The human body the built-in sensor physiological parameters acquisition technology

Physiological parameters acquisition refers to a person under the specific environment static or activities of some physiological parameters measurement, processing and transmission. The technical application field widely, such as medical, health care, sports, military and clothing comfort evaluation. The realization of the physiological parameters acquisition method is put sensors in the human body parts, corresponding to a cable or wireless way to transfer sensor collected data to the terminal for processing.

in the use of cable transmission way sometimes is restricted, it is necessary to adopt the way of wireless data transmission. Such as in the clothing comfort evaluation of applications, the main methods are: table to the human body in a real environment temperature and humidity measurement; In the simulation environment ( Artificial climate chamber) Under the real or false body temperature and humidity measurement, according to the measured value of subjective and objective evaluation is given. In the real environment in human body dynamic experiment, wireless data collection and transmission mode will bring great convenience. Wireless sensor network technology has developed rapidly, this technology has been applied to the human physiological parameters acquisition in the domestic related applications, such as based on Zigbee technology of wireless sensor network application in the remote home monitoring, put forward the application of wireless sensor technology in the medical ward. Combined with practical application, this paper from the wireless sensor network node hardware and software platform selection, network architecture, the MAC layer protocol, node, low power design parameter acquisition analysis and design aspects of the human body.

network architecture and protocol

network topology describes the connection mode of this network node. Human physiological parameters acquisition range is small, sensor node set, generally do not need to communication between each node. According to these characteristics, you can use the star network topology. In a star topology, each branch node is connected to the center node in the form of point to point, when the center mass communication between nodes and the branch node, USES the star topology is the most effective. Its advantage is to be able to concentrate resources, network routing algorithm is easy to management, the range of concentration, relatively simple, there is a problem of node easily without affecting the performance of the other nodes are center node isolation.

in the wireless sensor network (WSN), MAC ( 介质访问控制) Agreement decided the use of wireless channel, allocate limited wireless communication between sensor nodes resources, have great influence on the performance of the sensor network, wireless sensor network is to ensure that the work of one of the key network protocol for low power consumption. Human physiological parameters acquisition applications, the sensor node periodically collect data, often using small button battery power supply, and the center node general power supply, so adopt CSMACA ( 载波监听多路访问与避碰) Control protocol. Received rf module, center node does not shut down. Sensor nodes time sampling, send data, open the rf module, if it is necessary to send data first listens to channel, if the channel is occupied, the retreat after a random time continue to listen to, if the channel has not been occupied, sending data, confirmed after close the rf module, MCU into sleep mode, waiting for the next trigger regularly.