A multi-physiological signal sensor and a method of manufacturing the same

Abstract

The application discloses a multi-physiological signal sensor and a preparation method thereof. The sensor comprises a cladding layer, a fitting layer and a multi-physiological signal sensing body encapsulated in the cladding layer. The fitting layer is attached to the surface of the cladding layer, and is used for being attached to an underwater organism, so that the multi-physiological signal sensing body starts to detect an underwater physiological signal. The multi-physiological signal sensing body comprises a circuit board, a power module, a sensor module, a communication module, a data processing module and a microcontroller which are arranged on the circuit board. The power module, the sensor module, the communication module and the data processing module are electrically connected with the microcontroller. The microcontroller is used for realizing the collection, transmission and processing of the underwater physiological signal through the sensor module, the communication module and the data processing module respectively. The multi-physiological signal sensor has the advantages of miniaturization, light weight, ultrathin and multifunction.

Description

Technical Field

[0001] This application relates to the field of sensor technology, and in particular to a multi-physiological signal sensor and its fabrication method. Background Technology

[0002] In sports, whether it's competitive sports that pursue higher, faster, and stronger achievements and challenge human limits, or mass sports that aim to improve physical fitness and lose weight, both require scientific monitoring and guidance. With the rapid development of flexible sensing technology, new sensing materials, and advanced manufacturing strategies, the demand for motion sensors has evolved from accurately collecting data to requiring lightweight, ultra-thin, flexible, and compact designs. These sensors should be comfortable to wear for extended periods without interfering with normal movement, easy to put on and take off, and usable in any scenario. However, in wet environments, especially during water sports such as swimming, diving, canyoning, and dragon boating, flexible electronics are prone to detaching from the skin, and poor signal stability poses a significant challenge to electronic products worn on the skin.

[0003] Currently, significant progress has been made in multi-physiological sensing technology and wet adhesion. However, most multi-physiological sensing technologies utilize terrestrial acquisition methods, while challenges remain in acquiring diverse physiological signals from underwater environments, miniaturizing and lightweighting sensors, and achieving greater flexibility. Although substantial progress has been made in the field of wet adhesion, limitations still exist in rapid adhesion response, continuous fabrication, stable wet adhesion, especially in high-salt environments, and biocompatibility. Summary of the Invention

[0004] The main technical problem addressed in this application is to provide a multi-physiological signal sensor and its fabrication method, which solves the challenges of underwater sensors easily detaching from the skin, the acquisition of multi-physiological signals in underwater environments, and the miniaturization, lightweighting, and flexibility of the sensor.

[0005] To address the aforementioned technical problems, this application provides a multi-physiological signal sensor, comprising a coating layer, an adhesive layer, and a multi-physiological signal sensing body encapsulated within the coating layer. The adhesive layer is attached to the surface of the coating layer and is used to attach to an underwater organism, enabling the multi-physiological signal sensing body to detect underwater physiological signals. The multi-physiological signal sensing body includes a circuit board, and a power module, a sensor module, a communication module, a data processing module, and a microcontroller disposed on the circuit board. The power module, sensor module, communication module, and data processing module are all electrically connected to the microcontroller, which is used to acquire, transmit, and process underwater physiological signals through the sensor module, the communication module, and the data processing module, respectively.

[0006] This application also provides a method for preparing a multi-physiological signal sensor, which is used to prepare the above-mentioned multi-physiological signal sensor. The method includes the steps of: preparing a multi-physiological signal sensing subject; preparing a coating layer and encapsulating the multi-physiological signal sensing subject in the coating layer; preparing an adhesive layer and attaching the adhesive layer to the coating layer to obtain a multi-physiological signal sensor; the adhesive layer is used to attach to an organism so that the multi-physiological signal sensor can detect underwater physiological signals.

[0007] The beneficial effects of this application are as follows: This application discloses a multi-physiological signal sensor and its fabrication method. The sensor includes a coating layer, an adhesive layer, and a multi-physiological signal sensing body encapsulated within the coating layer. The adhesive layer is attached to the surface of the coating layer and is used to attach to an underwater organism, enabling the multi-physiological signal sensing body to detect underwater physiological signals. The multi-physiological signal sensing body includes a circuit board, and a power module, a sensor module, a communication module, a data processing module, and a microcontroller disposed on the circuit board. The power module, sensor module, communication module, and data processing module are all electrically connected to the microcontroller, which is used to acquire, transmit, and process underwater physiological signals through the sensor module, communication module, and data processing module, respectively. The multi-physiological signal sensor proposed in this application has the advantages of miniaturization, light weight, ultrathinness, and multifunctionality. Attached Figure Description

[0008] Figure 1 This is an exploded view of the multi-physiological signal sensing subject in one embodiment of a multi-physiological signal sensor according to this application;

[0009] Figure 2 This is a circuit schematic diagram of an embodiment of a multi-physiological signal sensor according to this application;

[0010] Figure 3 This is a circuit diagram of the linear voltage regulator chip XC6206P332MR used in one embodiment of a multi-physiological signal sensor of this application;

[0011] Figure 4 This is a circuit diagram of the KS1081 chip used in one embodiment of a multi-physiological signal sensor of this application;

[0012] Figure 5 This is a circuit diagram of the MAX30205 chip used in one embodiment of a multi-physiological signal sensor of this application;

[0013] Figure 6 This is a circuit diagram of the MPU6050 chip used in one embodiment of a multi-physiological signal sensor of this application;

[0014] Figure 7 This is a circuit diagram of the TCA9543A chip used in one embodiment of a multi-physiological signal sensor of this application;

[0015] Figure 8 This is a circuit diagram of the STM32L432KCU6 chip used in one embodiment of a multi-physiological signal sensor of this application;

[0016] Figure 9 This is a circuit diagram of the chip XDFP-0090-012 used in one embodiment of a multi-physiological signal sensor of this application;

[0017] Figure 10 This is a flowchart of an embodiment of a method for fabricating a multi-physiological signal sensor according to this application;

[0018] Figure 11 This is a flowchart of step S3 in one embodiment of the preparation method of a multi-physiological signal sensor of this application;

[0019] Figure 12 This is a flowchart illustrating the preparation of a dry gel film in one embodiment of a method for preparing a multi-physiological signal sensor according to this application.

