|
|
Automatic fire alarm system based on MCU
Abstract: The paper introduced an automatic warehouse fire a1arm system based on MCU. The system was mainly made up of ATmega16, temperature sensors, smoke sensors, and EX-1 auto dialed alarm module. In the system, temperature signals were transformed to serial data, and smoke signals were transformed to voltage signals. All the data were processed by MCU. When the surveillance system checked fire in warehouse, alarm signal was turn on, meanwhile the messages were transmitted to managers through EX-1. Application of the system was convenient to deal with fire in-time, efficiently by warehouse manager.
Keywords: fire alarm transducer;smoke sensor system;ATmega16;temperature transducer;smoke sensor
I. INTRODUCTION
Automatic fire alarm control system has experienced a process from the simple to the complex and intelligence system increasingly in China. The characteristic is automatic fire detection and alarm technology has a great progress along with computing and detection technology development. At present, automatic fire alarm control system was used in bulk storage plant, shopping malls, high-level office buildings, hotels and other places. They were used in a number of collections focused on one area of intelligent alarm control method with higher levels of bus-type alarm control system, and in some residential areas and commercial buildings were installed by a single automatic fire alarm detection device. These alarm detection devices fail to report sometimes, or misinformation. Its reliability is not high because of using single sensor. Therefore, it is needed to develop a simple structure, low cost, high reliability, fast responding, automatic fire detection system.
II. GENERAL PROJECT OF THE SYSTEM
The hardware block diagram shown in Figure 1, hardware by temperature sensors, smoke sensors, signal processing module, MCU modules and automatic alarm module. Non electrical quantity that is through the sensing element sensors (smoke sensors and temperature sensors) will be on-site temperature, smoke and other non-electrical signal into an electrical signal, as well as signals for signal processing to convert analog quantity to digital quantity. Finally, the sampled data were processed and compared with the limits by MCU system. This system can produce local and remote auto-alarm signals.
Figure 1. Automatic fire alarm system structure
Ⅲ. THE HARDWARE COMPONENTS
A. ATmega16
The system used by the U.S. Atmel’s micro controller ATmega16 micro controller. ATmega16 is based on the AVR RISC architecture to enhance low-power 8-bit CMOS micro controller. Because of its advanced instruction set and a single clock cycle instruction execution time, ATmega16 data throughput of up to 1 MIPS / MHz. Thereby mitigate the system in the power and the contradiction between the processing rate. ATmega16 has the following characteristics: 16K bytes in-system programmable Flash (with the ability to read and write at the same time, that is, RWW), 512 bytes EEPROM, 1K bytes SRAM, 32 general-purpose I / O port lines, 32 general-purpose working registers, for the JTAG boundary scan interface, support the on-chip debugging and programming, 3 has a more flexible mode of timer / counter (T / C), chip internal / external interrupts, programmable serial USART, there are initial conditions detector universal serial interface, 8-channel 10-bit with optional differential input stage programmable gain (TQFP package) of the ADC, with on-chip oscillator of programmable watchdog timer, an SPI serial port, as well as six can be selected by software power-saving mode.
The chip is based on Atmel high-density nonvolatile memory technology production on-chip ISP Flash allows the program memory through the ISP serial interface or a general-purpose programmer for programming; you can also run on the AVR core among the bootstrap to program. Boot program can use any interface to download the application to the Flash memory area (Application Flash Memory). Application of Flash storage area is updated when the boot Flash area (Boot Flash Memory) program continues to run, RWW operation achieved. ATmega16 to become a powerful micro controller by 8-bit RISC CPU and the system programmable flash in a single chip, for many embedded control applications provides a flexible and cost-effective solution. ATmega16 has a set of programming and system development tools, including: C language compiler, macro assembler, program debugger / software emulator, emulators and evaluation boards.
B. Temperature Sensor
Temperature sensor manufactured by DALLAS Semiconductor DS18B20-type single intelligence temperature sensor, its performance features include:
1)This sensor have single-bus-specific technology, either through the serial port cable also through other I / O port lines and computer interfaces,without going through other conversion circuits Direct output measured temperature value (9-bit binary number, with sign bit).
