LoRaWAN tilt angle sensor system with high precision and low power consumption

Abstract

The utility model relates to a high-precision and low-power-consumption LoRaWAN tilt angle sensor system. The system comprises a lithium thionyl chloride battery management circuit used for realizing charging and discharging management of a lithium thionyl chloride battery; the power switch circuit is connected with the lithium thionyl chloride battery management circuit and is used for providing voltage output; the temperature sensor circuit is used for detecting the system environment temperature and sending the system environment temperature to the single chip microcomputer; the three-axis accelerometer and power supply and discharge control circuit is used for detecting three-axis acceleration data of the current position and sending the three-axis acceleration data to the single chip microcomputer; the LoRaWAN wireless communication module circuit is connected with the single-chip microcomputer and is used for realizing wireless communication of the system; and the single-chip microcomputer is used for realizing power supply control and angle calculation of each circuit. Compared with the prior art, the utility model has the advantages of large effective measuring range, high precision, small sensitivity temperature excursion, long service life of the battery and the like, and is not influenced by small differences of gravitational acceleration values at different altitudes and regions.

Description

Technical Field

[0001] This utility model relates to the field of tilt sensors, and in particular to a high-precision, low-power LoRaWAN tilt sensor system. Background Technology

[0002] A tilt sensor is a device used to measure the angle of inclination of an object relative to a horizontal plane. It determines the tilt angle by detecting the component of gravitational acceleration along the sensor axis and is widely used in construction, automotive, aerospace, and industrial equipment to monitor and control tilt conditions.

[0003] Currently, tilt sensors use MEMS accelerometers to detect static tilt angles. Typically, the tilt angle value is obtained by performing an arcsine function calculation on the gravitational acceleration component along a certain axis of the accelerometer. Since the output change caused by the input change is very small when the sine function is close to ±90°, i.e., the sensitivity is low, this method cannot perform high-precision large-angle range measurements. In addition, the static tilt angle detection by MEMS accelerometers is easily affected by the actual gravitational acceleration values ​​of different regions or latitudes, and also suffers from high power consumption and short battery life. Utility Model Content

[0004] To address the technical problems in the background art, this utility model provides a high-precision, low-power LoRaWAN tilt sensor system, which includes:

[0005] Lithium-ion battery management circuit: used to manage the charging and discharging of lithium-ion batteries;

[0006] Power switch circuit: connected to the lithium-ion battery management circuit to provide voltage output;

[0007] Temperature sensor circuit: used to detect the system ambient temperature and send it to the microcontroller;

[0008] Triaxial accelerometer and power supply / discharge control circuit: used to detect triaxial acceleration data at the current position and send it to the microcontroller;

[0009] LoRaWAN wireless communication module circuit: connected to a microcontroller to enable wireless communication of the system;

[0010] The microcontroller is connected to the power switch circuit, temperature sensor circuit, triaxial accelerometer and power supply control circuit, and LoRaWAN wireless communication module circuit to realize the power supply control and angle calculation of each circuit.

[0011] Furthermore, the lithium-ion battery management circuit includes a lithium-ion battery, a charge / discharge management module, and an external power output port. The charge / discharge management module consists of a charge / discharge management chip, a resistor, and a jumper resistor. The negative terminal of the lithium-ion battery is grounded, and the positive terminal is connected to the power supply pin of the charge / discharge management chip and the external power output port through a Schottky diode. The external power output port is connected to the power switch circuit.

[0012] Furthermore, the power switch circuit includes a battery power supply interface, a power input port, a jumper interface, a low-dropout reverse connection protection circuit, and an external power switch, all connected to the external power output port of the lithium-ion battery management circuit. The power input port is connected in sequence to the external power switch, the jumper interface, and the low-dropout reverse connection protection circuit via a resettable fuse and a reverse connection protection dual diode, respectively. The jumper interface is connected in parallel with a jumper resistor.

[0013] Furthermore, the low-dropout reverse connection protection circuit includes a PMOS transistor and a resistor. The gate of the PMOS transistor is grounded through the resistor, the drain is connected to the jumper interface, and the source serves as the power output terminal VDD of the power switch circuit.

[0014] Furthermore, the temperature sensor circuit includes a temperature sensor chip, which communicates with the microcontroller via a single-bus communication interface and is powered by the microcontroller's GPIO interface.