[0020] Figure 13 This is a schematic diagram illustrating the adhesion principle of the adhesive layer of the coating layer to the skin in one embodiment of the preparation method of a multi-physiological signal sensor of this application.

[0021] Figure 14 This application describes a method for preparing a multi-physiological signal sensor, which uses the multi-physiological signal sensor to monitor electrocardiogram signals of a swimmer at rest and while swimming.

[0022] Figure 15 This is an embodiment of a method for fabricating a multi-physiological signal sensor according to the present application. Figure 14 Calculated heart rate graphs of swimmers at rest and while swimming;

[0023] Figure 16 This is an embodiment of a method for fabricating a multi-physiological signal sensor according to the present application. Figure 14 Calculated power spectral density maps of swimmers' resting and swimming heart rates;

[0024] Figure 17 This is an embodiment of a method for fabricating a multi-physiological signal sensor according to the present application. Figure 14 Calculated respiratory signal diagrams of swimmers at rest and while swimming;

[0025] Figure 18 This is an embodiment of a method for preparing a multi-physiological signal sensor according to this application, which uses the same multi-physiological signal sensor to monitor the electrocardiogram signals of a swimmer during swimming for five consecutive days.

[0026] Figure 19This is a diagram showing the acceleration changes of a swimmer during swimming, monitored by a multi-physiological signal sensor in one embodiment of the preparation method of the multi-physiological signal sensor of this application.

[0027] Figure 20 This is an example of a method for preparing a multi-physiological signal sensor according to this application, showing the pitch angle and temperature changes of a swimmer during swimming, monitored using the multi-physiological signal sensor. Detailed Implementation

[0028] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly set on the other component; when a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to the other component.

[0030] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0031] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" or "several" means two or more, unless otherwise explicitly specified.

[0032] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0033] For the description of this application, non-limiting terms are used. Figure 1 The labels “front,” “back,” “up,” “down,” “left,” and “right” shown are used to facilitate understanding of this embodiment and are not intended to limit this application. Specifically, front-back indicates longitudinal direction, left-right indicates lateral direction, and up-down indicates vertical direction.

[0034] Figure 1 and Figure 2 An embodiment of the multi-physiological signal sensor of this application is shown, including a coating layer (not shown), an adhesive layer (not shown), and a multi-physiological signal sensing body encapsulated within the coating layer; the adhesive layer is attached to the surface of the coating layer and is used to attach to an underwater organism, enabling the multi-physiological signal sensing body to start detecting underwater physiological signals; the multi-physiological signal sensing body includes a circuit board 10, and a power module 1, a sensor module 2, a communication module 3, a data processing module 5, and a microcontroller 4 disposed on the circuit board 10. The power module 1, sensor module 2, communication module 3, and data processing module 5 are all electrically connected to the microcontroller 4, and the microcontroller 4 realizes the acquisition, transmission, and processing of underwater physiological signals through the sensor module 2, communication module 3, and data processing module 5, respectively.

[0035] In this embodiment, the battery in the power module 1 is an ultra-thin lithium-ion battery 11, which is used to power the entire circuit board 10. At the same time, in order to achieve a constant voltage of the circuit board 10, a power management module 12 is designed next to the ultra-thin lithium-ion battery 11 to control the voltage stability of the entire circuit board 10.

[0036] like Figure 3As shown, the power management module 12 uses a linear regulator chip XC6206P332MR to manage the ultra-thin lithium-ion battery 11. The maximum input operating voltage is 8V, and the output voltage is 3.3V. It features low power consumption and built-in overcurrent and short-circuit protection circuits, effectively protecting the lifespan of the ultra-thin lithium-ion battery 11. Furthermore, the external circuit design is simple, ensuring a small size for the circuit board and multiple physiological signal sensors. The positive terminal VIN of the ultra-thin lithium-ion battery 11 is connected to the input voltage terminal VIN of the linear regulator chip XC6206P332MR, and the negative terminal GND is connected to the ground terminal VSS / VOUT of the linear regulator chip XC6206P332MR. The voltage range of the ultra-thin lithium-ion battery 11 is 3.7V to 8V. An independent switch button can be connected to the power line interface. After passing through the linear regulator chip XC6206P332MR, the circuit outputs a stable voltage VCC of 3.3V.

[0037] like Figure 2 As shown, the sensor module 2 mainly consists of three parts: an electrocardiogram sensor 21, a temperature sensor 22, and an inertial sensor 23, in order to monitor the electrocardiogram, respiration, body temperature, and IMU (including signals such as acceleration and angular acceleration during exercise) during the exercise process.

[0038] It should be noted that electrocardiogram (ECG) signals are dynamic curves generated by monitoring the periodic potential changes of myocardial cells through surface electrodes. They exhibit distinct P, Q, R, S, and T waveforms and are important physiological indicators for assessing cardiac health and exercise status. Currently, the main types of chips used for ECG signal detection on the market include ADS1292, ADS1298, MAX3003, MAX86150, BDM101, and KS1081. ADS1292, ADS1298, MAX3003, and MAX86150 are all chips from American companies. Domestically produced chips have a significant price advantage; the KS10821 chip costs only 18.5 yuan, less than one-tenth the price of the ADS1298 chip. The chip's package size and peripheral dimensions determine the overall circuit board size. Comparatively, the MAX3003 (2.6×2.7mm) and KS1081 (3×3mm) chips have significant advantages. Furthermore, the KS1081 chip has low noise, a built-in low-noise amplifier, an input reference noise of approximately 3μV, and a common-mode rejection ratio of approximately 85dB (DC to 100Hz), enabling it to accurately extract weak bioelectrical signals. In addition, the KS1081 chip provides a programmable gain range of 50dB to 720dB to meet different application requirements. It also has the advantage of a high sampling frequency (1kHz), which can capture more accurate ECG signals for easier subsequent processing. Its ultra-low power consumption capability, with a power supply current of approximately 130μA in single-channel operating mode, can extend standby time. Therefore, this application selects the KS1081 chip from Chipsen Microelectronics Co., Ltd. as the ECG sensor 21.