2) Temperature range is -55 ℃ ~ +125 ℃, measurement resolution of 0. 0625 ℃.
3) Containing 64 as amended through the laser-read-only memory ROM.
4) Fit a variety of SCM or system machine.
5) Users can set separate ways each temperature upper and lower limit.
6) Includes parasitic power.
DS18B20 and the main chip connection diagram shown in Figure 2: DS18B20 number one pin grounded, then on the 3rd pin high and the 2nd pin then a 5. 1K of the pull-up resistor, at the same time received a single output signal of the PD0 pin. Pull-up is to pull the uncertainty signal through a resistor embedded in the high places, resistance at the same time current－limited . Program from the DQ pin in high impedance state to ensure that the beginning, so that you can pull on the pull-up resistor to the high DQ. At the same time the main chip also can be an external site alarm buzzer.
Figure 2. ds18b20 and the main chip connection diagram.
C. Smoke Monitoring Module
Smoke sensors choose HIS-07 ion smoke detectors when the flow through the inside and outside the ionization chamber ionization electron flow is unbalanced, collector charges current until the ionization balance. In a smoke-free or non-combustion, the collector being subject to the impact ionization current statistical fluctuation, the potential to maintain a balance. Ionization current have impact when the smoke into the ionization chamber, easily into the ionization chamber smoke outside than inside the ionization chamber of the affected, ionization current decline in and collector to re-charge until the new equilibrium potential, this potential change can be used to trigger the alarm circuit. Technical parameters such as Table 1.
TABLE I.HIS-07 ION SMOKE SENSOR THCHNICAL DATA
Smoke signals are processed on the chip of choice is the Motorola company’s MC14468, MC14468 for DIP 16-pin package, contain oscillator, timer, latch, alarm control logic circuit, high input impedance comparator etc. When not detected smoke, MC14468 internal oscillator that oscillation cycle 1.67s. Each 1.67s cycle the internal power supply is provided to the work of the entire chip. It’s all kept detect any smoke in addition to LED flashes, battery voltage alarm and smoke alarm. The oscillator oscillation period becomes 40ms when the MC14448 Once detection smoke, this time piezoelectric buzzer driving circuit to start oscillation, start to be able to output to maintain the high 160 ms after the cessation of 80ms.Continued during the detection of smoke cessation of changes, at this time if not detected smoke beeper will not be issued a warning sound.
In figure 3, the MC14468 1 pin joint PD1 pin of SCM when the ion chamber of the ion current as the scene of smoke detection and change, voltage change generation a weak side-spread seized 15, by the MC14468 internal logic processing circuit processing, the smoke is detected by 1 pin-out high micro controller for processing. 13-pin then slide rheostat is set to facilitate detection sensitivity when the led flashes and the buzzer sounded a piercing sound of an audio alarm when the department has a fire alarm signal-based.
In figure 3, the MC14468 1 pin joint PD1 pin of SCM when the ion chamber of the ion current as the scene of smoke detection and change, voltage change generation a weak side-spread seized 15, by the MC14468 internal logic processing circuit processing, the smoke is detected by 1 pin-out high micro controller for processing. 13-pin then slide rheostat is set to facilitate detection sensitivity when the led flashes and the buzzer sounded a piercing sound of an audio alarm when the department has a fire alarm signal-based.
Figure 3. Smoke detection circuit
D. Auto-dial alarm module
Dial-up alarm module choices are the EX-1 dial-up module is a DTMF signal receiving, storing, and sending as integration communications circuits. Module built-in micro controller and dial-up management process can provide users with a variety of signal input and output ports, in security alarm, signal acquisition, automatic control, remote communication and information transmission areas such as flexible application. 5 groups can have cell phone or group of seven local telephone numbers are stored, power-down is not lost; Telephone line status detection, automatic fault signal output ;Telephone / external switching two kinds of dial-up state control; Trigger time, nine times loop dial preset numbers; To work independently, independent dial-up, do not rely on telephone and other external devices.
