A battery-powered, offline data storage, high-temperature resistant, and waterproof weighing sensor

Abstract

This invention relates to the field of weighing sensors, specifically to a battery-powered, offline data storage, high-temperature resistant, and waterproof weighing sensor, comprising: a main control circuit module, a data acquisition module, a signal conversion module, a USB communication module, and a power supply module. The battery-powered, offline data storage, high-temperature resistant, and waterproof weighing sensor provided by this invention has a simple structure, is lightweight, small in size, high accuracy, and is portable. It enables real-time data storage in high-temperature, dense water mist, signal-shielded conditions, and situations where wired power is unavailable, exhibiting strong adaptability and allowing for real-time measurement and data storage of weight data under harsh environmental conditions.

Description

Technical Field

[0001] This invention relates to the field of weighing sensors, and more specifically to a battery-powered, offline data storage, high-temperature resistant, and waterproof weighing sensor. Background Technology

[0002] With the increasing application of digital technology in the glass fiber manufacturing industry, digital technologies are being used more and more in all aspects of the glass fiber production process. Digital technology is used to achieve energy conservation and carbon reduction in glass fiber production. Among these processes, glass fiber drying is a very important step that determines the quality and grade of the product. At the same time, the glass fiber drying process is also a very energy-intensive process. In order to achieve the goals of energy conservation, carbon reduction, and cost reduction in various industries, energy-saving and cost-reducing measures need to be taken.

[0003] In the glass fiber drying process, load cells are used to monitor the moisture evaporation of the glass fiber products in real time. A mathematical model of the relationship between "energy consumption, product weight, and drying time" is established using a large amount of real-time data. Through continuous model optimization, the optimal points for energy saving, carbon reduction, and cost reduction can be found. However, traditional load cells use wired power supplies and wired or wireless signal transmission, and all require operation in a normal temperature, dry environment with unshielded signals. Furthermore, the measured data cannot be stored in real time. These limitations of traditional load cells make them unsuitable for use in glass fiber drying ovens. Glass fiber drying ovens are constructed with metal shells and are enclosed spaces. The internal operating temperature ranges from 100 to 140 degrees Celsius, and a large amount of water mist is present during operation. Additionally, the glass fiber products move periodically during the drying process due to time constraints and production requirements. Therefore, the development of a portable, real-time data-storage-capable, high-temperature-resistant, waterproof, and highly accurate new type of load cell is imperative. Summary of the Invention

[0004] To address the challenges posed by the high temperature, high humidity, and enclosed environment of fiberglass drying ovens, and the fact that existing traditional load cells use wired power supplies, have poor signal strength, and cannot operate in such high-temperature and high-humidity environments, thus rendering them unsuitable for use in drying ovens, this invention provides a battery-powered, offline data storage, high-temperature resistant, and waterproof load cell that solves the aforementioned problems.

[0005] The technical solution of the present invention is as follows: This invention provides a battery-powered offline data storage high-temperature resistant and waterproof weighing sensor, characterized in that it includes a stainless steel shell, a protective layer, an internal circuit board, a removable battery compartment, and a sealed USB interface; the stainless steel shell completely encapsulates and fixes the protective layer to the internal circuit board; the protective layer is formed by encapsulating and curing the internal circuit board with polyurethane; the removable battery compartment and the sealed USB interface are partially disposed on the stainless steel shell and electrically connected to the internal circuit board via a sealed waterproof connector or sealed lead wire. The internal circuit board includes functional circuit units, which include: a power module, a data acquisition module, a signal conversion module, a main control circuit module, and a USB communication module. The power module includes a replaceable battery and an LDO voltage regulator circuit. The replaceable battery is placed in a removable battery compartment. The positive and negative output terminals of the battery are electrically connected to the input terminals of the LDO circuit through sealed waterproof connectors. The output terminals of the LDO circuit are electrically connected to the power input terminals of the data acquisition bridge module, the signal conversion module, the main control circuit module, and the USB communication module, respectively. The output terminal of the data acquisition module is electrically connected to the analog input terminal of the signal conversion module; a thermistor is installed inside the data acquisition bridge module, and the thermistor is connected to the reference voltage terminal of the bridge. The analog input terminal of the signal conversion module is electrically connected to the output terminal of the data acquisition bridge module, and its digital output terminal is electrically connected to the digital input terminal of the main control circuit module. The digital input terminal of the main control circuit module is electrically connected to the digital output terminal of the signal conversion module, and its serial port output terminal is electrically connected to the serial port input terminal of the USB communication module. The serial port input terminal of the USB communication module is electrically connected to the serial port output terminal of the main control circuit module. Its USB interface is electrically connected to the USB dock through a sealed waterproof cap or a waterproof USB connector. The output terminal is electrically connected to the USB dock. The signal is converted into a USB protocol signal by a serial port converter chip and output to an external device through the USB dock. The USB interface is sealed by a waterproof cap. The cap is briefly opened during use to connect to an external device.

