A water immersion sensor

Abstract

The present invention discloses a water immersion sensor, including a sensing head, a signal processing circuit and a wireless communication module; the sensing head includes two metal probes and a water-absorbing sponge; the two metal probes are inserted in parallel on the water-absorbing sponge; the signal processing circuit includes an oscillation circuit, a frequency selection circuit, a primary filtering circuit, a secondary filtering circuit, a differential amplifier circuit and a controller module; the controller module is electrically connected to the wireless communication module. The water immersion sensor can form a frequency domain monitoring circuit of two metal probes using an oscillation circuit and a frequency selection circuit, and transmit the feedback signal to the primary filtering circuit; the primary filtering circuit, the secondary filtering circuit and the differential amplifier circuit can sequentially perform primary filtering, secondary filtering and amplification processing on the feedback signal to enhance the reliability of signal acquisition; the wireless communication module can wirelessly transmit the collected relative humidity to an IoT platform to achieve remote monitoring and management.

Description

Technical Field

[0001] The invention relates to a sensor, in particular to a water immersion sensor. Background Art

[0002] At present, most of the flood alarms on the market are switch type, but in some cold storage or water room environments, a small amount of water accumulation is allowed, so it is necessary to not use a switch type flood alarm. Therefore, it is necessary to design a flood alarm that can detect the percentage of flooding and set a threshold value, and alarm when the threshold is exceeded. Summary of the invention

[0003] Purpose of the invention: to provide a water immersion alarm that can detect the percentage of water immersion and set a threshold value, and an alarm will be sounded when the threshold is exceeded.

[0004] Technical solution: The water immersion sensor of the present invention includes a sensor head, a signal processing circuit and a wireless communication module;

[0005] The sensor head includes two metal probes and a water-absorbing sponge; the two metal probes are inserted in parallel on the water-absorbing sponge;

[0006] The signal processing circuit includes an oscillation circuit, a frequency selection circuit, a primary filtering circuit, a secondary filtering circuit, a differential amplifier circuit and a controller module; two metal probes are electrically connected to the frequency selection circuit for receiving analog signals of the two metal probes; the oscillation circuit is electrically connected to the frequency selection circuit for providing an oscillation signal to the frequency selection circuit; the primary filtering circuit is electrically connected to the frequency selection circuit for filtering the output signal of the frequency selection circuit; the secondary filtering circuit is electrically connected to the primary filtering circuit for filtering the output signal of the primary filtering circuit; the differential amplifier circuit is electrically connected to the secondary filtering circuit for differentially amplifying the output signal of the secondary filtering circuit; the differential amplifier circuit is electrically connected to the controller module, and the controller module collects and processes the output signal of the differential amplifier circuit; the controller module is electrically connected to the wireless communication module, and the wireless communication module wirelessly transmits the output signal of the controller module.

[0007] Furthermore, when the controller module is performing acquisition processing,

[0008] If the collected voltage value is less than 0.336V, the relative humidity S is 0%;

[0009] If the collected voltage value is between 0.336V and 0.742V, the relative humidity is calculated in one step. The calculation formula of relative humidity S is:

[0010] S=(12519×X 5 -25696×X 4+19460×X 3 -6339.1×X 2 +770.82×X-7.3991) / 100×100%

[0011] In the formula, X is the collected voltage value;

[0012] If the collected voltage value is between 0.742V and 0.77V, the relative humidity is calculated in one step. The calculation formula of relative humidity S is:

[0013] S=(-68392×X 2 +104831×X-40068) / 100×100%

[0014] In the formula, X is the collected voltage value;

[0015] If the collected voltage value is greater than 0.77V, the relative humidity S is 100%;

[0016] The relative humidity S is wirelessly transmitted by the controller module through the wireless communication module.

[0017] Furthermore, the frequency selection circuit includes a resistor R24, a capacitor C14, a capacitor C16, a resistor R25 and a capacitor C17; one end of the resistor R24 ​​is electrically connected to the oscillation output signal end of the oscillation circuit, and the other end of the resistor R24 ​​is electrically connected to one end of the capacitor C14; the other end of the capacitor C14 is electrically connected to a metal probe; another metal probe is electrically connected to one end of the capacitor C16, one end of the resistor R25 and one end of the capacitor C17 respectively; the other end of the capacitor C16, the other end of the resistor R25 and the other end of the capacitor C17 are all grounded.