[0039] like Figure 1 As shown, the ECG sensor 21 is externally equipped with multiple ECG electrodes 6. The ECG sensor 21 also incorporates an amplifier, a filter, and a bio-potential acquisition front-end. Each ECG electrode 6 includes an electrode lead 61 and an electrode pad 62. One end of the electrode lead 61 is connected to the corresponding signal input terminal of the ECG sensor 21 via a gold finger 63. The electrode lead 61 comprises, from top to bottom, a top solder resist layer 64, a dielectric layer 65, and a bottom solder resist layer 66. The electrode pad 62 is disposed at the other end of the electrode lead 61 and is used for attachment to a living organism.

[0040] Furthermore, the ECG electrode 6 is provided with three electrodes, including one reference electrode and two auxiliary electrodes. When monitoring the human body, the electrode pad 62 of the reference electrode is attached to the right side away from the heart, and the electrode pads 62 of the other two auxiliary electrodes are attached to the left side and the sternum, respectively, closer to the heart.

[0041] In this embodiment, the ECG electrode 6 adopts a serpentine flexible circuit design with immersion gold electrodes, which has a certain degree of flexibility and can adapt to the stretching of the skin during exercise. Furthermore, the immersion gold electrodes have extremely low resistance, which can improve the transmission effect of electrical signals. Meanwhile, to minimize the design of peripheral circuitry, the respiratory signal will be extracted from the ECG signal.

[0042] like Figure 4 As shown, the KS1081 chip has three signal input ports: RL (first signal input), LA (second signal input), and RA (third signal input). Three ECG electrodes 6 are attached to the skin of a living organism to collect underwater physiological signals. The ECG signals are output via an analog-to-digital converter (ADC) or SPI. To reduce peripheral circuitry, an ADC is used to output the ECG signal; the ECG signal output interface VO1 is connected to the ADC interface of the microcontroller 4. The KS1081 chip is connected to the first timer interface of the microcontroller 4 via the ECG timing interface LDF to control the sampling frequency of the ECG signal. The analog ground terminal AGND and analog power terminal AVDD of the KS1081 chip prevent signal contamination from digital noise. The current-limiting resistor R2 protects the circuit design. The capacitor is designed for filtering, removing high-frequency noise from the signal. In terms of circuit design, the KS1081 chip requires only a 3.3V power input, three signal inputs, and one signal output, with only six peripheral components. The circuit design is very simple, meeting the application requirements of small size, light weight, and ultra-thin multi-signal sensing patches.

[0043] It should be noted that the range of options for temperature sensor 22 is very wide, mainly including both contact and non-contact temperature sensors. Contact temperature sensors mainly include thermistors, platinum resistance thermometers, and semiconductor temperature sensors, while non-contact temperature sensors mainly refer to infrared resistors. Platinum resistance thermometers are expensive and have a slow response time, making them unsuitable for the multi-physiological signal sensor proposed in this application; infrared resistors have low accuracy and cannot obtain accurate temperature values; semiconductor temperature sensors have higher accuracy than thermistors and smaller package size, making them more suitable for the multi-physiological signal sensor proposed in this application.

[0044] like Figure 5 As shown, the temperature sensor 22 uses the MAX30205 chip. The MAX30205 chip uses the principle of semiconductor temperature measurement, and has high accuracy in the temperature range of 35℃-50℃. It has stable linear characteristics and does not require additional calibration. It has low power consumption, 600µA (working) / 0.1µA (standby). It has a small package size (2mm×2.5mm) and a simple peripheral circuit, requiring only 4 peripheral components.

[0045] In this embodiment, the MAX30205 chip transmits signals to the microcontroller 4 via the IIC bus. The temperature data transmission terminal MAX_SDA is the data line in IIC communication mode, used to transmit temperature data; while the synchronous temperature data transmission terminal MAX_SCL is the clock line in IIC communication mode, used for synchronous data transmission. The three pins, first address selection terminal A0, second address selection terminal A1, and third address selection terminal A2, are used for address selection in IIC communication mode. When all three pins are grounded, the address of the MAX30205 chip is 0x48. The first resistor R26 and the second resistor R27 are pull-up resistors for the IIC bus. The IIC protocol requires the temperature data transmission terminal MAX_SDA and the synchronous temperature data transmission terminal MAX_SCL to remain high when idle. The pull-up resistors can pull the bus voltage up to the stable voltage VCC, ensuring signal integrity and preventing the bus from floating. The voltage divider resistor R24 ​​can protect the circuit design. The filter capacitor C4 is used for decoupling and filtering out high-frequency noise in the signal.

[0046] It should be noted that the inertial sensor 23 can detect signals such as acceleration and angular acceleration during motion, thereby understanding the posture of the human body during movement. Currently, there are many inertial sensor chips on the market, and their performance differences are not significant. This application selects the MPU6050 chip. The MPU6050 chip integrates a 3-axis accelerometer and a 3-axis gyroscope, with an internal signal processing unit that can directly output quaternions, acceleration, angular acceleration, and pitch angle. It also has a wide measurement range, with acceleration measurement range from ±2g to ±16g and gyroscope measurement range from ±250° / s to ±2000° / s, which can meet the monitoring needs of human motion signals. In addition, the MPU6050 chip has low power consumption and can support sleep mode.

[0047] like Figure 6 The diagram shows the peripheral circuit design of the MPU6050 chip. It uses the IIC bus for signal transmission. The inertial timing interface IMU_TIM is connected to the second timer interface of the microcontroller 4 to synchronize the sampling frequency of the MPU6050 chip. The third resistor R9 and the fourth resistor R10 are pull-up resistors for the IIC bus. The capacitor is used to filter out high-frequency noise in the circuit. The peripheral circuit design is simple, with only 6 components, which can effectively reduce the area of ​​the entire circuit board and achieve the goal of making the multi-physiological signal sensor flexible and small in size.

