Application of wireless sensor network in mine monitoring system

To meet the need of safe production in coal mine, a monitoring system based on wireless sensor networks is designed. Consideration of the topographic features of coal mine, two-level network is adopted. The upper level network uses 433 MHz as communication frequency which has the characteristics of long transport distance and strong penetration, while the lower level network (in working face) uses 2.4 GHz to communicate. We construct communication protocols and the most important one is tree routing protocol which combines the real-time transmission of data with routing maintenance. The collection of underground environmental data (gas concentration, temperature, etc.) and the physiological parameters of miners are available, and we can locate the miners on real time. Monitoring program has been developed to save the received data from sink nodes and display it on real time and analyze all kinds of information for decision function.