[0006] Preferably, the data acquisition module includes resistors, bridge arms, a null pointer, and a thermistor; the resistors, bridge arms, and null pointer form a bridge circuit, with its excitation input terminal electrically connected to the LDO output terminal of the power supply module to receive a constant excitation voltage, and the output terminal of the bridge circuit electrically connected to the analog input terminal of the signal conversion module; when there is no load, the bridge arm resistance values ​​are balanced, and the output voltage difference is close to zero; when the weight signal causes a change in the bridge arm resistance, the bridge becomes unbalanced, thereby generating a weak differential analog voltage signal proportional to the weight at the output terminal; the null pointer is connected to the bridge arm circuit in a series-parallel manner to adjust the bridge arm balance, compensate for the initial imbalance, and make the no-load output close to zero; the thermistor is connected to the reference voltage terminal of the bridge circuit and electrically connected to the reference voltage terminal of the bridge circuit.

[0007] Preferably, the signal conversion module includes a rectifier-filter unit, a sampling unit, a quantization circuit, and a digital output circuit. The input of the rectifier-filter unit is electrically connected to the output of the data acquisition bridge module, amplifying, filtering, and performing common-mode suppression on the weak differential analog voltage signal from the data acquisition module, and outputting a clean, amplified continuous analog voltage signal. The input of the sampling unit is electrically connected to the output of the rectifier-filter unit, capturing the continuous analog voltage signal to form discrete-time analog samples. The input of the quantization circuit is electrically connected to the output of the sampling unit, using an analog-to-digital converter as its core, comparing the analog samples with a reference voltage and converting them into discrete digital code values. The input of the digital output circuit is electrically connected to the output of the quantization circuit, and its output is electrically connected to the digital input of the main control circuit module, formatting and outputting the digital code values ​​to the main control circuit module according to a predefined protocol, thereby realizing the conversion from analog signal to digital signal.

[0008] Preferably, the sampling frequency of the sampling unit is 1Hz; the digital output circuit adopts the SPI or I2C protocol, and its output terminal is electrically connected to the corresponding protocol input terminal of the main control circuit module to transmit the digital code value to the main control circuit module.

[0009] Preferably, the main control circuit module includes a decoupling circuit, a crystal oscillator circuit, a reset and boot circuit, a program input and debug interface circuit, flash memory, a data storage unit, and a microcontroller; the input terminal of the decoupling circuit is electrically connected to the LDO output terminal of the power supply module, and its output terminal is electrically connected to the power supply pin of the microcontroller; the output terminal of the crystal oscillator circuit is electrically connected to the clock input pin of the microcontroller; the output terminal of the reset and boot circuit is electrically connected to the reset pin and boot pin of the microcontroller; the program input and debug interface circuit is electrically connected to the debug pin of the microcontroller. The Flash output is electrically connected to the program storage interface of the microcontroller; the read / write interface of the data storage unit is electrically connected to the storage controller of the microcontroller; the digital input pin of the microcontroller is electrically connected to the digital output of the signal conversion module; its UART output pin is electrically connected to the serial port input of the USB communication module's serial port chip; the microcontroller executes a preset algorithm to process the discrete digital signal, and packages the processed weight value and timestamp information into a data frame; the microcontroller writes the data frame into the data storage unit in real time to achieve offline append storage.

[0010] Preferably, the preset algorithm performs digital filtering, temperature compensation, and unit conversion functions; the UART output pin of the microcontroller is electrically connected to the RX input terminal of the serial port chip of the USB communication module, and sends data frames to the USB communication module according to the serial port protocol.

[0011] Preferably, the USB communication module includes a USB dock, a serial port converter chip, and an indicator light; the RX input terminal of the serial port converter chip is electrically connected to the UART TX output terminal of the main control circuit module, receives data from the main control circuit module, and converts it into USB protocol data packets; the USB differential signal terminal of the serial port converter chip is electrically connected to the USB pin of the USB dock, serving as a physical interface for the computer to recognize as a virtual serial port; the control terminal of the indicator light is electrically connected to the indicator pin of the serial port converter chip, used to display the power status.

[0012] Preferably, the data frame includes a weight value and a timestamp.

[0013] Preferably, a constantly lit indicator light indicates normal power supply, while a flashing indicator light indicates that data is being sent or received.

[0014] Preferably, the power module includes an LDO circuit, the input of which is electrically connected to the positive and negative output terminals of the external replaceable battery; the output of the LDO circuit is electrically connected to the power input terminals of the data acquisition bridge module, the signal conversion module, the main control circuit module, and the USB communication module, respectively; the LDO maintains a constant output voltage, ensuring that the main control circuit module, data acquisition module, signal conversion module, and USB communication module operate stably in harsh environments with high temperature and high humidity when the battery voltage fluctuates or the load changes.