[0015] Furthermore, the triaxial accelerometer and power supply / discharge control circuit includes a triaxial MEMS accelerometer chip and a power supply / discharge control sub-circuit. One end of the power supply / discharge control sub-circuit is connected to the accelerometer power supply control pin of the microcontroller, and the other end is connected to the power supply pin of the triaxial MEMS accelerometer chip. The triaxial MEMS accelerometer chip communicates with the microcontroller via an SPI interface. The microcontroller calculates and outputs angle data using an arctangent algorithm.

[0016] Furthermore, the power supply and discharge control sub-circuit consists of a resistor, a TVS diode, and a capacitor. The accelerometer power supply control pin of the microcontroller is connected to the power supply terminal of the triaxial MEMS accelerometer chip through the resistor. The TVS diode and the capacitor are connected in parallel, with one end connected between the resistor and the power supply terminal of the triaxial MEMS accelerometer chip, and the other end grounded.

[0017] Furthermore, the LoRaWAN wireless communication module circuit includes a LoRaWAN module power supply control sub-circuit and a LoRaWAN module sub-circuit. The LoRaWAN module power supply control sub-circuit includes a PMOS transistor and a transistor. The base of the transistor is connected to the wireless communication module power supply control pin of the microcontroller, the transmitter is grounded, the collector is connected to the gate of the PMOS transistor, the drain of the PMOS transistor is connected to the LoRaWAN module sub-circuit, and the source is connected to the output terminal of the power switch circuit.

[0018] Furthermore, the LoRaWAN module sub-circuit includes a LoRaWAN module and an indicator light module, a reset module, and an antenna module, which are respectively connected to the LoRaWAN module.

[0019] Furthermore, the microcontroller is connected to a crystal oscillator chip used by the microcontroller MCU core and a crystal oscillator chip used by the low-power RTC real-time clock module. Different crystal oscillator frequencies are set in different working modes corresponding to different workloads to reduce power consumption.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] I. Low power consumption: The LoRaWAN tilt sensor system designed in this utility model adopts a low power consumption circuit architecture, which can ensure low power consumption during operation and sleep. The sleep power consumption of this utility model is 30uA, and the power consumption when waking up to detect the angle is only 6mA. It only takes 0.28 seconds to complete one angle detection. It can guarantee long-term operation for more than 5 years when powered by battery, which is longer than the battery life of existing products of about 3 years.

[0022] II. Large Range: This utility model adopts a three-axis MEMS accelerometer chip, which measures three-axis angles and outputs three-axis angles. Because it adopts three-axis angle calculation, it overcomes the performance degradation and accuracy reduction problem caused by the gradual curve change near ±90° angle when performing arcsine calculation on a single axis.

[0023] II. High Precision: This utility model adopts a six-position calibration algorithm + three-axis angle calculation + multiple curve angle interpolation algorithm to achieve high precision and large range output of three axes ±90°. The accuracy can reach within ±0.01° in the ±85° range and ±0.5° in the ±85°~±90° range. At the same time, since the three-axis algorithm uses the three-axis acceleration ratio to calculate the angle, it can effectively suppress the sensitivity drift of the accelerometer and offset the influence of different acceleration values ​​at different latitudes. Therefore, it can also ensure that the design can still guarantee high precision after being calibrated in a fixed location and used in various parts of the world. In contrast, the existing arcsine calculation cannot guarantee the accuracy. Attached Figure Description

[0024] Figure 1 This is a circuit block diagram of the present invention;

[0025] Figure 2 This is the circuit schematic for a lithium-ion battery management circuit.

[0026] Figure 3 This is the circuit schematic of a power switch circuit;

[0027] Figure 4 This is the circuit schematic of a temperature sensor circuit.

[0028] Figure 5a The circuit diagram for the discharge control sub-circuit;

[0029] Figure 5b This is the circuit diagram of the triaxial accelerometer sub-circuit.

[0030] Figure 6a This is the circuit schematic of the microcontroller and its peripheral circuits.

[0031] Figure 6b This is the circuit schematic of the external crystal oscillator circuit for a microcontroller.

[0032] Figure 7a Circuit diagram of the power supply control sub-circuit for the LoRaWAN module;

[0033] Figure 7b This is a circuit diagram of the LoRaWAN module and indicator light sub-circuit.

[0034] Figure 8a This is the circuit schematic diagram of the key sub-circuit;

[0035] Figure 8b This is the circuit diagram of the indicator light sub-circuit;

[0036] Figure 9 This is a flowchart illustrating the working principle of this utility model;

[0037] Figure 10 This is a flowchart of angle calculation and calibration. Detailed Implementation

[0038] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. This embodiment is based on the technical solution of the present invention and provides detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following embodiments.