[0018] Furthermore, the primary filtering circuit includes a diode D1, a diode D2, a resistor R18 and a resistor R19; the positive terminal of the diode D1 is electrically connected to one end of the resistor R24, and the positive terminal of the diode D2 is electrically connected to the other end of the resistor R24; one end of the resistor R18 is electrically connected to the negative end of the diode D1; one end of the resistor R19 is electrically connected to the negative end of the diode D2; the other end of the resistor R18 and the other end of the resistor R19 are respectively electrically connected to the two input ends of the secondary filtering circuit.

[0019] Furthermore, the secondary filtering circuit includes a capacitor C7, a capacitor C10, a capacitor C8, a resistor R16, a resistor R15, a resistor R14, a resistor R12 and a resistor R13; one end of the capacitor C7 is electrically connected to one end of the resistor R16, and the other end of the capacitor C7 is electrically connected to one end of the capacitor C10 and the other end of the resistor R18; the other end of the capacitor C10 is electrically connected to the other end of the resistor R19 and one end of the capacitor C8; the other end of the capacitor C8 is electrically connected to one end of the resistor R15; the other end of the resistor R16 is electrically connected to one end of the resistor R12 and one end of the resistor R14; the other end of the resistor R15 is electrically connected to one end of the resistor R13 and the other end of the resistor R14; the other end of the resistor R12 and the other end of the resistor R13 are electrically connected to two input ends of the differential amplifier circuit.

[0020] Furthermore, the differential amplifier circuit includes an operational amplifier U3, an operational amplifier U4, an operational amplifier U5, a capacitor C3, a resistor R4, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10 and a resistor R11; the positive input terminal of the operational amplifier U4 is electrically connected to the other end of the resistor R12, and the positive input terminal of the operational amplifier U5 is electrically connected to the other end of the resistor R13; the negative input terminal of the operational amplifier U4 is electrically connected to one end of the resistor R10, and the negative input terminal of the operational amplifier U5 is electrically connected to one end of the resistor R11; one end of the resistor R9 is electrically connected to the other end of the resistor R10, the operational amplifier U5 and the capacitor C3. The output end of the operational amplifier U4 is electrically connected to one end of the resistor R7; the other end of the resistor R9 is electrically connected to the other end of the resistor R11, the output end of the operational amplifier U5 and one end of the resistor R8; the other end of the resistor R7 is electrically connected to one end of the capacitor C3, one end of the resistor R4 and the negative input end of the operational amplifier U3; the other end of the resistor R8 is electrically connected to the positive input end of the operational amplifier U3 and one end of the resistor R6; the other end of the resistor R6 is grounded; the output end of the operational amplifier U3 is electrically connected to the other end of the capacitor C3, the other end of the resistor R4 and the A / D acquisition end of the controller module.

[0021] Furthermore, a supporting mesh sleeve is provided on the outer side of the water-absorbing sponge, and the lower end surface of the water-absorbing sponge extends out of the supporting mesh sleeve; a top cover plate is provided at the upper end of the supporting mesh sleeve; two metal probes are installed on the top cover plate in a through-type manner; a limit retaining ring is provided on the upper end of the two metal probes; an external thread is provided on the metal probe above the limit retaining ring, and an electrode nut is threadedly installed on the external thread.

[0022] Furthermore, one side edge of the top cover plate extends to the outside of the upper port of the supporting mesh sleeve, and an adjusting sleeve is vertically installed on the extended side; an adjusting screw is vertically inserted into the adjusting sleeve, and two clamping nuts are threadedly installed on the adjusting screw, and the clamping nuts are respectively pressed on the upper and lower end pipe openings of the adjusting sleeve; an L-shaped mounting plate is fixedly installed at the lower end of the adjusting screw, and a mounting hole is provided on the vertical plate of the L-shaped mounting plate.

[0023] Compared with the prior art, the present invention has the following beneficial effects: an oscillation circuit can be used to provide a stable frequency source, and then the frequency selection circuit can screen out the frequency within a certain range and transmit the feedback signal to the primary filtering circuit; the primary filtering circuit, the secondary filtering circuit and the differential amplifier circuit can be used to perform primary filtering, secondary filtering and amplification processing on the feedback signal in turn, thereby enhancing the reliability of signal acquisition; the wireless communication module can be used to wirelessly transmit the collected relative humidity to the IoT platform, thereby realizing remote monitoring and management. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of the signal processing circuit of the present invention;

[0025] Figure 2 It is a schematic diagram of the structure of the sensor head of the present invention. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the embodiments.

