Non-blind area buried waterlogging water monitoring instrument and control method thereof

Abstract

The present application relates to a no blind area buried waterlogging water monitoring instrument and control method. The monitoring instrument comprises a shell upper cabin and a shell lower cabin connected by threads, the bottom of the shell lower cabin is provided with a control circuit and a battery, the top of the shell upper cabin is connected with an upper cover by threads, the top of the upper cover is connected with a piezoelectric sensor by threads, and an annular antenna is clamped between the piezoelectric sensor and the upper cover; an ultrasonic sensor is arranged in a central through hole of the upper cover and the piezoelectric sensor, and a silica gel ring is arranged between the ultrasonic sensor and the piezoelectric sensor; an electric telescopic rod is fixed on the bottom of the shell upper cabin by a screw, the ultrasonic sensor is fixed on the electric telescopic rod by a first inner groove barb buckle, the bottom of the shell upper cabin is reversely buckled with a second inner groove, and an aviation plug is arranged in the second inner groove; the top and the middle of the shell upper cabin are respectively provided with a first limiter for controlling the maximum upward stroke of the telescopic rod and a second limiter for controlling the maximum downward stroke of the telescopic rod.

Description

Technical Field

[0001] This invention belongs to the field of water level monitoring application technology, and specifically relates to a blind-spot-free buried waterlogging monitoring instrument for urban waterlogging monitoring and its control method. Background Technology

[0002] In recent years, affected by global climate change, extreme weather events such as torrential rains have had a significant impact on social management, urban operations, and the lives and livelihoods of the people. Coupled with lagging infrastructure development in drainage and flood control in some cities, and insufficient capacity for stormwater storage and emergency management, severe urban flooding disasters have occurred. Urban flooding refers to the phenomenon of water accumulation in cities caused by heavy or continuous rainfall exceeding the city's drainage capacity. The objective causes of flooding are high rainfall intensity and concentrated rainfall areas; areas with particularly rapid rainfall may experience water accumulation, and areas with relatively high rainfall intensity and prolonged duration may also experience water accumulation. Currently, flood monitoring systems on the market include both buried and non-buried types. Non-buried systems are complex to install, affect the city's appearance, and face significant approval difficulties. Buried systems, due to the characteristics of sensor operation, always have certain blind spots, which are not conducive to accurate monitoring of floodwater accumulation. Blind spots have always been a common challenge and pain point for sensor equipment.

[0003] CN202220058916.2 discloses a buried wireless liquid level monitoring sensor for urban flooding monitoring. Its purpose is to provide a solution to the problems of large-scale engineering work and impact on the city's appearance caused by the need for wiring and pole installation in current urban flooding monitoring methods. This buried wireless liquid level monitoring sensor enables real-time monitoring of water levels in urban culverts and low-lying road sections, establishing an urban flooding early warning system. The technical solution consists of a waterproof outer casing and a liquid level detection module, a power management module, and a communication management module housed within the casing. These modules are electrically connected. When it is necessary to measure water accumulation on urban roads, the sensor is buried in the ground to monitor the water depth in real time. This invention patent uses an ultrasonic sensor as the liquid level monitoring sensor. Its shortcomings are that ultrasonic sensors have blind spots and cannot detect water accumulation within these blind spots. Secondly, the sensor is flush with the road surface, which can easily lead pedestrians and vehicles to mistakenly perceive water accumulation when passing over it. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a blind-zone-free underground flooding monitoring instrument and its control method. When the piezoelectric sensor detects rain, the electric telescopic mechanism lowers the ultrasonic sensor by 3cm or other blind zone depths to monitor water depth. When the piezoelectric sensor detects that the rain has stopped or the flooding has receded, the motor drives the telescopic mechanism to raise the ultrasonic sensor by 3cm, stopping the water depth monitoring. The accumulated floating debris will then drift away.