[0048] like Figure 2 As shown, the communication module 3 transmits signals to the microcontroller 4 through the analog-to-digital converter 31 and the integrated circuit bus 32 (IIC1 / IIC2). For the acquired data, the microcontroller 4 performs simple on-chip processing and then stores the signals in the SD card 51 through the serial peripheral interface (SPI).

[0049] In this embodiment, both the inertial sensor 23 and the temperature sensor 22 employ IIC communication. To avoid signal crosstalk, the TCA9543A chip is selected as the selector. It enables multiple IIC devices to share the same bus, providing efficient signal routing without changing the host controller or slave device addresses. The TCA9543A chip consumes very low current during operation and supports both standard (100kHz) and fast (400kHz) modes of the IIC bus, providing good data transfer rates with low power consumption. Its operating voltage range is 2.3V to 5.5V, making it compatible with various IIC bus voltages.

[0050] like Figure 7 The diagram shows the circuit design of the TCA9543A chip. The temperature data transmission terminal MAX_SDA and synchronous temperature data transmission terminal MAX_SCL of the MAX30205 chip are connected to the first data terminal SDO and the first synchronous data terminal SCO of the TCA9543A chip, respectively. The inertial data transmission terminal IMU_SDA and the synchronous inertial data transmission terminal IMU_SCL of the MPU6050 chip are connected to the second data terminal SD1 and the second synchronous data terminal SC1 of the TCA9543A chip, respectively. The TCA9543A chip communicates with the microcontroller 4 through the strobe data output terminal SDA and the strobe synchronous data output terminal SCL. The TCA9543A chip operates through the IIC control interface, which has two control registers (one for selecting channels and the other for setting the on / off state of channels). Simple IIC commands are used to select which channel to activate. Control bytes allow the host to enable or disable each channel, controlling which slave devices can communicate with the host. Resistors act as pull-up resistors to prevent floating signals from causing communication failures. Capacitors act as filters to remove high-frequency noise.

[0051] It should be noted that the STM32L432KCU6 chip is a processor based on the ARM Cortex-M4 core architecture, supporting floating-point operations with a main frequency of up to 80MHz. The chip integrates 256KB of Flash memory and 32KB of SRAM; it has 32 GPIOs supporting various functions and modes; it has four 16-bit timers and one 32-bit timer, suitable for precise time control and event timing; it supports multiple communication methods such as SPI, IIC, and USART, and has a 12-bit ADC (up to 16 channels) and a 12-bit DAC (2 channels), a CAN interface, and a USB 2.0 interface. This microcontroller features low power consumption, high integration, superior performance, and supports multiple IDE development environments, providing a HAL library to reduce development difficulty, fully meeting the application requirements of this application. Therefore, this application selects the STMicroelectronics STM32L432KCU6 chip as the microcontroller.

[0052] like Figure 8 The diagram shows the peripheral circuit design of the STM32L432KCU6 chip. The STM32L432KCU6 operates at 3.3V and is connected to an external 32.768kHz low-speed crystal oscillator X2. The crystal oscillator and capacitors form an oscillation circuit to provide a low-speed external clock for the STM32L432KCU6's real-time clock (RTC). The SWD interface is used for debugging and programming the microcontroller. The synchronous clock signal terminal SWCLK provides a synchronous clock signal for debugging communication, generated by the debugger. The bidirectional data transmission terminal SWDIO is a bidirectional data line used to transmit debugging commands and data (such as register read / write, breakpoint setting, etc.). The reset pin NRST is connected to the button SW1 and is active low for hardware reset. The analog ground and digital ground, analog power supply and digital power supply are separated by ferrite beads and capacitors to isolate noise. An LED serves as a power indicator, lighting up when power is supplied.

[0053] Furthermore, the first data input terminal PA0 of the STM32L432KCU6 chip is connected to the ECG signal output interface VO1 of the KS1081 chip; the second data input terminal PA10 and the third data input terminal PA9 of the STM32L432KCU6 chip are electrically connected to the strobe data output terminal SDA and the strobe synchronization data output terminal SCL of the TCA9543A chip. MOSI, MISO, CLK, and SD_CS serve as the SPI signal interface connecting to the SD card's SPI signal input. MOSI is the signal line for the master device to send data to the slave device, MISO is the signal line for the slave device to send data to the master device, CLK is the clock signal generated by the master device for synchronizing data transmission, and SD_CS is the chip select signal used to select the target slave device on the SPI bus. When SD_CS is low, the SD card is activated and responds to master device commands; when it is high, the SD card enters a high-impedance state and disconnects from the bus. The resistors in the circuit act as pull-up and pull-down resistors and provide protection; the capacitors in the circuit serve as power supply decoupling, crystal oscillator load, and noise filtering.

[0054] Furthermore, the data processing module 5 mainly transmits the data stored in the SD card 51 to the host computer 52 (mobile phone or computer), processes and analyzes the collected data again, and presents it in the form of charts, so that users can have a more intuitive understanding of their physiological data such as electrocardiogram, respiration, body temperature, acceleration, and pitch angle during exercise.

[0055] In this embodiment, the main function of the SD card 51 is to store the collected physiological signal data for later signal processing.

[0056] like Figure 9As shown, SD card 51 uses chip XDFP-0090-012 and communicates with chip STM32L432KCU6 using SPI transmission mode. MOSI is used for chip STM32L432KCU6 to send data to chip XDFP-0090-012; MISO is used for chip XDFP-0090-012 to return data to chip STM32L432KCU6. That is, the slave device receiver DAT1 of chip XDFP-0090-012 is electrically connected to the master device output PB5 of chip STM32L432KCU6, and the slave device output CMD of chip XDFP-0090-012 is electrically connected to the master device receiver PB4 of chip STM32L432KCU6. The STM32L432KCU6's master clock pin PB2 is electrically connected to the XDFP-0090-012's slave clock pin CLX, used as a synchronization signal generated by the master controller to control the data transmission rate. The STM32L432KCU6's master chip select pin PA11 is electrically connected to the XDFP-0090-012's slave chip select pin CS; when CS is low, the SD card is activated. Resistor R12 acts as a pull-up resistor to prevent floating signals that could lead to communication failure. Capacitors C25 and C26 filter and remove high-frequency noise. The XDFP-0090-012 has a small package size (15*15mm) and simple peripheral circuitry, facilitating miniaturized circuit board design.