EX-1 wiring diagram shown in figure 4, The PD4 pin to connect the main chip HTO , the module began to dial alarm when PD4 output high level signal, PD5 connection ON / OFF pin input is high level signal to open the dial-up settings, the input does not work when this pin become low, ERR pin connected to PD6 pin of MCU, PD6 output 1 begun to test whether the telephone line failure, READY pin connect MCU PD7 pin detection and alarm is completed, the alarm is end when PD7 pin is high .
Figure 4. EX-1 wiring diagram
IV. SOFIW AREDESIGN
Figure 5. The main program flow chart
Because in the early stages of fires and the smoldering phase will produce a large number of aerosol particles and smoke particles .In the stage of incipient fire substances in the combustion process produces a lot of heat, so should make the smoke sensor and temperature sensor used in conjunction, first with the smoke sensor detects whether there is smoke generation, then the temperature sensor detects the temperature, temperature sensor alarm value is set to 50 degrees. When the smoke is detected R0 is 1, not smoke R0 is 0. Then test the temperature when the temperature reaches the value of seasonal early warning R1 is 1, the value of seasonal temperature not to reach an early warning R1 to 0, at this time compared to the R0 and R1 is equal to the main chip when the dial-up alarm, if not equal is not to alarm re-tested. This smoke sensor and temperature sensor used in conjunction with greatly improved the reliability of detection to prevent the omission of false positives, program flow diagram shown in Figure 5.
V. CONCLUSION
By the cooperation of using of temperature and smoke sensors, through detecting the temperature and smoke on-site, the automatic alarm system could find any fire in warehouse and send the message to managers of warehouse in the early time by the form of short messages. So its application could greatly reduce fire losses and enhanced the safe reliability of warehouse more than the former single equipment of fire alarm, and prevent failing of reporting and misinformation. The system has a high reliability, low price and high sensitivity.
REFERENCES