[0015] The beneficial effects of this invention are as follows: This invention relates to a battery-powered, offline data storage, high-temperature resistant, and waterproof weighing sensor. The internal circuit board is completely encapsulated by a protective layer formed by cured polyurethane. Because polyurethane is high-temperature resistant and stable, its cured form is a dense, non-porous polymer protective layer, providing waterproof, moisture-proof, insulating, and high-temperature resistant properties. The potting process fills all tiny gaps and dead corners inside the shell, eliminating leaks that are easily left by traditional sealing rings and preventing water vapor from condensing and seeping in at high temperatures. Stainless steel is characterized by high-temperature resistance, corrosion resistance, chemical stability, and uniform thermal conductivity. It will not deform at high temperatures, thus the stainless steel shell can block direct impacts from external water vapor, liquids, and dust, preventing mechanical damage, scratches, or long-term exposure to extreme environments to the polyurethane layer. This makes the cured polyurethane protective layer less prone to deformation or cracking. Simultaneously, the stainless steel shell can evenly conduct heat from the external environment, avoiding localized overheating. Together with the cured polyurethane protective layer, it forms an internal and external thermal buffer structure, reducing the temperature of the internal circuit board and minimizing thermal stress damage to electronic components. A rigid stainless steel shell and a cured polyester protective layer form a composite protective structure, achieving an IP67 protection rating. This allows the sensor to operate stably in a wide temperature range of -10℃ to 140℃, and in enclosed environments with dense water mist, preventing damage to the circuitry from water vapor penetration, condensation, corrosion, leakage current, or thermal stress. High and low temperatures can cause strain gauge resistance shifts, leading to inaccurate sensor weighing. The compensation design of the thermistor connected to the reference voltage terminal within the data acquisition module, due to the characteristic that the thermistor's resistance decreases with increasing temperature, allows the supply voltage to automatically and inversely adjust with temperature changes, thereby offsetting the weighing error caused by strain gauge resistance shifts due to high and low temperatures.

[0016] The power module employs a replaceable battery power supply and an LDO circuit design. The negative feedback control loop within the LDO circuit can monitor and automatically adjust the output voltage in real time. Combined with a low-noise reference source and high PSRR characteristics, it can force a constant, low-noise output voltage regardless of battery voltage fluctuations, load changes, or high-temperature environments, thus ensuring the sensor operates reliably for extended periods under extreme conditions. Therefore, it supports the sensor to operate independently for extended periods in enclosed, wire-free, or high-temperature environments, avoiding the failure of traditional wired sensors due to wiring difficulties, high-temperature melting, or power outages.

[0017] The output of the data acquisition module is electrically connected to the input of the signal conversion module, converting the mechanical weight signal into a weak differential analog voltage signal. The signal conversion circuit then converts the analog signal into a discrete digital signal and outputs it to the digital input of the main control circuit, realizing full-link local conversion and processing from analog to digital. This eliminates reliance on wireless or wired real-time transmission and avoids interference from metal casing shielding, high-temperature thermal noise, water mist parasitic capacitance, or leakage current, providing a clean, stable, and high-precision input for subsequent digital processing.

[0018] After receiving the output of the signal conversion module, the input terminal of the main control circuit module is electrically connected to the serial port input terminal of the USB communication module through the serial port output terminal. After being processed by the local preset algorithm, the data is written to the data storage unit in real time to realize the recording of weighing data. No external real-time communication is required, ensuring that all tiny weight change data under extreme environments such as high temperature, water mist, and shielding are completely preserved.

[0019] The serial port output of the main control circuit module is electrically connected to the serial port input of the USB communication circuit. The USB communication module converts data frames into USB protocol signals through a serial port converter chip, and then connects to the USB dock via the USB output. It can be recognized as a virtual serial port simply by connecting to a computer with a USB cable. The host computer software reads and parses all historical data frames to export offline collected data, reducing the cost and complexity of data collection in harsh environments.

[0020] The composite structure of stainless steel housing combined with cured polyurethane potting makes the sensor small in size, light in weight (<1kg), and highly portable. It is suitable for extreme working conditions such as high temperature, high humidity, airtight shielding, or inability to lay power cables in industries such as glass fiber drying ovens, steel, coal power, petrochemicals, and pharmaceutical manufacturing. It provides stable and reliable data support for product quality monitoring, process control, and energy conservation and carbon reduction.