[0039] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0040] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the utility model product is usually placed in during use. They are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the utility model.

[0041] The terms “first”, “second”, etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0042] In the description of this embodiment, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0043] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.

[0044] Example

[0045] like Figure 1 As shown, this utility model provides a high-precision, low-power LoRaWAN tilt sensor system to achieve high-precision, large-range, and low-power three-axis angle detection. The system includes a microcontroller and a lithium-ion battery management circuit, a power switch circuit, a temperature sensor circuit, a three-axis accelerometer and power supply / discharge control circuit, a LoRaWAN wireless communication module circuit, and button and indicator light circuits, all connected to the microcontroller.

[0046] like Figure 2 As shown, the lithium-ion battery management circuit includes a lithium-ion battery BT201, a composite pulse capacitor C201, a Schottky diode D201, a charge / discharge management chip U201, a resistor R201, a jumper resistor R202, and an external power output port P201.

[0047] The negative terminal of the lithium-ion battery BT201 (model ER34615 in this example) is grounded, and the positive terminal is connected to pin 1 of the Schottky diode D201. This is to prevent the positive and negative terminals of the lithium-ion battery BT201 from being incorrectly connected and to prevent the composite pulse capacitor C201 from charging the non-rechargeable lithium-ion battery BT201 in reverse. The composite pulse capacitor C201 is connected between pin 3 of the Schottky diode D201 and ground. The charge / discharge management chip U201, resistor R201, and jumper resistor R202 form a charge / discharge management circuit for the composite pulse capacitor C201 to prevent over-discharge of the composite pulse capacitor C201. Pin 2 of the charge / discharge management chip U201 is grounded and connected to pin 4 through jumper resistor R202. Pins 4 and 5 are both grounded. Pin 3 is connected to pin 3 of the Schottky diode D201 and the external power output port P201 through resistor R201.

[0048] The battery discharge management circuit, as the battery power supply part of this utility model, combines a lithium-ion battery BT201 and a composite pulse capacitor C201 with a low-power charge and discharge management chip U201 (model DW02 is used in this example). It can achieve a battery life of more than 10 years with an extremely low self-discharge rate, and can also handle large currents for short periods of time, such as wireless communication.

[0049] like Figure 3 As shown, the power switch circuit includes a power input port P4 for debugging, a reverse polarity protection dual diode D1, a resettable fuse F1, an external power switch J1, a battery power interface J2, a jumper interface P2, a jumper resistor R6, and a low-dropout reverse polarity protection sub-circuit. One end of the power input port P4 is connected sequentially through the resettable fuse F1 and the reverse polarity protection dual diode D1 to one end of the jumper interface P2, one end of the battery power interface J2, and the Vi pin of the external power switch J1. The other ends of the power input port P4 and the battery power interface J2 are grounded respectively. The other end of jumper interface P2 is connected to the Vo pin of external power switch J1 and the low-dropout reverse connection protection circuit, respectively. The function of jumper interface P2 is to conduct the circuit for easy testing when external power switch J1 is not soldered. The L- pin of external power switch J1 is grounded through resistor R1, and the L+ pin is connected to the microcontroller chip U3. The low-dropout reverse connection protection circuit consists of PMOS transistor Q2 and resistor R8. The gate of PMOS transistor Q2 is grounded through resistor R8, the drain is connected to jumper interface P2, and the source is used as the power output terminal VDD of the power switch circuit.

[0050] The reverse polarity protection dual diode D1 is used to prevent the positive and negative terminals of the power supply from being reversed and burning out the downstream circuit components when the tilt sensor motherboard is not using the power board and is operating independently; the self-resetting fuse F1 is used to prevent overcurrent; the jumper interface P2 is used to ensure circuit continuity during debugging; the jumper resistor R6 is connected across the jumper interface P2 as an option; the battery power interface J2 is connected to the external power output port P201 via a wire; the low voltage drop reverse polarity protection sub-circuit is used to prevent reverse power from the battery power interface J2.

[0051] In this invention, the use of an external power switch J1 ensures zero power consumption of the tilt sensor product during shipping. Since the external power switch J1 is a physical switch with an indicator light, the switch is turned off during transportation, thus cutting off the current loop and achieving zero power consumption. The low voltage drop anti-reverse connection circuit has an extremely low voltage drop, which can effectively reduce unnecessary power consumption.

