Low power consumption rope-type crack meter and method of using the same

Abstract

The present invention relates to a low-power draw-wire crack meter, comprising a bottom plate and a casing covered on the bottom plate. The low-power draw-wire crack meter further comprises a crack monitor, and the crack monitor comprises a low-power draw-wire displacement sensor, a low-power configurable comparator, an analog-to-digital converter, a microcontroller unit, a real-time clock, a low-power Bluetooth element, a LoRa / NB-IoT remote communication module, a metal oxide semiconductor field effect transistor, an electronic compass, an ultra-low voltage power supply module, a power management system, a switch and a battery. The draw-wire crack meter of the present invention has low power consumption, strong adaptability and reliable monitoring.

Description

Technical Field

[0001] The invention relates to the field of crack monitoring, and in particular to a high-frequency, low-power draw-rope type crack meter for monitoring crack distance and a use method thereof. Background Art

[0002] The pull-wire displacement sensor is a sophisticated integration of linear displacement sensors in structure, which fully combines the advantages of angle sensors and linear displacement sensors. This product can be used in situations where large travel or small space is inconvenient to install. It has been widely used in position control and measurement in various industries.

[0003] Chinese utility model patent CN208635710U discloses a pull-rope linear displacement sensor, including an aluminum alloy shell, a potentiometer installed on the top of the aluminum alloy shell, a reel and a winding roller installed inside the aluminum alloy, a steel wire rope with one end wound around the reel and the other end wound around the winding roller and passing through the aluminum alloy shell, and a spring installed under the aluminum alloy shell. The shell end is fixed to one side of the crack, and the steel wire rope passing through the aluminum alloy shell is bound to the other end of the crack. When the crack cracks, the steel wire rope is stretched to measure the cracking displacement data. This pull-rope linear displacement sensor requires manual on-site reading of displacement and recording of data, and requires long-term on-site monitoring. The monitoring environment is harsh, which is not conducive to the personal safety of the monitoring personnel.

[0004] With the development of 5G technology, a pull-string crack meter with remote high-frequency monitoring has become a need in the industry to reduce manual on-site operations and risk factors. Remote high-frequency monitoring requires the establishment of network communication for signal transmission and remote control. The high-frequency monitoring method requires the pull-string crack meter to be in a working monitoring state for a long time, which consumes a lot of power. Therefore, it is still necessary to manually replace the battery of the pull-string crack meter regularly, which brings inconvenience in use.

[0005] Therefore, it is necessary to provide a new low-power draw-wire crack meter and a method of using the same to solve the above problems. Summary of the invention

[0006] The present invention provides a rope-drawing crack meter and a method for using the same, so as to achieve the purposes of remote high-frequency monitoring, low power consumption, strong adaptability and reliable monitoring.

[0007] In order to achieve the above-mentioned purpose, the present invention provides a low-power drawstring crack meter, comprising a base plate and a casing covered on the base plate, the low-power drawstring crack meter further comprising a crack monitor, the crack monitor comprising a low-power drawstring displacement sensor, a low-power configurable comparator, an analog-to-digital converter, a microcontroller unit, a real-time clock, a low-power Bluetooth component, a LoRa / NB-IoT remote communication module, a metal oxide semiconductor field effect transistor, an electronic compass, an ultra-low voltage power supply module, a power management system, a switch and a battery; the analog signal output end of the drawstring displacement sensor is respectively connected to the signal input end of the low-power configurable comparator and the analog signal input end of the analog-to-digital converter through a signal line, the digital signal output end of the analog-to-digital converter is connected to the microcontroller unit through a signal line, and the microcontroller unit is also respectively connected to the low-power configurable comparator, the real-time clock, the low-power Bluetooth component, the LoRa / NB-IoT remote communication module, Two metal oxide semiconductor field effect transistors and an electronic compass, one metal oxide semiconductor field effect transistor is connected to an analog-to-digital converter and an electronic compass through a signal line, and the other metal oxide semiconductor field effect transistor is connected to a LoRa / NB-IoT remote communication module through a signal line. The power management system is respectively connected to a low-power configurable comparator, a micro control unit, a metal oxide semiconductor field effect transistor and an ultra-low voltage power supply module through signal lines. The ultra-low voltage power supply module is connected to a pull-rope displacement sensor through a signal line, and a battery is connected to the power management system through a wire connected in series with a switch; the pull-rope displacement sensor and the battery are installed on a bottom plate; the low-power configurable comparator, the analog-to-digital converter, the micro control unit, the real-time clock, the low-power Bluetooth component, the LoRa / NB-IoT remote communication module, the metal oxide semiconductor field effect transistor, the electronic compass, the ultra-low voltage power supply module, the power management system and the switch are arranged on a circuit board and fixed inside the casing.

