent need for a water detection solution that is structurally simple, cost-effective, and easy to assemble. Utility Model Content

[0003] In view of the above situation, it is necessary to provide a circuit device for water detection that solves at least one of the above problems, comprising: A printed circuit board (100) integrating a microcontroller unit (110). At least one metal fixing screw (102) passes through the device housing (120) and is electrically connected to the printed circuit board (100); One end of the fixing screw (102) is mechanically fixed to the equipment housing (120), while the other end is exposed to the external environment; The input terminal of the microcontroller unit (110) is directly connected to the electrical connection point of the fixing screw (102), and the water contact state is determined by detecting the change in the electrical characteristics of the fixing screw (102).

[0004] Preferably, the exposed portion of the fixing screw (102) is located in the detection area of ​​the equipment housing (120), and the exposed axial length is ≥3mm.

[0005] Preferably, the electrical connection point of the fixing screw (102) is directly connected to the input pin of the microcontroller unit (110) through a metallized via (105) of the printed circuit board (100).

[0006] Preferably, the microcontroller unit (110) is configured to detect the capacitance change between the fixing screw (102) and the grounding terminal, and output a water detection signal according to a preset threshold.

[0007] Preferably, the surface of the fixing screw (102) is covered with an anti-oxidation insulating layer, and the insulating layer is punctured and conductive when in contact with water.

[0008] Preferably, the printed circuit board (100) is provided with a reference ground copper foil (130), and the fixing screw (102) is in contact with the reference ground copper foil (130).

[0009] Preferably, the reference grounding copper foil (130) is arranged in a ring around the mounting hole (140) of the fixing screw (102).

[0010] Preferably, the fixing screw (102) can be replaced with a rivet or a metal clip fastener. Attached Figure Description

[0011] Figure 1 This is a first-view structural schematic diagram of a circuit device for water detection according to an embodiment of the present invention.

[0012] Figure 2 This is a second-view structural schematic diagram of the circuit device for water detection according to an embodiment of the present invention. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0014] In the description of this utility model, unless otherwise stated, "a plurality of" means two or more; the terms "center," "longitudinal," "lateral," "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0015] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0016] Please see Figure 1 as well as Figure 2 A circuit device for water detection according to an embodiment of the present invention includes: a printed circuit board (100) integrating a microcontroller unit (110); at least one metal fixing screw (102) passing through a device housing (120) and electrically connected to the printed circuit board (100); one end of the fixing screw (102) is mechanically fixed to the device housing (120), and the other end is exposed to the external environment; the input terminal of the microcontroller unit (110) is directly connected to the electrical connection point of the fixing screw (102), and the water contact state is determined by detecting the change in the electrical characteristics of the fixing screw (102). The fixing screw (102) directly serves as a water contact sensing element. When water contacts its exposed end, the electrical characteristics such as capacitance or resistance of the fixing screw (102) change significantly with the conductivity of water. The microcontroller unit (110) detects this change through an internal program and triggers an alarm or control signal. By eliminating the need for traditional independent sensor modules and external signal processing circuits, this device simplifies the structure and production process and reduces costs by reusing the mechanical and sensing functions of the fixing screw (102).

[0017] Please see Figure 1 as well as Figure 2 In another embodiment, the exposed portion of the fixing screw (102) is located in the detection area of ​​the equipment housing (120), and the exposed axial length is ≥3mm. The exposed end of the fixing screw (102) extends to the bottom or side detection area of ​​the equipment housing (120), and the exposed length ensures that water can effectively contact the surface. When water submerges the exposed portion, the longer axial contact area can improve detection sensitivity and avoid false judgments. The position layout of the exposed portion can be adjusted according to the equipment application scenario (such as water tank, water accumulation on the ground) to adapt to different detection scenario requirements.

[0018] Please see Figure 1 as well as Figure 2 In another embodiment, the electrical connection point of the fixing screw (102) is directly connected to the input pin of the microcontroller unit (110) via a metallized via (105) of the printed circuit board (100). The metallized via (105) extends through the upper and lower layers of the printed circuit board (100), directly connecting the screw head or threaded segment of the fixing screw (102) to the input pin of the microcontroller unit (110) located on the bottom layer of the PCB. This design reduces the need for wire soldering or circuit transitions, reduces parasitic capacitance / resistance interference, improves signal transmission stability, and simplifies the assembly process.