[0021] Through the integrated design of the stainless steel shell, protective layer, and internal circuit modules, the problem of traditional weighing sensors failing to function properly in high temperature, high humidity, and enclosed environments has been solved. This provides a reliable and effective weighing data acquisition solution for high temperature, high humidity, shielded, or unwired working conditions in industries such as fiberglass drying ovens, steel, coal power, petrochemicals, and pharmaceutical manufacturing. Attached Figure Description

[0022] Figure 1 Diagram showing the internal module relationships of a battery-powered, offline data storage, high-temperature resistant, and waterproof weighing sensor.

[0023] Figure 2 Circuit diagram of the power module for a battery-powered, offline data storage, high-temperature resistant, and waterproof weighing sensor.

[0024] Figure 3 Circuit diagram of the data acquisition module for a battery-powered offline data storage, high-temperature resistant, and waterproof weighing sensor.

[0025] Figure 4 Circuit diagram of the signal conversion module for a battery-powered, offline data storage, high-temperature resistant, and waterproof weighing sensor.

[0026] Figure 5 Circuit diagram of the main control circuit module of a battery-powered offline data storage, high-temperature resistant, and waterproof weighing sensor.

[0027] Figure 6 Circuit diagram of USB communication module for battery-powered offline data storage, high temperature resistance, and waterproof weighing sensor. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the following detailed description of the battery-powered offline data storage high-temperature resistant and waterproof weighing sensor proposed in this invention, in conjunction with the accompanying drawings and specific embodiments, will provide further clarity. The advantages and features of this invention will become clearer from the following description. It should be noted that the accompanying drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of this invention. Please refer to the accompanying drawings for a more apparent and understandable understanding of the objectives, features, and advantages of this invention.

[0030] This invention provides a battery-powered offline data storage high-temperature resistant and waterproof weighing sensor, characterized in that it includes a stainless steel shell, a protective layer, an internal circuit board, a removable battery compartment, and a sealed USB interface; the stainless steel shell completely encapsulates and fixes the protective layer to the internal circuit board; the protective layer is formed by encapsulating and curing the internal circuit board with polyurethane; the removable battery compartment and the sealed USB interface are partially disposed on the stainless steel shell and electrically connected to the internal circuit board via a sealed waterproof connector or sealed lead wire. The internal circuit board includes functional circuit units, which include: a power module, a data acquisition module, a signal conversion module, a main control circuit module, and a USB communication module. The interconnection relationships between these circuit modules are as follows: Figure 1 As shown.

[0031] The power module includes a replaceable battery and an LDO voltage regulator circuit. The replaceable battery is housed in a removable battery compartment. The positive and negative output terminals of the battery are electrically connected to the input terminals of the LDO circuit via sealed waterproof connectors. The output terminals of the LDO circuit are electrically connected to the power input terminals of the data acquisition bridge module, the signal conversion module, the main control circuit module, and the USB communication module, respectively. Figure 2 As shown.

[0032] The output terminal of the data acquisition module is electrically connected to the analog input terminal of the signal conversion module; the data acquisition bridge module has a thermistor inside, and the thermistor is connected to the reference voltage terminal of the bridge, such as... Figure 3 As shown.

[0033] The analog input terminal of the signal conversion module is electrically connected to the output terminal of the data acquisition bridge module, and its digital output terminal is electrically connected to the digital input terminal of the main control circuit module, such as... Figure 4 As shown.

[0034] The digital input terminal of the main control circuit module is electrically connected to the digital output terminal of the signal conversion module, and its serial port output terminal is electrically connected to the serial port input terminal of the USB communication module, such as... Figure 5 As shown; The serial port input terminal of the USB communication module is electrically connected to the serial port output terminal of the main control circuit module. Its USB interface is electrically connected to the USB dock via a sealed waterproof cap or a waterproof USB connector, and its output terminal is electrically connected to the USB dock. Figure 6 As shown, the signal is converted to a USB protocol signal via a serial port chip and output to an external device via a USB dock; the USB interface is sealed with a waterproof cap, which is briefly opened to connect to the external device during use.

[0035] In some embodiments of the present invention, the power module is powered by an external replaceable battery and includes an LDO circuit, such as... Figure 2 As shown in the diagram, the power module is electrically connected to the main control circuit module, data acquisition module, signal conversion module, and USB communication module, and is used to provide power to other circuit modules.

[0036] In some embodiments of the present invention, the data acquisition module includes a resistor, a bridge arm, and a null pointer, such as... Figure 3As shown. The data acquisition module is electrically connected to the signal conversion module and the power supply module. It is used to measure the object being weighed and output the detected signal changes in the form of voltage / current. When the power supply is turned on, the object being weighed will cause a change in the voltage drop of the circuit in the acquisition module. This change will be presented in the form of voltage or current signals, thereby enabling the acquisition module to acquire the weighing measurement signal in real time. The thermistor added inside the acquisition module can compensate for the reference voltage of the sensor at high and low temperatures, so that the sensor of this invention can work stably within the operating range of -10 degrees Celsius to 140 degrees Celsius, and output the obtained analog signal to the signal conversion module in the form of power or current.