[0052] like Figure 4 As shown, the temperature sensor circuit includes a high-precision temperature sensor chip U2 (model M1820P in this example), which communicates with the microcontroller via a single-bus communication interface. The power supply is controlled by the microcontroller's GPIO interface and is only powered when in use, and is turned off when not in use to reduce power consumption.

[0053] The triaxial accelerometer and power supply / discharge control circuit includes the triaxial accelerometer chip U1 (in this example, the ADXL35x series chip is used) and the power supply / discharge control sub-circuit directly controlled by the microcontroller, such as... Figure 5a As shown, the power supply and discharge control sub-circuit consists of resistor R2, TVS diode D2, capacitor C3, and resistor R15. The control pin ACC_POWER of the microcontroller chip U3 is connected to the power supply terminal AVDD of the triaxial accelerometer through resistor R2. TVS diode D2 and capacitor C3 are connected in parallel, with one end connected between resistor R2 and the power supply terminal AVDD of the triaxial accelerometer, and the other end grounded. The power supply and discharge control sub-circuit only turns on the power supply when the triaxial accelerometer chip U1 is in use, and turns off to save power when not in use.

[0054] like Figure 5b As shown, the triaxial accelerometer chip U1, which is the core component of the tilt sensor, is a triaxial MEMS accelerometer chip. The capacitors around the chip are its power supply bypass and decoupling capacitors. The triaxial accelerometer chip U1 is connected to the microcontroller through the SPI interface.

[0055] like Figure 6a and 6bAs shown, the microcontroller and peripheral circuits include the microcontroller chip U3 and the peripheral circuits. In the peripheral circuits, Y1 and Y2 are external crystal oscillators, where Y1 is used by the microcontroller's MCU core and Y2 is used by the microcontroller's internal low-power RTC real-time clock module, and is equipped with load capacitors. C20 to C23 are the power supply bypass and decoupling capacitors for the microcontroller chip U3, respectively. In this example, the microcontroller chip U3 uses a low-power ARM core microcontroller chip, which has extremely low power consumption. The peripheral devices constitute the minimum system of the microcontroller, and J3 is used for SWD program burning and debugging. The interface J4 is the debugging serial port for product calibration. The microcontroller chip U3 uses different crystal oscillator frequencies to minimize power consumption under different workloads, enabling data acquisition from chips such as the triaxial accelerometer chip U1 and the high-precision temperature sensor chip U2, as well as the calculation of angle and temperature data. For example, when calculating angles at full speed, the microcontroller's operating frequency is set to 16MHz; when periodically waking up to acquire accelerometer data, the microcontroller's operating frequency is set to 1MHz; and before entering sleep mode, the microcontroller's operating frequency is set to 32.768kHz.

[0056] The LoRaWAN wireless communication module circuit includes a LoRaWAN module power supply control sub-circuit and a LoRaWAN module and indicator light sub-circuit, such as... Figure 7a As shown, the core components of the LoRaWAN module power supply control sub-circuit include a PMOS transistor Q4 and a transistor Q5. The base of transistor Q5 is connected to pin 21, PW_CTL_LR, of the microcontroller chip U3, the emitter is grounded, the collector is connected to the gate of PMOS transistor Q4, the drain of PMOS transistor Q4 is connected to LoRaWAN module U5, and the source is connected to the output terminal VDD of the power switch circuit. The remaining decoupling capacitors and TVS diodes form a power supply bypass to prevent excessively high transient voltages that may occur when the circuit is turned on.

[0057] like Figure 7bAs shown, the LoRaWAN module and indicator light sub-circuit include a LoRaWAN module U5 that communicates with the microcontroller chip U3, and an indicator light module, a reset module, and an antenna module connected to the LoRaWAN module U5. The indicator light module is located between pins 1 and 3 of the LoRaWAN module U5 and the output of the LoRaWAN module power supply control sub-circuit to indicate power supply and sleep. The reset module includes a reset capacitor C33 and a reset resistor R29. The output VBAT of the LoRaWAN module power supply control sub-circuit is connected to the reset pin of the LoRaWAN module U5 through the reset resistor R29. One end of the reset capacitor C33 is connected to the reset pin of the LoRaWAN module U5, and the other end is grounded. The antenna module includes an antenna connector J5 (model 20279-001E-01 in this example) and matching capacitors and resistors. The LoRaWAN module U5 communicates with the microcontroller chip U3 through the UART port and is powered only when communicating, and powered off when not communicating to achieve low power consumption.

