【正文】 ustype alarm control system, and in some residential areas and mercial 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 onsite temperature, smoke and other nonelectrical 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 pared with the limits by MCU system. This system can produce local and remote autoalarm signals. Figure 1. Automatic fire alarm system structureⅢ. THE HARDWARE COMPONENTSA. Atmega16The system used by the . Atmel’s microcontroller ATmega16 microcontroller. ATmega16 is based on the AVR RISC architecture to enhance lowpower 8bit 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 following characteristics: 16K bytes insystem programmable Flash (with the ability to read and write at the same time, that is, RWW), 512 bytes EEPROM, 1K bytes SRAM, 32 generalpurpose I / O port lines, 32 generalpurpose working registers, for the JTAG boundary scan interface, support the onchip 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, 8channel 10bit with optional differential input stage programmable gain (TQFP package) of the ADC, with onchip oscillator of programmable watchdog timer, an SPI serial port, as well as six can be selected by software powersaving mode.The chip is based on Atmel highdensity nonvolatile memory technology production onchip ISP Flash allows the program memory through the ISP serial interface or a generalpurpose programmer for programming。每當(dāng)我在畢業(yè)設(shè)計(jì)中遇到問(wèn)題的時(shí)候，我都會(huì)找馬東老師需求幫助，而每次馬東老師即使很忙，也會(huì)抽出時(shí)間給我細(xì)心的講解。在畢業(yè)設(shè)計(jì)的過(guò)程中我也學(xué)到了很多新的知識(shí)，知道了電子產(chǎn)業(yè)的知識(shí)是需要不斷更新的。在控制領(lǐng)域和數(shù)字測(cè)溫領(lǐng)域，DS18B20數(shù)字溫度傳感器都有著廣泛的應(yīng)用。諸如地鐵、輕軌、高鐵等新型交通工具漸漸融入了我們的生活，一些新型的建筑材料也走進(jìn)了我們家庭與工作環(huán)境。首先，打了一壺?zé)崴瑹崴臏囟却蠹s在80度上下。然后點(diǎn)燃一根香煙進(jìn)行測(cè)試，將香煙燃燒釋放出的氣體對(duì)準(zhǔn)MQ2型煙霧傳感器，顯示出的示數(shù)明顯低于甲烷氣體顯示的示數(shù)，且在釋放出氣體一段時(shí)間后，LED燈才亮，蜂鳴器才發(fā)出報(bào)警聲音。在調(diào)試過(guò)程中發(fā)現(xiàn)接通電源的前幾分鐘，煙霧會(huì)發(fā)生報(bào)警，本來(lái)以為是焊接的電路出現(xiàn)了問(wèn)題或者是MQ2型煙霧傳感器壞了，但是通過(guò)查閱資料我了解到MQ2型煙霧傳感器具有初期穩(wěn)定的特性。第五步，將數(shù)據(jù)線(xiàn)拉升至高電平。首先，先將數(shù)據(jù)線(xiàn)置于高電平“1”，然后進(jìn)行延時(shí)操作。