Research On The Monitoring And Alarming System Of Combustible Gas In Vehicle Based On Wireless Communication Network

Bus is an important part of urban public transport system,which provides a quick and economical way to travel.In recent years,bus fire accident occurs frequently,which caused a huge threat to the public’s life and property security.Most of these accidents are due to criminals carry flammable liquids on the bus and make a fire or explosion.However,because of various reasons,our country has not yet developed a kind of efficient and reliable security equipment to detect whether the passengers on the bus carry explosive dangerous goods.Therefore,the research and development of bus security system has become an urgent requirement to prevent the occurrence of bus arson.Under this background,this paper studies and designs a kind of combustible gas monitoring and alarming system based on wireless communication network.The system is divided into detection equipment and control terminal.Detection equipment will be real-time monitoring whether the passengers carry flammable liquids,and the detection results will be transmitted to the control terminal,and the control terminal displays detection information.Firstly,according to the requirement of the information communication between the detection equipment and the control terminal,the transmission mode of the wireless communication is adopted,and suitable short range wireless transmission scheme is selected.The software frequency hopping spread spectrum technology is used to solve the problem of interference in the wireless transmission environment.Based on the basic theory of spread spectrum communication and the principle of frequency hopping communication,this paper expounds the selection and arrangement of frequency hopping points,the handshake process between the two sides of the radio frequency transceiver and the realization of the frequency hopping communication algorithm.At the same time,data encryption algorithm is designed to improve the security of data transmission.Secondly,through the analysis of system functional requirements,this paper realizes the specific hardware design and software design.System hardware design includes:selection of sensor,signal amplifier and filter circuit,malfunction self-diagnosing circuit,wireless transmission circuit,data storage circuit,power circuit,clock circuit,display circuit,alarm circuit,and some core function modules are analyzed in depth.The paper uses the modular design idea to realize the system software design,and uses the embedded C language to program.The software design mainly completes the system main program,malfunction self-diagnosing subroutine,file system transplant and data storage subroutine,wireless transmission subroutine,display subroutine.In addition,in view of the shortcomings of the traditional threshold alarm cannot distinguish the danger signal and false alarm signal,so this paper proposes to use BP neural network to identify and classify three kinds of combustible gas signals.Through simulation experiments,it is proved that the BP neural network can better distinguish three kinds of signals,which can greatly reduce the system false alarm rate and improve the reliability of the system.Finally,the module function of the system and the whole machine are tested.Experimental results show that the design of combustible gas monitoring and alarming system can be sensitive to find the passengers carrying flammable liquid on the bus,meet the needs of public security,and has good practicability and application value.