Weak signal electronic detection system adaptable to various types of sensors and use method

Abstract

The invention relates to a weak signal electronic detection system adaptable to various types of sensors and a use method, and the system comprises a power management module which is used for converting an input power supply into a stable digital power supply and an analog power supply, and supplying power to each part of the system; the signal conditioning link is configured to be a bias circuit, an instrument amplification circuit and a filter circuit which are electrically connected in sequence; and the biasing circuit is used for providing direct-current bias voltage and lifting the common-mode potential of the output signal of the sensor to be within the linear input range of the instrument amplification circuit so as to adapt to a single-power-supply power supply environment. According to the invention, a complete adjustable signal generation-amplification-filtering-acquisition-processing link is constructed, and a three-layer stacked structure, a sensor and a foam material for collecting body fluid are integrated, so that the system has the characteristics of low power consumption, expandability, portability, easiness in use and the like, and a feasible scheme is provided for full integration of medical detection equipment.

Description

Technical Field

[0001] This invention relates to the field of electronic testing equipment technology, specifically to a weak signal electronic testing system and its usage method that can be adapted to multiple types of sensors. Background Technology

[0002] Electrochemical detection technology, widely used in biomedicine, environmental monitoring, and food safety, has gradually become an important tool in analysis and monitoring due to its advantages such as high sensitivity, rapid response, and low cost. Electrochemical sensors achieve quantitative or qualitative analysis of the concentration of a target substance by measuring signals (such as changes in current, voltage, or resistance) related to the electrochemical reaction of the substance. Compared with traditional optical detection methods, electrochemical detection not only has higher sensitivity and selectivity but also provides more stable and reliable detection results in complex environments. Especially in the biomedical field, electrochemical sensors are widely used for the detection of various physiological parameters, such as blood glucose monitoring, lactate measurement, and biomarker analysis, because they can perform rapid, non-invasive analysis of body fluids. In these applications, electrochemical detection technology can provide effective solutions for early disease diagnosis, health monitoring, and disease management.

[0003] However, despite the numerous theoretical advantages of electrochemical detection technology, existing technologies still face several challenges. For example, improving sensor sensitivity and selectivity, enhancing the stability and anti-interference capabilities of detection systems, achieving portable, low-power detection devices, and integrating bodily fluid collection with electrochemical detection remain bottlenecks in the development of electrochemical detection technology.

[0004] Sweat sensors based on electrochemical detection mechanisms have shown great potential in disease diagnosis in recent years as a novel health monitoring tool. Sweat is a biological fluid secreted by sweat glands, containing abundant metabolic products and ions, including sodium, chloride, and potassium ions. Because its composition is closely related to the body's physiological state, sweat has become an ideal non-invasive detection medium. Accurately measuring changes in chloride ion concentration in sweat can provide effective evidence for diagnosing a range of metabolic diseases. In particular, for cystic fibrosis (CF), a hereditary disease, changes in chloride ion concentration are widely recognized as an important biomarker for its early diagnosis.

[0005] Cystic fibrosis (CF) is a hereditary disease that primarily affects the lungs, digestive system, and other glands. Due to mutations in the CFTR gene leading to chloride channel dysfunction, CF patients typically exhibit significantly elevated chloride ion concentrations in their sweat. Therefore, abnormally elevated chloride ion concentrations have become a crucial diagnostic criterion for CF. Traditional CF diagnostic methods typically employ sweat tests, stimulating sweat glands to secrete sweat and measuring the chloride ion concentration in the sweat to help determine if a patient has cystic fibrosis. However, traditional methods often require specialized equipment and a clinical setting, and the testing process is complex and time-consuming, limiting their widespread application and real-time monitoring capabilities. Furthermore, existing testing equipment largely relies on traditional sensors and sampling methods, making it difficult to guarantee long-term, stable, and accurate acquisition of weak sweat samples. In addition, most existing equipment is incompatible with different types of sensors, hindering flexible system integration and expansion, thus limiting its use in diverse application scenarios. Summary of the Invention

[0006] The purpose of this invention is to provide a weak signal electronic detection system and its usage method that can be adapted to various types of sensors.