與共陽(yáng)極的數(shù)碼管類(lèi)似，共陰極的數(shù)碼管是把所有LED的陰極連接到共同接點(diǎn)，而每個(gè)LED的陽(yáng)極分別為a、b、c、d、e、f、g及dp。 LED燈電路圖 按鍵報(bào)警按鍵報(bào)警對(duì)于火災(zāi)自動(dòng)報(bào)警系統(tǒng)來(lái)說(shuō)也是非常重要的一部分，有些時(shí)候人們預(yù)先發(fā)現(xiàn)火災(zāi)的隱情，可以通過(guò)報(bào)警按鍵發(fā)出報(bào)警的信號(hào)，通過(guò)這種方式提醒其他人做好保護(hù)措施。 氣體采集模塊如圖所示。當(dāng)2 位數(shù)據(jù)為“0”、“0”時(shí)，將CH0作為正輸入端IN+，CH1作為負(fù)輸入端IN進(jìn)行輸入。但因?yàn)镈O端和DI端在通信時(shí)并未同時(shí)有效的，并且與單片機(jī)的接口是雙向的，所以在電路的設(shè)計(jì)過(guò)程中可以把DO與DI 并聯(lián)連接在一根數(shù)據(jù)線(xiàn)上。 CH0是模擬輸入通道0，或者被當(dāng)做IN+/使用。第四，當(dāng)5V電源供電時(shí)輸入電壓范圍在0到5V之間。C)下工作，所以需要對(duì)其加熱。 MQ2氣體傳感器的指標(biāo)MQ2型傳感器的一般對(duì)于液化石油氣與天然氣等煙霧有著很高的靈敏度，尤其對(duì)烷類(lèi)的煙霧MQ2型傳感器表現(xiàn)得更加敏感。C溫度的時(shí)候，二氧化錫會(huì)吸附空氣中的氧氣，形成氧的負(fù)離子吸附，半導(dǎo)體中的電子密度迅速降低，從而使得它的電阻值變大。EEPROM 非易失性記憶體，用于存放長(zhǎng)期需要保存的數(shù)據(jù)，上下限溫度報(bào)警值和校驗(yàn)數(shù)據(jù)，DS18B20共3位EEPROM，并在RAM都存在鏡像，以方便用戶(hù)操作。數(shù)據(jù)在出產(chǎn)時(shí)設(shè)置不由用戶(hù)更改。DS18B20擁有以下特點(diǎn)：測(cè)量范圍比較寬，達(dá)到55℃~+125℃。復(fù)位電路的作用是給單片機(jī)一個(gè)復(fù)位信號(hào)，讓單片機(jī)的程序從頭開(kāi)始，復(fù)位電路與單片機(jī)的RESET接口相連接。如有必要，可通過(guò)對(duì)特殊功能寄存器（SFR）區(qū)中的8EH單元的D0位置位，可禁止ALE操作。EA/VPP是外部訪(fǎng)問(wèn)允許，如果要使CPU僅訪(fǎng)問(wèn)外部程序存儲(chǔ)器EA端必須保持在低電平（接地）。當(dāng)向P2端口書(shū)寫(xiě)“1”時(shí)，內(nèi)部上拉電阻會(huì)將端口拉高，這樣可以被當(dāng)做輸入端口來(lái)使用。當(dāng)處于這種情況時(shí)，P0是不具有內(nèi)部上拉電阻的。第三，擁有3個(gè)16位的定時(shí)器/計(jì)數(shù)器與8個(gè)中斷源。單片機(jī)的實(shí)時(shí)數(shù)據(jù)處理能力與控制功能，可以讓系統(tǒng)處于最佳的工作狀態(tài)。第三點(diǎn)是單片機(jī)在分布式多機(jī)系統(tǒng)中的應(yīng)用。第二階段是從1978年到1982年，這是高性能單片機(jī)微機(jī)的處理階段，這個(gè)時(shí)期的單片機(jī)相比之前而言擁有多級(jí)中斷處理系統(tǒng)，也擁有I/O 串行端口，RAM、ROM的容量變大，有15 位時(shí)序同步技術(shù)器，尋址范圍可以達(dá)到64KB。就目前而言，大規(guī)模的集成電路技術(shù)已經(jīng)有了很好的發(fā)展，可以在一塊芯片上集成中央處理器（CPU）、數(shù)據(jù)存儲(chǔ)器（RAM）、程序存儲(chǔ)器（ROM）、定時(shí)器計(jì)數(shù)器和輸入/輸出（I/O）接口電路等主要的計(jì)算機(jī)部件。另一種是利用金屬熱脹冷縮的性質(zhì)。光電感應(yīng)探測(cè)器上有著一個(gè)光敏元件與一個(gè)發(fā)光的元件，正常工作的情況下，發(fā)光元件會(huì)發(fā)出光，經(jīng)過(guò)透鏡的作用照到光敏元件上，電路保持暢通，當(dāng)有煙霧產(chǎn)生時(shí)，煙霧會(huì)阻斷光的傳射，光敏電阻上所接收到的光明顯減少，這時(shí)光敏電阻就會(huì)把光強(qiáng)弱的變化轉(zhuǎn)換為電的變化，經(jīng)過(guò)放大電路的作用報(bào)警。 