A method for preparing a carbon-based composite material, a sensitive layer and a wireless pulse detection system

Abstract

The embodiment of the application provides a kind of carbon-based composite material preparation method, sensitive layer and wireless pulse detection system, including flexible tactile sensor, the flexible tactile sensor is attached in the position of pulse, for detecting pulse beat condition;Resistor to be measured, one end of resistor to be measured is electrically connected with one end of flexible tactile sensor, the other end of resistor to be measured is connected with power supply, for current limiting, voltage division and protection circuit;Signal acquisition module, the signal acquisition module is connected in parallel with resistor to be measured, for real-time measurement voltage value of resistor to be measured two ends.This system will be converted into the signal transmission to user terminal based on carbon-based material tactile sensor acquisition through communication module, according to signal display corresponding pulse signal waveform diagram, realizes the real-time monitoring of pulse signal, with practicality, low cost, simple operation and the like.

Description

Technical Field

[0001] This application relates to the field of flexible tactile sensor technology, and in particular to a method for preparing a carbon-based composite material, a sensitive layer, and a wireless pulse detection system. Background Technology

[0002] In today's rapidly developing medical technology, pulse detection, as a fundamental means of assessing human health, is undeniably important. However, traditional pulse detection systems typically use wired data transmission, which not only limits the patient's range of motion but also increases inconvenience during use. With the continuous advancement of wireless communication technology, especially the widespread application of Bluetooth, there is a growing expectation for a pulse detection system using Bluetooth communication to provide more convenient and flexible medical services.

[0003] However, there are currently few reports on pulse detection systems using Bluetooth communication. This is mainly because the application of Bluetooth communication in pulse detection still faces many technical challenges. For example, how to ensure the stability and reliability of Bluetooth communication to accurately transmit pulse data; how to optimize the power consumption of Bluetooth communication to extend the usage time of the pulse detection system; and how to ensure the security of Bluetooth communication to protect patient privacy and data security.

[0004] Furthermore, traditional pulse diagnosis devices, both domestically and internationally, are generally bulky and expensive, which greatly limits their widespread adoption in ordinary households. Therefore, developing a small, affordable, and easy-to-use pulse detection system is of great significance for improving basic medical care in my country and meeting the health needs of the general public. Summary of the Invention

[0005] This application provides a method for preparing carbon-based composite materials, a sensitive layer, and a wireless pulse detection system, which solves the technical problem that traditional pulse diagnosis devices, both domestically and internationally, are generally bulky and expensive, greatly limiting their widespread use in ordinary households.

[0006] The technical solution adopted in this application is as follows: In a first aspect, this application provides a method for preparing a carbon-based composite material, comprising: The carbon cloth is cleaned and dried once. The carbon cloth consists of multiple carbon fibers. The dried carbon cloth is used as the base of the carbon-based composite material. Carbon nanotubes are tightly wrapped around the surface of each carbon fiber, and the tip of each carbon nanotube is wrapped with nickel nanoparticles to obtain the pretreated carbon cloth. The pretreated carbon cloth is placed in an autoclave, sealed and left to stand for a preset time to obtain the carbon cloth after secondary treatment. The carbon cloth after secondary processing is taken out, and then subjected to secondary cleaning and secondary drying to obtain the first product. The first product and a ceramic boat containing dicyandiamide were wrapped in copper foil and calcined under high temperature and protective gas. After natural cooling, a carbon-based composite material was obtained.

[0007] Secondly, this application provides a sensitive layer for a flexible tactile sensor, comprising a carbon-based composite material prepared by the aforementioned carbon-based composite material preparation method. The carbon-based composite material serves as the upper electrode layer and the lower electrode layer of the sensitive layer, respectively. Each of the upper electrode layer and the lower electrode layer has a lead wire extending out, which serves as the input and output leads of the sensitive layer, respectively.

[0008] Thirdly, this application provides a wireless pulse detection system, including a flexible tactile sensor having the aforementioned sensitive layer, the flexible tactile sensor being attached to the pulse location for detecting pulse beats, the system further comprising: The resistor to be tested has one end electrically connected to one end of the flexible tactile sensor, and the other end of the resistor to be tested is connected to the power supply for current limiting, voltage division and protection circuits. A signal acquisition module is connected in parallel with the resistor under test and is used to measure the voltage across the resistor under test in real time.