[0007] To address the aforementioned technical problems, this invention provides a weak signal electronic detection system adaptable to various types of sensors, comprising: The power management module is used to convert the input power into stable digital and analog power to power various parts of the system. The signal conditioning link is configured as a bias circuit, an instrumentation amplifier circuit, and a filter circuit connected in sequence. The bias circuit is used to provide a DC bias voltage to raise the common-mode potential of the sensor output signal to the linear input range of the instrumentation amplifier circuit to adapt to a single power supply environment. The instrumentation amplifier circuit is used to differentially amplify the signal, and the filter circuit is used to filter out noise interference. The main control unit is connected to the signal conditioning link and the sensor respectively; the main control unit integrates a digital-to-analog converter and an analog-to-digital converter; the digital-to-analog converter is used to output a configurable excitation signal to the sensor, and the analog-to-digital converter is used to acquire the feedback signal processed by the signal conditioning link; The wireless communication module, connected to the main control unit, is used to establish a wireless communication link with external terminal devices to achieve bidirectional data transmission; The main control unit runs a real-time operating system and controls the collaborative work of the digital-to-analog converter and the analog-to-digital converter through a kernel-level optimized task scheduling strategy to achieve continuous excitation and real-time acquisition of signals; it can also configure internal detection logic to adapt to electrochemical, impedance, or potential sensors.

[0008] Furthermore, the bias circuit includes a single-supply bias network, which introduces a DC potential to maintain linear output of the instrumentation amplifier circuit under conditions without negative power supply. The instrumentation amplifier circuit includes a gain switching network. The main control unit is connected to the gain switching network and adjusts the resistance value of the external gain resistor by controlling a digital potentiometer or an analog switch to achieve automatic gain adjustment for weak signals of different orders of magnitude. The filter circuit is configured as a fourth-order active low-pass filter structure.

[0009] Furthermore, when the main control unit performs signal acquisition, it configures the analog-to-digital converter to work in conjunction with the direct memory access controller; the direct memory access controller is configured in a ring buffer mode, and half-buffer interrupt and full-buffer interrupt are set up. Data processing tasks are triggered through a double buffering mechanism to achieve uninterrupted data acquisition.

[0010] Furthermore, the kernel-level optimized task scheduling strategy of the real-time operating system includes a priority-based inheritance mechanism; the main control unit maintains a priority inheritance bitmap in the task control block, and when a high-priority task is blocked due to resource contention, the priority of the task holding the resource is recorded and increased through the bitmap; when the resource is released, the priority is rolled back step by step according to the state of the bitmap to suppress the priority inversion phenomenon.

[0011] Furthermore, the real-time operating system is also configured with a delayed merge memory management strategy; when the system releases a memory block, it does not immediately perform the merge operation of adjacent free blocks, but records the fragmentation index; when the fragmentation index reaches a preset threshold, the idle task performs memory merging in batches during the CPU idle cycle, and limits the maximum execution time of a single merge operation.

[0012] Furthermore, the system also includes a physical integration component for portable packaging; the physical integration component adopts a stacked structure, consisting of a liquid absorption buffer layer, a sensor layer, and an electronic circuit layer from bottom to top; the liquid absorption buffer layer is made of absorbent foam material, and the front-end interface of the sensor layer and the electronic circuit layer is fixedly connected by plug-in or contact method, so that body fluid collection and signal conditioning are completed in the same integrated component.

[0013] Furthermore, the main control unit is configured with an adaptive low-power management strategy; the main control unit dynamically switches between running mode, light sleep mode, and deep sleep mode according to the current task load and sensor connection status; in deep sleep mode, the real-time clock (RTC) maintains the minimum system operation and provides a timed wake-up signal.

[0014] Furthermore, the external terminal device runs a monitoring application; the monitoring application adopts a dual-thread architecture with separate data receiving threads and interface refresh threads; and has a built-in signal quality monitoring mechanism, which automatically sends a command to the main control unit to adjust the data transmission frequency when the signal strength (RSSI) of the wireless communication link is detected to be lower than a preset threshold.

[0015] Furthermore, the sensor is an electrochemical microneedle sensor for detecting the concentration of chloride ions in human sweat; the external terminal device is equipped with a linear regression model to map the collected voltage signal into a chloride ion concentration value to assist in the screening of cystic fibrosis.

