Double Wavelength Transmission Oximeter Based On ZigBee

Aiming at problems of aging population nowadays, M-Health has provided a series of technical solutions which are reliable and suitable for requirement of elder’s health management. M-Health realizes real-time and continuous measurement that makes remote monitoring possible. Compared with traditional physiological measurement, M-Health is more convenient and reliable, and has a increasingly wide range of application in daily health care.Blood oxygen saturation is percentage of oxygen in the blood, which is an important indicator about body oxygen situation. Oximeter is a part of M-Health applications. Most of M-Health devices are wearable, which will be used in all cases of situation. So that, movement interference and environmental interference are inevitable, which limit measure accuracy. Key techniques for dealing with such interferences are signal extraction in hardware and processing algorithm in software.This thesis designed a wireless oximeter based on ZigBee networking technique. Independent processors, cooperating through universal asynchronous receiver/transmitter, were used to deal with digital signal processing and wireless communication. Design of the system contained two aspects: software and hardware. In hardware, a sensor driver was designed to switch the light sources and control the light’s strength. A band-pass filter, which was composed of a Butterworth high pass filter and a Butterworth low pass filter, was used to extract the signal, and an adjustable amplification circuit was designed to enhance the SNR. The minimum system was designed for digital peripheral circuit which includeing a microcontroller and ZigBee So C ship. As to software, it was divided into two parts, microcontroller system and ZigBee system. The former contained an architecture for the entire system, a basic drivers of the processor, a sensor driver, a LCD display function and a signal processing algorithm. The algorithm, which contained a series of handlers such as digital filter, motion artifact detection, baseline drift extraction and signal amplify controlling, was developed to calculate pulse rate and Sp O2. The latter applied the ZigBee network communication by developing the Z-stack programming. All in all, the results were compared in time domain, as well as, frequent domain, so as to analyze the range of mistake measurement.This thesis researched a wireless oximeter based on ZigBee. Hardware and software of the system were designed. Experiments showed that algorithm of pulse rate and Sp O2 calculation was feasible and the system could satisfy requirements of measurement and ZigBee networking.