復(fù)合型火災(zāi)自動(dòng)報(bào)警系統(tǒng)在一個(gè)火災(zāi)自動(dòng)報(bào)警系統(tǒng)中，如果能夠?qū)崿F(xiàn)對(duì)光輻射、溫度與煙霧中兩種及兩種以上的參數(shù)做出檢測(cè)的，我們稱(chēng)這種報(bào)警系統(tǒng)為復(fù)合型的火災(zāi)自動(dòng)報(bào)警系統(tǒng)，復(fù)合型火災(zāi)自動(dòng)報(bào)警系統(tǒng)可分為感煙感光型火災(zāi)自動(dòng)報(bào)警系統(tǒng)，感煙感溫型火災(zāi)自動(dòng)報(bào)警系統(tǒng)，感光感溫型火災(zāi)自動(dòng)報(bào)警系統(tǒng)以及感煙感光感溫型火災(zāi)自動(dòng)報(bào)警系統(tǒng)。 感光型火災(zāi)自動(dòng)報(bào)警系統(tǒng)物質(zhì)在燃燒的過(guò)程中會(huì)產(chǎn)生光的輻射，感光型的火災(zāi)自動(dòng)報(bào)警系統(tǒng)就是通過(guò)感應(yīng)物質(zhì)燃燒中產(chǎn)生的光的特性，即擴(kuò)散火焰的閃爍頻率與火焰的光強(qiáng)度，來(lái)觸發(fā)火災(zāi)自動(dòng)報(bào)警系統(tǒng)的。集中報(bào)警器也是將信號(hào)通過(guò)聲光報(bào)警的形式展現(xiàn)，通過(guò)特有的通訊設(shè)備向消防隊(duì)報(bào)警。結(jié)構(gòu)計(jì)較簡(jiǎn)單，價(jià)格計(jì)較便宜，性能較為穩(wěn)定，有著不錯(cuò)的使用價(jià)值。這些數(shù)字無(wú)時(shí)無(wú)刻不提醒我們，社會(huì)在不斷地發(fā)展，人類(lèi)也在不斷地進(jìn)步，諸如火災(zāi)這類(lèi)的災(zāi)害也在不斷地?cái)U(kuò)大危害范圍，火災(zāi)毀壞的不僅僅是我們努力創(chuàng)造的財(cái)產(chǎn)，還摧殘著我們的心靈。DS18B20。沈陽(yáng)理工大學(xué)學(xué)士學(xué)位論文摘 要本篇文章通過(guò)將單片機(jī)與傳感器技術(shù)相結(jié)合，設(shè)計(jì)出了這套基于單片機(jī)的火災(zāi)自動(dòng)報(bào)警系統(tǒng)。關(guān)鍵字：火災(zāi)自動(dòng)報(bào)警系統(tǒng)；DS18B20；MQ2；ADC0832Abstract This thesis by microcontroller and sensor technology, design a set of microcontrollerbased automatic fire alarm system. The design of the core selection ATMEL Corporation AT89S52 MCU. AT89S52 microcontroller with low power consumption, high performance and other features, and is patible with standard MCS51 instruction set and 80C51 pin structure. The design uses a temperature sensor and smoke sensor signal acquisition, temperature sensors use the United States produced DALLAS DS18B20 digital temperature sensor, the sensor temperature signal can be directly converted into a digital signal to the microcontroller, and can set the temperature alarm value, the circuit simple structure, functions more plete. Smoke sensor selection MQ2 type semiconductor bustible gas sensors smoke sensor, the sensor is sensitive sensor, the bustible gas concentration in the air or a current signal into a voltage, the A / D converter converts the analog ADC0832 digital amount and sent to microcontroller. Final selection LED module shows realtime gas concentrations and temperatures. This microcontrollerbased automatic fire alarm system function m