[0027] Embodiment 1:

[0028] like Figure 1 and 2 As shown, the water immersion sensor of the present invention comprises: a sensor head, a signal processing circuit and a wireless communication module 7; the sensor head comprises two metal probes 8 and a water-absorbing sponge 11; the two metal probes 8 are parallelly inserted on the water-absorbing sponge 11;

[0029] The signal processing circuit includes an oscillation circuit 1, a frequency selection circuit 2, a primary filter circuit 3, a secondary filter circuit 4, a differential amplifier circuit 5 and a controller module 6; two metal probes 8 are electrically connected to the frequency selection circuit 2 for receiving analog signals of the two metal probes 8; the oscillation circuit 1 is electrically connected to the frequency selection circuit 2 for providing an oscillation signal to the frequency selection circuit 2; the primary filter circuit 3 is electrically connected to the frequency selection circuit 2 for filtering the output signal of the frequency selection circuit 2; the secondary filter circuit 4 is electrically connected to the primary filter circuit 3 for filtering the output signal of the primary filter circuit 3; the differential amplifier circuit 5 is electrically connected to the secondary filter circuit 4 for differentially amplifying the output signal of the secondary filter circuit 4; the differential amplifier circuit 5 is electrically connected to the controller module 6, and the controller module 6 collects and processes the output signal of the differential amplifier circuit 5; the controller module 6 is electrically connected to the wireless communication module 7, and the wireless communication module 7 wirelessly transmits the output signal of the controller module 6.

[0030] The oscillation circuit 1 can provide a stable frequency source, and the frequency selection circuit 2 can filter out the frequency within a certain range and transmit the feedback signal to the primary filter circuit 3; the primary filter circuit 3, the secondary filter circuit 4 and the differential amplifier circuit 5 can perform primary filtering, secondary filtering and amplification processing on the feedback signal in turn to enhance the reliability of signal acquisition; the wireless communication module 7 can wirelessly transmit the collected relative humidity to the IoT platform to realize remote monitoring and management.

[0031] Furthermore, when the controller module 6 performs acquisition processing,

[0032] If the collected voltage value is less than 0.336V, the relative humidity S is 0%;

[0033] If the collected voltage value is between 0.336V and 0.742V, the relative humidity is calculated in one step. The calculation formula of relative humidity S is:

[0034] S=(12519×X 5 -25696×X 4 +19460×X 3 -6339.1×X 2 +770.82×X-7.3991) / 100×100%

[0035] In the formula, X is the collected voltage value;

[0036] If the collected voltage value is between 0.742V and 0.77V, the relative humidity is calculated in one step. The calculation formula of relative humidity S is:

[0037] S=(-68392×X 2+104831×X-40068) / 100×100%

[0038] In the formula, X is the collected voltage value;

[0039] If the collected voltage value is greater than 0.77V, the relative humidity S is 100%;

[0040] The relative humidity S is wirelessly transmitted by the controller module 6 through the wireless communication module 7 .

[0041] Furthermore, the frequency selection circuit 2 includes a resistor R24, a capacitor C14, a capacitor C16, a resistor R25 and a capacitor C17; one end of the resistor R24 ​​is electrically connected to the oscillation output signal end of the oscillation circuit 1, and the other end of the resistor R24 ​​is electrically connected to one end of the capacitor C14; the other end of the capacitor C14 is electrically connected to a metal probe 8; another metal probe 8 is electrically connected to one end of the capacitor C16, one end of the resistor R25 and one end of the capacitor C17 respectively; the other end of the capacitor C16, the other end of the resistor R25 and the other end of the capacitor C17 are all grounded. The RC frequency selection circuit of the frequency selection circuit 2 can be used to select the frequency, and then the frequency between the two metal probes 8 is fed back to the two ends of the resistor R24, so as to facilitate the input processing of the primary filter circuit 3.

[0042] Furthermore, the primary filtering circuit 3 includes a diode D1, a diode D2, a resistor R18 and a resistor R19; the positive terminal of the diode D1 is electrically connected to one end of the resistor R24, and the positive terminal of the diode D2 is electrically connected to the other end of the resistor R24; one end of the resistor R18 is electrically connected to the negative end of the diode D1; one end of the resistor R19 is electrically connected to the negative end of the diode D2; the other end of the resistor R18 and the other end of the resistor R19 are respectively electrically connected to the two input ends of the secondary filtering circuit 4.