[1] Shunning Miao,Guangming Xiong,Yongping Li etc.Automatic Fire Alarm System Design and Research, Equipment Manufacturing Technology, 2006(2), P909.
[2] Liang Ge, Qi Cong. Intelligent Analysis of office building fire.
[3] Ti Zhou. Building Fire System Design, Yunnan Construction,2008(6).
[4] Honeywell (Honeywel1)'s construction equipment Monitoring System, Intelligent Building and City Information, 2008(4).
[5] Derek Clements-Croome, Intelligent buildings: design, management and operation, Thomas Telford Publishing, 2004.
[6] Zhang Huazhong, Commanding System of Fire Automatic Alarm and Fire Control Linkage based on Internet, Computer Engineering, 2001.
[7] ANSI, Radiant Energy-Sensing Fire Detectors for Automatic Fire Alarm Signaling, US: ANSI/FMRC FM3260-2004.
基于智能校区的自动报警系统
摘要：本文介绍了基于智能校区的自动仓库自动报警系统。该系统主要由ATmega16的，温度传感器，烟雾传感器，EX-1自动拨通报警模块。在系统，温度信号转换为串行数据，烟雾信号转化为电压信号。由MCU的所有数据进行处理。监控系统检查时，在仓库防火，报警信号被打开，同时消息通过EX-1传送到管理者。该系统的应用是由仓库经理有效地处理。
关键词：报警传感器，烟雾传感器系统; ATmega16的温度传感器，烟雾传感器
1 序言
自动报警控制系统经历了一个过程，从简单到复杂和情报系统在中国越来越多。其特点是自动探测报警技术，随着计算机和检测技术的发展有很大的进步。目前，自动报警控制系统采用大容量的抽水蓄能电站，商场，高层办公楼，酒店和其他地方。他们被用在一些更高层次的总线型报警控制系统，智能报警控制方法的一个区域集中的集合，在一些居民区和商业楼宇安装了由单一的自动报警检测装置。这些检测报警装置，有时失败报告，或误传。它的可靠性不高，因为使用单一传感器。因此，需要开发具有结构简单，成本低，可靠性高，响应快的自动检测系统。
2 该系统的一般项目
硬件框图如图1所示，由温度传感器，烟雾传感器，信号处理模块，MCU模块和自动报警模块的硬件。非电气量，是通过传感元件传感器（烟雾传感器和成电信号，信号处理以及信号转换成模拟量，数字量，温度传感器）将现场温度，烟雾等非电信号。最后，对采样数据进行处理，并与智能校区系统的限制。该系统可以产生本地和远程自动报警信号
图1 自动报警系统结构
3 硬件组件
A. ATmega16
美国爱特梅尔的微控制器ATmega16智能校区所使用的系统。 ATmega16的基于AVR RISC结构的低功耗8位CMOS微控制器提高。由于其先进的指令集以及单时钟周期指令执行时间，ATmega16的数据吞吐量高达1 MIPS / MHz的。从而减轻系统在功耗和处理速度之间的矛盾。 ATmega16的有以下特点：16K字节的系统内可编程Flash（读取和写在同一时间，也就是有能力，RWW区），512字节EEPROM，1K字节SRAM，32个通用I / O口线， 32个通用工作寄存器，JTAG边界扫描接口，支持片上调试编程，3定时器/计数器（T / C），片内/外中断，可编程串行USART有更灵活的方式，有初始条件探测器通用串行接口，8通道10位具有可选差分输入级可编程增益（TQFP封装）的ADC，片上振荡器的可编程看门狗定时器，一个SPI串行端口，以及六个可以通过软件节电模式选择。
该芯片是以Atmel高密度非易失性内存技术生产的片上ISP Flash允许程序存储器通过ISP串行接口或编程的通用编程，你也可以运行在AVR内核之间的自举程序。引导程序可以使用任何接口下载申请快闪记忆体领域（应用快闪记忆体）。应用程序更新Flash存储区时引导Flash区（引导闪存）程序继续运行，RWW区操作实现。 ATmega16的成为一个强大的8位RISC CPU的微控制器和系统单芯片可编程闪存，为许多嵌入式控制应用，提供了一个灵活和具有成本效益的解决方案。 ATmega16的一个编程和系统开发工具集，包括：C语言编译器，宏汇编，程序调试器/软件仿真器，仿真器和评估板。
B. 温度传感器
Dallas半导体公司的DS18B20型单智能温度传感器的温度传感器制造，其性能特点包括：
1）该传感器具有单总线专用技术，通过串口电缆，还可以通过其它I / O口线和电脑接口，无需通过其他转换电路直接输出被测温度值（9位二进制数，用符号位）。