[0005] The technical solution of this invention is a blind-spot-free buried waterlogging monitoring device, characterized by comprising a threaded upper and lower outer casing. The bottom of the lower casing sequentially houses a control circuit and a battery. The top of the upper casing has an external thread that is threaded to the internal thread of a top cover. A portion of the top of the top cover has a reduced diameter external thread. A piezoelectric sensor has an internal thread. A loop antenna is sandwiched between the piezoelectric sensor and the top cover and threadedly connected. An ultrasonic sensor is positioned within a central through-hole between the top cover and the piezoelectric sensor. The diameter of the ultrasonic sensor is smaller than the inner ring diameter of the piezoelectric sensor. A silicone ring is provided between the ultrasonic sensor and the piezoelectric sensor. An electric telescopic rod is fixed to the bottom of the upper casing with screws. The ultrasonic sensor is fixed to the electric telescopic rod by barbed clips in an inner groove. The top and middle sections of the upper casing are respectively provided with a first limiter for controlling the maximum upward travel of the telescopic rod and a second limiter for controlling the maximum downward travel of the telescopic rod. The blind-spot-free buried waterlogging monitoring device is installed on the road surface, with its top flush with the ground.

[0006] Preferably, the electric telescopic rod consists of a cylindrical sleeve and a telescopic rod that is inserted into the cylindrical sleeve and can extend and retract. The top of the telescopic rod has an installation interface for fixing an ultrasonic sensor. The electric telescopic rod sleeve is fixed to the bottom of the upper outer shell. The top of the telescopic rod is connected to the ultrasonic sensor, and its extension length is not less than 3cm or other blind zone length. The telescopic part has protrusions for identifying the maximum upward and downward travel. The top of the electric telescopic rod sleeve is connected to the ultrasonic sensor via an inverted snap-fit. The top of the telescopic rod has a limiting protrusion. When the telescopic rod rises to the top, the protrusion will touch the first limiter of the upper outer shell. The signal from the first limiter being pressed, collected by the controller, will control the telescopic rod to stop rising. When the telescopic rod descends to the bottom, the protrusion will touch the second limiter of the upper outer shell. The signal from the second limiter being pressed, collected by the controller, will control the telescopic rod to stop descending.

[0007] Preferably: when the piezoelectric sensor detects rain, the electric telescopic pole and the ultrasonic sensor descend synchronously. The descent stops when the protruding end of the electric telescopic pole contacts the second limiter in the middle of the upper compartment of the outer shell. The controller controls the ultrasonic sensor to generate ultrasonic waves, and the monitoring distance will be 3cm greater than the actual water depth on the road surface. Before sending the data to the backend via the antenna, the monitoring distance is subtracted by 3cm to obtain the true water depth for water depth monitoring. If, within any fifteen minutes after the telescopic pole descends 3cm, the detected water depth does not exceed 3cm, it is considered that there is no flooding or the water has receded. The motor drives the electric telescopic pole to rise, and the pole stops rising when the protrusion contacts the first limiter at the top of the upper compartment of the outer shell. Water depth monitoring stops, and accumulated floating debris will drift away. The "any fifteen minutes" refers to the fifteen minutes preceding any given moment.

[0008] Preferably, the piezoelectric sensor uses the impact measurement principle to determine whether it is raining. During its descent, a raindrop is affected by its own weight and air resistance, reaching a constant velocity v upon impact. The weight of the raindrop is m, and according to the impact force P = mv, the impact force causes a slight deformation on the surface of the piezoelectric sensor, thus changing its output voltage. Different impact forces produce different voltage changes. A standard raindrop's voltage change is defined as Vd. When the voltage change monitored by the piezoelectric sensor exceeds Vd, it is determined to be raining; when the voltage change is less than Vd, it is determined to be rainless.

[0009] Because the blind-spot-free ground-based urban flooding monitoring equipment is installed on the road surface, pedestrians / vehicles frequently pass by, and the piezoelectric sensor will detect a large momentum value; however, the weight of raindrops is much smaller than that of pedestrians or vehicles, so the control board distinguishes between raindrops and pedestrians or vehicles passing by.

[0010] Preferably, the upper outer shell is equipped with a waterproof aviation connector; the upper outer shell is connected to the lower outer shell via a waterproof wire; the outer ring at the top of the upper outer shell is provided with threads for fixing to the top cover; the inner ring at the bottom of the upper outer shell is provided with threads for fixing to the lower outer shell; and the bottom of the upper outer shell is sealed.

