| Wireless monitoring can reducing the work of medical staff, giving patients more activity freedom, has become the trend of the medical field. As for the long-term cared needs for patients with chronic diseases, we design a wireless monitoring system. The measuring nodes and networking for them is an important part of this system. However, there are several problems for existing modules: too big size, lacking of hardware interface and lacking of communication standards which making it’s hard to communication and management. So we need design them ourselves. The aim of this paper is to design the wireless monitor and the wireless networking for them.This paper select Zig Bee as the communication technology according to the characters of various technologies. It also develops a cross network routing mechanism and determines the overall framework of the wireless measuring network for endpoints. Besides, it discusses the principle of blood oxygen and blood pressure measurement in detail. The error and interrupt is determined according to literature and experiment. The processes are designed to suppress them respectively.Endpoint consists of measuring modules and wireless part. CC2530 is response for network management and communication and it also coordinate the measuring modules. It can response interrupt requests, upload the data to the server, and can control the modules by parsing the commands from server. The data message can be transported cross different network by routing though the gateway. The routing process has been designed and verified carefully.The measuring modules are based on PSo C29466, making them very small. As for blood oxygen measuring, it realized probe driving, signal filtering, signal amplification and put forward a real-time anti-jamming algorithm, improving the SNR of the signal, and realized the rapid process of automatic gain, guaranteeing the stability of signal channel. After morphological filtering, automatic gain and coherent filtering, the results are obtained. The results are output to CC2530 in BCI protocol format, and then the data are transported to the server.In blood pressure design, the signal will be separated by hardware, making the process faster. A real-time peak extraction process is designed based on variable length window. A fast algorithm is also proposed to approximate the envelope. The result is calculated then and sent to CC2530.Finally, the blood oxygen, blood pressure module and wireless communication are verified in detail. The endpoint can measure physiological parameters correctly and the network communication works well. Experiment shows that the wireless module can achieve stable ad-hoc network ability, have a strong coordination between measuring modules, and can send and receive data timely and correctly. Blood oxygen module can eliminate jitter and baseline interference, suppress differences between different persons, and achieve a precise result. The error of Sp O2 is less than 1% and the error of pulse frequency is less than 1 times/min, meeting the requirements of the clinical accuracy. Blood pressure module can accurately extract the oscillation wave and the average error is less than 5 mm Hg, and error of single measuring is less than 8mm Hg, meeting the requirements of AAMI standards... |
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