[0016] This invention also provides a weak signal electronic detection system adaptable to multiple types of sensors and a method for using the electronic detection system, comprising the following steps: Step S1: The system is powered on, and the power management module outputs stable digital and analog power. Step S2: The main control unit configures its internal detection logic to adapt to the currently connected sensor type based on user instructions or automatic identification results; Step S3: The main control unit generates a corresponding excitation signal and applies it to the sensor through a digital-to-analog converter; Step S4: The response signal output by the sensor is boosted by the bias circuit, amplified by the instrument amplifier circuit, and filtered by the filter circuit before being input to the main control unit. Step S5: The main control unit uses an analog-to-digital converter combined with the scheduling strategy of the real-time operating system to collect data and sends it to the external terminal device through the wireless communication module.

[0017] The beneficial effects of this invention are as follows: by constructing a complete adjustable signal generation-amplification-filtering-acquisition-processing chain, and integrating a three-layer stacked structure with sensors and foam materials for collecting bodily fluids, it features low power consumption, scalability, portability, and ease of use. Compared with existing technologies, it has significant advantages in adaptability, signal processing stability, and portability. Through the design of an adjustable gain instrumentation amplifier circuit and a fourth-order active low-pass filter circuit, it can process weak signals of different orders of magnitude, effectively suppressing power frequency and external interference noise in the human body environment, and improving the stability and signal-to-noise ratio of weak electrochemical signals. Based on the FreeRTOS kernel-level optimized control system, by modifying the task control block to add priority stage inheritance attributes, the impact of "priority inversion" is reduced, and the real-time performance of the system is improved. In the example application of sweat chloride ion detection, the system can realize real-time acquisition and response of samples with different concentrations, verifying its feasibility in the early screening of cystic fibrosis, and providing a feasible solution for the full integration of medical testing equipment. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Figure 1 This is a block diagram illustrating the overall principle of the weak signal detection system in this embodiment of the invention. Figure 2 This is the power supply circuit for the portable weak signal detection system in this embodiment of the invention; Figure 3 This refers to the instrument amplification circuit of the portable weak signal detection system in this embodiment of the invention. Figure 4 This refers to the filter circuit of the portable weak signal detection system in this embodiment of the invention. Figure 5 This is the APP-side visual interface of the portable weak signal detection system in this embodiment of the invention; Figure 6 The portable weak signal detection system in this embodiment of the invention detects the relationship between chloride ion concentration and voltage in a solution. Figure 7 Linear regression analysis was performed to detect different chloride ion concentrations and voltages in a solution using the portable weak signal detection system in this embodiment of the invention. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0021] Example 1: The present invention provides a weak signal electronic detection system that can be adapted to multiple types of sensors. It mainly consists of a power management module, which is used to convert the input power into stable digital power and analog power to power various parts of the system respectively. The signal conditioning link is configured as a bias circuit, an instrumentation amplifier circuit, and a filter circuit connected in sequence. The bias circuit is used to provide a DC bias voltage to raise the common-mode potential of the sensor output signal to the linear input range of the instrumentation amplifier circuit to adapt to a single power supply environment. The instrumentation amplifier circuit is used to differentially amplify the signal, and the filter circuit is used to filter out noise interference. The main control unit is connected to the signal conditioning link and the sensor respectively; the main control unit integrates a digital-to-analog converter and an analog-to-digital converter; the digital-to-analog converter is used to output a configurable excitation signal to the sensor, and the analog-to-digital converter is used to acquire the feedback signal processed by the signal conditioning link; The wireless communication module, connected to the main control unit, is used to establish a wireless communication link with external terminal devices to achieve bidirectional data transmission; The main control unit runs a real-time operating system and controls the collaborative work of the digital-to-analog converter and the analog-to-digital converter through a kernel-level optimized task scheduling strategy to achieve continuous excitation and real-time acquisition of signals; it can also configure internal detection logic to adapt to electrochemical, impedance, or potential sensors.

[0022] like Figure 1 As shown, the present invention mainly consists of a power management module, a main control unit (MCU), a signal conditioning link, a wireless communication module, and a front-end sensor component.

[0023] Power management module: such as Figure 3 As shown, the system is powered by a 3.7V button lithium battery. After the power input, it is converted into a stable 3.3V voltage by a low dropout linear regulator (LDO). In order to prevent high-frequency noise from the digital circuit from entering the analog measurement circuit, the digital power supply (DVDD) and the analog power supply (AVDD) are isolated by a ferrite bead or a 0-ohm resistor in the circuit design, which power the MCU / Bluetooth module and the operational amplifier circuit respectively.

