Study On The Wireless Sensor Network Applications In Train Fire Monitoring System

With the increasing development of the railway technology, and being fast, comfortable, economic, environmental and other advantages, train has slowly become the primary choice of transport during people’s traveling, which plays a crucial role on China’s economy development. As a necessary component of the security safeguard of people’s traveling by train, train’s fire monitoring system to timely detecting fire and fire alarm is very important. Due to the limited internal train’s complex environment of traditional train’s fire monitoring system, arranging wires becomes very difficult. Therefore, a train’s fire monitoring system based on the wireless sensor network, designed which can timely and effectively monitor the fire, and avoid unnecessary losses caused by the fire.The thesis analyzes the causes of the train fire, due to the large staff on the train density, flammable materials, all kinds of electrical equipment is easily caused, some of those who neglect or failure of electrical equipment, can easily lead to a fire. The fire can be judged by some simple features in the fire monitoring, however, it is often inaccurate and can easily lead to false negative phenomenon. In this system, combining multi-sensor technology, we chose digital temperature sensor DS18B20, light-sensitive smoke sensors and ultraviolet light-sensitive sensor, which collect the corresponding the different fire characteristic signal values of temperature, smoke, ultraviolet, etc. While the application data fusion technology is used to process comprehensively to collected data, in order to achieve accurate, timely, and effective fire detection.Through wireless sensor network technology and multi-sensor technology, a set of train fire monitoring system is designed consisting of software and hardware components. The fire detection system in the thesis consists of sensor nodes, the convergence nodes, and the composition of vehicle control terminal. Among them, the sensor nodes and sink nodes are basically the same in the hardware configuration, and they both have taken a modular design. Microprocessors of sensor nodes and sink nodes both choose the CC2430, gathering the set processors and wireless transmitter chip together. Through aggregating and initial processing of the convergence nodes, the data by the sensor nodes collecting is sent to the vehicle control terminal. The vehicle control terminal not only processes data thoroughly, drives the fire alarm system to alarm and monitors the display of data, but also send system working orders. The processor of control terminal choose STM32 with Cortex-M3 core. Completion of the main terminal board control monitoring abnormal data display, storage, analysis for the fire signal to drive the alarm system alarm. In this part of the periphery of the completion of the single microprocessor design, JTAG debug program download interface, LCD display, an external memory SD design and alarm circuits. According to the hardware design, the completion of three major modules corresponding software design.Due to the interference of external factors, in the time of designing the system to work, it causes the system to fail. Through the analysis of the system failure, it improves the reliability of the system in the aspect of both hardware and software.