[0011] Preferably, the lower compartment of the outer shell is equipped with a waterproof aviation connector; the lower compartment is connected to the upper compartment of the outer shell via a waterproof wire; the top outer ring of the lower compartment is provided with threads for fixing to the bottom of the upper compartment; the bottom of the lower compartment is sealed; after the lower compartment and the upper compartment are fixed together by threads and a waterproof ring, an IP68 waterproof rating is achieved.

[0012] Preferably, the piezoelectric sensor has a piezoelectric element inside, with a ring-shaped top; the signal line of the piezoelectric sensor is connected to the lower compartment of the outer shell via an aviation connector.

[0013] Preferably, the ultrasonic sensor is cylindrical with a buckle at the bottom for fixing it to the top of the telescopic rod; the ultrasonic signal line is connected to the lower compartment of the outer shell via an aviation plug; the ultrasonic sensor emits ultrasonic waves for a period of time through its probe, and after the emission, the ultrasonic radar has a brief aftershock. After the aftershock stops, the reflected wave can be received; due to the existence of the aftershock, the ultrasonic radar has a blind zone; the blind zone underwater is 3cm, which may vary slightly depending on the design and the duration of the wave generation.

[0014] Preferably, the control circuit includes a control board, a piezoelectric sensor, an ultrasonic sensor, an electric telescopic rod, a first limiter for the upper compartment of the outer shell, a second limiter for the upper compartment of the outer shell, a loop antenna, and a battery, all electrically connected to the control board; the control circuit is fixed to the lower compartment of the outer shell by screws; the battery is fixed to the lower compartment of the outer shell by screws; the power and signal lines between the upper and lower compartments of the dual-compartment outer shell are connected by aviation connectors.

[0015] Another technical solution of the present invention is the control method for the blind-spot-free buried urban flooding monitoring system, which is characterized by including the following steps:

[0016] (1) The pressure value of the piezoelectric sensor changes;

[0017] (2) Determine if the pressure change value is greater than the value of a normal raindrop. If no, return to step (1); if yes, proceed to the next step.

[0018] (3) Further determine whether the pressure change value is greater than 5 times the value of a normal raindrop. If no, return to step (1); if yes, proceed to the next step.

[0019] (4) Control the ultrasonic sensor to descend;

[0020] (5) The ultrasonic sensor identifies the water depth and determines whether it is less than 3cm. If yes, the process proceeds to step (1) after the step "controlling the ultrasonic sensor to rise 3cm and the main controller to stop working for 15 minutes"; otherwise, it proceeds to the next step.

[0021] (6) Subtract 3cm from the detected water depth and then transmit the data wirelessly to the receiving end or backend.

[0022] (7) After detecting the water depth using the ultrasonic sensor, return to step (5).

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] (1) Blind spots have always been a difficult and painful point for various sensors. This invention uses a piezoelectric sensor to detect rain, and an electric telescopic mechanism to lower the ultrasonic sensor by 3cm or a set blind spot depth to monitor water depth. After the rain stops or the flood recedes, the motor drives the telescopic mechanism to raise the ultrasonic sensor by 3cm, stopping water depth monitoring. The accumulated floating debris will then drift away. Therefore, this invention solves the long-standing technical problem of sensor blind spots.

[0025] (2) The piezoelectric sensor of the present invention contains a piezoelectric element. The piezoelectric sensor uses the impact measurement principle to determine whether it is raining. During the fall, raindrops are affected by their own weight and air resistance. When they reach the ground, their speed is a constant v. The weight of the raindrop is m. According to the impact force P = mv, the impact force of the raindrop will cause a slight deformation on the surface of the piezoelectric sensor, thereby changing its output voltage value. Different impact forces will produce different voltage value changes. The voltage value change generated by a standard raindrop is set as Vd. When the voltage change value monitored by the piezoelectric sensor exceeds Vd, it is determined that it is raining; when the voltage change is less than Vd, it is determined that there is no rain.