[0008] Furthermore, the pull rope displacement sensor includes a reel shaft end located in the middle, a potentiometer end located on the right side of the reel shaft end, and a coil spring end located on the left side of the reel shaft end. The reel shaft end includes a wheel with a pull rope wound around it, the potentiometer end includes a resistor, and the coil spring end includes a coil spring. When the pull rope is pulled, the wheel rotates, and the coil spring becomes tighter and tighter as the wheel rotates. At the same time, the resistance value of the resistor in the potentiometer end changes, and the change in displacement is calculated by the change in resistance value.

[0009] Furthermore, the low-power draw-wire crack meter further includes a sponge pad, a fixing plate and a sealing ring. The bottom plate is plate-shaped and has mounting holes on both sides. The battery is placed on the bottom plate, and the sponge pad is placed on the battery. The fixing plate is trapezoidal and buckled on the sponge pad and the battery, and the fixing plate is fixed to the bottom plate by bolts to fix the battery. The sponge pad prevents the fixing plate from damaging the battery. The sealing ring is annular and clamped in a groove on the bottom plate. The casing cover is arranged on the bottom plate, and the sealing ring seals the gap between the bottom plate and the casing.

[0010] Furthermore, the low-power draw-rope crack meter further includes a waterproof sealing device, which includes a sealing pad, a clamping block, an insulating rubber and a draw-rope joint. The sealing pad is provided with a conical protrusion, which is embedded in the rear end of the clamping block, and its conical protrusion protrudes into the middle notch of the clamping block. The insulating rubber is clamped into the draw-rope joint. One end of the draw rope at the end of the reel shaft passes through the draw rope outlet end of the casing, and passes through the sealing pad, the clamping block and the insulating rubber to connect to the draw rope joint. The sealing pad and the clamping block are fixed to the draw rope outlet end of the casing by sealant to form a fixed end, and the insulating rubber and the draw rope joint are pullable free ends.

[0011] Furthermore, when in use, the low-power drawstring crack meter is installed on one side of the crack of the structure to be measured, and the drawstring joint is fixed to a right-angle piece with a mounting hole by screws, and the right-angle piece is fixed to the other side of the crack. When the crack increases, the drawstring is pulled out.

[0012] Furthermore, when in use, the low-power draw-rope crack meter is installed on one side of the crack of the structure to be measured, and the draw-rope joint is connected to a lifting eye expansion screw through a steel wire rope, and the lifting eye expansion screw is fixed to the other side of the crack. When the crack increases, the draw-rope is pulled out.

[0013] Furthermore, the casing of the low-power draw-wire crack meter is provided with an antenna for wireless signal transmission with external devices, or the casing of the low-power draw-wire crack meter is provided with an aviation plug and a cable is connected through the aviation plug for wired signal transmission with external devices.

[0014] The present invention further provides a method for using a low-power draw-wire crack meter, which is implemented in the following steps:

[0015] i. Find a relatively flat installation surface on one side of the crack of the structure to be tested;

[0016] ii. Place the low-power pull-wire crack meter on the mounting surface so that the bottom of the base plate is attached to the mounting surface, and use a marker to pass through the mounting holes on both sides of the base plate to mark the mounting surface;

[0017] iii. Use a drill bit to drill holes on the mounting surface;

[0018] iv. Use expansion screws to first fix the rope crack meter on one side of the crack of the structure to be measured;

[0019] v. After fixing the pull-wire joint of the pull-wire crack meter to the right-angle piece through screws, fix the right-angle piece to the other side of the crack of the measured structure through expansion screws, and monitor the crack data through the pull-wire displacement sensor;

[0020] Or connect the rope joint of the rope crack meter to the eye expansion screw through a steel wire rope, fix the eye expansion screw to the other side of the crack of the structure to be measured, and monitor the crack data through the rope displacement sensor;

[0021] vi. Use a smart mobile terminal to wake up the crack monitor through the low-power Bluetooth component. At this time, the indicator light of the power management system is always on and enters the configuration waiting state;

[0022] vii. Use a smart mobile terminal to read the initial crack data collected by the pull-wire displacement sensor, the initial acceleration and initial geomagnetic data collected by the electronic compass, and observe the data stability;

[0023] viii. After the data is stable, record the initial value; the user sets the preset threshold value of the crack data through the smart mobile terminal a t The microcontroller collects crack data 20-30 times in one minute and automatically determines the stability of the crack data. If the fluctuation within one minute is less than the preset threshold a t Then, through self-checking, the microcontroller unit automatically records the average value of the crack data within 1 minute as the initial value a0;

[0024] ix. The user sets the normal upload time interval and the encrypted upload time interval of the crack data, acceleration and geomagnetic data through the smart mobile terminal;