[0037] In some embodiments of the present invention, the signal conversion module includes a rectification and filtering unit, a sampling unit, a quantization circuit, and a digital output circuit, such as... Figure 4 As shown. The signal conversion module is electrically connected to the sensor data acquisition module, the main control circuit module, and the power supply module, and is used to convert analog signals into discrete digital signals. When the power supply is turned on, the rectification and filtering unit rectifies and filters the input signal and outputs it to the sampling unit. The sampling unit transmits the signal to the quantization circuit at a frequency of 1 second. After processing by the quantization circuit, the required discrete digital signal is obtained, and this digital signal is transmitted to the external main control circuit module through the output circuit.

[0038] In some embodiments of the present invention, the main control circuit module includes a decoupling circuit, a crystal oscillator circuit, a reset and boot circuit, a program input and debug interface circuit, a flash memory, a data storage unit, and a microcontroller, such as... Figure 5 As shown. The main control circuit is electrically connected to the signal conversion module, USB communication module, and power supply module, and is used for digital signal processing, data storage, and debugging. When the power is turned on, this module processes and stores the discrete digital signals obtained from the signal conversion module. The preset program is downloaded to the main control circuit module through the input and debugging interface circuit. The discrete digital signals obtained by this module are processed by the written processing program through the decoupling circuit, crystal oscillator circuit, reset, and BOOT circuit. The processed digital signals are then stored in the data storage unit after passing through the microcontroller and flash circuit.

[0039] The preset program performs digital filtering, temperature compensation, and unit conversion functions. After power-on initialization, the preset program embedded in the microcontroller enters an infinite main loop (while(1)). First, it completes the configuration of hardware peripherals (such as GPIO, UART, timers, etc.), and then, driven by timer interrupts, it periodically reads discrete digital signals (ADC raw code values) from the signal conversion module at a fixed frequency of 1Hz. Within each sampling period, the program executes the following command sequence in sequence: First, it calls the digital filtering sub-function (such as moving average filtering, median filtering, or first-order low-pass filtering) to smooth the original digital signal and eliminate random noise and environmental interference; then, it reads the temperature value collected by the thermistor and executes a temperature compensation algorithm (such as linear compensation, lookup table interpolation, or polynomial fitting) to correct zero-point drift and sensitivity drift caused by high temperature; subsequently, it runs the engineering unit conversion command to convert the compensated code value into the actual weight value (kg or g) through a pre-calibrated zero-point offset and scaling factor, adding nonlinear correction if necessary; after processing, the program packages the weight value, timestamp (generated by an internal timer), checksum, and other information into a standard data frame; finally, it executes the storage command to append the data frame to the data storage unit (internal Flash partition of the microcontroller or external non-volatile storage) to achieve offline real-time recording; at the same time, it monitors the USB connection status, and once an export request or trigger condition is detected, it reads the data frame from the storage area and sends it byte by byte to the serial port chip of the USB communication module through the built-in UART peripheral according to the serial port protocol to complete the data output. The entire preset program execution commands—reading raw data, filtering and denoising, temperature compensation, unit conversion, data packaging, storage / sending—are all completed locally on the microcontroller, ensuring that the sensor can reliably achieve real-time acquisition, processing, and offline storage of weighing data in harsh environments such as high temperature, water mist, and metal shielding.

[0040] In some embodiments of the present invention, the USB communication module includes a USB dock, a serial port converter chip, and indicator lights, such as... Figure 6 As shown. The USB communication module is electrically connected to the main control circuit module and the power supply module, and is used to output the signals measured by the sensor to the outside. After power-on, the internal serial port chip will obtain the stored data from the main control circuit module and transmit this data to external devices, such as an external computer.

[0041] In some embodiments of the present invention, the battery-powered offline data storage high-temperature resistant and waterproof weighing sensor is composed of a stainless steel shell, cured polyurethane, circuit board and leads. The shell is tightly packaged, which greatly improves the IP protection level to IP67. The sensor of the present invention weighs less than 1kg, is small in size and easy to carry.

[0042] In some embodiments of the present invention, the stainless steel shell and the cured polyurethane protective layer are fixed by a mechanical bonding method. The specific steps are as follows: First, a layer of high-temperature resistant silane coupling agent or special adhesive primer is pre-coated on the inner wall of the stainless steel shell to enhance the chemical adhesion between the polyurethane and the stainless steel surface; then, the internal core circuit board is placed inside the shell cavity, and grooves, bosses, or chamfer structures (mechanical interlocking structures) are designed on the inner wall of the shell; next, liquid two-component polyurethane potting compound is poured into the cavity, completely filling all gaps between the shell and the circuit board, and cured at room temperature or under heating conditions; during the curing process, the polyurethane chemically bonds with the inner wall of the shell, while simultaneously filling the grooves and chamfers to form a mechanical interlock; finally, the stainless steel shell and the cured polyurethane protective layer are fixed together by adhesive force and mechanical interlocking, forming a tight, seamless composite structure, achieving electrical insulation, moisture resistance, corrosion resistance, and mechanical buffering functions. Testing showed that it can operate continuously for more than 72 hours in a high-temperature environment of 140°C and a dense water mist environment, achieving a protection level of IP67.

