Information fusion technology based on wireless fire detection and alarm system NIU LINGHUI 1,a,HU ZHUGE 2,b

Transcription

1 Advanced Materials Research Online: ISSN: , Vols , pp doi: / Trans Tech Publications, Switzerland Information fusion technology based on wireless fire detection and alarm system NIU LINGHUI 1,a,HU ZHUGE 2,b 1 The Hong Kong Polytechnic University,China 2 Shanghai Xian Dai Architecture,Engineering&Consulting Co.,China a nlhjessica@gmail.com, b @qq.com Key words: Fire detection; STM32; ZigBee technology; Information fusion Abstract. In order to solve the problem, which is "the traditional fire alarm system is only used to detect a particular physical or chemical signal of the fire, moreover, false alarm and failure alarm can occur easily. We apply multi-sensor composite detection technology and wireless communication technology in the fire detection and alarm system,and design an intelligence distributed wireless fire detection alarm system, which is mainly based on STM32 control chip. Introduction The application of fire played an extremely important role in the development of human civilization. While the fire always threaten human life and cause great losses of lives and property. At present, automatic fire detection and alarm system is widely used, and it plays an important role to protect our safety. But there are many problems in the practical application of fire detection and alarm system. The quality of existing products in market is uneven. These products only detect a certain kind of fire parameter. Many problems can be occured, such as false alarm and failure alarm. With the continuous development of microprocessor technology, sensor technology, communication technology, control technology and artificial intelligence technology, fire detection and alarm system has beening developed to be a high reliablity, low false alarm and failure alarm, networking, and intelligence system[2]. The purpose of this thesis is to propose a fire detection system solution based on multi-sensor information fusion technology. It can collect a lot of fire parameters with different characteristics, transfer data by wireless sensor networks, and process and judge data by intelligent algorithms, then detect and alarm fires timely and accurately. 1 Structural Design 1.1 Design Ideas 1) The multi- sensor composite detection technology Generally, fire process is divided into four stages, which are early stage, smoldering stage, flame heat release stage and attenuation stage. The most of release is burning gas during the early stage of the fire,smoke, flame and heat are very less. It will produce a lot of visible or invisible smoke during smoldering stage. Flame and heat are not too much. The heat will be radiated out during fire flame heat release stage. The ambient temperature will rise up rapidly[3]. Fire signals include a number of characteristic parameters. The more fire parameters are used for system, the higher intelligence level will be, the lower false alarm and failure alarm will be[4]. 2) Distributed Fire Alarm System Centralized control was used for early system,the detector is just a absolute sensor, it will transmit collected signals to controller at all times. The result can be got by processing and judging those signals by controller. But when the scale of system is become bigger, negative factors will be produced, such as: the load for controller will be over its ability and the response speed will lower. Therefore, the distributed control mode will be gradually used instead of the centralized control method [5]. All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, (ID: , Pennsylvania State University, University Park, USA-10/05/16,04:16:45)