[0057] In this application, the multi-physiological signal sensor integrates a high-precision electrocardiogram sensor, a temperature sensor, and an inertial sensor, which can realize the synchronous acquisition of multiple physiological parameters such as heart rate, body temperature, and movement posture.

[0058] Combination Figure 1 The top of circuit board 10 is defined as the end closest to the ECG electrode, and the bottom is defined as the other end. The circuit board is 42mm long, 28mm wide at the bottom, 20mm wide at the top, and 0.11mm thick. There are three electrode leads, each 85mm long, with identical length, size, and shape. The electrode pads are 10mm in diameter, and the gold fingers of the electrode leads are 3.7mm long and 1.8mm wide.

[0059] In other embodiments, the circuit board typically has a length of 40mm-50mm, a bottom width of 25mm-30mm, a top width of 15mm-25mm, and a thickness of 0.07mm-0.15mm; the electrode wire length is 80mm-90mm, the gold finger length is 3.5mm-4.2mm, the width is 1.5mm-2.0mm, and the electrode plate diameter is 5mm-15mm. Other dimensions are also possible, as long as the dimensions of each part meet the actual requirements.

[0060] Combination Figure 1 and Figure 2 The microcontroller 4, ECG sensor 21, temperature sensor 22, inertial sensor 23, and their related electronic components are designed on the front of the circuit board 10, while the power management module 12 and SD card 51 are designed on the back of the circuit board 10. The ultra-thin lithium-ion battery 11 is attached to the back of the circuit board 10, next to the SD card 51. This circuit structure design can well adapt to the distribution of human pectoral muscles and effectively utilize the area of ​​the circuit board 10.

[0061] In this embodiment, the selection of chips and circuit design in the multi-physiological signal sensor were completed, and the hardware design of the circuit nodes was completed, including the design of power module 1, microcontroller 4 and communication module 3, thus realizing the application requirements of small size, light weight and ultra-thin multi-physiological signal sensor.

[0062] In other embodiments, the sensor can also be designed as a multi-physiological signal sensor suitable for detecting multiple physiological signals in other organisms, depending on actual needs.

[0063] like Figure 10 As shown, based on the same inventive concept, this application also provides a method for fabricating a multi-physiological signal sensor, which includes the following steps:

[0064] Step S1: Prepare a multi-physiological signal sensing subject.

[0065] Combination Figure 1 and Figure 2 Select a circuit board 10 of appropriate size and the chip mentioned above, and install the chip on the corresponding position of the circuit board 10. This circuit structure design can adapt well to the distribution of human pectoral muscles and effectively utilize the area of ​​the circuit board 10.

[0066] Step S2: Prepare a coating layer and encapsulate the multi-physiological signal sensing subject within the coating layer.

[0067] In this embodiment, the coating layer is made of silicone. The specific preparation process is as follows: first, the liquid silicone matrix and curing agent are thoroughly mixed for 3 minutes, followed by 1 minute of vacuum degassing to remove air bubbles, resulting in a degassed mixture; then, the degassed mixture is poured into a specially designed mold and cured at room temperature (25±2℃) for 1 hour to obtain the coating layer, ensuring optimal mechanical properties. The mold is designed with a central cavity to accommodate the multi-physiological signal sensing subject; before pouring the degassed mixture into the mold, the multi-physiological signal sensing subject needs to be placed in the central cavity to achieve encapsulation of the multi-physiological signal sensing subject.

[0068] Furthermore, before encapsulating the multi-physiological signal sensing subject within the covering layer, specifically before placing the multi-physiological signal sensing subject into the central cavity, the method further includes: applying a waterproof coating to the multi-physiological signal sensing subject to further prevent water from entering the multi-physiological signal sensing subject and affecting the monitoring of multi-physiological signals.

[0069] Step S3: Prepare the bonding layer and attach the bonding layer to the covering layer to obtain a multi-physiological signal sensor.

[0070] Specifically, such as Figure 11 As shown, step S3 includes the following sub-steps:

[0071] Step S31: Prepare the raw materials and preparation instruments for the bonding layer.

[0072] The raw materials include polyacrylamide (PAM), polyethylene oxide (PEO), polyethylene terephthalate (PET), N-hydroxysuccinimide ester (NHS), dimethyl sulfoxide (DMSO), benzophenone, anhydrous calcium chloride, 6-aminofluorescein, anhydrous ethanol, and deionized water. The preparation equipment includes an electronic balance, ultraviolet lamp, oven, electronic universal testing machine, degassing mixer, Fourier transform infrared spectrometer (FT-IR), fluorescence microscope, freeze dryer, ion sputtering instrument, and high-resolution scanning electron microscope.

[0073] Step S32: Using raw materials and preparation instruments, prepare the bonding layer on a large scale.

[0074] In this embodiment, firstly, a pre-hydrogel solution needs to be prepared; then, the pre-hydrogel solution is coated onto a substrate to obtain a pre-hydrogel; the pre-hydrogel is dried to obtain a dry gel film; finally, the dry gel film is cut and swollen to obtain an adhesive layer.

[0075] Combination Figure 12 First, a suitable amount of PAM and PEO are mixed evenly using a degassing mixer to obtain a pre-hydrogel solution 7. Then, on a printing table, a blade is used to coat a 2 mm thick layer of the pre-hydrogel solution 7 onto a roll of PET substrate 8 (made of polyethylene terephthalate) that has undergone hydrophobic coating treatment to obtain a pre-hydrogel. Subsequently, the pre-hydrogel is allowed to dry naturally at 60°C to form a continuous dry gel film 9.

