Research And Implementation Of The Sleep Apnea Monitor

With the development of electronic technology, computer technology and digital signal processing technology, the monitor is applied widely as a well used instrument in various levels hospital. Though the traditional sleep apnea monitor can be able to cut down death rate of apnea disease patient effectively, it can not carry out real time monitor on most patients with apnea disease, especially the early sufferer with light disease. The state of illness diagnosed and cured in time is troubled by the random happening and shorten durative time of the disease. So the round-the-clock inspecting and analyzing to the state of respiration is benefit to the evaluation of respiratory function and the early diagnoses of sleep apnea disease. In recent years, all-day dynamic recording and analyzing systems in various levels relating to the sleep apnea the on the block are not widely used because they are expensive and needed to import.This paper studies and designs a sleep apnea monitor to check and show the respiratory rate, respiratory state and real time of the patients. Meanwhile, the monitor can alarm with the acousto-optic when the respiration or the voltage is abnormal. Furthermore, more monitors can make up of distribute monitor system with PC so as to transmit the data of patients respiratory state to PC and achieve centralized management to the data and dispersedly control function of the monitor.MSP430F149 is core of the monitor, including voltage unit, signal process unit, keyboard unit, LCD unit, alarm unit, PC communication unit, JTAG interface unit, reset unit and crystal unit, etc. Respiration signal was sampled by silicon piezoresistance transducer. The signal was dealt and the circuit was controlled by MSP430F149.The monitor's software includes the main procedure, initialization module, self-check module, keyboard interruption module, timer interruption module, data processing module, alarm module, LCD module and PC communication module. The main procedure is responsible for interactiving with each interruption procedure. First, the watch dog timer is interposed, interruption is turned off and system self-check is processed. Secondly, each modules, parameters and variables that used in MCU are initialized. Third, opening the interruption, allow the MCU to respond to various interruption and alarming, then the MCU enters into low power mode and waits for interruption.Besides, the monitor adopts some anti-interference measures in hardware and software through analyzing the reason of the interference.The monitor can carry out real time status and physiology parameter of the guarded patient the whole day, and has the merits of low power dissipation, easy handling and low cost, and has the value of practical application in hospital and family monitoring.