[0026] Because the blind-spot-free ground-based urban flooding monitoring equipment is installed on the road surface, pedestrians / vehicles frequently pass by, and the piezoelectric sensor will detect a large momentum value; however, the weight of raindrops is much smaller than that of pedestrians or vehicles, so the control board distinguishes between raindrops and pedestrians or vehicles passing by.

[0027] (3) Because the flood monitoring equipment needs to be installed on the road surface, pedestrians and vehicles will pass by, which will also cause changes in the voltage value output by the circular piezoelectric sensor. However, the voltage change caused by pedestrians or vehicles passing by is much larger than that caused by raindrops, and the interval between raindrops falling is much smaller than that between pedestrians or vehicles passing by. Therefore, the present invention can easily distinguish between them through the controller. Attached Figure Description

[0028] Figure 1 This is an exploded view of the structure of the buried waterlogging monitoring instrument with no blind spots according to the present invention;

[0029] Figure 2 This is a cross-sectional view of the assembled structure of the buried waterlogging monitoring instrument with no blind spots according to the present invention.

[0030] Figure 3 This is a block diagram of the control circuit of the present invention;

[0031] Figure 4 This is the control flowchart of the blind-spot-free underground waterlogging monitoring system of the present invention.

[0032] Explanation of key component symbols:

[0033] Upper hull 1 Lower outer shell compartment 2 Control circuit 21 Battery 22 Top cover 3 External thread part 31 Groove 32 piezoelectric sensor 4 Through hole 41 Loop antenna 51 Silicone ring 52 Ultrasonic sensor 6 First inner groove 61 Second inner groove 62 Electric telescopic pole 7 Cylindrical sleeve 71 Telescopic pole 72 First limiter 8 Second limiter 9 Detailed Implementation

[0034] The present invention will now be described in further detail with reference to the accompanying drawings:

[0035] Please see Figure 1 , Figure 2As shown, the blind-spot-free buried waterlogging monitoring device includes a threaded upper chamber 1 and a lower chamber 2. A control circuit 21 and a battery 22 are sequentially arranged at the bottom of the lower chamber 2. The external thread at the top of the upper chamber 1 is threaded to the internal thread of the upper cover 3. A portion of the top of the upper cover 3 has a reduced diameter external thread 31. A piezoelectric sensor 4 has an internal thread. A loop antenna 51 is sandwiched between the piezoelectric sensor 4 and the upper cover 3 and threadedly connected. An ultrasonic sensor 6 is arranged in the central through-hole 41 between the upper cover 3 and the piezoelectric sensor 4. The diameter of the ultrasonic sensor 6 is... The diameter of the inner ring of the ultrasonic sensor 6 is smaller than that of the piezoelectric sensor 4. A silicone ring 52 is provided between the ultrasonic sensor 6 and the piezoelectric sensor 4. The electric telescopic rod 7 is fixed to the bottom of the upper compartment 1 of the outer shell by screws. The ultrasonic sensor 6 is fixed to the electric telescopic rod 7 by the barbed buckle of the first inner groove 61. The top and middle parts of the upper compartment 1 of the outer shell are respectively provided with a first limiter 8 for controlling the maximum upward stroke of the electric telescopic rod 7 and a second limiter 9 for controlling the maximum downward stroke of the electric telescopic rod 7. The outer ring of the top of the upper compartment 1 of the outer shell is provided with external threads for fixing the top cover 3. There is an upper limiter 8 at the top of the upper compartment 1 of the outer shell. There is a lower limiter 9 3cm below the upper limiter 8. The bottom inner ring (not shown in the figure) of the lower compartment 2 of the outer shell is provided with threads for fixing it. The bottom of the upper compartment 1 of the outer shell is an inverted second inner groove 62. An aviation plug (not shown in the figure) is provided at the inner groove 61, which is used to connect the signal line and the power line. The lower compartment 2 of the outer shell has an external thread on its top outer ring for fixing to the upper compartment 1 of the outer shell. A waterproof rubber ring (not shown in the figure) is inserted at the top for sealing and waterproofing. The control circuit is set on the control board and installed in the lower compartment 2 of the outer shell; the battery 22 is installed in the lower compartment 2 of the outer shell. The blind-spot-free buried waterlogging monitor is installed on the road surface with its top flush with the ground. Before installation, only a slightly larger hole needs to be drilled in the road surface, and then it can be fixed with cement. Because the waterlogging monitoring equipment needs to be installed on the road surface, pedestrians and vehicles will pass by, which will also cause changes in the voltage value output by the circular piezoelectric sensor 4. However, the voltage change caused by pedestrians or vehicles passing by is much greater than that of raindrops, and the interval between raindrops falling is much smaller than that of pedestrians or vehicles passing by, so it can be easily distinguished by the controller. The loop antenna 51 is led out from the controller through the aviation plug (not shown in the figure) of the upper compartment 1 of the outer shell and is locked in the groove 32 of the upper cover 3. The thread on the top of the upper cover 3 can fix the annular piezoelectric sensor 4, the groove 32 can fix the ring antenna 51, and the thread on the bottom inner ring (not shown in the figure) can be fixed to the top of the upper compartment 1 of the outer shell. The inner diameter of the silicone ring 52 is the same as that of the ultrasonic sensor 6, and its outer diameter is the same as that of the upper compartment 1 of the outer shell.