[0076] Furthermore, to introduce the NHS ester network, the dry gel film was cut to the desired size, swollen in water for 15 seconds to reach a water content of 90%, and then immersed in anhydrous DMSO solution containing 2 mg / mL NHS ester and 0.2% benzophenone by mass. It was then cured by irradiation under 365 nm UV light for 30 seconds to complete the crosslinking reaction and obtain the bonding layer. Finally, the prepared bonding layer was freeze-dried and stored at -20°C until further use.

[0077] It should be noted that the main component of the dry gel film is poly(ethylene oxide / polyacrylamide) (PAMP) dry gel. The PAMP dry gel forms a three-dimensional porous network with bicontinuous phase separation through polymer entanglement, optimizing water transport channels. This unique structure significantly improves the expansion rate, achieving instant adhesion through rapid hydration kinetics. When the dry gel film comes into contact with moist tissue of a living organism, it rapidly expands within 10 seconds, transforming into a PAMP hydrogel. When the water content reaches 90%, the adhesive force reaches its maximum within 15 seconds, forming adhesive bonds with the skin through various molecular interactions, thus establishing stable adhesion. Specifically, the hydroxyl groups on the PEO chain and the amide groups on the PAM chain form hydrogen bonds with the polar functional groups on the skin surface. The ester groups grafted onto the hydrogel surface by NHS form covalent bonds with the amine groups on the skin. Through interaction with the Ca on the substrate... 2+ The post-crosslinking forms a sacrificial toughening network, thereby achieving high fracture toughness in the PAMP hydrogel. Furthermore, the abundant entanglement structures act as molecular pinning sites, significantly enhancing the toughness of the PAMP hydrogel while preventing mechanical fracture under external stress.

[0078] In this process, PAM molecules act as a supporting phase, providing structural stability and mechanical strength to the hydrogel. High-molecular-weight PEO molecules act as a toughening phase, enhancing the cohesion and interfacial adhesion of the gel network through entanglement. The two work synergistically to form a bicontinuous phase-separated network structure. The high-molecular-weight entanglement points can act as pinning points to enhance the toughness of the hydrogel and prevent the PAMP hydrogel from being torn by external forces. In addition, the surface-grafted NHS can form covalent bonds with the amine groups (-NH2) on the skin surface to enhance the adhesion of the PAMP hydrogel.

[0079] In this embodiment, the bonding layer was prepared based on a molecular synergistic mechanism, constructing a three-dimensional porous network cross-linked system with PAM and high molecular weight (8000kDa) PEO bicontinuous phase separation. This was achieved by introducing Ca... 2+ As a crosslinking agent and a conductive agent, it achieves dual-functional modification of conductivity and structure. Combined with surface NHS grafting technology, it successfully developed a PAMP hydrogel with biomimetic wet adhesion properties.

[0080] Furthermore, as the PEO content gradually increases, the adhesion of PAMP hydrogel is enhanced. However, when the ratio of PAM to PEO molecules is 5:5, its excellent bicontinuous phase separation network structure makes the internal structure of the molecules more stable, enhances the intermolecular interaction, and has stronger van der Waals forces when it comes into contact with the substrate surface, which can generate more hydrogen bonds, thus resulting in stronger adhesion performance.

[0081] In this embodiment, the PAMP hydrogel exhibits superior wet adhesion performance (interfacial toughness > 230 J / m²) surpassing the adhesion strength of biological soft tissue, skin-like mechanical properties (shear strength > 60 kPa), rapid response capability (adhesion completed within 10 s), and optimized conductivity (conductivity reaching 10). -3 The PAMP hydrogel (S / cm) meets the requirements for bioelectrical signal acquisition, and its synergistic mechanism of polymer entanglement and ionic cross-linking effectively solves the technical problem of easy detachment of underwater electronic devices. Furthermore, experiments have demonstrated that the PAMP hydrogel can rapidly form a strong skin adhesive on tissues, exhibiting strong wet adhesion, maintaining adhesion even after 30 minutes of water rinsing, while allowing for separation without allergic reactions. The PAMP hydrogel meets the key requirements of underwater applications such as sports monitoring, emergency rescue operations, and marine biological telemetry. Notably, it systematically solves long-standing problems, including slow adhesion kinetics, weak interfacial bonding, and poor manufacturing scalability. Therefore, the PAMP hydrogel can be rapidly deployed as an underwater bioelectronic adhesive layer.

[0082] Step S33: Adhere the bonding layer to the covering layer to obtain a multi-physiological signal sensor.

[0083] It should be noted that the cured silicone surface also needs to be treated with a proprietary primer to enhance adhesion. Therefore, before applying the bonding layer to the overlay layer, a primer needs to be applied to the surface of the overlay layer. After the primer is evenly applied, allow it to dry naturally under laboratory conditions for 10 minutes before bonding the bonding layer to the surface of the overlay layer through the primer.

[0084] In this embodiment, the bonding layer is directly bonded to the surface of the coating layer through the primer, which can ensure continuous interface coupling in physiological monitoring applications.

[0085] Furthermore, after the covering layer and the bonding layer are bonded together, they are pre-pressed under a pressure of 1 kPa for 30 seconds to ensure full adhesion.

[0086] like Figure 13The diagram illustrates the adhesion principle of the adhesive layer (substrate) to the skin. Specifically, it shows the process from the adhesion of the electronic device substrate to the hydrogel, to the rapid physical cross-linking of the hydrogel with the moist skin, and finally to the formation of a stable covalent cross-link between the hydrogel and the skin. Specifically, the PAMP hydrogel first forms a stable adhesion with the coating layer through van der Waals forces, hydrogen bonds, and covalent bonds. Subsequently, the PAMP hydrogel comes into contact with the skin surface, forming rapid physical cross-links (De Waals forces, hydrogen bonds). These hydrogen bonds primarily originate from polar functional groups such as hydroxyl groups (-OH) on the PEO molecular chain and amide groups (-CONH2) on the PAM chain, forming hydrogen bonds with functional groups such as hydroxyl groups (-OH), amino groups (-NH2), or carboxyl groups (-COOH) on the skin surface. Afterward, the ester groups of NHS (C4H5NO3, containing a five-membered ring structure (succinimide ring) and an ester group (-COO-)) grafted onto the hydrogel molecule surface form covalent bonds with the amino groups (-NH2) on the skin surface. Following the reaction, the five-membered ring naturally detaches and decomposes into non-toxic products, posing no harm to the human body or the environment. The PAMP hydrogel achieves stable adhesion to the skin within 10 seconds. Therefore, using PAMP hydrogel as an intermediate adhesive layer allows for strong wet adhesion between flexible bioelectronic devices and the skin, increasing its application scenarios and scope.