[0025] x. The microcontroller unit converts the preset threshold into an absolute voltage value and configures a low-power configurable comparator; at the same time, the interrupt setting of the real-time clock is configured according to the normal upload time interval;

[0026] xi. After the intelligent mobile terminal completes the operation, the indicator light of the power management system goes out and the crack monitor (2) enters standby mode;

[0027] xii. When the crack data of the structure under test does not exceed the threshold value, the microcontroller unit is in standby mode, and the analog-to-digital converter, the low-power Bluetooth component, the LoRa / NB-IoT remote communication module, the metal oxide semiconductor field effect transistor and the electronic compass are in sleep mode. At this time, only the pull rope displacement sensor, the low-power configurable comparator, the real-time clock, the ultra-low voltage power supply module and the power management system of the crack monitor are in working mode, and the overall power consumption of the crack monitor is less than 100 μA;

[0028] xiii. When the normal upload time comes, the real-time clock generates an interrupt signal to wake up the microcontroller unit. After receiving the interrupt signal, the microcontroller unit controls the power management system to power on the analog-to-digital converter and the electronic compass to collect the crack value, acceleration and geomagnetic data and transmit the collected data to the microcontroller unit. Then the power management system controls the power on the LoRa / NB-IoT remote communication module, and sends the crack value, acceleration and geomagnetic data transmitted by the microcontroller unit to the LoRa / NB-IoT remote communication module to the monitoring cloud platform;

[0029] xiv. If the crack monitor is in standby mode, the crack value a occurs in one of the following two situations: a>a0+a t or a <a0–a t , the low-power configurable comparator sends an interrupt signal, the microcontroller is awakened and controls the power management system to power on the analog-to-digital converter and the electronic compass to collect crack values, acceleration and geomagnetic data and transmit the collected data to the microcontroller, and then controls the power management system to start the LoRa / NB-IoT remote communication module to upload the crack values, acceleration and geomagnetic data transmitted by the microcontroller to the LoRa / NB-IoT remote communication module (207) at a periodic encrypted upload time interval;

[0030] xv. The monitoring cloud platform issues corresponding warning information after receiving the encrypted crack value, acceleration and geomagnetic data.

[0031] Furthermore, in step viii, the preset threshold a t Set to 5mm, mm refers to the unit of crack length;

[0032] The normal upload interval is set to once an hour, and the encrypted upload interval is set to once a minute.

[0033] The present invention proposes a method for monitoring cracks in a measured structure and a corresponding hardware device, which achieves extremely low power consumption while ensuring the real-time performance of crack monitoring, thereby ensuring the long-term reliability of the monitoring equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a three-dimensional composite diagram of the low-power draw-rope type crack meter of the present invention;

[0035] Figure 2 It is a partial exploded perspective view of the low power consumption rope-type crack meter of the present invention;

[0036] Figure 3 It is a partial exploded perspective view of the low power consumption rope-type crack meter of the present invention;

[0037] Figure 4 It is a circuit schematic diagram of a crack monitor of a low-power draw-wire crack meter of the present invention;

[0038] Figure 5 It is a three-dimensional combination diagram of a low-power draw-wire crack meter according to another embodiment of the present invention.

[0039] In the figure: 1. bottom plate; 2. crack monitor; 21. reel shaft end; 22. potentiometer end; 23. coil spring end; 201. rope displacement sensor; 202. low power configurable comparator; 203. analog-to-digital converter; 204. micro control unit; 205. real-time clock; 206. low power Bluetooth component; 207. LoRa / NB-IoT remote communication module; 208. metal oxide semiconductor field effect transistor; 209. electronic compass; 210. ultra-low voltage power supply module; 211. power management system; 212. switch; 213. battery; 3. sponge pad; 4. fixing plate; 5. sealing ring; 6. housing; 7. antenna; 7', aviation plug; 8. waterproof sealing device; 81. sealing pad; 82. pressing block; 83. insulating rubber; 84. rope connector; 9. right-angle piece; 10. circuit board. DETAILED DESCRIPTION

[0040] The following combination Figures 1 to 5 , the present invention is further illustrated by specific implementation methods.

[0041] Please refer to Figures 1 to 4 As shown, a low-power draw-wire crack meter includes a base plate 1, a crack monitor 2, a sponge pad 3, a fixing plate 4, a sealing ring 5, a housing 6, an antenna 7 and a waterproof sealing device 8.

[0042] The bottom plate 1 is in the shape of a plate, and a groove opening downward is provided at the bottom thereof, and two mounting holes are respectively provided on both sides of the bottom plate 1.

[0043] The crack monitor 2 includes a low-power pull-wire displacement sensor 201, a low-power configurable comparator 202, an analog-to-digital converter 203, a microcontroller unit 204, a real-time clock 205, a low-power Bluetooth component 206, a LoRa / NB-IoT remote communication module 207, a metal oxide semiconductor field effect transistor 208, an electronic compass 209, an ultra-low voltage power supply module 210, a power management system 211, a switch 212 and a portable battery 213.