[0024] Signal conditioning link: such as Figure 4 As shown, the bias circuit includes a single-supply bias network, which introduces a DC potential to maintain linear output of the instrumentation amplifier circuit under conditions without negative power supply. The instrumentation amplifier circuit includes a gain switching network. The main control unit is connected to the gain switching network and adjusts the resistance value of the external gain resistor by controlling a digital potentiometer or an analog switch to achieve automatic gain adjustment for weak signals of different orders of magnitude. The filter circuit is configured as a fourth-order active low-pass filter structure.

[0025] Bias circuit (single power supply adapter): Since the system is powered by a single power supply (0V-3.3V), ordinary operational amplifiers cannot handle negative signals. This embodiment sets up a bias network at the input of the instrumentation amplifier to provide a precise reference voltage (e.g., 1.65V). This bias voltage "boosts" the weak AC signal output by the sensor to approximately 1.65V, keeping it always within the linear operating range of the operational amplifier and avoiding signal clipping distortion. Configurable gain instrumentation amplifier circuit: The instrumentation amplifier, employing a three-operation-amplifier structure, has a high common-mode rejection ratio, and its gain resistor R... G Connected to a set of analog switches or digital potentiometers controlled by an MCU, the MCU automatically switches R based on the acquired signal amplitude. G The resistance value is adjusted to change the amplification factor (e.g., from 10x to 1000x), enabling automatic range measurement of signals over a wide range. Filtering circuits include: Figure 4 and 5As shown, the amplified signal enters a fourth-order active low-pass filter (composed of high-precision operational amplifiers such as the OPA388), with a cutoff frequency set to 1Hz (for slowly varying biological signals) and a quality factor Q of 0.707 (Butterworth response). Appropriate resistor and capacitor parameters are calculated and selected to ensure the filter circuit has the flattest amplitude-frequency response curve, quickly stabilizes without peak oscillations, and minimizes fluctuations within the operating frequency range. This circuit design improves system stability while avoiding signal distortion, providing reliable signal quality for subsequent signal processing and analysis.

[0026] When the main control unit performs signal acquisition, it configures the analog-to-digital converter to work in conjunction with the direct memory access controller. The direct memory access controller is configured in a ring buffer mode, and half-buffer interrupt and full-buffer interrupt are set up. The data processing task is triggered through the double buffer mechanism to achieve uninterrupted data acquisition.

[0027] The kernel-level optimized task scheduling strategy of the real-time operating system includes a priority-based inheritance mechanism. The main control unit maintains a priority inheritance bitmap in the task control block. When a high-priority task is blocked due to resource contention, the priority of the task holding the resource is recorded and increased through the bitmap. When resources are released, the priority is rolled back step by step according to the bitmap state to suppress priority inversion. The real-time operating system is also configured with a delayed merging memory management strategy. When the system releases a memory block, it does not immediately perform the merging operation of adjacent free blocks, but records the fragmentation index. When the fragmentation index reaches a preset threshold, the idle task performs batch memory merging within the CPU idle cycle, and limits the maximum execution time of a single merging operation.

[0028] At the signal acquisition end, a "timer + ADC + DMA ring buffer" structure is used to achieve continuous sampling, with a sampling frequency covering 0.0167Hz to 854.7kHz. The DMA operates in ring mode, submitting data to processing tasks in segments through a half-buffer and full-buffer callback mechanism to ensure uninterrupted sampling during the acquisition process. In this embodiment, the buffer submission logic is combined with task priority scheduling to keep data transfer synchronized with task scheduling, avoiding sampling loss caused by task switching delays.

[0029] To further improve system real-time performance and scheduling determinism under multi-task resource contention conditions, this embodiment extends the task scheduling unit of the real-time operating system. In traditional FreeRTOS, when mutex contention is complex, tasks directly inherit the highest priority and restore their original priority all at once after releasing the mutex. This "jump recovery" may prevent the waiting relationships of intermediate priority tasks from being reflected in the scheduling process, thus exacerbating priority inversion. Therefore, this embodiment adds a bitmap field to the task control block to record the inherited priority hierarchy. This field marks the temporary priority increases of tasks in different mutex contention scenarios. When a task needs to increase its priority due to mutex contention, the corresponding priority bit is set in the bitmap, and the task's current priority is automatically updated based on the most significant bit of the current bitmap, enabling a gradient-based response to resource contention. Verified in parallel operation scenarios of waveform generation, sampling, and communication tasks, this mechanism significantly reduces scheduling latency caused by priority inversion, improves the execution stability of real-time tasks, and ensures stable response times for critical path tasks under fluctuating load conditions.