[0043] In some embodiments of the present invention, the stainless steel shell and the cured polyurethane protective layer are fixed by integral die casting / welding. The specific steps are as follows: First, the internal core circuit board is placed in the lower half of the stainless steel shell cavity, and liquid polyurethane potting compound is poured in to completely encapsulate the circuit board, leads, and electronic components; the polyurethane cures at room temperature or under heating conditions to form a protective layer; then, the upper half (cover plate) of the stainless steel shell is permanently sealed to the lower half by argon arc welding or laser welding, and the welding part adopts continuous weld seam to ensure no pores or cracks; after welding, the entire shell completely encapsulates and mechanically fixes the cured polyurethane protective layer to form a rigid external protective structure; this structure has extremely high sealing performance and mechanical strength in high temperature (140℃) and dense water mist environments, and the protection level has been tested to reach IP67.

[0044] In some embodiments of the present invention, the stainless steel shell and the cured polyurethane protective layer are fixed by a combination of compression and sealing ring assistance. The specific steps are as follows: First, a flange or groove structure is reserved on the inner wall of the stainless steel shell, and a high-temperature resistant O-ring (silicone or fluoropolymer material, temperature resistance ≥150℃) is installed on the edge of the shell; then, the internal core circuit board is placed in the shell cavity, and liquid polyurethane potting compound is poured in to completely wrap the circuit board and cure to form a protective layer; after curing, the flange or groove on the edge of the shell is pressed tightly by hydraulic compression or rolling process, so that the sealing ring is compressed and deformed and closely adheres to the outer surface of the polyurethane protective layer; after compression, the shell completely wraps the cured polyurethane protective layer and is mechanically fixed, and the sealing ring provides an auxiliary sealing function; after testing, this structure can work continuously for more than 72 hours in a high-temperature environment of 140℃ and dense water mist, with a protection level of IP67, without water leakage or loosening, and is suitable for portable high-temperature sensor scenarios.

[0045] In some embodiments of the invention, the top surface of the stainless steel casing serves directly as the weighing surface. The object is placed directly on the upper surface or the top slightly convex platform / end face of the stainless steel casing. The top of the casing is designed as a flat or slightly convex structure, and the surface is made of stainless steel, which has high hardness, high temperature resistance (≥140℃), and corrosion resistance, making it suitable for directly bearing heavy objects. The weight is transferred vertically downwards through the top of the casing to the internal elastic body (strain beam or columnar structure). The elastic body undergoes slight deformation, causing a change in the resistance value of the strain gauges attached to it, resulting in an imbalance in the Wheatstone bridge and outputting a weak differential analog voltage signal proportional to the weight. This signal is processed by subsequent circuitry to achieve the weighing function.

[0046] In some embodiments of the present invention, the stainless steel casing is designed as a single piece, machined into an S-shaped beam, column, or beam structure, with a thin-walled or grooved area in the middle serving as an elastic deformation zone (i.e., an internal elastic body). An object is placed directly on the top platform or end face of the casing (the upper platform of an S-shaped beam or the top end face of a columnar casing). The weight is transferred through the top of the casing to the thin-walled area in the middle, causing a small, reversible deformation of the casing. Strain gauges are attached to the inner surface of the thin-walled area of ​​the casing, sensing this deformation and causing a change in resistance, resulting in an imbalance in the Wheatstone bridge and outputting a weak differential analog voltage signal proportional to the weight. This signal is processed by subsequent circuitry to achieve the weighing function.

[0047] In some embodiments of the present invention, the sensor is used in industrial scenarios such as glass fiber drying ovens (closed, high temperature 100–140°C, dense water mist). The sensor is embedded or installed below or at the force measuring point of a drying cart, material tray, or weighing bracket via a fixed bracket or bolts. The object (glass fiber roll or material tray) is placed on the tray or bracket of the drying cart. The weight is vertically transferred through the tray / bracket to the top end face of the sensor or the force measuring platform, and then acts on the elastic body through the force transmission path inside the housing. The elastic body undergoes slight deformation, the resistance value of the strain gauge changes, causing the Wheatstone bridge to become unbalanced, and outputting a weak differential analog voltage signal proportional to the weight. This signal is processed by subsequent circuitry to realize the weighing function. In this method, the object is actually placed on the tray / bracket, and the force is ultimately transmitted to the top force measuring surface of the sensor housing. The housing does not directly contact the object, but the force is transmitted through the bracket.