[0044] The analog signal output end of the pull rope displacement sensor 201 is connected to the signal input end of the low-power configurable comparator 202 and the analog signal input end of the analog-to-digital converter 203 through signal lines, and the digital signal output end of the analog-to-digital converter 203 is connected to the micro control unit 204 through signal lines. The micro control unit 204 is also connected to the low-power configurable comparator 202, the real-time clock 205, the low-power Bluetooth component 206, the LoRa / NB-IoT remote communication module 207, two metal oxide semiconductor field effect transistors 208 and the electronic compass 209 through signal lines. The field effect transistor 208 is connected to the analog-to-digital converter 203 and the electronic compass 209 through a signal line, another metal oxide semiconductor field effect transistor 208 is connected to the LoRa / NB-IoT remote communication module 207 through a signal line, and the power management system 211 is respectively connected to the low-power configurable comparator 202, the micro control unit 204, the metal oxide semiconductor field effect transistor 208 and the ultra-low voltage power supply module 210 through signal lines, the ultra-low voltage power supply module 210 is connected to the pull-wire displacement sensor 201 through a signal line, and the battery 213 is connected to the power management system 211 through a wire connected in series with a switch 212.

[0045] The pull rope displacement sensor 201 and the battery 213 are installed on the base plate 1; the low-power configurable comparator 202, the analog-to-digital converter 203, the micro control unit 204, the real-time clock 205, the low-power Bluetooth component 206, the LoRa / NB-IoT remote communication module 207, the metal oxide semiconductor field effect transistor 208, the electronic compass 209, the ultra-low voltage power supply module 210, the power management system 211 and the switch 212 are arranged on a circuit board 10 and fixed inside the housing 6.

[0046] The pull rope displacement sensor 201 of the crack monitor 2 includes a reel shaft end 21 located in the middle, a potentiometer end 22 located on the right side of the reel shaft end 21, and a coil spring end 23 located on the left side of the reel shaft end 21. The reel shaft end 21 includes a wheel with a pull rope wound around it, the potentiometer end 22 includes a resistor, and the coil spring end 23 includes a coil spring. When the pull rope is pulled, the wheel rotates, and the coil spring becomes tighter and tighter as the wheel rotates. At the same time, the resistance value of the resistor in the potentiometer end 22 changes, and the change in displacement, that is, the change in the cracking degree of the crack, is calculated by the change in resistance value.

[0047] The portable battery 213 of the crack monitor 2 is a lithium-thionyl chloride battery with an annual leakage rate of less than 1%. The battery 213 is placed on the bottom plate 1, and the sponge pad 3 is placed on the battery 213. The fixing plate 4 is buckled on the sponge pad 3 and the battery 213 in a trapezoidal shape, and the fixing plate 4 is fixed to the bottom plate 1 by bolts to fix the battery 213. The sponge pad 3 prevents the fixing plate 4 from damaging the battery 213. The battery 213 power data is uploaded to the cloud monitoring system once an hour, which is convenient for users to understand the status of the battery 213. Of course, the user can also set it to upload power data at other frequencies.

[0048] The sealing ring 5 is annularly clamped in a groove on the bottom plate 1 .

[0049] The housing 6 is in the shape of an inner hollow box. The housing 6 is fixed on the bottom plate 1 by bolts. The sealing ring 5 seals the gap between the bottom plate 1 and the housing 6 to achieve waterproof and anti-fouling effects. An acrylic transparent observation window can be set on the housing 6. The Bluetooth PCB signal line (built-in) and the power status light are arranged on the back to realize the configuration communication and status prompt functions. Specifically: the red light in the power status light flashes to indicate that the pull-wire crack meter is communicating with the smart mobile terminal through Bluetooth, the green light flashes to indicate that the antenna 7 is sending data to the monitoring cloud platform, and the blue light flashes to indicate that the pull-wire displacement sensor 201 is collecting crack data and the electronic compass is collecting acceleration and geomagnetic data.

[0050] The housing 6 is equipped with an external SMA socket for narrowband communication (such as LoRa or NB-IoT) antenna, and the interior is glued to achieve waterproofing. The antenna 7 is installed on the SMA socket to transmit wireless signals with external devices and can be used to transmit crack data, acceleration and geomagnetic data collected by the low-power cable-type crack meter to the monitoring cloud platform. The antenna 7 can use a fiberglass antenna or a suction cup antenna with different gains according to the on-site environment.