[0087] In this embodiment, an irregularly shaped flexible circuit structure adapted to the distribution of the anterior pectoral muscle group is developed through ergonomic optimization design. Flexible printed circuit and silicone encapsulation technology are used to ensure stable signal quality in dynamic water environment. Then, a self-made bonding layer is attached to the silicone to form a multi-physiological signal sensor for detecting underwater physiological signals. This can perfectly realize the attachment and monitoring of the human chest without affecting the daily life of the human body.

[0088] Furthermore, using this multi-physiological signal sensor in swimming experiments, attaching the sensor to the middle of the pectoral muscle can effectively interfere with electromyography signals and reduce motion artifacts.

[0089] like Figure 14 As shown, the electrocardiogram signals of a swimmer at rest and while swimming are monitored using the multi-physiological signal sensor proposed in this application.

[0090] like Figure 15 As shown, this displays the swimmer's resting and swimming heart rate graphs calculated from the electrocardiogram signal.

[0091] Combination Figure 14 and Figure 15As can be seen, the swimmer's heart rate increased from 72 beats / minute (SNR=16dB) before swimming to 132 beats / minute (SNR=17dB) during swimming. Both SNR values ​​exceeded 15dB, confirming that the signal was sufficient for wearable health monitoring.

[0092] like Figure 16 The image shows the heart rate power spectral density maps of swimmers at rest and during swimming, calculated from electrocardiogram signals. It can be seen that before exercise, the predominantly low-frequency (LF) component indicates sympathetic activation due to test anxiety; during swimming, the high-frequency (HF) component increases, indicating parasympathetic dominance and stress relief, consistent with known autonomic nervous system responses. The ultra-low-frequency (ULF) component is the least prominent at both rest and during swimming.

[0093] like Figure 17 The image shows the respiratory signals of a swimmer at rest and while swimming, calculated based on electrocardiogram (ECG) signals. It can be seen that the regular 0.3Hz breathing pattern before swimming transforms into an irregular 0.4Hz pattern while swimming.

[0094] like Figure 18 As shown, the electrocardiogram (ECG) signals of swimmers during swimming were monitored using the same multi-physiological signal sensor over five consecutive days. It can be seen that the continuous monitoring over five days demonstrates the good signal stability of this multi-physiological signal sensor.

[0095] like Figure 19 As shown, this diagram illustrates the acceleration variations of a swimmer during swimming, monitored using multiple physiological signal sensors, revealing distinct biomechanical patterns across different phases of the stroke. Upon entry into the water, the swimmer exhibits significant acceleration peaks of approximately 1.5g in both the forward-backward (y-axis) and vertical (z-axis) directions, while lateral (x-axis) acceleration remains relatively low. During continuous swimming, overall acceleration decreases significantly, with forward propulsion stabilizing at 0.3g, and vertical oscillations primarily caused by breathing, averaging 0.1g. Lateral acceleration is almost negligible, indicating minimal lateral movement. In the final phase of swimming, sudden acceleration peaks are generated through flipping and pushing off the pool wall, reaching 3g in the vertical direction and 1g in the forward-backward direction.

[0096] like Figure 20 The image shows the pitch angle and temperature changes of a swimmer during swimming, monitored using multiple physiological signal sensors. It can be seen that the temperature remained at 37°C during exercise, with a slight increase, which may be due to the warm pool conditions or heat generated by metabolism.

[0097] Combination Figures 14-20A multi-physiological signal sensor based on PAMP hydrogel successfully detected continuous multi-physiological signals from swimmers, demonstrating its reliability in underwater human health monitoring.

[0098] Therefore, this application discloses a multi-physiological signal sensor and its fabrication method. The sensor includes a coating layer, an adhesive layer, and a multi-physiological signal sensing body encapsulated within the coating layer. The adhesive layer is attached to the surface of the coating layer and is used to attach to an underwater organism, enabling the multi-physiological signal sensing body to detect underwater physiological signals. The multi-physiological signal sensing body includes a circuit board, and a power module, a sensor module, a communication module, a data processing module, and a microcontroller mounted on the circuit board. The power module, sensor module, communication module, and data processing module are all electrically connected to the microcontroller, which is used to acquire, transmit, and process underwater physiological signals through the sensor module, communication module, and data processing module, respectively. The multi-physiological signal sensor proposed in this application has the advantages of miniaturization, light weight, ultrathinness, and multifunctionality.

[0099] The above are merely embodiments of this application and do not limit the scope of this patent application. Any equivalent structural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this application.

Claims

1. A multi-physiological signal sensor, characterized in that, It includes a covering layer, an adhesive layer, and a multi-physiological signal sensing subject encapsulated within the covering layer; The adhesive layer is attached to the surface of the covering layer and is used to attach to the underwater organism, so that the multi-physiological signal sensing subject can start detecting underwater physiological signals. A pre-hydrogel solution is prepared; then the pre-hydrogel solution is coated onto a substrate to obtain a pre-hydrogel. The pre-hydrogel is dried to obtain a dry gel film; The dry gel film is cut and swollen to obtain the bonding layer; The bonding layer comprises polyacrylamide, polyethylene oxide, and a crosslinking agent. The polyacrylamide molecules act as a supporting phase, providing structural stability and mechanical strength to the hydrogel. The polyethylene oxide has a molecular weight of 8000 kDa; the high molecular weight of the polyethylene oxide acts as a toughening phase, enhancing the cohesive force and interfacial adhesion of the gel network through entanglement. The ratio of polyacrylamide to polyethylene oxide molecules is 5:

5. The crosslinking agent is used to crosslink the polyacrylamide and polyethylene oxide; the crosslinking agent is Ca. 2+ ; The dry gel film comprises polyethylene oxide / polyacrylamide dry gel, which forms a three-dimensional porous network with two continuous phases separated by polymer entanglement; when the dry gel film comes into contact with the moist tissue of a living organism, it transforms into polyethylene oxide / polyacrylamide hydrogel, and the ester groups of N-hydroxysuccinimide grafted on the surface of the hydrogel form covalent bonds with the amine groups on the skin. The multi-physiological signal sensing body includes a circuit board, and a power module, a sensor module, a communication module, a data processing module and a microcontroller disposed on the circuit board. The power module, sensor module, communication module and data processing module are all electrically connected to the microcontroller. The microcontroller is used to collect, transmit and process underwater physiological signals through the sensor module, the communication module and the data processing module respectively. The sensor module includes an electrocardiogram (ECG) sensor, a temperature sensor for acquiring underwater temperature signals, and an inertial sensor for acquiring underwater inertial signals. The microcontroller, the ECG sensor, the temperature sensor, and the inertial sensor are located on the front of the circuit board, and the power supply module is located on the back of the circuit board.

2. The multi-physiological signal sensor according to claim 1, characterized in that, The power module includes a battery and a power management module; The battery is used to power the circuit board; The power management module uses a linear voltage regulator chip. The positive terminal of the battery is connected to the input voltage terminal of the linear voltage regulator chip, and the negative terminal of the battery is connected to the ground terminal of the linear voltage regulator chip.

3. The multi-physiological signal sensor according to claim 1, characterized in that, The electrocardiogram (ECG) sensor is externally connected to multiple ECG electrodes. Each ECG electrode includes an electrode wire and an electrode pad. One end of the electrode wire is connected to the corresponding signal input terminal of the ECG sensor via a gold finger. The electrode pad is disposed at the other end of the electrode wire and is used to attach to a living organism.

4. The multi-physiological signal sensor according to claim 3, characterized in that, The first signal input terminal, the second signal input terminal, and the third signal input terminal of the ECG sensor are each connected to one of the ECG electrodes; the ECG signal output interface of the ECG sensor is electrically connected to the analog-to-digital conversion interface of the microcontroller; the ECG timing interface of the ECG sensor is electrically connected to the first timer interface of the microcontroller, and is used to control the sampling frequency of the ECG signal.

5. The multi-physiological signal sensor according to claim 4, characterized in that, The temperature data transmission terminal and synchronous temperature data transmission terminal of the temperature sensor are electrically connected to the corresponding data input terminals of the microcontroller.

6. The multi-physiological signal sensor according to claim 5, characterized in that, The inertial timing interface of the inertial sensor is connected to the second timer interface of the microcontroller for synchronizing the sampling frequency of the inertial sensor; the inertial data transmission terminal and the synchronous inertial data transmission terminal of the inertial sensor are electrically connected to the corresponding data input terminals of the microcontroller.

7. The multi-physiological signal sensor according to claim 6, characterized in that, The communication module includes a selector, wherein the first data terminal and the first synchronous data terminal of the selector are electrically connected to the temperature data transmission terminal and the synchronous temperature data transmission terminal of the temperature sensor, respectively; the second data terminal and the second synchronous data terminal of the selector are electrically connected to the inertial data transmission terminal and the synchronous inertial data transmission terminal of the inertial sensor, respectively; and the selected data output terminal and the selected synchronous data output terminal of the selector are electrically connected to the corresponding data input terminal of the microcontroller, respectively.

8. The multi-physiological signal sensor according to claim 7, characterized in that, The first data input terminal of the microcontroller is electrically connected to the ECG signal output interface of the ECG sensor; the second and third data input terminals of the microcontroller are respectively electrically connected to the gating data output terminal and the gating synchronization data output terminal of the selector.

9. The multi-physiological signal sensor according to claim 1, characterized in that, The data processing module includes an SD card, which communicates with the microcontroller via SPI. The slave device receiving end of the SD card is electrically connected to the master device output end of the microcontroller, the slave device output end of the SD card is electrically connected to the master device receiving end of the microcontroller, and the slave clock end of the SD card is electrically connected to the master clock end of the microcontroller.

10. A method for fabricating a multi-physiological signal sensor, characterized in that, The method for preparing the multi-physiological signal sensor as described in any one of claims 1-9 includes the following steps: Preparation of a multi-physiological signal sensing subject; A coating layer is prepared, and the multi-physiological signal sensing subject is encapsulated within the coating layer; An adhesive layer is prepared and attached to the covering layer to obtain a multi-physiological signal sensor; the adhesive layer is used to attach to an organism so that the multi-physiological signal sensor can detect underwater physiological signals; Preparation of pre-hydrogel solutions; The pre-hydrogel solution is then coated onto the substrate to obtain a pre-hydrogel. The pre-hydrogel is dried to obtain a dry gel film; The dry gel film is cut and swollen to obtain the bonding layer; The bonding layer comprises polyacrylamide, polyethylene oxide, and a crosslinking agent. The polyacrylamide molecules act as a supporting phase, providing structural stability and mechanical strength to the hydrogel. The polyethylene oxide has a molecular weight of 8000 kDa; the high molecular weight of the polyethylene oxide acts as a toughening phase, enhancing the cohesive force and interfacial adhesion of the gel network through entanglement. The ratio of polyacrylamide to polyethylene oxide molecules is 5:

5. The crosslinking agent is used to crosslink the polyacrylamide and polyethylene oxide; the crosslinking agent is Ca. 2+ ; The dry gel film comprises polyethylene oxide / polyacrylamide dry gel, which forms a three-dimensional porous network with bicontinuous phase separation through polymer entanglement; when the dry gel film comes into contact with the moist tissue of a living organism, it transforms into polyethylene oxide / polyacrylamide hydrogel, and the ester groups of N-hydroxysuccinimide ester grafted on the surface of the hydrogel form covalent bonds with the amine groups on the skin.

Images