[0048] In some embodiments, the battery-powered offline data storage high-temperature and waterproof weighing sensor is used as follows: The user places the sensor at the location to be measured, such as a tray or weighing platform inside a fiberglass drying oven. After the sensor is powered on, the internal replaceable battery powers all modules through an LDO circuit, and the microcontroller of the main control circuit module starts up and enters the working state. The weight applied to the object being weighed causes the elastic body in the data acquisition module to deform, thereby changing the resistance of the strain gauge (bridge arm) attached to it, causing the bridge to become unbalanced. This causes the data acquisition bridge module to output a weak differential analog voltage signal. This analog voltage signal is transmitted to the signal conversion module, and after amplification, filtering, sampling, and quantization, it is converted into a discrete digital signal (ADC code value). This digital signal is transmitted to the main control circuit module. After receiving it, the microcontroller executes a preset algorithm to generate the actual weight value and packages it into a data frame. The data frame is appended to the data storage unit (local Flash) in real time, realizing offline real-time storage.

[0049] During use, the entire measurement and storage process is completed independently, requiring no external power cable or real-time wireless transmission. Users can remove the sensor from harsh environments at any time. When data needs to be read, simply connect the sensor's USB dock to the computer using a USB cable. At this time, the microcontroller of the main control circuit module sends the historical data frames (containing weight values, timestamps, etc.) stored in the data storage unit frame by frame to the serial port chip of the USB communication module through its built-in UART peripheral. The serial port chip receives the TTL level serial port data and converts it into a differential signal conforming to the USB protocol. The computer automatically recognizes the device as a virtual serial port (COM port). Users can open the corresponding COM port through host computer software (such as a serial port assistant or a dedicated reading program) to read and parse all historical data frames, thereby obtaining a complete weighing record.

Claims

1. A battery-powered, offline data storage, high-temperature resistant, and waterproof weighing sensor, characterized in that, It includes a stainless steel shell, a protective layer, an internal circuit board, a removable battery compartment, and a sealed USB interface; the stainless steel shell completely encapsulates and fixes the protective layer to the internal circuit board; the protective layer is formed by encapsulating and curing the internal circuit board with polyurethane; the removable battery compartment and the sealed USB interface are partially disposed on the stainless steel shell and are electrically connected to the internal circuit board through a sealed waterproof connector or sealed lead wire. The internal circuit board includes functional circuit units, which include: a power module, a data acquisition module, a signal conversion module, a main control circuit module, and a USB communication module. The power module includes a replaceable battery and an LDO voltage regulator circuit. The replaceable battery is placed in a removable battery compartment. The positive and negative output terminals of the battery are electrically connected to the input terminals of the LDO circuit through sealed waterproof connectors. The output terminals of the LDO circuit are electrically connected to the power input terminals of the data acquisition bridge module, the signal conversion module, the main control circuit module, and the USB communication module, respectively. The output terminal of the data acquisition module is electrically connected to the analog input terminal of the signal conversion module; a thermistor is installed inside the data acquisition bridge module, and the thermistor is connected to the reference voltage terminal of the bridge. The analog input terminal of the signal conversion module is electrically connected to the output terminal of the data acquisition bridge module, and its digital output terminal is electrically connected to the digital input terminal of the main control circuit module. The digital input terminal of the main control circuit module is electrically connected to the digital output terminal of the signal conversion module, and its serial port output terminal is electrically connected to the serial port input terminal of the USB communication module. The serial port input terminal of the USB communication module is electrically connected to the serial port output terminal of the main control circuit module. Its USB interface is electrically connected to the USB dock through a sealed waterproof cap or a waterproof USB connector. The output terminal is electrically connected to the USB dock. The signal is converted into a USB protocol signal by a serial port converter chip and output to an external device through the USB dock. The USB interface is sealed by a waterproof cap. The cap is briefly opened during use to connect to an external device.

2. The battery-powered offline data storage high-temperature resistant and waterproof weighing sensor according to claim 1, characterized in that, The data acquisition module includes resistors, bridge arms, a null pointer, and a thermistor. The resistors, bridge arms, and null pointer form a bridge circuit, whose excitation input is electrically connected to the LDO output of the power supply module to receive a constant excitation voltage. The output of the bridge circuit is electrically connected to the analog input of the signal conversion module. When there is no load, the bridge arm resistance values ​​are balanced, and the output voltage difference is close to zero. When the weight signal causes a change in the bridge arm resistance, the bridge circuit becomes unbalanced, thereby generating a weak differential analog voltage signal proportional to the weight at the output. The null indicator is connected to the bridge arm circuit in series and parallel to adjust the bridge arm balance, compensate for the initial imbalance, and make the no-load output close to zero; the thermistor is connected to the reference voltage terminal of the bridge and is electrically connected to the reference voltage terminal of the bridge.