[0051] The waterproof sealing device 8 includes a sealing pad 81, a pressing block 82, an insulating rubber 83 and a drawstring connector 84. The sealing pad 81 is provided with a conical protrusion, which is embedded in the rear end of the pressing block 82, and its conical protrusion protrudes into the middle notch of the pressing block 82, and the insulating rubber 83 is clamped into the drawstring connector 84. One end of the drawstring of the reel shaft end 21 passes through the drawstring outlet end of the housing 6, passes through the sealing pad 81, the pressing block 82 and the insulating rubber 83, and then connects to the drawstring connector 84. The sealing pad 81 is made of EPDM rubber. The sealing pad 81 and the clamping block 82 are fixed to the pull rope outlet end of the casing 6 by 704 sealant to form a fixed end. The insulating rubber 83 and the pull rope joint 84 are pullable free ends. In the process of the pull rope joint 84 pulling the pull rope to move, the sealing pad 81, the clamping block 82 and the insulating rubber 83 can jointly form a waterproof effect to prevent water vapor from entering the low-power pull rope type crack meter during the process of pulling the rope.

[0052] When in use, the bottom plate 1 of the low-power draw-wire crack meter is fixed to one side of the crack of the measured structure by bolts, the draw-wire connector 84 is fixed to a right-angle piece 9 with a mounting hole by screws, and the right-angle piece 9 is fixed to the other side of the crack. When the crack increases, the draw-wire will be pulled out, so as to measure the displacement of the crack. Of course, in other embodiments, the draw-wire connector 84 can also be connected to a lifting ring expansion screw by a steel wire rope, and the lifting ring expansion screw is fixed to the other side of the crack. When the crack increases, the draw-wire is pulled out, and the purpose of measuring the displacement of the crack can also be achieved.

[0053] When this embodiment is used, the following steps are implemented in sequence:

[0054] i. Find a relatively flat installation surface on one side of the crack of the structure to be tested, with the size of the installation surface not less than 150mm×300mm;

[0055] ii. Place the low-power draw-wire crack meter on the mounting surface so that the bottom of the base plate 1 is in contact with the mounting surface. Use a marker to pass through the mounting holes on both sides of the base plate 1 and make marks on the mounting surface.

[0056] iii. Use an 8mm drill bit to drill a hole on the mounting surface with a depth of no less than 40mm;

[0057] iv. Use four M5 expansion screws to first fix the rope crack meter on one side of the crack of the structure to be measured;

[0058] v. After fixing the draw wire joint 84 of the draw wire crack meter to the right angle piece 9 by screws, fix the right angle piece 9 to the other side of the crack of the measured structure by M5 expansion screws, and monitor the crack data by the draw wire displacement sensor 201;

[0059] Or the pull rope joint 84 of the pull rope crack meter is connected to the eye expansion screw through a steel wire rope, the eye expansion screw is fixed to the other side of the crack of the measured structure, and the crack data is monitored by the pull rope displacement sensor 201;

[0060] vi. Use a smart mobile terminal equipped with a dedicated APP and on-site Bluetooth communication function to wake up the crack monitor 2 through the low-power Bluetooth component 206. At this time, the indicator light of the power management system 211 is always on and enters the configuration state;

[0061] vii. Use a smart mobile terminal to read the initial crack data collected by the pull-wire displacement sensor 201, the initial acceleration and initial geomagnetic data collected by the electronic compass 209, and observe the data stability;

[0062] viii. After the data is stable, record the initial value; the user sets the preset threshold value of the crack data through the smart mobile terminal a tThe microcontroller unit 204 collects crack data 20-30 times within one minute and automatically determines the stability of the crack data. If the fluctuation within one minute is less than the preset threshold a t (The default value is 5 mm, mm refers to the unit of crack length) Then through self-checking, the micro control unit 204 automatically records the average value of crack data within 1 minute as the initial value a0;

[0063] ix. The user sets the normal upload time interval (the default value is once every hour) and the encrypted upload time interval (the default value is once every minute) of the crack data, acceleration and geomagnetic data through the smart mobile terminal;

[0064] x. The microcontroller unit 204 converts the preset threshold into an absolute voltage and configures the low-power configurable comparator 202; and configures the interrupt setting of the real-time clock 205 according to the normal upload time interval;

[0065] xi. After the intelligent mobile terminal completes the operation, the indicator light of the power management system 211 goes out, and the crack monitor 2 enters standby mode;

[0066] xii. When the crack data of the measured structure does not exceed the threshold value, the microcontroller unit 204 is in standby mode, and the analog-to-digital converter 203, the low-power Bluetooth component 206, the LoRa / NB-IoT remote communication module 207, the metal oxide semiconductor field effect transistor 208 and the electronic compass 209 are in sleep mode. At this time, only the pull rope displacement sensor 201, the low-power configurable comparator 202, the real-time clock 205, the ultra-low voltage power supply module 210 and the power management system 211 of the crack monitor 2 are in working mode, and the overall power consumption of the crack monitor 2 is less than 100 μA;

