Passive wireless temperature and humidity measuring device

Abstract

The utility model relates to the technical field of power equipment environment monitoring, in particular to a passive wireless temperature and humidity measuring device, which structurally comprises an upper shell, a lower shell buckled at the bottom of the upper shell, a circuit board arranged between the upper shell and the lower shell, an MCU (Microprogrammed Control Unit) processor, a power supply module, a wireless transmitting module, a temperature sensor and a humidity sensor arranged on the circuit board, the wireless transmitting module, the temperature sensor and the humidity sensor are all in communication connection with the MCU processor, and the MCU processor is electrically connected with the power supply module; according to the utility model, electricity is taken through alternating current electromagnetic energy, no battery is needed for power supply, the maintenance cost is reduced, the trouble of frequent battery replacement is reduced, the installation is simple and convenient, the overall cost is reduced, high-precision temperature and humidity monitoring can be provided, the system adapts to various severe environments, and long-term stable operation of the system is ensured.

Description

Technical Field

[0001] This utility model relates to the field of environmental monitoring technology for power equipment, and in particular to a passive wireless temperature and humidity measuring device. Background Technology

[0002] Temperature and humidity measuring devices are widely used in power equipment such as high-voltage transmission lines, substations, distribution cabinets, and switch cabinets, as well as in rail transit power supply systems, industrial electrical equipment, and new energy power generation and storage systems. They are designed to solve equipment failures caused by excessively high or low ambient temperature and humidity, and to ensure the stable and safe operation of power systems and large electrical equipment.

[0003] In practical applications, these devices still have the following shortcomings: Existing active wireless temperature and humidity measurement devices generally use batteries or external power supplies and can transmit environmental data wirelessly. However, they have limitations in high-voltage or high-current environments, short battery life, and are not suitable for frequent replacement, especially in dangerous or inaccessible electrical equipment, increasing maintenance workload. At the same time, this technology cannot fully meet the application needs in high and low voltage, high-current environments. Wired temperature and humidity monitoring devices usually rely on cables for power supply and transmit data via wired means. These devices can work in high-voltage, high-current industrial environments, but their installation and maintenance costs are high, wiring is complex, and maintenance requires specialized personnel. Once a fault occurs, repair and replacement are very time-consuming, especially in some remote or difficult-to-wire environments (such as power transmission lines, tunnels, etc.), where they are limited and costly. Furthermore, existing AC-powered devices can usually only achieve single-function monitoring of temperature or humidity. For example, devices in complex environments such as transformers or switch cabinets cannot provide comprehensive environmental data, affecting the monitoring effect.

[0004] In summary, existing measuring equipment has many limitations in terms of power dependence, environmental adaptability, monitoring range, functional integration, and maintenance complexity, and cannot meet the temperature and humidity monitoring needs under high and low voltage and high current environments. Utility Model Content

[0005] This invention provides a passive wireless temperature and humidity measuring device, which can effectively solve the above-mentioned problems.

[0006] This utility model is implemented as follows:

[0007] A passive wireless temperature and humidity measuring device includes: an upper shell and a lower shell fastened to the bottom of the upper shell. A circuit board is installed between the upper shell and the lower shell. The circuit board is equipped with an MCU processor, a power module, a wireless transmission module, a temperature sensor, and a humidity sensor. The wireless transmission module, temperature sensor, and humidity sensor are all communicatively connected to the MCU processor. The MCU processor and the power module are electrically connected. The power module includes a CT power supply and a rectification and regulation circuit.

[0008] As a further improvement, a metal heat-conducting sheet is provided at the bottom of the lower shell, the metal heat-conducting sheet is integrally formed with the lower shell, and the temperature measuring head of the temperature sensor is in contact with the metal heat-conducting sheet.

[0009] As a further improvement, the rectifier and regulator circuit consists of four Schottky diodes, a filter capacitor, and an LDO linear regulator.

[0010] As a further improvement, the circuit board is also equipped with a monitoring and reset module, which is connected to the MCU processor and uses a watchdog timer.

[0011] As a further improvement, the bottom of the lower shell is provided with ventilation holes.

[0012] As a further improvement, the bottom of the lower shell is provided with a glue-filling hole.

[0013] As a further improvement, the CT power supply includes a plastic frame, an inductor coil wound on the plastic frame, and PET tape covering the inductor coil. The inductor coil adopts a multi-layer flat winding form.

[0014] The beneficial effects of this utility model are:

[0015] 1. This utility model uses AC electromagnetic energy to generate power, eliminating the need for battery power, reducing maintenance costs and the hassle of frequent battery replacements. It is easy to install, lowers the overall cost, and can provide high-precision temperature and humidity monitoring, adapting to various harsh environments and ensuring long-term stable operation of the system.

