| Computer technology, embedded system, and network technology have become mature. This makes monitors can be used both in hospitals and at home. The embedded system integration technology makes it possible to produce small size, low power consumption, low cost, stable performance, easily operated, and portable monitoring systems. Life monitoring system can acquire, process, and save life-physiological parameters of patients, and can also send these parameters through the 3G network to both the patients'family member and hospital physician. In this way patients can receive treatment for their disease in time.(1) This thesis contains parts of a portable remote monitoring system design, i.e. the front part of the whole subject, inside which life signal collecting has been completed. Our study mainly has two ingredients: one is the hardware design, and the other is the software design. The hardware design consists of three parts, namely the signal conditioning circuit in the respiratory module, the overall circuit in the blood pressure measurement module, and the overall design of body temperature measurement module. The software design includes the analog-to-digital (AD) conversion driving program and the retrieving program of the three physiological parameters (respiration rate, blood pressure, and body temperature). The details are as following:The AD driving program development based on Linux operating system.(2) We choose mini2440 development board to collect physiological parameters, and develop an AD driving program based on Linux operating system. After that, we implant the program to the kernel, and dynamically load it onto the development board. Finally, the AD conversion of physiological parameters is realized. The design of respiratory measurement module(3) We choose thoracoabdominal motion sensor for the respiratory measurement. An arithmetic circuit whose function is to convert the negative voltage to positive voltage, allowing signal collection by the development board, has been designed for the sensor output voltage AD conversion. The voltage signal is sent to the AD conversion port and the breath waveform can be drawn. The respiratory rate is then calculated from the wave forms. The experimental result error is within±1.The design of blood pressure measurement module We apply oscillometric method for the blood pressure measurement. Firstly, we record the pulse wave signal and the static wave forms during the course of deflated cuff. We then design a circuit which is to amplify or filter the sensor output signal, and extract static pressure signal from the pulse wave signal. We also design an air pump solenoid valve control circuit to control the cuff deflation. The amplitude coefficient method is used to calculate the systolic and diastolic blood pressure values, which are compared with those measured via a medical mercury sphygmomanometer. The results show that the errors are within±5mmHg.(4) The design of body temperature measurementWe introduce negative temperature coefficient thermistor to measure body temperature. After the AD conversion, a temperature-dependent resistance curve can be obtained and the body temperature is retrieved according to the resistance. In such way, the patients'body temperature can be displayed continuously. Comparison between the experiment data to those measured by a standard mercury thermometer shows that the error is±1℃In summary, this thesis achieves three kinds of physiological signal acquisition and data processing. It can not only measure human respiratory rate, blood pressure, and body temperature measurement, but also collect the three physiological signals for further processing. The thesis contains several key parts of the portable remote monitoring system, and provides accurate data for 3G telecommunications and the man-machine interface. |
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