2）温度范围为-55℃〜+125℃，测量分辨率为0。 0625℃。
3）包含64修订通过激光只读存储器ROM。
4）适合各种智能校区或系统机。
5）用户可以设置每个温度的上限和下限分道扬镳。
6）包括寄生电源。
DS18B20与主芯片连接图如图2所示：DS18B20的数字一个引脚接地，然后在第三针和第二针，然后5。 1K的上拉电阻，在同一时间，收到了单一的PD0引脚输出信号。拉是拉电阻器的电流限制在同一时间通过嵌入在高的地方，阻力不确定性的信号。计划，以确保从DQ引脚处于高阻抗状态开始，让你可以上拉电阻拉来的高DQ的。在同时主芯片也可以是外部的现场报警蜂鸣器。
图2 DS18B20与主芯片连接图
C.烟雾监控模块
烟雾传感器选择HIS-07离子烟雾探测器，通过内外电离室电离电子流的流动不平衡时，集电极收费，直到目前的电离平衡。在无烟或无燃烧，收集受到碰撞电离电流的统计波动，保持平衡的潜力。电离电流影响烟雾进入电离室，容易进入电离室烟雾外，比内的影响，重新充电，直到新的平衡电位和集电极电流下降电离电离室时，这种潜在的变化可以用触发报警电路。技术参数如表1。
表1 HIS-07离子烟雾传感器THCHNICAL数据
烟雾信号处理芯片的选择，是摩托罗拉公司的MC14468，DIP16管脚封装的MC14468，包含振荡器，定时器，闩锁，当没有检测到烟雾报警控制逻辑电路，高输入阻抗比较等，MC14468内部振荡器，振荡周期1.67s。每个1.67s循环内部电源提供整个芯片的工作。这一切都保持除了指示灯闪烁，电池电压报警器，烟雾报警器检测到任何烟雾。振荡器的振荡周期变为40ms的MC14448一旦检测烟雾，此时压电蜂鸣器驱动电路开始振荡时，开始能够输出保持高160毫秒后停止在戒烟的变化检测80ms.Continued在这个时候，如果没有检测到烟雾蜂鸣器会不会发出警告声。
在图3中，MC144681针联合PD1引脚智能校区作为弱侧蔓延检获15 MC14468内部的逻辑处理电路处理，现场烟雾探测和变化，产生电压变化的离子电流的离子室时，烟雾检测引脚输出高微控制器处理。 13针，然后滑动变阻器时LED闪烁，蜂鸣器响起了刺耳的声音音频报警时，该部门有报警信号，以方便检测的灵敏度。
在图3中，MC144681针联合PD1引脚智能校区作为弱侧蔓延检获15 MC14468内部的逻辑处理电路处理，现场烟雾探测和变化，产生电压变化的离子电流的离子室时，烟雾检测引脚输出高微控制器处理。 13针，然后滑动变阻器设置，以方便检测的灵敏度，当LED闪烁和蜂鸣器刺耳的声音响起了一个声音报警，当部门有报警信号。
图3 烟雾检测电路
D.自动拨号报警模块
拨号报警模块的选择是EX-1拨号模块是一个DTMF信号的接收，存储和发送作为一体化通信电路。智能校区和拨号管理过程中建立的模块可以为用户提供的各种信号输入和输出端口，防盗报警，信号采集，自动控制，远程通信和信息传输领域，如灵活的应用，。 5组，可以有7个本地电话号码的手机或组存储，掉电不丢失;电话线路状态检测，自动故障信号输出;电话/外部切换两种拨号状态控制;触发时间，9次循环拨号预设号码;独立工作，独立的拨号上网，不依靠电话和其他外部设备。
EX-1接线图，在图4所示，将PD4引脚连接主芯片氚，模块开始拨号报警台PD4输出高电平信号，PD5连接ON/ OFF端子输入是高电平信号打开拨号设置，输入不工作时，此引脚变低，错误连接引脚PD6智能校区引脚PD6输出1开始测试是否完成电话线路故障，READY引脚连接智能校区的PD7引脚检测和报警，报警结束当PD7引脚是高的。
图4 EX-1接线图
4.主程序流程图
图5 主程序流程图
因为在和阴燃阶段的早期阶段会产生大量的气溶胶粒子和烟雾粒子。阶段初期的物质在燃烧过程中产生大量的热量，所以应使用烟雾传感器和温度传感器结合，先用烟雾传感器检测是否有烟生成，然后温度传感器检测到的温度，温度传感器报警值设置为50度。当检测到烟雾R0为1，不吸烟，R0为0。然后进行测试时的温度，当温度达到季节性预警R1的值是1，季节温度值达到预警R1为0，在这个时候相比，R0和R1等于主芯片拨号报警，如果不等于不报警重新测试。这烟雾传感器和温度传感器配合使用，大大提高了检测的可靠性，防止漏报，误报，程序流程图如图5所示。
5. 总结
自动报警系统的使用温度和烟雾传感器，通过检测现场的温度和烟，合作，可以找到任何在仓库失火，仓库管理人员通过短消息的形式发送消息，在早期。所以它的应用可以大大减少损失，提高了仓库的安全可靠性比以前单一的报警设备，并防止失败的报告和误导。该系统具有可靠性高，价格低，灵敏度高。
参考文献
[1] 苗顺兵，熊光明，李永平等等自动报警系统的设计与研究，机械制造技术，2006（2），P909
[2] 良玉葛，办公大楼的智能分析。
[3] 周倜。建筑消防系统的设计，云南建设，2008（6）
[4] 霍尼韦尔,建筑设备监控系统，智能建筑与城市信息，2008（4）
[5] 德里克·克莱门茨，智能建筑设计，管理和操作，托马斯出版社，2004
[6] 张华中，自动报警及消防指挥系统基于因特网的联动控制，计算机工程，2001年
[7] 安斯，辐射能传感的探测器，自动报警信号，美国：安斯/ 富姆里刻 FM3260，2004年
