Research And Design Of Wrist Pulse Real-time Detection System

ECG signal contains a large number of health information of human body, the accurate measurement of ECG signal is of great significance in the prevention and treatment of cardiovascular disease, and valuable to improving people’s live quality and health level. The existing pulse detection instrument is unable to meet the requirement of portability and real-time any more in terms of portability and real-time, especially for the elderly with cardiovascular disease, it almost has nothing effect on real-time monitoring, besides, the variation of the pulse in the period of disease is also an important diagnostic basis for doctors. Therefore, a wrist pulse real-time monitoring system is designed in this dissertation, which can make real-time detection and record the pulse information, and do short-term HRV (Heart Rate Variability, HRV) analysis to the pulse information gained. Besides, the system can react and sent a distress signal with multilevel alarm mechanism in time when the patient is sick, trying the best to ensure the safety of patients’life.First of all, the wrist pulse real-time monitoring system was designed based on PVDF (Poly-vinylidene Fluoride) piezoelectric sensor, which is mainly composed of the pulse detection device, blue-tooth mobile phone and emergency center, etc. Pulse detection device plays an important role in pulse signal detection, signal conditioning, signal storage and analysis, and can make alarm under abnormal condition.Secondly, hardware circuit of the system was designed so as to get stable and reliable pulse signal, which adopts PVDF piezoelectric sensor as acquisition front end and blue-tooth module as sending equipment. The signal conditioning circuit is mainly composed of primary amplifier, trap, filtering, secondary amplifying and shaping circuit, etc. which can insure the pulse signals gained is stable and reliable and can be identified by single chip microcomputer. At the same time, blue-tooth interface circuit and3.3V voltage regulator circuit also was designed.Finally, in order to verify the stability and reliability of system, hardware circuit simulation was conducted, and HRV sample entropy analysis has been done on pulse signals of with normal persons and CHF (Chronic Heart Failure) patients.Experimental results show that the hardware circuit of this system is stable and reliable, can provide stable and ideal peak pulse signal, and satisfy the requirement of system. In addition, the analysis results of sample entropy show that s ample entropy analysis method is very suitable for short-term analysis, which is also conforms to the system characteristics of the small amount of data collected in short time.In a word, this system can be used for cardiovascular patients monitoring tools. It is convenient, reliable and stable.