[0058] The button and indicator light circuit includes a button sub-circuit and an indicator light sub-circuit, such as Figure 8a As shown, the button sub-circuit is used to test the manual triggering of the wireless communication function. It includes button S1, resistor R23, capacitor C26, and resistor R21. The output of the power switch circuit is connected to pin 29 (RES_KEY) of the microcontroller chip U3 via button S1 and resistor R21. Resistor R23 and capacitor C26 are connected in parallel, with one end grounded and the other end connected between button S1 and resistor R21. Figure 8b As shown, the indicator light sub-circuit includes LEDs D5 and D6 to indicate the product's working status. One end of LED D5 is grounded, and the other end is connected to pin 28 of the microcontroller chip U3 through resistor R17. One end of LED D6 is grounded, and the other end is connected to pin 18 of the microcontroller chip U3 through resistor R18. Neither the button sub-circuit nor the indicator light sub-circuit generates power consumption in sleep mode, further achieving low power consumption.

[0059] like Figure 9As shown, this invention implements a high-precision, large-range, low-power LoRaWAN tilt sensor system. The main flow of the program running in the microcontroller chip includes initialization and a main loop. During initialization, the power supply control and initialization of components such as the counting microcontroller peripheral, the triaxial accelerometer, and the temperature sensor are completed. After entering the main loop, the watchdog timer is fed first, and then the power supply voltages of the triaxial accelerometer, temperature sensor, and microcontroller are collected to calculate the angle, temperature, and voltage data. Subsequently, the data is transmitted wirelessly to a remote server platform via the LoRaWAN module. After the data transmission is completed, the tilt sensor enters a low-power sleep state. The low-power RTC real-time clock module inside the microcontroller wakes up the system periodically and repeats the above steps. This invention employs a periodic sleep-wake low-power design in the main process flow to minimize the active time of the tilt sensor. By controlling the power supply of components such as the temperature sensor, accelerometer chip, and LoRaWAN module, the power supply to these circuits is turned off when not needed. At the same time, combined with reducing the operating frequency of the microcontroller, the tilt sensor product achieves low-power operation. Under the condition of reporting one data point every 5 minutes, a single ER34615 lithium-ion battery can work continuously for about 8 years, which exceeds the 3-5 years working life of similar products at home and abroad under the same working conditions.

[0060] like Figure 10 As shown, the angle calculation and calibration process of this utility model first involves the microcontroller sampling the triaxial accelerometer via the SPI interface. Then, the raw values ​​are filtered to remove high-frequency noise and jitter. Subsequently, a six-position calibration algorithm is used to perform preliminary calibration of the filtered acceleration values ​​for installation alignment error, cross axis, and sensitivity. Next, a triaxial arctangent algorithm is used to calculate the angle. This step is the foundation for achieving a large range and high precision for the triaxial accelerometer. Then, the angle is calibrated, and finally, a factory zero-point calibration is performed. This completes the entire angle calculation and calibration process, achieving a high-precision, large-range output of ±90° for the triaxial accelerometer.

[0061] The tilt sensor system of this invention achieves an accuracy of within ±0.01° within a ±85° range, and ±0.5° within ±85° to ±90°. Furthermore, because the triaxial angle calculation algorithm uses triaxial ratios, the sensitivity is not affected by varying acceleration values ​​in different locations. This also ensures that the tilt sensor product will not experience accuracy loss due to differences in gravitational acceleration at different latitudes or altitudes. Therefore, this invention can achieve more comprehensive high-precision measurements. Actual testing has verified that the final accuracy level is superior to that of similar products both domestically and internationally.

[0062] The preferred embodiments of this utility model have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of this utility model without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of this utility model through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A high-precision low-power LoRaWAN tilt sensor system, characterized in that, The system comprises: Lithium sub-battery management circuit: to realize the charge and discharge management of lithium sub-battery; Power switch circuit: connected with lithium sub-battery management circuit, to provide voltage output; Temperature sensor circuit: to detect the system environment temperature and send to single-chip microcomputer; Three-axis accelerometer and power supply and discharge control circuit: to detect the three-axis acceleration data of the current position and send to single-chip microcomputer; LoRaWAN wireless communication module circuit: connected with single-chip microcomputer, to realize the wireless communication of the system; Single-chip microcomputer: connected with power switch circuit, temperature sensor circuit, three-axis accelerometer and power supply and discharge control circuit and LoRaWAN wireless communication module circuit, to realize the power supply control and angle solution of each circuit.