[0019] Please see Figure 1 as well as Figure 2In another embodiment, the microcontroller unit (110) is configured to detect the capacitance change between the fixing screw (102) and the grounding terminal, and output a water detection signal according to a preset threshold. The microcontroller unit (110) integrates a capacitance detection module that measures the equivalent capacitance between the fixing screw (102) and the grounding terminal (such as the device housing or a reference grounding copper foil) through periodic charging and discharging. When water comes into contact with the exposed screw, the capacitance value increases, and the microcontroller unit (110) compares the real-time value with a preset threshold; if the threshold is exceeded, it outputs a high / low level signal. This method eliminates the need for an external capacitance conversion chip, further simplifying the circuit design.

[0020] Please see Figure 1 as well as Figure 2 In another embodiment, the surface of the fixing screw (102) is covered with an anti-oxidation insulating layer, and the insulating layer breaks down and conducts when in contact with water. The metal surface of the fixing screw (102) is covered with an insulating layer (such as an aluminum oxide film) by electroplating or spraying, which prevents oxidation from causing signal drift under normal conditions. When water covers the exposed part, the conductivity of the water causes the insulating layer to break down locally, forming a conductive path and triggering a sudden change in electrical characteristics. This design balances corrosion prevention and detection reliability, significantly extending the sensor's lifespan.

[0021] Please see Figure 1 as well as Figure 2 In another embodiment, a reference ground copper foil (130) is provided on the printed circuit board (100), and the fixing screw (102) is conductive to the reference ground copper foil (130) through contact. The reference ground copper foil (130) serves as the reference end for capacitance detection, is directly disposed on the surface of the printed circuit board (100), and is conductive to the fixing screw (102) through the mechanical pressure of the screw mounting hole. By separating the grounding of the device housing (120) from the circuit reference grounding, the influence of external electromagnetic interference on the detection results can be reduced, and the signal-to-noise ratio can be improved.

[0022] Please see Figure 1 as well as Figure 2 In another embodiment, the reference grounding copper foil (130) is arranged in a ring around the mounting via (140) of the fixing screw (102). The reference grounding copper foil (130) is arranged in a ring around the mounting via (105) of the fixing screw (102) to ensure that the contact area between the screw and the grounding copper foil is maximized, while forming a symmetrical electric field distribution. The ring layout can reduce the edge effect during capacitance detection, improve detection accuracy, and is suitable for stable operation in high humidity environments.

[0023] Please see Figure 1 as well as Figure 2In another embodiment, the fixing screw (102) can be replaced with a rivet or a metal clip fastener. For example, a rivet penetrates the device housing (120) and conducts electricity to the printed circuit board (100) through riveting, achieving the same water contact detection function; a metal clip is fixed to the housing using an elastic clamping structure, and its exposed metal head also serves as a sensing terminal. These variations adapt to different installation scenarios, broadening the application range.

[0024] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.

Claims

1. A circuit device for water detection, characterized in that, include: A printed circuit board (100) integrating a microcontroller unit (110). At least one metal fixing screw (102) passes through the device housing (120) and is electrically connected to the printed circuit board (100); One end of the fixing screw (102) is mechanically fixed to the equipment housing (120), while the other end is exposed to the external environment; The input terminal of the microcontroller unit (110) is directly connected to the electrical connection point of the fixing screw (102), and the water contact state is determined by detecting the change in the electrical characteristics of the fixing screw (102).

2. The circuit device as claimed in claim 1, characterized in that: The exposed portion of the fixing screw (102) is located in the detection area of ​​the equipment housing (120), and the exposed axial length is ≥3mm.

3. The circuit device as claimed in claim 1, characterized in that: The electrical connection point of the fixing screw (102) is directly connected to the input pin of the microcontroller unit (110) through a metallized via (105) of the printed circuit board (100).

4. The circuit device as claimed in claim 1, characterized in that: The microcontroller unit (110) is configured to detect the capacitance change between the fixing screw (102) and the grounding terminal, and output a water detection signal according to a preset threshold.

5. The circuit device as claimed in claim 1, characterized in that: The surface of the fixing screw (102) is covered with an anti-oxidation insulating layer, and the insulating layer is punctured and conductive when in contact with water.

6. The circuit device as claimed in claim 1, characterized in that: The printed circuit board (100) is provided with a reference ground copper foil (130), and the fixing screw (102) is in contact with the reference ground copper foil (130).

7. The circuit device as claimed in claim 6, characterized in that: The reference grounding copper foil (130) is arranged in a ring around the mounting through hole (140) of the fixing screw (102).

8. The circuit device as claimed in claim 1, characterized in that: The fixing screw (102) can be replaced with a rivet or a metal clip fastener.

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