[0036] Please see Figure 1 , Figure 2As shown, the electric telescopic rod 7 consists of a cylindrical sleeve 71 and a telescopic rod 72 that is inserted into the cylindrical sleeve 71 and can extend and retract. The top of the telescopic rod 72 has an installation interface for fixing the ultrasonic sensor 6. The sleeve 71 of the electric telescopic rod 7 is fixed to the bottom of the upper outer casing 1, and the top of the telescopic rod 72 is connected to the ultrasonic sensor 6. Its telescopic length is not less than 3cm or other blind zone length. The telescopic rod 72 has protrusions (not shown) for identifying the maximum upward and downward travel. The top of the sleeve 71 of the electric telescopic rod is connected to the ultrasonic sensor 6 by an inverted snap-fit. The telescopic rod 6 is a relatively mature telescopic rod currently on the market, and its base is fixed to the bottom of the upper outer casing 1 by screws. The top of the telescopic rod 72 is provided with a protrusion (not shown in the figure) for limiting movement. When the telescopic rod 71 rises to the top, the protrusion (not shown in the figure) will touch the first limiter 8 of the upper cabin shell. The signal collected by the controller after the first limiter 8 is pressed will control the telescopic rod 72 to stop rising. When the telescopic rod 72 descends to the bottom, the protrusion (not shown in the figure) of the telescopic rod 72 will touch the second limiter 9 of the upper cabin 1 of the shell. The signal collected by the controller after the second limiter 9 is pressed will control the telescopic rod 72 to stop descending.

[0037] Please see Figure 1 , Figure 2 As shown, when the piezoelectric sensor 4 detects rain, the electric telescopic pole 7 and the ultrasonic sensor 6 descend synchronously. The descent stops when the protruding end (not shown) of the electric telescopic pole 7 contacts the second limiter 9 in the middle of the upper chamber 1 of the outer shell. The controller controls the ultrasonic sensor 6 to generate ultrasonic waves, and the monitoring distance will be 3cm greater than the actual water depth on the road surface. Before sending the data to the backend via the antenna, the monitoring distance is subtracted by 3cm to obtain the true water depth for water depth monitoring. If the detected water depth does not exceed 3cm within any fifteen minutes after the telescopic pole 72 descends 3cm, it is considered that there is no flooding or the water has receded. The motor drives the electric telescopic pole 7 to rise. The telescopic pole 72 stops rising after the protruding part (not shown) of the telescopic pole contacts the first limiter 8 at the top of the upper chamber 1 of the outer shell. Water depth monitoring stops, and accumulated floating debris will drift away. The "any fifteen minutes" refers to the fifteen minutes preceding any given moment.

