火灾自动报警系统英文.docx

1、火灾自动报警系统英文Automatic fire alarm system based on MCUAbstract: 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 transforme

2、d 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

3、 deal with fire in-time, efficiently by warehouse manager.Keywords: fire alarm transducer;smoke sensor system;ATmega16;temperature transducer;smoke sensorI. INTRODUCTION Automatic fire alarm control system has experienced a process from the simple to the complex and intelligence system increasingly

4、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

5、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 detectio

6、n 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

7、 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-e

8、lectrical 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. Temperature Ionizatio

9、n Transducer smoke detector signal processing PD0 PD1SCMauto alarm module T ephoneelInter f ace Figure 1. Automatic fire alarm system structure. THE HARDWARE COMPONENTSA. Atmega16The system used by the . Atmels microcontroller ATmega16 microcontroller. ATmega16 is based on the AVR RISC architecture

10、to enhance low-power 8-bit CMOS microcontroller. 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 f

11、ollowing 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

12、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)

13、 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 in

14、terface 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 Fla

15、sh area (Boot Flash Memory) program continues to run, RWW operation achieved. ATmega16 to become a powerful microcontroller 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

16、 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

17、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 bi

18、t).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 mai

19、n 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 h

20、igh places, resistance at the same time currentlimited . 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

21、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, th

22、e 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, ion

23、ization 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 ION SMOKE SENSOR THCHNICAL DATA Table Head Table Column head Equilibrium potential collector Collector

24、 potential with the smoke Reduced light rate of 1% / ft Reduced light rate of 4% / ft Capacitor 6PFSmoke signals are processed on the chip of choice is the Motorola companys MC14468, MC14468 for DIP 16-pin package, contain oscillator, timer, latch, alarm control logic circuit, high input impedance c

25、omparator etc. When not detected smoke, MC14468 internal oscillator that oscillation cycle . Each cycle the internal power supply is provided to the work of the entire chip. Its all kept detect any smoke in addition to LED flashes, battery voltage alarm and smoke alarm. The oscillator oscillation pe

26、riod 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 during the detection of smoke cessation of changes, at this time if not detected smoke beeper wi

27、ll 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 d

28、etected by 1 pin-out high microcontroller 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 pi

29、n 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 microcontroller for processing. 13-pin then slide

30、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 detection circuitD. Auto-dial alarm moduleDial-up alarm module choices are the EX-1 dial-up module is a DTMF si

31、gnal receiving, storing, and sending as integration communications circuits. Module built-in microcontroller 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 informatio

32、n 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