[0043] Furthermore, the secondary filtering circuit 4 includes a capacitor C7, a capacitor C10, a capacitor C8, a resistor R16, a resistor R15, a resistor R14, a resistor R12 and a resistor R13; one end of the capacitor C7 is electrically connected to one end of the resistor R16, and the other end of the capacitor C7 is electrically connected to one end of the capacitor C10 and the other end of the resistor R18; the other end of the capacitor C10 is electrically connected to the other end of the resistor R19 and one end of the capacitor C8; the other end of the capacitor C8 is electrically connected to one end of the resistor R15; the other end of the resistor R16 is electrically connected to one end of the resistor R12 and one end of the resistor R14; the other end of the resistor R15 is electrically connected to one end of the resistor R13 and the other end of the resistor R14; the other end of the resistor R12 and the other end of the resistor R13 are electrically connected to two input ends of the differential amplifier circuit 5.

[0044] Furthermore, the differential amplifier circuit 5 includes an operational amplifier U3, an operational amplifier U4, an operational amplifier U5, a capacitor C3, a resistor R4, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10 and a resistor R11; the positive input terminal of the operational amplifier U4 is electrically connected to the other end of the resistor R12, and the positive input terminal of the operational amplifier U5 is electrically connected to the other end of the resistor R13; the negative input terminal of the operational amplifier U4 is electrically connected to one end of the resistor R10, and the negative input terminal of the operational amplifier U5 is electrically connected to one end of the resistor R11; one end of the resistor R9 is electrically connected to the other end of the resistor R10, the operational amplifier U5 and the capacitor C3. The output end of the operational amplifier U4 is electrically connected to one end of the resistor R7; the other end of the resistor R9 is electrically connected to the other end of the resistor R11, the output end of the operational amplifier U5 and one end of the resistor R8; the other end of the resistor R7 is electrically connected to one end of the capacitor C3, one end of the resistor R4 and the negative input end of the operational amplifier U3; the other end of the resistor R8 is electrically connected to the positive input end of the operational amplifier U3 and one end of the resistor R6; the other end of the resistor R6 is grounded; the output end of the operational amplifier U3 is electrically connected to the other end of the capacitor C3, the other end of the resistor R4 and the A / D acquisition end of the controller module 6.

[0045] Furthermore, a support mesh sleeve 10 is provided on the outer side of the water-absorbing sponge 11, and the lower end surface of the water-absorbing sponge 11 extends out of the support mesh sleeve 10; a top cover plate 9 is provided at the upper end of the support mesh sleeve 10; two metal probes 8 are both installed on the top cover plate 9 in a through-type manner; a limit retaining ring 12 is provided on the upper end of the two metal probes 8; an external thread 13 is provided on the metal probe 8 above the limit retaining ring 12, and an electrode nut 14 is threadedly installed on the external thread 13. The coordinated arrangement of the support mesh sleeve 10 and the top cover plate 9 can enhance the relative stability between the water-absorbing sponge 11 and the two metal probes 8, and ensure the accuracy and reliability of the dielectric constant measurement.

[0046] Furthermore, one side edge of the top cover plate 9 extends to the outside of the upper port of the support mesh sleeve 10, and an adjusting sleeve 15 is installed vertically through the extended side; an adjusting screw 16 is inserted vertically through the adjusting sleeve 15, and two clamping nuts 19 are installed on the adjusting screw 16 by threading, and the clamping nuts 19 are pressed on the upper and lower ends of the adjusting sleeve 15 respectively; an L-shaped mounting plate 17 is fixedly installed at the lower end of the adjusting screw 16, and a mounting hole 18 is provided on the vertical plate of the L-shaped mounting plate 17. By using the cooperation of the adjusting sleeve 15, the adjusting screw 16 and the two clamping nuts 19, the height of the lower end surface of the water-absorbing sponge 11 can be adjusted to meet the needs of on-site installation.

[0047] Furthermore, the oscillation circuit 1 is composed of a magnetic bead L2 and a crystal oscillator Y2, and can provide an oscillation signal of 100 MHz.

[0048] In the water immersion sensor described in the present invention, the wireless communication module 7 adopts the existing Zigbee wireless communication module, which can perform wireless networking communication with the gateway, thereby wirelessly transmitting the detection results to the IoT platform; the controller module 6 adopts the existing single-chip microcomputer module, and the single-chip microcomputer module itself has an A / D acquisition port to realize the acquisition of analog signals; the operational amplifier U3, the operational amplifier U4 and the operational amplifier U5 all adopt the operational amplifier model LMV344IDR.