2 884 Advances in Mechatronics, Automation and Applied Information Technologies 3)Wireless Data Transmission The energy supply and information transmission for traditional fire detectors was usually realized by cable. For cable laying during installation, not only the cost will be very high and work load will be very heavy, but also building structure will be damaged sometimes. Wireless Sensor Network (Wireless Sensor Network, WSN), will use wireless communication technology and microsensor with small size and low power consumption. It is composed by a large number of micro sensor nodes located in the monitoring region. It is a multi-hop self-organizing network system formed by wireless communication mode[6] [7]. Therefore, it will be a new important research direction of fire detection by combining the fire detection technology and the wireless communication technology to realize a wireless,network and intelligent fire detection system. 4) Intelligence Algorithm of Fire Signals For different burning material and environment detected, the difference dynamic characteristic parameters value collect by sensors is very big. During fire detection, the traditional thresholds method for setting alarm delay time and alarm threshold is too simplify. Therefore, the application of intelligent algorithm in fire detection system has an important positive role in reduce false alarm and failure alarm for fire alarm system [8]. 1.2 Wireless Composite Fire Detection Alarm System For fire detection alarm system researched in this paper, it respectively designed the fire alarm controller and composite fire detectors by using STM32 as processor to form fire alarm system controlled by distributed control mode. The composite detection node can collect smoke concentration, temperature and CO concentration signals. The processing and judgment of fire information are realized in detecting node. the information will be transferred to fire alarm controller through ZigBee wireless network. The storing and display of fire data and management of detection node are done by fire alarm controller. Figure 1 shows the system's overall structure diagram. Figure 1 The overall system structure diagram (1) Compound detection node: Collecting site environment signal through three kinds of sensors, the fire information is processed by intelligent algorithm. The fire information is transferred to fire alarm controller through ZigBee communication module. The alarm device will be started if there is a fire, fire alarm information will be sent to the fire alarm controller at the same time. If there is no fire, the verification signal will be sent to fire alarm controller for process at regular time. As Shown in Figure 2. (2) Fire alarm controller: Be responsible for receiving information from composite detection node. Record the date and time of fire by clock chip for future query. Store historical information by using SD card. Display related detection node information on the LCD in real time. Starting alarm and actuators when alarm information is detected, it can regularly check each compound detection node at the same time to determine whether it works properly or not. As shown in Figure 3.

3 Advanced Materials Research Vols Alarm circuit LCD display Button Temperature sensor Smoke sensor CO sensor STM32 Communication interface JTAG interface Clock circuit Serial port circuit STM32 Communication interface Alarm circuit Power supply Figure 2 Composite detection node SD storage Power supply Figure 3 Fire alarm controller 2 Hardware Design for System 2.1 Circuit Design for Microcontroller The system selected 32-bit processing chip STM32F103RBT6 as the master control chip for fire alarm controller and composite detection node. STM32F103RBT6 is new 32-bit microcontrollers created by ST by using advanced architecture ARM Cortex-M3 core. Flexible static memory controller makes it very convenient to connect with many memories and peripheral connections, meanwhile because of its wealth on-chip peripherals, the design of peripheral circuits can be simplified. 2.2 Sensor Selection LM35DZ is used for temperature sensor in this system., it connects temperature sensor and amplifying circuit in a silicon slice to form an integrated temperature sensor. the sensitivity is 10 mv /. Working temperature range is Working voltage is 4-30 V. Precision is ±1. The maximum linear error is ±0.5.the static current is 80 µa. Its output voltage is a linear relation with Celsius temperature scale. conversion formula is as follows: Vout_LM35(T)=10mV/ T The smoke sensor and CO sensor will use common MQ-2 and MQ-7 gas sensors separately. Those two sensors are metal semiconductor sensor based on stannic dioxide (Sn02). Here we take MQ- 2 gas sensor as an example to introduce its working principle. MQ-2 gas sensor has different resistance values for different gas types and concentrations. Power supply for heating end and measurement input end for MQ-2 gas sensor is 5V DC. the output end V1 can be input to MCU after the conditioning, the magnitude of V1 is directly related to smoke concentration. 2.3 ZigBee communication module ZigBee is a close-range, low power consumption, low data transfer rate, low complexity and low-cost wireless network technology. ZigBee wireless network is based on DSSS spread spectrum technology. it will use CSMA / CA (Carrier Sense Multiple Access / Collision Avoidance) channel access method. Communication distance between nodes is from 10 m to100m. The distance can be reached to one thousand meters with PA module [9]. The wireless communication module of this article will use Shun Zhou SZ05 series Z- BEE embedded wireless serial interface communication module. Reinforced ZIGBEE wireless technology will be used for this module. It has many characteristics and advantages such as long communicating distance, anti-jamming ability, flexible networking. It can group mesh network structure. 3 Software design for system Overall, the system software can be divided into two parts: the fire alarm controller software program and the composite detection node software program. In this system, in order to ensure that each node works properly, the alarm controller can determine whether each node works properly or not according to received ID number of each node at regular time. 3.1 The fire algorithm design for composite detection node The collected temperature, smoke and CO data are converted to actual temperature values, smoke concentration and CO concentration. Related values are extracted to determine whether there is a fire or not. The fire is determined based on following six values: temperature (T), smoke value (S), CO