[0016] 2. This utility model is suitable for high and low voltage and high current environments, has strong anti-electromagnetic interference capabilities, ensures stable operation of temperature and humidity detection in complex environments, and provides accurate and reliable monitoring data. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a passive wireless temperature and humidity measuring device provided by this utility model;

[0019] Figure 2 This is a three-dimensional assembly structure diagram of a passive wireless temperature and humidity measuring device provided by this utility model;

[0020] Figure 3 This is a schematic diagram of the circuit principle of a passive wireless temperature and humidity measuring device provided by this utility model.

[0021] In the diagram: Upper shell-1, Lower shell-2, Circuit board-3, MCU processor-4, Power module-5, Wireless transmission module-6, Temperature sensor-7, Humidity sensor-8, CT power supply-51, Rectifier and voltage regulator circuit-52, Metal heat-conducting sheet-21, Monitoring and reset module-9, Vent hole-22, Potting hole-23. Detailed Implementation

[0022] All embodiments of this utility model are intended to fall within the scope of protection of this utility model. Therefore, the following detailed description of the embodiments of this utility model provided in the accompanying drawings is not intended to limit the scope of the claimed utility model, but merely to illustrate selected embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

[0023] Existing measuring equipment has many limitations in terms of power dependence, environmental adaptability, monitoring range, functional integration, and maintenance complexity, and cannot meet the temperature and humidity monitoring requirements under high and low voltage and high current environments. In order to solve the above-mentioned technical problems, this paper proposes the following technical solution:

[0024] Reference Figures 1 to 3As shown, a passive wireless temperature and humidity measuring device includes: an upper shell 1, and a lower shell 2 fastened to the bottom of the upper shell 1. A circuit board 3 is installed between the upper shell 1 and the lower shell 2. The circuit board 3 is equipped with an MCU processor 4, a power module 5, a wireless transmission module 6, a temperature sensor 7, and a humidity sensor 8. The wireless transmission module 6, temperature sensor 7, and humidity sensor 8 are all communicatively connected to the MCU processor 4. The MCU processor 4 is electrically connected to the power module 5. The power module 5 includes a CT power supply 51 and a rectifier and voltage regulator circuit 52.

[0025] Specifically, MCU processor 4 is the core controller of the entire system, responsible for collecting data from temperature and humidity sensors, processing the data, controlling the wireless transmission module, and monitoring the system status. This solution uses a low-power MCU processor 4 to better support passive design, extend the working time of the device, and reduce the bus AC current. In addition, a low-power mode (such as deep sleep mode) is set during use to reduce power consumption, and MCU processor 4 is only woken up when data is collected and transmitted.

[0026] Meanwhile, the temperature sensor uses an NTC resistance thermometer to detect the temperature of the AC line node. Its resistance value changes with the temperature. The NTC resistance thermometer is connected to the ADC pin of the MCU processor 4 through a voltage divider circuit. The MCU processor 4 converts the measured voltage into the corresponding temperature value. In order to improve the temperature measurement accuracy, multiple samplings and averaging can be used.

[0027] The humidity sensor 8 is used to detect ambient humidity. The sensor communicates directly with the MCU processor 4 via a digital interface, through I... 2 The C protocol reads the humidity data from the sensor. The humidity data needs to be processed by linearization and compensation algorithms to obtain an accurate humidity value. The humidity data acquisition frequency is set to every few minutes to reduce power consumption.

[0028] The wireless transmitter module 6 is equipped with an RF antenna. It wirelessly transmits the collected temperature and humidity data to the receiver at a frequency of 433MHz, which offers advantages such as long transmission distance and strong penetration. A readily available 433MHz wireless transmitter module is selected and connected to the MCU processor 4 via an SPI interface. After acquiring data, the MCU processor 4 sends the data to the wireless transmitter module 6 via SPI, and the module transmits the data through the 433MHz frequency band. Considering power consumption, the wireless transmitter module 6 is configured for intermittent operation; that is, after data acquisition and transmission are completed, it enters sleep mode and is periodically woken up to transmit again.

[0029] This solution obtains electromagnetic energy from the AC circuit through a current transformer (CT) 51 and converts it into voltage. The power supply module includes the CT 51 and a rectifier and voltage regulator circuit 52. When AC current flows through the main circuit, an induced current is generated on the secondary side of the current transformer. This induced current is very small, but it can be converted into an induced voltage by connecting a load. The CT 51 module induces current from the AC circuit, so the output current signal is an AC waveform. The amplitude of the induced AC voltage is proportional to the main circuit current, so the induced signal will be relatively small when the current is small. The AC signal generated by the CT transformer is converted into a DC signal to provide stable power to the subsequent circuits. The MCU processor 4 acquires the temperature signal from the temperature sensor 7 via an ADC and reads humidity data from the humidity sensor 8. The MCU processor 4 performs simple signal processing as needed, such as data filtering or calibration, and then transmits the processed data through the wireless transmission module 6.

