The Design And Research Of Wireless Monitoring System For Granary Situation

Grain is the foundation of the national economy, grain security is closely related to people’s health and social stability. Usually, there are many factors that affecting grain storage security, such as the temperature, humidity and moisture. In order to ensure grain quality and reduce the loss in the process of storage, the warehouse workers must timely know about the changes of various environmental factors, that monitoring and managing grain depot effectively to prevent the food mildewing and other problems.In generally, the granary monitoring system, which consists of the host computer, the host machine and the extension machine, that connected by the cable, and each module transmits data by the wire. However, in practical applications, such systems has it’s limit, it need to lay out a lot of cable, that increasing the difficulty of installation and maintenance because of complex wiring. At the same time, there may be dangerous situations such as circuit aging, short circuit, and disconnection. Therefore, this thesis designs a wireless granary monitoring system, which consisted of the host machine、the extension machine、data acquisition module、3G module, and the main work is as follows:(1) This thesis identify a way of wireless data transmission, which has the advantages of flexible networking, wiring convenience, low cost and low power consumption because of using wireless RF module Si4432. Field data is storaged in the host through the extension, the system transmits data in independent radio spectrum, which raising the utilization ratio of the frequency.(2) In order to meet the requirements of the system for low power consumption, the data acquisition module of each node uses the lithium battery power supply, the system adopts time division strategy and wake-up mechanism, the extension timing awaken the data acquisition module, the whole network is in a low power mode, that improving the accuracy and reliability of the system.(3) This thesis design a 3G wireless communication module, which applied to this granary monitoring system, for which users can access to the Internet by wireless. 3G network have advantages of wide coverage, high stability and high data transmission.3G module will be connected to the host machine, and data are transmitted to 3G module through RS232 serial port.3G module transforms the data to UDP protocol packets, and then access to the Internet through the 3G network, the managers access the server by the browser for obtaining grain information. This approach greatly reduces the grain depot workers, improves the efficiency of management, achieves the sharing of data in different places and mostly meets the needs of users.(4) This thesis studies the multi-sensor data fusion method, introduces the principle and process of fusion, and applied to the safety assessment of grain quality. This thesis adopts D-S evidence theory to merge and compute the multi-sensor data. Finally, and obtain a consistency interpretation and description of the grain situation.