[0030] To address the common issues of memory fragmentation and allocation jitter in real-time systems, this embodiment introduces a "deferred merging and timed compaction" mechanism. First, this embodiment defines the fragmentation index as the total number of non-contiguous free blocks in the current memory heap. When memory is released, fragmentation merging is not performed immediately; instead, the fragmentation index is recorded first. When the fragmentation index reaches a preset threshold (e.g., 50), an idle task processes adjacent blocks in batches during CPU idle periods, setting a maximum merge duration per operation to avoid long critical sections blocking the system. This strategy effectively reduces the time jitter of the FreeRTOS default allocator, ensuring stable real-time response for sampling tasks even under high load scenarios. Through the above control structure, this embodiment achieves synergistic optimization of "waveform excitation, continuous acquisition, real-time scheduling, and low-jitter memory management," resulting in higher reliability and timing stability for the system in weak signal detection scenarios.

[0031] Main Control Unit: The main control unit uses a microcontroller based on the ARM Cortex-M core (such as the STM32 series). Excitation and Acquisition: The MCU uses its internal DAC to generate sine waves, square waves, or constant potentials as excitation signals applied to the sensor. Simultaneously, it uses an ADC in conjunction with DMA (Direct Memory Access) for acquisition. The DMA is configured in a ring buffer mode. When the buffer is half full, an interrupt is triggered for data processing, while the DMA continues to fill the full buffer, ensuring uninterrupted data flow. Kernel-level Scheduling Optimization: The system runs the FreeRTOS real-time operating system. Addressing the "priority inversion" problem that may occur in standard RTOS (i.e., a low-priority task holding a mutex lock, causing a high-priority sampling task to be preempted by a medium-priority task), the bitmap mapping logic is as follows: Each bit in the bitmap corresponds to a priority level in the system. For example, Bit0 corresponds to priority 0, Bit31 corresponds to priority 31. When a bit is set to 1, it indicates that a task with that priority is waiting for the currently held resource. Source, Inheritance Process: When a high-priority task (TaskA, priority P_A) attempts to acquire a mutex held by a low-priority task (TaskB, priority P_B) and enters a blocked state, the kernel does not directly modify the current priority value of TaskB. Instead, it sets bit P_A in TaskB's uxPriorityBitmap to 1. The kernel quickly calculates the most significant bit in uxPriorityBitmap using hardware instructions (such as the CLZ leading zero counting instruction in the ARM Cortex-M series). The priority corresponding to this bit is TaskB's "inherited priority." If this value is higher than TaskB's original priority, TaskB's current priority is immediately updated. Rollback Process: When TaskB releases the mutex, the corresponding bit in uxPriorityBitmap is cleared.

[0032] The CLZ instruction is executed again to calculate the highest priority in the remaining bitmap. If the bitmap is not empty, TaskB is downgraded to the highest priority remaining in the bitmap; if the bitmap is completely empty, TaskB is restored to its original base priority. This mechanism reduces the time complexity of priority calculation from O(N) of linked list traversal to O(1) of bit operations, ensuring the real-time performance of the system under complex nested interrupts and multi-task contention.

[0033] Simultaneously, the Task Control Block (TCB) was modified, adding a priority inheritance bitmap. When resource contention occurs, the priority of all tasks waiting for the resource is recorded through the bitmap, and the priority of the task holding the lock is promoted to the highest level in the bitmap. When the lock is released, the original priority is not simply restored, but the priority is rolled back step by step according to the bitmap state. This ensures that critical sampling tasks still have a definite response time in complex concurrent environments. Memory management is optimized: a delayed merging strategy is adopted. When a task releases a memory block, the system does not immediately execute the time-consuming adjacent free block merging algorithm, but marks it and puts it into the fragment list. Only when the fragmentation index reaches the threshold or the CPU is in an idle task (IdleTask) will the merging operation be executed in batches, and a time limit for a single operation is set to prevent memory management from blocking system operation.