[0030] Therefore, this utility model draws power from AC electromagnetic energy, eliminating the need for batteries and external power sources, thus reducing maintenance costs and the hassle of frequent battery replacements. It is easy to install, lowering the overall cost. Furthermore, it employs 433MHz wireless communication technology to wirelessly transmit data to the monitoring terminal, reducing wiring complexity, enabling remote real-time monitoring, reducing the need for manual inspections, and improving operational efficiency. In addition, it can monitor not only temperature but also humidity, adapting to various harsh environments and ensuring comprehensive monitoring of the equipment's operating environment.

[0031] Power facilities such as substations, distribution cabinets, and switchgear are frequently exposed to high voltage and high current environments, and these devices have strict requirements for temperature and humidity. Excessive humidity can lead to insulation failures or corrosion of electrical equipment; excessive temperature can cause overheating and system failure. This device can be installed inside high-voltage distribution cabinets or low-voltage switchgear in substations to monitor temperature and humidity changes in real time. When the ambient temperature or humidity exceeds safe limits, the system can issue an early warning to prevent equipment failures caused by overheating or humidity, thereby ensuring the reliability and safety of the power system.

[0032] Transmission lines, especially high-voltage transmission lines, typically operate in harsh environments. Drastic changes in temperature and humidity can affect the working condition of conductors and insulators, increasing power loss and even causing short circuits or electrical accidents. This device can be installed on the towers or near the transmission lines, transmitting temperature and humidity data wirelessly to help maintenance personnel remotely monitor the line environment in real time, promptly address potential hazards, reduce line faults, and ensure the stable operation of the power grid.

[0033] The power supply systems for rail transit systems such as subways and light rail are typically located in underground tunnels or enclosed spaces. These environments have high humidity, and the power supply equipment operates under high voltage, making it susceptible to temperature and humidity fluctuations, which can lead to equipment failures. Installing this device in the rail transit power supply equipment allows for real-time monitoring of temperature and humidity within the tunnels or enclosed spaces. This ensures that the power supply system operates in a suitable environment, preventing power failures caused by high humidity or overheating, and improving the operational safety of rail transit.

[0034] Building automation systems in intelligent buildings require precise control of ambient temperature and humidity to ensure the comfort and safety of equipment and personnel, especially in temperature and humidity-sensitive areas such as power distribution rooms and machine rooms. This device can be used for environmental monitoring in intelligent buildings. Through real-time monitoring and wireless transmission, it coordinates with the building automation system to adjust the environment, ensuring the comfort of the building's interior and the normal operation of equipment.

[0035] The bottom of the lower shell 2 is provided with a metal heat-conducting plate 21, which is integrally formed with the lower shell 2. The temperature measuring head of the temperature sensor 7 is in contact with the metal heat-conducting plate 21, thereby making full use of the thermal conductivity of the metal to transfer the junction temperature of the AC circuit to the sensor end, so as to reduce the measurement error.

[0036] Among them, the metal heat-conducting sheet 21 is made of 304 stainless steel, which can prevent the heat-conducting sheet from rusting when used in environments with high humidity, ensuring detection accuracy and reducing maintenance costs.

[0037] The rectifier and voltage regulator circuit 52 consists of four Schottky diodes, a filter capacitor, and an LDO linear regulator.

[0038] Since the CT 51 outputs an AC signal, a bridge rectifier circuit is typically used to convert it to a DC signal. A full-bridge rectifier circuit is built using four Schottky diodes. Schottky diodes are suitable for low-voltage, low-power circuits due to their low forward voltage drop (approximately 0.2V) and short reverse recovery time. However, the rectified signal still exhibits some fluctuation and ripple. Therefore, a filter capacitor (with a value between 10μF and 100μF) is added at the output to smooth the DC voltage and reduce ripple interference. The size of the filter capacitor depends on the CT's output power and load current. To further improve the stability of the output voltage, a low-dropout regulator (LDO) is added after the rectified circuit to stabilize the voltage at a specific value. A low-power, low-quiescent-current LDO linear regulator is selected to stabilize the high input voltage to a stable output of 3.3V.

[0039] Therefore, it is suitable for high and low voltage and high current environments, has strong anti-electromagnetic interference capabilities, ensures stable operation in complex environments, and provides accurate and reliable monitoring data.

