Research And Design Of Sensor Nodes In Coal Mine Safety Early Warning System

As an important resource of China’s economy construction, the production safety of coal miningengineering has been the key question of coal mine exploitation engineering at home and abroad. Due tothe complexity of underground environment, the colliery accidents occur frequently in our country. Nowmost of the coal mine monitoring system uses cable wiring in the actual runtime and it will appear somequestions, such as the transmission cable wiring difficult, monitoring scope of small, intensity ofelectromagnetic interference, the high price of the system and maintenance costs, more energy consumption,and poor scalability. So it is very important for coal mine safety to design a reliable security early warningsystem of coal mine. The sensor nodes of coal mine safety’s early warning system is designed by thewireless sensor network technology, which has flexible networking, solves the shortcomings arising fromcable transmission, grasps the environment factors down hole timely, prevents accidents and reducesunnecessary casualties.According to the detail requirement of the coal mine, the overall design of sensor nodes is mainlydivided into four modules, they are processor module, sensor module, wireless communication module andpower module. The Processor module chooses ST company’s STM32W108which is built-in ARM Cortex-M3microprocessor, has32bit high performance kernel, uses ARM Thumb2instruction set, and has somespecialty, such as high characteristic, low power consumption and high memory utilization. Wireless RFmodule uses STM32W108to transmit data, and applies ZigBee protocol to transfer data between eachsensor node. Sensor nodes adopt DHT22digital temperature and humidity sensor to collect temperature andhumidity and the gas sensor chooses the MJC/3.0L gas sensitive element sensor. Power management chipselects TI’s TPS73230DBVT and TPS73233DBVT. Gas sensors, processor chip, and the temperature andhumidity respectively are provided power by low power consumption of the circuit design.The software of sensor nodes is designed with IAR EWARM by IAR System company for the ARMmicroprocessor development as development platform and ZigBee protocol stacks TI company as base.Eventually it succeeds to collect environment parameters of coal mine. The sensor has strong portabilityand is also convenient to increase or decrease the nodes. Taking the temperature parameter as experimentalobject and analyzing the collected date of the nodes show that the sensor nodes have feasibility, stabilityand reliability.