[0034] The system also includes a physical integration component for portable packaging; the physical integration component adopts a layered structure, consisting of a liquid absorption buffer layer, a sensor layer, and an electronic circuit layer from bottom to top; the liquid absorption buffer layer is made of absorbent foam material, and the front-end interfaces of the sensor layer and the electronic circuit layer are fixedly connected by plug-in or contact methods, so that body fluid collection and signal conditioning are completed in the same integrated component.

[0035] Physical integrated structure such as Figure 2 As shown, in order to improve portability and reduce external interference, this system adopts a layered structure design. The bottom layer (skin contact layer) is a liquid-absorbing buffer layer, which uses medical-grade absorbent foam material to quickly collect sweat and form a stable liquid channel. The middle layer (sensing layer) is an electrochemical microneedle sensor. The microneedles pass through the foam and come into contact with the skin or are immersed in the sweat in the foam.

[0036] The main control unit is configured with an adaptive low-power management strategy; the main control unit dynamically switches between running mode, light sleep mode and deep sleep mode according to the current task load and sensor connection status; in deep sleep mode, the real-time clock (RTC) maintains the minimum system operation and provides a timed wake-up signal.

[0037] The main control unit is equipped with an adaptive low-power management strategy, which can dynamically switch between running mode, light sleep mode, and deep sleep mode based on the current task load and sensor connection status. In running mode, the system maintains full-function operation; in light sleep mode, the system shuts down unnecessary peripherals to reduce power consumption; in deep sleep mode, the real-time clock maintains the minimum system operation and provides a timed wake-up signal to achieve ultra-low power standby. This strategy effectively extends the battery life of portable devices through intelligent power management, while ensuring that the system can quickly resume working state when needed. By injecting hibernation instructions into the FreeRTOS idle task, the device automatically enters Sleep mode when there are no tasks running, and when periodically executing tasks, it maintains a minimum system operation through the RTC peripheral, using Standby mode to achieve ultra-low power hibernation. The system can automatically select the appropriate low power level based on task load, wake-up requirements and peripheral status, and implement a reliable wake-up mechanism through RTC timer interrupt. This design effectively reduces the overall energy consumption of portable devices, extends battery life, and ensures system real-time performance and functionality. It can be widely used in long-standby application scenarios such as wearable detection devices, unmanned inspection, and environmental monitoring.

[0038] The external terminal device runs a monitoring application; the monitoring application adopts a dual-thread architecture with separate data receiving thread and interface refresh thread; and has a built-in signal quality monitoring mechanism. When the signal strength (RSSI) of the wireless communication link is detected to be lower than a preset threshold, it automatically sends a command to the main control unit to adjust the data transmission frequency.

[0039] The wireless communication module connects to the main control unit via a serial port and establishes a stable wireless communication link with external terminal devices using Bluetooth technology, enabling bidirectional transmission of detection data. This module not only sends the collected detection data to the mobile application in real time but also receives control commands from external terminals, enabling remote parameter configuration and system control.

[0040] The external terminal device runs a dedicated monitoring application. This application adopts a dual-thread architecture design with separate data receiving and interface refresh threads. The data receiving thread is specifically responsible for communication with the detection system and data processing, while the interface refresh thread independently handles the display updates of the user interface. The two threads run in parallel without interfering with each other, ensuring the real-time performance of data processing and the smoothness of the user interface. The monitoring application has a built-in signal quality monitoring mechanism that can monitor the signal strength of the wireless communication link in real time. When the RSSI is detected to be lower than the preset threshold, the application automatically sends a command to the main control unit to adjust the data transmission frequency. Through the linkage between the upper and lower computer, the stability of the system is enhanced when the signal quality deteriorates, which significantly reduces the data loss caused by short-term disconnection of the mobile Bluetooth in complex environments such as outdoors and sports.

[0041] The microcontroller connects to the Bluetooth module and establishes a wireless communication link with the APP via serial port transceiver. Figure 5 The app serves as the human-computer interaction interface. Developed using Android Studio, it differs from traditional Bluetooth data display software by employing a dual-threaded architecture (the data receiving thread and the interface refresh thread run independently). It also incorporates a Bluetooth RSSI monitoring mechanism, enabling the system to automatically reduce the refresh rate or send a "slowdown command" to the MCU when link quality deteriorates, forming a stability enhancement mechanism through upper and lower-level machine collaboration. This mechanism significantly reduces data loss caused by short-term Bluetooth disconnections in outdoor and sports scenarios. Furthermore, the app includes an updatable calibration model module that automatically maps real-time voltage signals collected by the MCU to corresponding biomarker concentrations.