[0038] Please see Figure 1 , Figure 2As shown, the piezoelectric sensor uses the impact measurement principle to determine whether it is raining. During its descent, a raindrop is affected by its own weight and air resistance, reaching a constant velocity v upon reaching the ground. The weight of the raindrop is m, and according to the impact force P = mv, the impact force causes a slight deformation on the surface of the piezoelectric sensor, thus changing its output voltage. Different impact forces produce different voltage changes. A standard raindrop's voltage change is defined as Vd. When the voltage change monitored by the piezoelectric sensor exceeds Vd, it is determined to be raining; when the voltage change is less than Vd, it is determined to be rainless.

[0039] Because the blind-spot-free ground-based urban flooding monitoring equipment is installed on the road surface, pedestrians / vehicles frequently pass by, and the piezoelectric sensor will detect a large momentum value; however, the weight of raindrops is much smaller than that of pedestrians or vehicles, so the control board distinguishes between raindrops and pedestrians or vehicles passing by.

[0040] Please see Figure 1 , Figure 2 As shown, the upper outer compartment 1 is equipped with a waterproof aviation connector (not shown in the figure); the upper outer compartment 1 is connected to the lower outer compartment 2 via a waterproof wire; the outer ring at the top of the upper outer compartment 1 (not shown in the figure) is threaded for fixing to the upper cover 3; the inner ring at the bottom of the upper outer compartment 1 (not shown in the figure) is threaded for fixing to the lower outer compartment 2; the bottom of the upper outer compartment 1 is sealed. The lower outer compartment 2 is equipped with a waterproof aviation connector (not shown in the figure); the lower outer compartment 2 is connected to the upper outer compartment 1 via a waterproof wire; the outer ring at the top of the lower outer compartment 2 (not shown in the figure) is threaded for fixing to the bottom of the upper outer compartment 1; the bottom of the lower outer compartment 2 is sealed; after the lower outer compartment 2 and the upper outer compartment 1 are fixed by threads and a waterproof ring (not shown in the figure), an IP68 waterproof rating is achieved.

[0041] Please see Figure 1 , Figure 2 As shown, the piezoelectric sensor 4 has a piezoelectric element inside, with a ring-shaped top. The signal line of the piezoelectric sensor 4 is connected to the lower compartment 2 of the outer shell via an aviation connector (not shown). The ultrasonic sensor 6 is cylindrical, with a buckle (not shown) at its bottom for fixing it to the top of the telescopic rod 72. The ultrasonic signal line is connected to the lower compartment 2 of the outer shell via an aviation connector (not shown). The ultrasonic sensor 6 emits ultrasonic waves for a period of time through its probe. After emission, the ultrasonic radar has a brief aftershock. After the aftershock stops, the reflected wave can be received. Due to the aftershock, the ultrasonic radar has a blind zone. The blind zone underwater is 3 cm, which may vary slightly depending on the design and the duration of wave generation.

[0042] Please see Figure 3As shown, the control circuit of the present invention includes a control board, a piezoelectric sensor 4, an ultrasonic sensor 6, an electric telescopic rod 7, a first limiter 8 for the upper compartment of the outer shell, a second limiter 9 for the upper compartment of the outer shell, a loop antenna 51, and a battery 22, all electrically connected to the control board. The processor module is fixed to the lower compartment 2 of the outer shell by screws. The battery 22 is fixed to the lower compartment 2 of the outer shell by screws. The power lines and signal lines between the upper compartment 1 and the lower compartment 2 of the dual-compartment outer shell are connected by an aviation plug (not shown in the figure).

[0043] Please see Figure 4 As shown, the control method for blind-spot-free underground urban flooding monitoring includes the following steps:

[0044] (1) The pressure value of the piezoelectric sensor 4 changes;

[0045] (2) Determine if the pressure change value is greater than the value of a normal raindrop. If no, return to step (1); if yes, proceed to the next step.

[0046] (3) Further determine whether the pressure change value is greater than 5 times the value of a normal raindrop. If no, return to step (1); if yes, proceed to the next step.