[0067] xiii. When the normal upload time comes, the real-time clock 205 generates an interrupt signal to wake up the micro control unit 204. After receiving the interrupt signal, the micro control unit 204 controls the power management system 211 to power on the analog-to-digital converter 203 and the electronic compass 209 to collect the crack value, acceleration and geomagnetic data and transmit the collected data to the micro control unit 204, and then controls the power management system 211 to power on the LoRa / NB-IoT remote communication module 207, and transmits the crack value, acceleration and geomagnetic data transmitted by the micro control unit 204 to the LoRa / NB-IoT remote communication module 207 to the monitoring cloud platform;

[0068] xiv. If the crack monitor 2 is in standby mode, the crack value a occurs in one of the following two situations: a>a0+a t or a <a0–a t, the low-power configurable comparator 202 sends an interrupt signal, the microcontroller unit 204 is awakened and controls the power management system 211 to power on the analog-to-digital converter 203 to collect crack values, acceleration and geomagnetic data, and then controls the power management system 211 to turn on the LoRa / NB-IoT remote communication module 207 to report the monitored cracks, acceleration and geomagnetic data at a periodic encrypted upload time interval;

[0069] xv. The monitoring cloud platform issues corresponding warning information after receiving the encrypted crack, acceleration and geomagnetic data.

[0070] The above describes a low-power drawstring crack meter that transmits wireless signals through antenna 7 and its use method. However, in actual use, a wired method can be used for signal transmission. Please refer to Figure 5 As shown, Figure 5 As shown in the figure, an opening is opened on the housing 6 to install the aviation plug 7', and a cable is connected through the aviation plug 7' to perform wired signal transmission with an external device.

[0071] The parameters and performances of the present invention are as follows:

[0072] 1. When the pull-cord crack meter is in standby mode, the power consumption is less than 100uA;

[0073] 2. All configuration parameters in the above process can be quickly configured through the on-site Bluetooth connection of the smart mobile terminal; they can also be remotely modified through the cloud afterwards;

[0074] 3. The battery 213 power data and crack data will also be uploaded to the cloud monitoring system at an interval of 1 hour, so that users can understand the battery 213 status;

[0075] 4. Under normal circumstances, crack data is reported once an hour, and battery 213 can work continuously for more than 5 years; if a higher data sampling rate is required, or a longer monitoring period is required, it can be extended by adding battery 213;

[0076] 5. A special waterproof sealing device 8 is added to the rope outlet of the housing 6, and glue treatment is performed to achieve IP66 level sealing protection;

[0077] 6. An acrylic transparent observation window can be set on the housing 6, and a Bluetooth PCB signal line (built-in) and a power status light are arranged on the back. The Bluetooth PCB signal line is used to realize on-site configuration communication with a smart mobile terminal with Bluetooth communication function, and the power status light is used to prompt the status prompt function of Bluetooth communication, signal collection and data transmission to the monitoring cloud platform;

[0078] 7. The narrowband communication (such as LoRa or NB-IoT) antenna is external (SMA seat is installed on the casing, and the inside is glued). Fiberglass or suction cup antennas with different gains can be selected according to the site environment;

[0079] 8. A low-power drawstring displacement sensor 201, a low-power configurable comparator 202, a microcontroller unit 204, and a low-power Bluetooth component 206 are selected (the Bluetooth component can be built into the microcontroller unit 204, such as an STM32W series microcontroller unit of STMicroelectronics), and the standby power consumption is less than 100 μA;

[0080] 9. Through the low-power configurable comparator 202, using the threshold trigger mode, the real-time monitoring of the micro control unit 204 in the standby state is realized;

[0081] 10. Battery 213 uses lithium-thionyl chloride battery with an annual leakage rate of less than 1%;

[0082] 11. The power management system 211 has the battery power management and monitoring functions to send battery power data to the smart mobile terminal.