[0049] When the water immersion sensor of the present invention is installed and used, the sensor head is installed at the monitoring position by using the L-shaped mounting plate 17, and the height of the lower end surface of the water-absorbing sponge 11 is adjusted by two clamping nuts 19. After the signal processing circuit is powered on, the oscillation circuit 1 provides a 100Mhz active crystal oscillator, and then the frequency selection circuit 2 transmits the oscillation signal to the two metal probes 8, and at the same time, the feedback signals of the two metal probes 8 are fed back and transmitted to the two ends of the resistor R24, so as to facilitate the input of the primary filter circuit 3, and the diode D1 and the diode D2 of the primary filter circuit 3 perform a primary filter. The voltage of the water-absorbing sponge 11 after absorbing water is calculated by the controller module 6 using the collected analog data, and then the relative humidity S is further obtained. Finally, the relative humidity S is sent to the gateway using the wireless communication module 7 and uploaded to the IoT platform. The IoT platform performs alarms and other operations based on pre-set thresholds.

[0050] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the present invention itself. Various changes in form and details may be made without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. A water immersion sensor, characterized in that: It comprises a sensor head, a signal processing circuit and a wireless communication module (7); The sensor head comprises two metal probes (8) and a water-absorbing sponge (11); the two metal probes (8) are inserted in parallel on the water-absorbing sponge (11); The signal processing circuit comprises an oscillating circuit (1), a frequency selecting circuit (2), a primary filtering circuit (3), a secondary filtering circuit (4), a differential amplifier circuit (5) and a controller module (6); two metal probes (8) are electrically connected to the frequency selecting circuit (2) for receiving analog signals of the two metal probes (8); the oscillating circuit (1) is electrically connected to the frequency selecting circuit (2) for providing an oscillating signal to the frequency selecting circuit (2); the primary filtering circuit (3) is electrically connected to the frequency selecting circuit (2) for filtering the output signal of the frequency selecting circuit (2); and the secondary filtering circuit (4) is electrically connected to the frequency selecting circuit (2) for filtering the output signal of the frequency selecting circuit (2). The filter circuit (4) is electrically connected to the primary filter circuit (3) and is used to filter the output signal of the primary filter circuit (3); the differential amplifier circuit (5) is electrically connected to the secondary filter circuit (4) and is used to differentially amplify the output signal of the secondary filter circuit (4); the differential amplifier circuit (5) is electrically connected to the controller module (6), and the controller module (6) collects and processes the output signal of the differential amplifier circuit (5); the controller module (6) is electrically connected to the wireless communication module (7), and the wireless communication module (7) wirelessly transmits the output signal of the controller module (6); When the controller module (6) performs data collection and processing, If the collected voltage value is less than 0.336V, the relative humidity S is 0%; If the collected voltage value is between 0.336V and 0.742V, the relative humidity is calculated in one step. The calculation formula of relative humidity S is: S=(12519×X 5 -25696×X 4 +19460×X 3 -6339.1×X 2 +770.82×X-7.3991) / 100×100% In the formula, X is the collected voltage value; If the collected voltage value is between 0.742V and 0.77V, the relative humidity is calculated in one step. The calculation formula of relative humidity S is: S=(-68392×X 2 +104831×X-40068) / 100×100% In the formula, X is the collected voltage value; If the collected voltage value is greater than 0.77V, the relative humidity S is 100%; The relative humidity S is wirelessly transmitted by the controller module (6) through the wireless communication module (7).

2. The water immersion sensor according to claim 1, characterized in that: The frequency selection circuit (2) comprises a resistor R24, a capacitor C14, a capacitor C16, a resistor R25 and a capacitor C17; one end of the resistor R24 ​​is electrically connected to the oscillation output signal end of the oscillation circuit (1), and the other end of the resistor R24 ​​is electrically connected to one end of the capacitor C14; the other end of the capacitor C14 is electrically connected to a metal probe (8); another metal probe (8) is electrically connected to one end of the capacitor C16, one end of the resistor R25 and one end of the capacitor C17 respectively; the other end of the capacitor C16, the other end of the resistor R25 and the other end of the capacitor C17 are all grounded.