4 886 Advances in Mechatronics, Automation and Applied Information Technologies value (C), T of temperature rise, S of smoke rise, C of CO rise. Prewarning will be started when temperature, smoke or CO value reaches to threshold value, And then, pay attention to whether T / S or C reaches to threshold value. If it reaches, the fire can be determined, meanwhile the alarm will be activated and the information will be sent to fire alarm controller, otherwise it returns to prewarning condition. [11]. Flow diagram for fire determination is shown in Figure Software design for fire alarm controller The main program mainly includes communication program for STM32 chip, SD card store programs, LCD display procedure, etc. After the information from detection node is received by fire alarm controller, it will be stored in a circular queue and shown on the main interface. When unusual condition is determined, it will be shown and saved. Alarm circuit will be activated to warn worker. Software flow diagram for fire alarm controller is shown in figure 5 Start T / S / C threshold? Y Fire warning N Start System initialization Accept information of composite detection node System initialization Acquisition of signal Signal processing ΔT / ΔS /ΔC threshold? Y Show the fire and alarm Through the Zigbee module N No fire occurred If there is a node in a fire Alarm Y Display information through the LCD N Fire alarm controller Figure 4 Flow diagram for fire determination controller Store information Figure 5 Software flow diagram for fire alarm 4 Experiment and Conclusion In order to verify the reliability for fire detection and communication of this system, we test composite fire detecting node and fire alarm controller. Parts of environment data detected by this system is shown in table 1 Table 1 Environment data of composite fire detection node Species Materials Temperature output Smoke output CO output T S C Towel Flame Bubble Plastic Smoldering fire Paper Timber Plywood Interference Candle Cigarette Liquefied gas

5 Advanced Materials Research Vols By the data of composite detection node, We can see that lots of heat is released in open flame stage, and the temperature changes very quickly. During the smoldering stage, it mainly release gas and smoke, and the temperature slightly changes. In the case of interference, Although the smoke and CO output value over the threshold value, the change in value is very small. it can be determined as fire interference. Experiments show that by using of embedded technology, ZigBee wireless communication technology and compound detection technology, fire detection and alarm system can be a simple structure, fire algorithm is easy to realize, transmission of information between the system nodes is stable and reliable, fire signal can be effectively detectd and fire can be found in time. Reference [1] Wu Yuze, Yang xingrong. Technology Development of Fire Alarm System [J]. Fire Fighting Technology and Product Information, 2004 (1):16-19 [2] Xiao Jing. Development Trend of Fire Detection Alarm Technology[J]. Anhui Fire Fighting, 2007, 36 (16): [3] Du Jianhua, Zhang rencheng. Fire Early Stage Feature Information Research Based on Fourier Transform Infrared Spectroscopy Detection [J]. Spectroscopy and Spectral Analysis, 2008, 28 (3): [4] RESTAS A. Forest Fire Management at Aggtelek National Park Integrated Vegetation Fire Management Program from Hungary [C] / /The World Congress on Intelligent Control and Automation (W CICA), 2008: [5] Bai Zhuowen. Application Status and Development Trend of Fire Monitoring System in Building Automation[J]. Security Technology, 2003, (2): [6] Foreign New Fire Detection Product Introduction [J]. Fire control technology and product information, 2006 (9): [7] Reng Fengyuan, Huang Haining, Lin Chuang. Wireless sensor network [J]. Journal of Software, 2003, 14 (7) [8] Chen Tao, Yuan Shuihong, Fan Weicheng. Forecast for Fire Detection Technology Research [J]. Fire Science, 2001, 2 (10): 108 a 110 [9] Lv Zhian. Principles and Application Development of ZigBee Network[M]. Beijing: Beijing University of Aeronautics and Astronautics Press, [10] Zhu Ming. Research on control system of distribution intelligent fire alarm [D].wuhan: Huazhong University of Science and Technology, 2004:-41. [11] Liu Xuan, Liu Shixing. Bus Type Smoke and Temperature Composite Fire Detector[J]. Hefei University of Technology, 2010 (7), and (7): 23 a 24.

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