[0009] The beneficial effects of this application are as follows: This system transmits the converted signal collected by the carbon-based tactile sensor to the user terminal through the communication module, and displays the waveform of the corresponding pulse signal according to the signal, realizing real-time monitoring of the pulse signal. It has the characteristics of strong practicality, low cost and simple operation. Attached Figure Description

[0010] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the structure of a wireless pulse detection system provided in one embodiment of this application; Figure 2 This is a scanning electron microscope image of carbon nanotubes provided in an embodiment of this application; Figure 3 This is a circuit connection diagram of a signal acquisition module provided in an embodiment of this application; Figure 4 This is a graph showing the rate of change of pressure versus current measured by this system. Figure 5 This is a graph showing the tensile strength range of a single carbon fiber in the carbon-based composite material of this application. Detailed Implementation

[0011] 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 some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of this application.

[0012] Wireless pulse detection systems are a convenient, efficient, and real-time health monitoring technology. They transmit data wirelessly, allowing users to monitor their pulse anytime, anywhere. These systems typically combine advanced sensor technology, wireless communication technology, and data analysis algorithms to provide users with comprehensive health monitoring services.

[0013] like Figure 1 As shown, this application provides a wireless pulse detection system, the system comprising: Flexible tactile sensors are used by attaching them to the pulse location, such as the wrist or other areas where the pulse can be clearly felt, to detect the pulse and convert physiological signals into measurable electrical signals. The resistor to be tested has one end electrically connected to one end of the flexible tactile sensor, and the other end connected to the power supply. It is used for current limiting, voltage division and protection circuits. When the flexible tactile sensor detects a pulse, it will cause a change in the current in the circuit, thereby changing the voltage across the resistor to be tested. A signal acquisition module, connected in parallel with the resistor under test, is used to measure the voltage across the resistor in real time. In some embodiments, when the sensitive layer of the flexible tactile sensor is stimulated by external factors causing a decrease in resistance, the voltage measured by the signal acquisition module increases. Conversely, when the resistance of the sensitive layer increases due to changes in external conditions (such as a decrease or release of pressure), the voltage measured by the signal acquisition module decreases accordingly. This inverse relationship between voltage and resistance changes provides the system with high-sensitivity detection capabilities, ensuring accurate and reliable measurement data under different environmental and physiological conditions. Therefore, the signal acquisition module plays a crucial role in the wireless pulse detection system, providing strong support for subsequent data processing and analysis.

[0014] The communication module is used to transmit the voltage value acquired by the signal acquisition module to the user terminal. In specific implementation, the communication module uses Bluetooth for transmission. The user terminal receives voltage values ​​in real time, converts voltage changes into pulse rate data, and then converts the pulse rate data into a waveform. In practice, the user terminal can be a smartphone, tablet, or dedicated device. The user terminal has one or more preset thresholds for pulse rate. When the user terminal receives voltage values ​​transmitted by the communication module and converts them into pulse rate data, it continuously counts and analyzes the pulse rate. If the pulse rate exceeds the preset maximum threshold or falls below the preset minimum threshold, it usually indicates a possible abnormality in the user's physiological state. In this case, the user terminal immediately activates an automatic alarm mechanism. The user terminal also includes functions such as user login / logout and enabling / disabling Bluetooth functionality.

[0015] The display unit is communicatively connected to the user terminal and is used to receive and display waveforms. In specific implementations, the display unit can be a display screen built into the user terminal or other display devices connected to the user terminal, such as a computer monitor or a television.

[0016] In one embodiment of this application, as Figure 3 As shown, the construction process of the signal acquisition module includes the following steps: 1) First, prepare four 1.5V dry cell batteries and place them sequentially in the battery compartment, ensuring they are correctly connected and form a stable 6V voltage source. This step is fundamental to building the signal acquisition module, providing a stable power supply for subsequent circuit connections and voltage measurements. Next, connect a 750-ohm resistor in series in the circuit. This resistor limits current and protects the circuit, preventing damage to other components due to excessive current.

[0017] 2) Place the previously constructed flexible tactile sensor (in...) Figure 3 (Seen in the form of a variable resistor) is connected in series in the circuit. The sensitive layer of the flexible tactile sensor can sense external signals and convert them into electrical signals. To measure the voltage change across the resistor under test, we used the NATIONAL INSTRUMENTS 6002 integrated system. Figure 3 The voltage is expressed as a voltage. This system has high-precision voltage measurement capabilities, accurately capturing minute voltage changes across the resistor under test. The system's probes are placed across the resistor under test, forming a parallel circuit. In this way, voltage changes across the resistor under test can be monitored in real time, and this data can be transmitted to the user terminal for analysis and processing.