[0047] (4) Control the ultrasonic sensor 6 to descend;

[0048] (5) The ultrasonic sensor 6 identifies the water depth and determines whether it is less than 3cm. If so, after step "controlling the ultrasonic sensor 6 to rise 3cm, and the main controller to stop working for 15 minutes", return to step (1); otherwise, proceed to the next step:

[0049] (6) Subtract 3cm from the detected water depth and then transmit the data wirelessly to the receiving end or backend.

[0050] (7) After detecting the water depth using ultrasonic sensor 6, return to step (5).

[0051] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be covered by the claims of the present invention.

Claims

1. A blind-spot-free buried urban flooding monitoring device, comprising a threaded upper chamber and a lower chamber, wherein a control circuit and a battery are sequentially arranged at the bottom of the lower chamber; the external thread at the top of the upper chamber is screwed to the internal thread of the upper cover; a portion of the top of the upper cover has a reduced diameter external thread; a piezoelectric sensor has an internal thread; a ring antenna is sandwiched between the piezoelectric sensor and the upper cover and threadedly connected; an ultrasonic sensor is arranged in the central through hole of the upper cover and the piezoelectric sensor, the diameter of the ultrasonic sensor being smaller than the inner ring diameter of the piezoelectric sensor; a silicone ring is provided between the ultrasonic sensor and the piezoelectric sensor; an electric telescopic rod is fixed to the bottom of the upper chamber by screws; the ultrasonic sensor is fixed to the electric telescopic rod by barbed buckles of a first inner groove; the bottom of the upper chamber is an inverted second inner groove, in which an aviation plug is provided; the top and middle of the upper chamber are respectively provided with a first limiter for controlling the maximum upward stroke of the telescopic rod and a second limiter for controlling the maximum downward stroke of the telescopic rod; the blind-spot-free buried urban flooding monitoring device is installed on the road surface, with its top flush with the ground, characterized in that... The electric telescopic rod consists of a cylindrical sleeve and a telescopic rod that is inserted into the cylindrical sleeve and can extend and retract. The top of the telescopic rod has an installation interface for fixing an ultrasonic sensor. The electric telescopic rod sleeve is fixed to the bottom of the upper outer shell, and the top of the telescopic rod is connected to the ultrasonic sensor. Its extension length is not less than 3cm or other blind zone length. The telescopic part has protrusions for identifying the maximum upward and downward travel. The top of the electric telescopic rod sleeve is connected to the ultrasonic sensor via an inverted snap-fit. The top of the telescopic rod has a limiting protrusion. When the telescopic rod rises to the top, the protrusion will touch the first limiter of the upper outer shell. The signal from the first limiter being pressed, collected by the controller, will stop the telescopic rod from rising. When the telescopic rod descends to the bottom, the protrusion will touch the second limiter of the upper outer shell. The signal from the second limiter being pressed, collected by the controller, will stop the telescopic rod from descending.

2. The underground floodwater monitoring instrument with no blind spot as described in claim 1, characterized in that, When the piezoelectric sensor detects rain, the electric telescopic pole and the ultrasonic sensor descend synchronously. The descent stops when the protruding end of the electric telescopic pole contacts the second limiter in the middle of the upper compartment of the outer shell. The controller controls the ultrasonic sensor to generate ultrasonic waves. The monitoring distance will be 3cm greater than the actual water depth on the road surface. Before sending the data to the backend through the antenna, the monitoring distance is subtracted by 3cm to obtain the true water depth for water depth monitoring. If the water depth does not exceed 3cm within any 15-minute period after the telescopic boom descends 3cm, it is considered that there is no waterlogging or the water has receded. The motor will then drive the electric telescopic boom to rise. The boom will stop rising after the protrusion of the telescopic boom contacts the first limiter on the top of the upper compartment of the outer shell. Water depth monitoring will stop, and any accumulated floating debris will drift away. The "any 15-minute period" refers to the period from the 15 minutes before the specified moment to the specified moment.