2. The high-precision low-power LoRaWAN tilt sensor system according to claim 1, characterized in that, The lithium sub-battery management circuit comprises lithium sub-battery (BT201), charge and discharge management module and external power supply output port (P201), the charge and discharge management module is composed of charge and discharge management chip (U201), resistor (R201) and jumper resistor (R202), the negative electrode of the lithium sub-battery (BT201) is grounded, the positive electrode is connected with the power supply pin of the charge and discharge management chip (U201) and the external power supply output port (P201) through Schottky diode (D201), and the external power supply output port (P201) is connected with the power switch circuit.

3. The high-precision low-power LoRaWAN tilt sensor system according to claim 2, characterized in that, The power switch circuit comprises battery power supply interface (J2) connected with the external power supply output port (P201) of the lithium sub-battery management circuit, power input port (P4), jumper interface (P2), low-voltage drop anti-reverse sub-circuit and external power switch (J1), the power input port (P4) is connected with the external power switch (J1), the jumper interface (P2) and the low-voltage drop anti-reverse sub-circuit in sequence through self-resetting fuse (F1) and anti-reverse double diode (D1) respectively, and the jumper interface (P2) is connected with jumper resistor (R6) in parallel.

4. The high-precision low-power LoRaWAN tilt sensor system according to claim 3, characterized in that, The low-voltage drop anti-reverse sub-circuit comprises PMOS tube (Q2) and resistor (R8), the gate of the PMOS tube (Q2) is grounded through the resistor (R8), the drain is connected with the jumper interface (P2), and the source is used as the power output end VDD of the power switch circuit.

5. The high-precision low-power LoRaWAN tilt sensor system according to claim 1, characterized in that, The temperature sensor circuit comprises temperature sensor chip (U2), the temperature sensor chip (U2) communicates with the single-chip microcomputer through single bus communication interface and is controlled by the GPIO interface of the single-chip microcomputer.

6. The high-precision low-power LoRaWAN tilt sensor system according to claim 1, characterized in that, The three-axis accelerometer and power supply and discharge control circuit comprises three-axis MEMS accelerometer chip (U1) and power supply and discharge control sub-circuit, one end of the power supply and discharge control sub-circuit is connected with the acceleration meter power supply control pin of the single-chip microcomputer, the other end is connected with the power supply pin of the three-axis MEMS accelerometer chip (U1), the three-axis MEMS accelerometer chip (U1) communicates with the single-chip microcomputer through SPI interface, and the single-chip microcomputer calculates the angle data through arctangent algorithm and outputs.

7. The high-precision low-power LoRaWAN tilt sensor system according to claim 6, characterized in that, The power supply control sub-circuit is composed of a resistor (R2), a TVS tube (D2) and a capacitor (C3), the acceleration sensor power supply control pin of the single-chip microcomputer is connected with the power supply end of the three-axis MEMS accelerometer chip (U1) through the resistor (R2), the TVS tube (D2) and the capacitor (C3) are connected in parallel, one end of which is connected between the resistor (R2) and the power supply end of the three-axis MEMS accelerometer chip (U1), and the other end is grounded.

8. The high-precision low-power LoRaWAN tilt sensor system of claim 1, wherein, The LoRaWAN wireless communication module circuit includes a LoRaWAN module power supply control sub-circuit and a LoRaWAN module sub-circuit, the LoRaWAN module power supply control sub-circuit includes a PMOS tube (Q4) and a triode (Q5), the base of the triode (Q5) is connected with the wireless communication module power supply control pin of the single-chip microcomputer, the emission level is grounded, the collector is connected with the gate of the PMOS tube (Q4), the drain of the PMOS tube (Q4) is connected with the LoRaWAN module sub-circuit, and the source is connected with the output end of the power switch circuit.

9. The high-precision low-power LoRaWAN tilt sensor system according to claim 8, characterized in that, The LoRaWAN module sub-circuit includes a LoRaWAN module (U5) and an indicator light module, a reset module and an antenna module connected with the LoRaWAN module (U5) respectively.

10. The high-precision low-power LoRaWAN tilt sensor system of claim 1, wherein, The single-chip microcomputer is connected with a crystal chip (Y1) used by the single-chip microcomputer MCU core and a crystal chip (Y2) used by a low-power RTC real-time clock module, and different crystal frequencies are set in different working modes corresponding to different working loads to reduce power consumption.

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