[0083] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A low-power draw-wire crack meter, comprising a base plate (1) and a housing (6) disposed on the base plate (1), characterized in that: The low-power draw-wire crack meter further comprises a crack monitor (2), wherein the crack monitor (2) comprises a low-power draw-wire displacement sensor (201), a low-power configurable comparator (202), an analog-to-digital converter (203), a microcontroller unit (204), a real-time clock (205), a low-power Bluetooth component (206), a LoRa / NB-IoT remote communication module (207), a metal oxide semiconductor field effect transistor (208), an electronic compass (209), an ultra-low voltage power supply module (210), a power management system (211), a switch (212) and a battery (213); The analog signal output end of the pull rope displacement sensor (201) is respectively connected to the signal input end of the low-power configurable comparator (202) and the analog signal input end of the analog-to-digital converter (203) through a signal line, the digital signal output end of the analog-to-digital converter (203) is connected to the micro control unit (204) through a signal line, the micro control unit (204) is also respectively connected to the low-power configurable comparator (202), the real-time clock (205), the low-power Bluetooth element (206), the LoRa / NB-IoT remote communication module (207), two metal oxide semiconductor field effect transistors (208) and the electronic compass (209) through signal lines, one metal oxide semiconductor field effect transistor (208) is connected to the analog-to-digital converter (203) and the electronic compass (209) through a signal line, the other metal oxide semiconductor field effect transistor (208) is connected to the LoRa / NB-IoT remote communication module (207) through a signal line, and the power management system (209) is connected to the analog-to-digital converter (203) and the electronic compass (209) through a signal line. 11) connecting a low-power configurable comparator (202), a microcontroller unit (204), a metal oxide semiconductor field effect transistor (208) and an ultra-low voltage power module (210) through signal lines, the ultra-low voltage power module (210) is connected to a pull rope displacement sensor (201) through a signal line, and a battery (213) is connected to a power management system (211) through a wire connected in series with a switch (212). The pull rope displacement sensor (201) includes a reel shaft end (21) located in the middle, a potentiometer end (22) located on the right side of the reel shaft end (21), and a coil spring end (23) located on the left side of the reel shaft end (21). The reel shaft end (21) includes a wheel disk around which a pull rope is wound, the potentiometer end (22) includes a resistor, and the coil spring end (23) includes a coil spring. When the pull rope is pulled, the wheel disk rotates, and the coil spring becomes tighter and tighter as the wheel disk rotates. At the same time, the resistance value of the resistor in the potentiometer end (22) changes, and the change in displacement is calculated by the change in resistance value. The pull-wire displacement sensor (201) and the battery (213) are mounted on a base plate (1); a low-power configurable comparator (202), an analog-to-digital converter (203), a microcontroller unit (204), a real-time clock (205), a low-power Bluetooth component (206), a LoRa / NB-IoT remote communication module (207), a metal oxide semiconductor field effect transistor (208), an electronic compass (209), an ultra-low voltage power supply module (210), a power management system (211) and a switch (212) are arranged on a circuit board (10) and fixed inside a housing (6).

2. The low power consumption wire-pull crack meter according to claim 1, characterized in that: The low-power draw-wire crack meter further comprises a sponge pad (3), a fixing plate (4) and a sealing ring (5); the bottom plate (1) is plate-shaped and has mounting holes on both sides; the battery (213) is placed on the bottom plate (1); the sponge pad (3) is placed on the battery (213); the fixing plate (4) is trapezoidally buckled on the sponge pad (3) and the battery (213); the fixing plate (4) is fixed to the bottom plate (1) by bolts to fix the battery (213); the sponge pad (3) prevents the fixing plate (4) from damaging the battery (213); the sealing ring (5) is annularly clamped in a groove on the bottom plate (1); the housing (6) is covered on the bottom plate (1); and the sealing ring (5) seals the gap between the bottom plate (1) and the housing (6).

3. The low power consumption wire-pull crack meter according to claim 1, characterized in that: The low-power draw-wire crack meter further comprises a waterproof sealing device (8), the waterproof sealing device (8) comprising a sealing pad (81), a pressing block (82), an insulating rubber (83) and a draw-wire connector (84), the sealing pad (81) being provided with a conical protrusion, the sealing pad (81) being embedded at the rear end of the pressing block (82), the conical protrusion of which protrudes into the middle notch of the pressing block (82), the insulating rubber (83) being clamped into the draw-wire connector (84), one end of the draw wire of the reel shaft end (21) passing through the draw-wire outlet end of the housing (6), and passing through the sealing pad (81), the pressing block (82) and the insulating rubber (83) and then connected to the draw-wire connector (84), the sealing pad (81) and the pressing block (82) being fixed to the draw-wire outlet end of the housing (6) by means of sealant to form a fixed end, the insulating rubber (83) and the draw-wire connector (84) being a free end that can be pulled.

4. The low power consumption wire-pull crack meter according to claim 3, characterized in that: When in use, the low-power drawstring crack meter is installed on one side of a crack in the structure to be measured, the drawstring joint (84) is fixed to a right-angle piece (9) with a mounting hole by means of screws, and the right-angle piece (9) is fixed to the other side of the crack. When the crack increases, the drawstring is pulled out.

5. The low power consumption wire-pull crack meter according to claim 3, characterized in that: When in use, the low-power draw-rope crack meter is installed on one side of a crack in the structure to be measured, and the draw-rope joint (84) is connected to a lifting eye expansion screw through a steel wire rope, and the lifting eye expansion screw is fixed to the other side of the crack. When the crack increases, the draw-rope is pulled out.