3. The battery-powered offline data storage high-temperature resistant and waterproof weighing sensor according to claim 2, characterized in that, The signal conversion module includes a rectifier-filter unit, a sampling unit, a quantization circuit, and a digital output circuit. The input of the rectifier-filter unit is electrically connected to the output of the data acquisition bridge module, amplifying, filtering, and performing common-mode suppression on the weak differential analog voltage signal from the data acquisition module, outputting a clean and amplified continuous analog voltage signal. The input of the sampling unit is electrically connected to the output of the rectifier-filter unit, capturing the continuous analog voltage signal to form discrete-time analog samples. The input of the quantization circuit is electrically connected to the output of the sampling unit, using an analog-to-digital converter as its core, comparing the analog samples with a reference voltage and converting them into discrete digital code values. The input of the digital output circuit is electrically connected to the output of the quantization circuit, and its output is electrically connected to the digital input of the main control circuit module, formatting the digital code values ​​according to a predefined protocol and outputting them to the main control circuit module, thus realizing the conversion from analog to digital signals.

4. The battery-powered, offline data storage, high-temperature resistant, and waterproof weighing sensor according to claim 3, characterized in that, The sampling frequency of the sampling unit is 1Hz; the digital output circuit adopts the SPI or I2C protocol, and its output terminal is electrically connected to the corresponding protocol input terminal of the main control circuit module to transmit the digital code value to the main control circuit module.

5. The battery-powered offline data storage high-temperature resistant and waterproof weighing sensor according to claim 4, characterized in that, The main control circuit module includes a decoupling circuit, a crystal oscillator circuit, a reset and boot circuit, a program input and debug interface circuit, flash memory, a data storage unit, and a microcontroller. The input terminal of the decoupling circuit is electrically connected to the LDO output terminal of the power supply module, and its output terminal is electrically connected to the power supply pin of the microcontroller. The output terminal of the crystal oscillator circuit is electrically connected to the clock input pin of the microcontroller. The output terminal of the reset and boot circuit is electrically connected to the reset and boot pins of the microcontroller. The program input and debug interface circuit is electrically connected to the debug pin of the microcontroller. The output terminal of the flash memory is electrically connected to the program storage interface of the microcontroller. The read / write interface of the data storage unit is electrically connected to the storage controller of the microcontroller. The digital input pin of the microcontroller is electrically connected to the digital output terminal of the signal conversion module. Its UART output pin is electrically connected to the serial port input terminal of the USB communication module's serial port converter chip. The microcontroller executes a preset algorithm to process the discrete digital signal and packages the processed weight value and timestamp information into a data frame; the microcontroller writes the data frame into the data storage unit in real time to achieve offline append storage.

6. The battery-powered, offline data storage, high-temperature resistant, and waterproof weighing sensor according to claim 5, characterized in that, The preset algorithm performs digital filtering, temperature compensation, and unit conversion functions; the UART output pin of the microcontroller is electrically connected to the RX input terminal of the serial port chip of the USB communication module, and sends data frames to the USB communication module according to the serial port protocol.

7. The battery-powered offline data storage high-temperature resistant and waterproof weighing sensor according to claim 6, characterized in that, The USB communication module includes a USB dock, a serial port converter chip, and an indicator light. The RX input terminal of the serial port converter chip is electrically connected to the UART TX output terminal of the main control circuit module to receive data from the main control circuit module and convert it into USB protocol data packets. The USB differential signal terminal of the serial port converter chip is electrically connected to the USB pin of the USB dock, serving as a physical interface for the computer to recognize as a virtual serial port. The control terminal of the indicator light is electrically connected to the indicator pin of the serial port converter chip to display the power status.

8. The battery-powered offline data storage high-temperature resistant and waterproof weighing sensor according to claim 7, characterized in that, The data frame includes a weight value and a timestamp.

9. The battery-powered offline data storage high-temperature resistant and waterproof weighing sensor according to claim 8, characterized in that, A constantly lit indicator light indicates normal power supply, while a flashing indicator light indicates that data is being sent or received.

10. The battery-powered offline data storage high-temperature resistant and waterproof weighing sensor according to claim 9, characterized in that, The power module includes an LDO circuit, whose input terminal is electrically connected to the positive and negative output terminals of the external replaceable battery. The output terminal of the LDO circuit is electrically connected to the power input terminals of the data acquisition bridge module, the signal conversion module, the main control circuit module, and the USB communication module, respectively. The LDO maintains a constant output voltage, ensuring stable operation of the main control circuit module, data acquisition module, signal conversion module, and USB communication module in harsh environments with high temperature and high humidity when the battery voltage fluctuates or the load changes.

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