[0018] The sensitive layer of the flexible tactile sensor comprises a carbon-based composite material. Specifically, this carbon-based composite material is a nickel@carbon nanotube / carbon cloth composite (Ni@CNTs / CC). In this composite material, carbon cloth (CC) serves as the substrate, forming the main structure of the composite. The carbon cloth is tightly woven from multiple carbon fibers with a diameter of approximately 5 micrometers. These carbon fibers not only possess excellent electrical conductivity but also superior mechanical properties, providing a stable support for the sensor. Each carbon fiber is tightly wrapped by grown carbon nanotubes, and nickel nanoparticles are wrapped at the tips of the carbon nanotubes. The diameter of the carbon nanotubes is approximately 20-30 nanometers, and the structure of the carbon nanotubes is as follows... Figure 2 As shown in the figure, carbon nanotubes are clearly arranged in an ordered and tightly packed manner, forming a highly ordered and stable structure. This structure enables the composite material to maintain stable performance when subjected to external forces, thereby ensuring the accuracy and reliability of the sensor.

[0019] The preparation method of the carbon-based composite material is as follows: S1. Carbon nanotubes were prepared on carbon cloth (CC). A piece of carbon cloth (1 cm × 2 cm × 0.35 mm, rectangular) was cleaned with concentrated hydrochloric acid solution, ethanol and deionized water under ultrasonic treatment for 10 minutes, and then vacuum dried at 60°C.

[0020] S2. The dried carbon cloth is used as the base of the carbon-based composite material. Carbon nanotubes are tightly wrapped around the surface of each carbon fiber. This step ensures the tight bonding between the carbon nanotubes and the carbon fibers, thereby improving the overall conductivity and mechanical strength of the material. The top of each carbon nanotube is wrapped with nickel nanoparticles to obtain the pretreated carbon cloth. S3. Place the pretreated carbon cloth (CC) into a 50 mL PTFE-lined autoclave containing a homogeneous 30 mL deionized water solution of 0.6 mmol NiCl2·6H2O, 2 mmol NH4F, and 4 mmol CO(NH2)2. Seal the PTFE-lined autoclave and place it at 120°C for 12 hours to ensure sufficient reaction time.

[0021] S4. The obtained Ni(OH)₂ / CC was washed several times with deionized water to remove unreacted substances and impurities, and finally dried at 60°C. A porcelain boat containing Ni(OH)₂ / CC and 20 mg of dicyandiamide was wrapped with copper foil and calcined at 700°C under an argon atmosphere for 2 hours at a heating rate of 5°C / min. Black Ni@NCNTs / CC was obtained when the tube furnace cooled naturally.

[0022] Through the above steps, this application successfully prepared a nickel@carbon nanotube / carbon cloth composite material with excellent performance, providing a high-quality material basis for the sensitive layer of flexible tactile sensors.

[0023] The sensitive layer of the flexible tactile sensor has a sandwich structure, comprising an upper electrode layer, a middle layer, and a lower electrode layer. Both the upper and lower electrode layers are made of carbon-based composite materials, and each has a lead wire (0.1mm diameter enameled copper wire) extending from it. These two leads serve as the input and output leads of the sensitive layer, transmitting the signals detected by the sensor to subsequent circuits for processing and analysis. One electrode layer in the upper and lower electrode layers is a positive electrode, and the other is a negative electrode. The sensitive layer is configured such that its resistance changes according to the magnitude of a pressure signal: if the pressure increases, the resistance decreases; if the pressure decreases, the resistance increases.

[0024] like Figure 4 The figure shows the current variation curve of this system with applied pressure. This graph plots the maximum current response for each applied pressure point by point. Based on the different amplitudes of the pressure-current rate of change curves, the entire process can be divided into three parts, corresponding to three stages of the pressure's influence on the system. By performing linear fitting on each of these three stages, we can evaluate the sensor performance in each stage. As shown in the figure, in the first stage, corresponding to the external force range of 0–0.5 kPa, the current rate of change changes linearly with the magnitude of the external force. The slope of the linear fitting is 17.18, therefore we consider the sensor's sensitivity in the first stage to be 17.18 kPa–1. In the second and third stages, corresponding to external forces of 0.5–4.4 kPa and 4.4–12 kPa respectively, using the same method as in the first stage, we can obtain the average sensitivities of the sensor in these two stages to be approximately 0.7359 kPa–1 and 0.1154 kPa–1.

[0025] like Figure 5The figure shows the tensile strength tolerance curve of a single carbon fiber in the carbon-based composite material used in this application. The horizontal axis represents the stress change (%), and the vertical axis represents the tensile force (N). From the curve's trend, initially, the tensile force gradually increases with increasing stress, indicating that the carbon-based composite material can withstand a certain amount of tensile force and exhibits some elasticity in the initial stage. However, when the stress change reaches approximately 6%, the curve suddenly drops, indicating that the material has entered a failure mode at this point, such as crack propagation or increased plastic deformation. Subsequently, the curve rises again because the material can continue to withstand tensile force after experiencing a stress release. Then, it drops sharply at approximately 8%, indicating that the tolerance limit of this carbon-based composite material is approximately at 8%. The overall curve exhibits an irregular sawtooth shape, indicating that the relationship between stress change and pressure is complex and involves multiple fluctuations.