6. The low power consumption wire-pull crack meter according to claim 1, characterized in that: The housing (6) of the low-power draw-wire crack meter is provided with an antenna (7) for wireless signal transmission with external equipment, or the housing (6) of the low-power draw-wire crack meter is provided with an aerial plug (7') and a cable is connected via the aerial plug (7') for wired signal transmission with external equipment.

7. The method for using the low power consumption wire-drawing crack meter according to any one of claims 1 to 6, characterized in that: Follow the steps below to implement: i. Find a relatively flat installation surface on one side of the crack of the structure to be tested; ii. Place the low-power pull-wire crack meter on the mounting surface so that the bottom of the base plate (1) is attached to the mounting surface, and use a marker to pass through the mounting holes on both sides of the base plate (1) to mark the mounting surface; iii. Use a drill bit to drill holes on the mounting surface; iv. Use expansion screws to first fix the rope crack meter on one side of the crack of the structure to be measured; v. After the draw wire joint (84) of the draw wire crack meter is fixed to the right angle piece (9) by screws, the right angle piece (9) is fixed to the other side of the crack of the measured structure by expansion screws, and the crack data is monitored by the draw wire displacement sensor (201); Or the pull rope joint (84) of the pull rope type crack meter is connected to the eye expansion screw through a steel wire rope, the eye expansion screw is fixed to the other side of the crack of the measured structure, and the crack data is monitored by the pull rope displacement sensor (201); vi. Using a smart mobile terminal, wake up the crack monitor (2) through the low-power Bluetooth component (206), at which time the indicator light of the power management system (211) is always on, and enters the configuration state; vii. Using a smart mobile terminal to read the initial crack data collected by the pull-wire displacement sensor (201), the initial acceleration and initial geomagnetic data collected by the electronic compass (209), and observe the data stability; viii. After the data is stable, record the initial value; the user sets the preset threshold value of the crack data through the smart mobile terminal a t The microcontrol unit (204) collects crack data 20-30 times within one minute and automatically determines the stability of the crack data. If the fluctuation within one minute is less than a preset threshold value a t Then, through self-checking, the micro control unit (204) automatically records the average value of the crack data within 1 minute as the initial value a0; ix. The user sets the normal upload time interval and the encrypted upload time interval of the crack data, acceleration and geomagnetic data through the smart mobile terminal; x. The microcontroller unit (204) converts the preset threshold value into an absolute voltage value and configures the low-power configurable comparator (202); and configures the interrupt setting of the real-time clock (205) according to the normal upload time interval; xi. After the intelligent mobile terminal completes the operation, the indicator light of the power management system (211) goes out and the crack monitor (2) enters standby mode; xii. When the crack data of the structure under test does not exceed the threshold value, the microcontroller unit (204) is in a standby mode, and the analog-to-digital converter (203), the low-power Bluetooth component (206), the LoRa / NB-IoT remote communication module (207), the metal oxide semiconductor field effect transistor (208) and the electronic compass (209) are in a sleep mode. At this time, only the pull rope displacement sensor (201), the low-power configurable comparator (202), the real-time clock (205), the ultra-low voltage power supply module (210) and the power management system (211) of the crack monitor (2) are in an operating mode, and the overall power consumption of the crack monitor (2) is less than 100 μA; xiii. When the normal upload time arrives, the real-time clock (205) generates an interrupt signal to wake up the micro control unit (204). After receiving the interrupt signal, the micro control unit (204) controls the power management system (211) to power on the analog-to-digital converter (203) and the electronic compass (209) to collect crack values, acceleration and geomagnetic data and transmit the collected data to the micro control unit (204). Then, the power management system (211) controls the LoRa / NB-IoT remote communication module (207) to power on the crack value, acceleration and geomagnetic data transmitted by the micro control unit (204) to the LoRa / NB-IoT remote communication module (207) to the monitoring cloud platform; xiv. If the crack monitor (2) is in standby mode, the crack value a occurs in one of the following two situations: a>a0+a t or a <a0–a t , the low-power configurable comparator (202) sends an interrupt signal, the microcontroller (204) is awakened and controls the power management system (211) to power on the analog-to-digital converter (203) and the electronic compass (209) to collect crack values, acceleration and geomagnetic data and transmit the collected data to the microcontroller (204), and then controls the power management system (211) to turn on the LoRa / NB-IoT remote communication module (207) to upload the crack values, acceleration and geomagnetic data transmitted by the microcontroller (204) to the LoRa / NB-IoT remote communication module (207) at a periodic encrypted upload time interval; xv. The monitoring cloud platform issues corresponding warning information after receiving the encrypted crack value, acceleration and geomagnetic data.

8. The method of use according to claim 7, characterized in that: In step viii, the preset threshold a t Set to 5mm, mm refers to the unit of crack length; The normal upload interval is set to once an hour, and the encrypted upload interval is set to once a minute.

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