[0040] Specifically, in high-voltage, high-current industrial environments, equipment such as transformers, large motors, and generators have strict requirements for temperature and humidity during normal operation, especially in heavy industries such as petrochemicals, steel, and papermaking, where these devices typically operate in high-temperature or high-humidity environments. This device can be installed inside or near industrial equipment to monitor the temperature and humidity data of the equipment's operating environment in real time. When adverse environmental conditions are detected, the system can issue warnings and implement automated controls, such as adjusting the ventilation system, activating heating or dehumidification devices, to extend the equipment's lifespan and reduce the occurrence of malfunctions.

[0041] To prevent the system from stopping due to software failure or external interference and to enhance the system's reliability, the circuit board 3 is also equipped with a monitoring and reset module 9. The monitoring and reset module 9 is connected to the MCU processor 4 and uses a watchdog timer.

[0042] The monitoring and reset module 9 is used to monitor the system's operating status and prevent system interruption due to abnormal conditions (such as system crashes). This module can automatically reset the MCU processor 4 when necessary. A watchdog timer module is used to periodically check the normal operating status of the MCU processor 4. The MCU processor 4 needs to be fed periodically during each data processing. If the watchdog is not fed within a set time, the watchdog triggers a reset signal, restarting the MCU processor 4.

[0043] The bottom of the lower shell 2 is provided with a vent 22, which facilitates the humidity sensor 8 to collect the ambient humidity through the vent.

[0044] The bottom of the lower shell 2 is provided with a potting hole 23, so that after the temperature sensor 7 is installed, thermally conductive adhesive is poured in through the potting hole 23, thereby waterproofing the potting hole 23, the circuit board 3, and the power module 5.

[0045] The CT power supply 51 includes a plastic frame, an inductor coil wound on the plastic frame, and PET tape covering the inductor coil. The inductor coil adopts a multi-layer flat winding form.

[0046] Furthermore, the upper shell has through slots on both sides for placing permalloy steel strips. The permalloy steel strips pass through the through slots and plastic skeleton of the upper shell, and the two ends of the permalloy steel strips are fixedly connected. One end of the inductor coil is electrically connected to the input terminal of the full-bridge rectifier circuit, and the other end is electrically connected to the negative terminal of the LDO linear regulator. The output terminal of the full-bridge rectifier circuit is electrically connected to the positive terminal of the LDO linear regulator. The positive and negative terminals of the LDO linear regulator are electrically connected to the MCU processor 4.

[0047] In summary, the passive wireless temperature and humidity measurement device of this solution, with its AC power supply, wireless communication, and anti-interference capabilities, is suitable for various applications in high and low voltage, high current, and complex environments. It is widely used in power systems, industrial equipment, new energy power generation, traffic tunnels, and intelligent buildings, providing a real-time monitoring, low-maintenance, and highly reliable environmental monitoring solution to ensure safe equipment operation and reduce maintenance costs.

[0048] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A passive wireless temperature and humidity measuring device, the structure of which includes: The upper shell (1) and the lower shell (2) attached to the bottom of the upper shell (1) are characterized in that: a circuit board (3) is installed between the upper shell (1) and the lower shell (2), and the circuit board (3) is provided with an MCU processor (4), a power module (5), a wireless transmission module (6), a temperature sensor (7), and a humidity sensor (8). The wireless transmission module (6), the temperature sensor (7), and the humidity sensor (8) are all connected to the MCU processor (4) in communication. The MCU processor (4) and the power module (5) are electrically connected. The power module (5) includes a CT power supply (51) and a rectifier and voltage regulator circuit (52).

2. The passive wireless temperature and humidity measuring device as described in claim 1, characterized in that: The bottom of the lower shell (2) is provided with a metal heat-conducting sheet (21), which is integrally formed with the lower shell (2), and the temperature measuring head of the temperature sensor (7) is in contact with the metal heat-conducting sheet (21).

3. The passive wireless temperature and humidity measuring device as described in claim 2, characterized in that: The rectifier and voltage regulator circuit (52) consists of four Schottky diodes, a filter capacitor, and an LDO linear regulator.

4. The passive wireless temperature and humidity measuring device as described in claim 3, characterized in that: The circuit board (3) is also provided with a monitoring and reset module (9), which is connected to the MCU processor (4) and uses a watchdog timer.

5. The passive wireless temperature and humidity measuring device as described in claim 4, characterized in that: The bottom of the lower shell (2) is provided with a vent hole (22).

6. The passive wireless temperature and humidity measuring device as described in claim 5, characterized in that: The bottom of the lower shell (2) is provided with a glue-filling hole (23).

7. A passive wireless temperature and humidity measuring device as described in claims 1-6, characterized in that: The CT power supply (51) includes a plastic frame, an inductor coil wound on the plastic frame, and PET tape covering the inductor coil. The inductor coil adopts a multi-layer flat winding form.

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