C8051F021 Microcontroller Based On The Measurement Of Oxygen Saturation Instrument Development

With the development of reform and society, the people's living standards have been greatly improved. However, the incidences of cardiovascular and cerebrovascular have also inclined. In addition, the rescue and monitor of body signals of military in battle field and high-altitude regions is a very important issue. The solvement of these problems involves an important measure-the oxygen saturation. The traditional measuring method is traumatic and can not be implemented continuously and real-time. The development of photoelectric detection technology can make up for these shortcomings. More and more researchers are concerning about the principle of photoelectric conversion oxygen saturation measurement.In this paper, the design of C8051F021 MCU pulse oxygen saturation measurement instrument is discussed, including the design of the hardware, software and the debug process.The main work of this paper is as follows:1. Hardware DesignAccording to the measuring principle of the pulse oxygen saturation measurement instrument, the circuit of the pulse oxygen saturation measurement instrument, in which C8051F021 microcontroller is the core, is designed. It includes optical driving circuit, programme controlled gain controlling circuit, a low-pass filter and amplifier, DC bias circuit, liquid crystal display circuit and power supply, etc.2. Software DesignProgrammes are used to produce timing sequence, control the driving circuit of optical source, data collection, the display of test results in LCD, controlling of the entire hardware system and the adjustment of signal gain; Digital filter technology is used to reduce noise and to reduce baseline drift; The self-learning threshold method is used to eliminate the interference of motion; a five-point difference method is used to extract the feature points of pulse wave.3. Numerical CalibrationAfter the completion of the hardware system of oxygen saturation meter and signal processing, to verify its accuracy, the pulse oxygen saturation meter is tested. In order to get a credible results in the application, the numerical measurement instrument should be firstly calibrated and obtain the most accurate calibration parameters.