[0026] The detection system provided in this application mainly consists of two parts: a carbon-based tactile sensor and mobile software capable of displaying pulse signal waveforms in real time. This system can transmit the signals collected and converted by the carbon-based tactile sensor to the user terminal via Bluetooth communication technology. Based on the signals, it displays the waveform of the corresponding pulse signal, enabling real-time monitoring of the pulse signal. It features strong practicality, low cost, and simple operation.

[0027] It is readily understood that, based on the several embodiments provided in this application, those skilled in the art can combine, split, or reorganize the embodiments of this application to obtain other embodiments, none of which exceed the protection scope of this application.

[0028] The above detailed embodiments further illustrate the purpose, technical solution, and beneficial effects of the embodiments of this application. It should be understood that the above are merely specific embodiments of the embodiments of this application and are not intended to limit the protection scope of the embodiments of this application. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solutions of the embodiments of this application should be included within the protection scope of the embodiments of this application.

Claims

1. A method for preparing a carbon-based composite material, characterized in that, include: The carbon cloth is cleaned and dried once. The carbon cloth consists of multiple carbon fibers. The dried carbon cloth is used as the base of the carbon-based composite material. Carbon nanotubes are tightly wrapped around the surface of each carbon fiber, and the tip of each carbon nanotube is wrapped with nickel nanoparticles to obtain the pretreated carbon cloth. The pretreated carbon cloth is placed in an autoclave, sealed and left to stand for a preset time to obtain the carbon cloth after secondary treatment. The carbon cloth after secondary processing is taken out, and then subjected to secondary cleaning and secondary drying to obtain the first product. The first product and a ceramic boat containing dicyandiamide were wrapped in copper foil and calcined under high temperature and protective gas. After natural cooling, a carbon-based composite material was obtained. The autoclave contains a mixed solution of NiCl2·6H2O, NH4F, CO(NH2)2, and deionized water.

2. A sensitive layer of a flexible tactile sensor, characterized in that, The carbon-based composite material prepared by the carbon-based composite material preparation method as described in claim 1 is included, wherein the carbon-based composite material serves as the upper electrode layer and the lower electrode layer of the sensitive layer, and an intermediate layer is further included between the upper electrode layer and the lower electrode layer. Each of the upper electrode layer and the lower electrode layer has a lead wire leading out, which serves as the input and output leads of the sensitive layer, respectively.

3. The sensitive layer of a flexible tactile sensor as described in claim 2, characterized in that, One of the upper and lower electrode layers is a positive electrode, and the other electrode layer is a negative electrode.

4. The sensitive layer of a flexible tactile sensor as described in claim 2, characterized in that, The sensitive layer is configured such that when a pressure signal is generated, the resistance of the sensitive layer changes according to the magnitude of the pressure signal. Specifically, if the pressure increases, the resistance of the sensitive layer decreases; if the pressure decreases, the resistance of the sensitive layer increases.

5. A wireless pulse detection system, characterized in that, The system includes a flexible tactile sensor having a sensitive layer as described in any one of claims 2-4, the flexible tactile sensor being attached to the pulse location for detecting pulse beats, and the system further includes: The resistor to be tested has one end electrically connected to one end of the flexible tactile sensor, and the other end of the resistor to be tested is connected to the power supply for current limiting, voltage division and protection circuits. A signal acquisition module is connected in parallel with the resistor under test and is used to measure the voltage across the resistor under test in real time.

6. The wireless pulse detection system as described in claim 5, characterized in that, The system also includes: The communication module is used to transmit the voltage values ​​acquired by the signal acquisition module to the user terminal; The user terminal is used to receive voltage values ​​in real time, convert voltage value changes into pulse status, and convert pulse status into waveform. The display unit is connected to the user terminal and is used to receive and display waveforms.

7. The wireless pulse detection system as described in claim 6, characterized in that, The signal acquisition module is configured such that when the resistance of the sensitive layer decreases, the measured voltage value increases; and when the resistance of the sensitive layer increases, the measured voltage value decreases.

8. The wireless pulse detection system as described in claim 6, characterized in that, The user terminal has a preset threshold. When the pulse rate exceeds or falls below the preset threshold, the user terminal will automatically issue an alarm.

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