3. The water immersion sensor according to claim 2, characterized in that: The primary filter circuit (3) comprises a diode D1, a diode D2, a resistor R18 and a resistor R19; the positive terminal of the diode D1 is electrically connected to one end of the resistor R24, and the positive terminal of the diode D2 is electrically connected to the other end of the resistor R24; one end of the resistor R18 is electrically connected to the negative terminal of the diode D1; one end of the resistor R19 is electrically connected to the negative terminal of the diode D2; and the other end of the resistor R18 and the other end of the resistor R19 are electrically connected to two input terminals of the secondary filter circuit (4), respectively.

4. The water immersion sensor according to claim 3, characterized in that: The secondary filtering circuit (4) comprises a capacitor C7, a capacitor C10, a capacitor C8, a resistor R16, a resistor R15, a resistor R14, a resistor R12 and a resistor R13; one end of the capacitor C7 is electrically connected to one end of the resistor R16, and the other end of the capacitor C7 is electrically connected to one end of the capacitor C10 and the other end of the resistor R18; the other end of the capacitor C10 is electrically connected to the other end of the resistor R19 and one end of the capacitor C8; the other end of the capacitor C8 is electrically connected to one end of the resistor R15; the other end of the resistor R16 is electrically connected to one end of the resistor R12 and one end of the resistor R14; the other end of the resistor R15 is electrically connected to one end of the resistor R13 and the other end of the resistor R14; the other end of the resistor R12 and the other end of the resistor R13 are electrically connected to two input ends of the differential amplifier circuit (5).

5. The water immersion sensor according to claim 4, characterized in that: The differential amplifier circuit (5) comprises an operational amplifier U3, an operational amplifier U4, an operational amplifier U5, a capacitor C3, a resistor R4, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10 and a resistor R11; the positive input terminal of the operational amplifier U4 is electrically connected to the other end of the resistor R12, and the positive input terminal of the operational amplifier U5 is electrically connected to the other end of the resistor R13; the negative input terminal of the operational amplifier U4 is electrically connected to one end of the resistor R10, and the negative input terminal of the operational amplifier U5 is electrically connected to one end of the resistor R11; one end of the resistor R9 is electrically connected to the other end of the resistor R10, the operational amplifier U5 and the capacitor C3 ...0, the operational amplifier U5 and the capacitor C3; the positive input terminal of the operational amplifier U4 is electrically connected to the other end of the resistor R10, the operational amplifier U5 and the capacitor C3; the positive input terminal of the operational amplifier U4 is electrically connected to the other end of the resistor R13, and the positive input terminal of the operational amplifier U5 is electrically connected to the other end of the resistor R13. The output end of U4 is electrically connected to one end of the resistor R7; the other end of the resistor R9 is electrically connected to the other end of the resistor R11, the output end of the operational amplifier U5 and one end of the resistor R8; the other end of the resistor R7 is electrically connected to one end of the capacitor C3, one end of the resistor R4 and the negative input end of the operational amplifier U3; the other end of the resistor R8 is electrically connected to the positive input end of the operational amplifier U3 and one end of the resistor R6; the other end of the resistor R6 is grounded; the output end of the operational amplifier U3 is electrically connected to the other end of the capacitor C3, the other end of the resistor R4 and the A / D acquisition end of the controller module (6).

6. The water immersion sensor according to claim 1, characterized in that: A support mesh sleeve (10) is provided on the outer side of the water-absorbing sponge (11), and the lower end surface of the water-absorbing sponge (11) extends out of the support mesh sleeve (10); a top cover plate (9) is provided at the upper end of the support mesh sleeve (10); two metal probes (8) are both installed on the top cover plate (9) in a through-type manner; a limit retaining ring (12) is provided on the upper end of the two metal probes (8); an external thread (13) is provided on the metal probe (8) above the limit retaining ring (12), and an electrode nut (14) is threadedly installed on the external thread (13).

7. The water immersion sensor according to claim 6, characterized in that: One side edge of the top cover plate (9) extends to the outside of the upper end of the supporting mesh sleeve (10), and an adjusting sleeve (15) is installed vertically through the extended side edge; an adjusting screw (16) is inserted vertically through the adjusting sleeve (15), and two clamping nuts (19) are installed on the adjusting screw (16) in a threaded manner, and the clamping nuts (19) are pressed on the upper and lower ends of the adjusting sleeve (15) respectively; an L-shaped mounting plate (17) is fixedly installed at the lower end of the adjusting screw (16), and a mounting hole (18) is provided on the vertical plate of the L-shaped mounting plate (17).

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