The Design And Implementation Of A Portable Pulse Oximeter Based On MSP430F169

With the development of economy and modern medicine and the improvement of people’s living standards, people’s consciousness of health care has improved significantly. Personal health check also is becoming more and more important and family medical electronics is becoming more and more popular. At present, low power consumption and portable medical electronics have become the theme of family medical consumer electronics. The measuring instrument of pulse oxygen saturation of transmission type can continuously provide real-time arterial blood oxygen saturation, heart rate and blood perfusion index and can contribute to the early diagnosis of some diseases. At last, it can also conduce to family care for chronic diseases. The transmission-type, low power consumption and portable pulse oximeter has become a current research direction of pulse blood oxygen design.A portable and low-power pulse oximeter based on the characteristics of ultra-low power MSP430microcontroller has been designed and realized in this paper. This pulse oximeter is made up of DS-100A probe and signals processing module. The probe is used to produce and receive light signals and can produce660nm red and near-infrared light of905nm. Then, the PPGs would be processed in the signal processing module of pulse blood oxygen. Firstly, the signals would be amplified by preamplifier circuit. The double-end differential signal would be turned into a signal referenced to ground and the common mode interference signals would be eliminated in the process. Secondly, the signals would be separated into red light and near-infrared light signals by the analog switch. Then, the signals would be filtered by a low-pass filter, which can only allow DC signals output and prevent high frequency signal. Thus, the results would filter out high frequency noises. At last, the signals would be amplified respectively and input into AD converters. The signals would be processed in the single-chip microcomputer and displayed in12864LCD. Of course, the data can also be send to the host-computer for processing and display via a serial port.The prototype would be calibrated by collecting the data of10testers. Due to limited experimental conditions and time, testers are from the healthy people. Therefore, the data results are very close. The calibration result is ideal within limits. Finally, the prototype is measured by the oscilloscope. The oscilloscope results show that the prototype that can work stability and can be used to preliminary measuring human physiological parameters has a certain practical value.