[0042] In a specific experiment, the detection of chloride ion concentration in a solution is used as an example application. This embodiment uses an electrochemical microneedle sensor that converts chloride ion concentration into a voltage output, connected to a signal conditioning module via a universal sensor interface. To improve the stability of body fluid collection, the microneedle tip is covered with an adsorbent foam structure, integrated with the electronic system using a three-layer stacked structure, forming a complete functional integration of the sample collection layer, sensor, and acquisition circuit. When the sensor comes into contact with solutions containing different chloride ion concentrations, the instrumentation amplification and filtering circuits in this embodiment can condition the weak signal in real time, transmit it to the MCU via the ADC-DMA module, and then upload it to the APP via the Bluetooth module. The final result is as follows: Figure 6 , Figure 7 As shown, the detection system in this embodiment can maintain good stability, linearity and signal-to-noise ratio under weak signal conditions, verifying its applicability in sweat chloride ion detection and other body fluid sensing scenarios.

[0043] The sensor is an electrochemical microneedle sensor that detects the concentration of chloride ions in human sweat; the external terminal device is equipped with a linear regression model to map the collected voltage signal into a chloride ion concentration value to assist in the screening of cystic fibrosis.

[0044] In a preferred embodiment, the sensor employs an electrochemical microneedle sensor for detecting chloride ion concentration in human sweat. This sensor converts changes in chloride ion concentration into a corresponding voltage signal output, establishing an electrical connection with the signal conditioning module through the system's universal sensor interface. To improve the stability and reliability of body fluid collection, the microneedle sensor's front end is covered with an absorbent foam structure, forming a complete functional integration with the electronic system. A dedicated linear regression model is deployed within the external terminal device, accurately mapping the voltage signal collected by the system to the corresponding chloride ion concentration value, providing reliable detection data support for cystic fibrosis screening. When the sensor contacts sweat samples containing different chloride ion concentrations, the system maintains excellent detection stability, linear response, and signal-to-noise ratio performance under weak signal conditions, verifying its practicality and reliability in sweat chloride ion detection and other body fluid sensing applications.

[0045] Example 2: This invention also provides a method for using a weak signal electronic detection system adaptable to various types of sensors, including the following steps: Step S1: The system is powered on, and the power management module outputs stable digital and analog power. Step S2: The main control unit configures its internal detection logic to adapt to the currently connected sensor type based on user instructions or automatic identification results; Step S3: The main control unit generates a corresponding excitation signal and applies it to the sensor through a digital-to-analog converter; Step S4: The response signal output by the sensor is boosted by the bias circuit, amplified by the instrument amplifier circuit, and filtered by the filter circuit before being input to the main control unit. Step S5: The main control unit uses an analog-to-digital converter combined with the scheduling strategy of the real-time operating system to collect data and sends it to the external terminal device through the wireless communication module.

[0046] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A weak signal electronic detection system adaptable to multiple types of sensors, characterized in that, include: The power management module is used to convert the input power into stable digital and analog power to power various parts of the system. The signal conditioning link is configured as a bias circuit, an instrumentation amplifier circuit, and a filter circuit that are electrically connected in sequence. The bias circuit is used to provide a DC bias voltage to raise the common-mode potential of the sensor output signal to the linear input range of the instrumentation amplifier circuit to adapt to the single power supply environment. The instrumentation amplifier circuit is used to differentially amplify the signal, and the filter circuit is used to filter out noise interference. The main control unit is connected to the signal conditioning link and the sensor respectively; the main control unit integrates a digital-to-analog converter and an analog-to-digital converter; the digital-to-analog converter is used to output a configurable excitation signal to the sensor, and the analog-to-digital converter is used to acquire the feedback signal processed by the signal conditioning link; The wireless communication module, connected to the main control unit, is used to establish a wireless communication link with external terminal devices to achieve bidirectional data transmission; The main control unit runs a real-time operating system and controls the collaborative work of the digital-to-analog converter and the analog-to-digital converter through a kernel-level optimized task scheduling strategy to achieve continuous excitation and real-time acquisition of signals; it can also configure internal detection logic to adapt to electrochemical, impedance, or potential sensors.