3. The underground waterlogging monitoring instrument with no blind spot according to claim 2, characterized in that, The piezoelectric sensor uses the impact measurement principle to determine whether it is raining. During its descent, a raindrop is affected by its own weight and air resistance. Upon reaching the ground, its velocity is constant, v. The weight of the raindrop is m. According to the impact force P=mv, the impact force of the raindrop causes a slight deformation on the surface of the piezoelectric sensor, resulting in a change in its output voltage. Different impact forces produce different voltage changes. A standard raindrop's voltage change is defined as Vd. When the voltage change monitored by the piezoelectric sensor exceeds Vd, it is determined to be raining; when the voltage change is less than Vd, it is determined to be rainless. Because the blind-spot-free ground-based urban flooding monitoring equipment is installed on the road surface, pedestrians / vehicles frequently pass by, and the piezoelectric sensor will detect a large momentum value; however, the weight of raindrops is much smaller than that of pedestrians or vehicles, so the control board distinguishes between raindrops and pedestrians or vehicles passing by.

4. The underground waterlogging monitoring instrument with no blind spot as described in claim 1, characterized in that, The upper outer shell is equipped with a waterproof aviation connector; the upper outer shell is connected to the lower outer shell via a waterproof cable; the outer ring at the top of the upper outer shell is provided with threads for fixing to the upper cover; the inner ring at the bottom of the upper outer shell is provided with threads for fixing to the lower outer shell; the bottom of the upper outer shell is sealed.

5. The underground waterlogging monitoring instrument with no blind spot according to claim 1, characterized in that, The lower compartment of the outer shell is equipped with a waterproof aviation connector; the lower compartment is connected to the upper compartment of the outer shell via a waterproof wire; the top outer ring of the lower compartment is provided with threads for fixing to the bottom of the upper compartment; the bottom of the lower compartment is sealed; after the lower compartment and the upper compartment are fixed together by threads and a waterproof ring, an IP68 waterproof rating is achieved.

6. The underground waterlogging monitoring instrument with no blind spot according to claim 1, characterized in that, The piezoelectric sensor contains a piezoelectric element with a ring-shaped top; the signal line of the piezoelectric sensor is connected to the lower compartment of the outer shell via an aviation connector.

7. The underground floodwater monitoring instrument with no blind spot according to claim 1, characterized in that, The ultrasonic sensor is cylindrical with a buckle at the bottom for fixing it to the top of the telescopic rod. The ultrasonic signal line is connected to the lower compartment of the outer shell via an aviation plug. The ultrasonic sensor emits ultrasonic waves for a period of time through its probe. After the emission, the ultrasonic radar has a brief aftershock. After the aftershock stops, the reflected wave can be received. Due to the existence of the aftershock, the ultrasonic radar has a blind zone. The blind zone underwater is 3 cm, which may vary slightly depending on the design and the duration of the wave generation.

8. The blind-spot-free underground waterlogging monitoring instrument according to any one of claims 1 to 7, characterized in that, The control circuit includes a control board, a piezoelectric sensor, an ultrasonic sensor, an electric telescopic rod, a first limiter for the upper outer compartment, a second limiter for the upper outer compartment, a loop antenna, and a battery, all electrically connected to the control board. The control circuit is fixed to the lower outer compartment with screws. The battery is fixed to the lower outer compartment with screws. The power and signal lines between the upper and lower compartments of the dual-compartment shell are connected via aviation connectors.

9. A control method for a blind-spot-free underground waterlogging monitoring instrument according to claim 1, characterized in that, Includes the following steps: (1) The pressure value of the piezoelectric sensor changes; (2) Determine if the pressure change value is greater than the value of a normal raindrop. If no, return to step (1); if yes, proceed to the next step. (3) Further determine whether the pressure change value is greater than 5 times the value of a normal raindrop. If no, return to step (1); if yes, proceed to the next step. (4) Control the ultrasonic sensor to descend; (5) The ultrasonic sensor identifies the water depth and determines whether it is less than 3cm. If yes, the process proceeds to step (1) after the step "controlling the ultrasonic sensor to rise 3cm and the main controller to stop working for 15 minutes"; otherwise, it proceeds to the next step. (6) Subtract 3cm from the detected water depth and then transmit the data wirelessly to the receiving end or backend. (7) After detecting the water depth using the ultrasonic sensor, return to step (5).

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