【正文】 按鍵電路 顯示模塊本次設(shè)計選用CAI3461BH數(shù)碼管，它具有外觀小巧、性能穩(wěn)定、價格低廉等特點(diǎn)，它的主要參數(shù)是：，工作電流為80ma，適合的工作環(huán)境溫度為零下10度到零上50度，接口方式為8線并行接口，顯示方式為反射式正顯示。第三，數(shù)碼管的表面有一層保護(hù)膜,在使用的時候可以撕下來。 顯示電路4 系統(tǒng)的軟件設(shè)計 程序編寫軟件在硬件系統(tǒng)設(shè)計完成之后，需要對軟件系統(tǒng)進(jìn)行編程，本次設(shè)計選用的編程軟件為Keil μVision2。 主程序的流程本次基于單片機(jī)的火災(zāi)自動報警系統(tǒng)的設(shè)計，它的主程序主要是為了檢測氣體傳感器MQ2和溫度傳感器DS18B20所采集的信號，經(jīng)過對采集到的信號的判斷與分析，決定是否要發(fā)出報警信號。將數(shù)據(jù)線拉到低電平“0”，然后再進(jìn)行延時，延時時間為480微妙到960微妙。最后，將數(shù)據(jù)線再一次拉升至高電平“1”，初始化完成。第六步，重復(fù)以上操作，直至所有字節(jié)傳送完成。將數(shù)據(jù)線拉到高電平“1”，延時15微秒。初期穩(wěn)定的特性就是半導(dǎo)體的煙霧傳感器在不通電很長時間的情況下，再次工作時，是很難馬上正常的工作。在預(yù)熱8分鐘左右的時間后，MQ2型煙霧傳感器基本達(dá)到穩(wěn)定的工作狀態(tài)，測試開始本次設(shè)計我選用了2種氣體測試的方法。這說明這個系統(tǒng)的反應(yīng)比較靈敏，對于不同氣體的采集結(jié)果比較準(zhǔn)確。經(jīng)過查閱相關(guān)的資料，MQ2型煙霧傳感器對于甲烷，丙烷，丁烷，氫氣，酒精以及液化石油氣等氣體都可以進(jìn)行檢測，它的反應(yīng)速度也很快，可以在火災(zāi)來臨之前及時準(zhǔn)確的提醒人們注意保護(hù)人身與財產(chǎn)的安全。將熱水倒入傳熱性能良好的金屬容器里，將容器放在一個較為密閉的空間里，將火災(zāi)自動報警系統(tǒng)貼近容器，過了一會兒，LED燈亮、蜂鳴器發(fā)出報警聲音。準(zhǔn)確及時的實(shí)現(xiàn)了按鍵報警。這些新興事物為我們帶來舒適與方便的同時也為我們帶來了火災(zāi)的隱患，火災(zāi)自動報警系統(tǒng)的應(yīng)用，可以有效地為我們的生活和生產(chǎn)帶來保障，有效地降低爆炸以及中毒事件的發(fā)生，火災(zāi)自動報警系統(tǒng)逐漸成為公共場所及住宅區(qū)必備的儀器，未來它的發(fā)展前景會非常的美好。AT89S52作為一個CMOS8位的微控制器，具有低功耗、高性能、應(yīng)用普遍、容易上手以及操作方便等特點(diǎn)。MQ2型半導(dǎo)體可燃?xì)怏w敏感元件煙霧傳感器，它屬于氣敏傳感器，是氣電變換器，MQ2可以把可燃性氣體在空氣中的濃度轉(zhuǎn)化成電流信號或者電壓信號，再經(jīng)過A/D轉(zhuǎn)換電路將模擬量轉(zhuǎn)換成數(shù)字量后最后傳入單片機(jī)，最后單片機(jī)完成數(shù)據(jù)方面的處理與報警控制的工作。本次畢業(yè)設(shè)計基本實(shí)現(xiàn)了預(yù)期目標(biāo)，但其中還有很多不足，比如焊接的水平不足，有時會出現(xiàn)焊接點(diǎn)不牢的問題。而對于工程設(shè)計的步驟與流程也有了清晰地認(rèn)識，我相信這些寶貴的經(jīng)驗(yàn)對我未來的學(xué)習(xí)與生活都會有著很大的幫助。感謝我們信息學(xué)院自動化專業(yè)的所有老師對我的關(guān)心鼓勵。從選題開始，大綱的確定，硬件選擇與焊接，期中期末的檢查以及論文的修改，馬東老師都給予了我精心的指導(dǎo)，這幾個月馬東老師不僅在學(xué)習(xí)上給我做了精心的指導(dǎo)，在思想上也給了我無微不至的關(guān)懷，我們成為了非常好的朋友，在此謹(jǐn)向馬東老師致以最崇高的敬意和最真誠的謝意。 smoke sensor system。 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 bee a powerful microcontroller by 8bit RISC CPU and the system programmable flash in a single chip, for many embedded control applications provides a flexible and costeffective solution. ATmega16 has a set of programming and system development tools, including: C language piler, macro assembler, program debugger / software emulator, emulators and evaluation boards.B. Temperature Sensor Temperature sensor manufactured by DALLAS Semiconductor DS18B20type single intelligence temperature sensor, its performance features include:1)This sensor have singlebusspecific technology, either through the serial port cable also through other I / O port lines and puter interfaces, without going through other conversion circuits Direct output measured temperature value (9bit binary number, with sign bit).2) Temperature range is 55 ℃ ~ +125 ℃, measurement resolution of 0. 0625 ℃.3) Containing 64 as amended through the laserreadonly 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 pullup resistor, at the same time received a single output signal of the PD0 pin. Pullup 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 pullup 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 HIS07 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 smokefree or nonbustion, 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 recharge 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 DATASmoke signals are processed on the chip of choice is the Motorola pany’s MC14468, MC14468 for DIP 16pin package, contain oscillator, timer, latch, alarm control logic circuit, high input impedance parator 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. It’s all kept detect any smoke in addition to LED flashes, battery voltage alarm and smoke alarm. The oscillator oscillation period bees 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 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 sidespread seized 15, by the MC14468 internal logic processing circuit processing, the smoke is detected by 1 pinout high microcontroller for processing. 13pin 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 signalbased.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 sidespread seized 15, by the MC14468 internal logic processing circuit processing, the smoke i