2. The weak signal electronic detection system adaptable to multiple types of sensors as described in claim 1, characterized in that, The bias circuit includes a single-supply bias network, which introduces a DC potential to maintain linear output of the instrumentation amplifier circuit under conditions without negative power supply. The instrumentation amplifier circuit includes a gain switching network. The main control unit is connected to the gain switching network and adjusts the resistance value of the external gain resistor by controlling a digital potentiometer or an analog switch to achieve automatic gain adjustment for weak signals of different orders of magnitude. The filter circuit is configured as a fourth-order active low-pass filter structure.

3. The weak signal electronic detection system adaptable to multiple types of sensors as described in claim 2, characterized in that, When the main control unit performs signal acquisition, it configures the analog-to-digital converter to work in conjunction with the direct memory access controller. The direct memory access controller is configured in a ring buffer mode, and half-buffer interrupt and full-buffer interrupt are set up. The data processing task is triggered through the double buffer mechanism to achieve uninterrupted data acquisition.

4. The weak signal electronic detection system adaptable to multiple types of sensors as described in claim 3, characterized in that, The kernel-level optimized task scheduling strategy of the real-time operating system includes a priority-based inheritance mechanism; the main control unit maintains a priority inheritance bitmap in the task control block, and when a high-priority task is blocked due to resource contention, the priority of the task holding the resource is recorded and increased through the bitmap; when the resource is released, the priority is rolled back step by step according to the state of the bitmap to suppress the priority inversion phenomenon.

5. A weak signal electronic detection system adaptable to multiple types of sensors as described in claim 4, characterized in that, The real-time operating system is also configured with a delayed merging memory management strategy; when the system releases a memory block, it does not immediately perform the merging operation of adjacent free blocks, but instead records the fragmentation index. When the fragmentation index reaches a preset threshold, the idle task performs memory merging in batches during the CPU idle cycle, and limits the maximum execution time of a single merge operation.

6. The weak signal electronic detection system adaptable to multiple types of sensors as described in claim 1, characterized in that, The system also includes a physical integration component for portable packaging; the physical integration component adopts a layered structure, consisting of a liquid absorption buffer layer, a sensor layer, and an electronic circuit layer from bottom to top; the liquid absorption buffer layer is made of absorbent foam material, and the front-end interfaces of the sensor layer and the electronic circuit layer are fixedly connected by plug-in or contact methods, so that body fluid collection and signal conditioning are completed in the same integrated component.

7. A weak signal electronic detection system adaptable to multiple types of sensors as described in claim 1, characterized in that, The main control unit is configured with an adaptive low-power management strategy; the main control unit dynamically switches between running mode, light sleep mode and deep sleep mode according to the current task load and sensor connection status; in deep sleep mode, the real-time clock (RTC) maintains the minimum system operation and provides a timed wake-up signal.

8. A weak signal electronic detection system adaptable to multiple types of sensors as described in claim 7, characterized in that, The external terminal device runs a monitoring application; the monitoring application adopts a dual-thread architecture with separate data receiving threads and interface refresh threads; It also has a built-in signal quality monitoring mechanism. When the signal strength (RSSI) of the wireless communication link is detected to be lower than a preset threshold, it automatically sends a command to the main control unit to adjust the data transmission frequency.

9. A weak signal electronic detection system adaptable to multiple types of sensors as described in claim 8, characterized in that, The sensor is an electrochemical microneedle sensor that detects the concentration of chloride ions in human sweat; the external terminal device is equipped with a linear regression model to map the collected voltage signal into a chloride ion concentration value to assist in the screening of cystic fibrosis.

10. A method of using the electronic detection system according to claim 1, characterized in that, Includes the following steps: Step S1: The system is powered on, and the power management module outputs stable digital and analog power. Step S2: The main control unit configures its internal detection logic to adapt to the currently connected sensor type based on user instructions or automatic identification results; Step S3: The main control unit generates a corresponding excitation signal and applies it to the sensor through a digital-to-analog converter; Step S4: The response signal output by the sensor is boosted by the bias circuit, amplified by the instrument amplifier circuit, and filtered by the filter circuit before being input to the main control unit. Step S5: The main control unit uses an analog-to-digital converter combined with the scheduling strategy of the real-time operating system to collect data and sends it to the external terminal device through the wireless communication module.

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