基于單片機的智能車載酒精檢測及控制系統(tǒng)設計文檔

1、基于單片機的智能車載酒精檢測及控制系統(tǒng)設計摘 要：本文介紹了一種基于單片機低功耗酒精檢測控制器，該控制器采用酒精傳感器、壓力傳感器、語音報警、電子鎖等與汽車組成車載酒精檢測及安全控制系統(tǒng)。該系統(tǒng)可以分為兩部分：一個為可手持的檢測部分，另一個為控制部分，安裝在車內，從而實現(xiàn)智能車載酒精檢測及安全控制。由于該系統(tǒng)具有高靈敏度和低功耗的功能，因此具有較高的實用價值。關鍵詞：酒精探測器；壓力傳感器；語音報警；車載一 引言近年來，酒后駕車造成的交通事故時常發(fā)生，給駕駛員自身和他人造成了巨大的損失，因此，對酒后駕車的檢測和管理成為必不可少的環(huán)節(jié)。但利用普通的監(jiān)測和管理成為必不可少的環(huán)節(jié)。但利用普通的監(jiān)測方

2、式，主要是駕駛員的自覺和交警的抽查，一方面，花了很大的精力但是效率極低；另一方面，酒后駕車引起的交通事故仍居高不下。盡管國家在去年5月實施了行的酒后駕車的處罰條例，但是酒駕事故仍時有發(fā)生。為此，筆者研究了具有智能化酒精檢測及語音報警的電路系統(tǒng)，有效地實現(xiàn)了簡單電路。簡單地說，就是當駕駛員呼出氣體中的酒精濃度達到設定的酒精濃度，就會語音提示，并強制切斷汽車電源總線，令其無法啟動汽車。此設計在綜合社會現(xiàn)象和前人設計的基礎上，經(jīng)過與同學、指導老師的仔細商討，在原有設計的基礎上注入我們的設計思想，融合我們的設計方法，基本上能實現(xiàn)令我們滿意的硬件電路。這樣最大限度地限制和減少酒后駕車的現(xiàn)象，盡可能降低交

3、警的工作量，同時提高交警的工作效率。二 系統(tǒng)結構及總體方案設計該控制系統(tǒng)主要以單片機為核心，配以檢測電路、控制電路、顯示電路、語音電路組成，并采用強制駕駛員呼氣的方法，以判斷駕駛員是否飲酒。具體工作流程為：首先壓力傳感器進行壓力檢測，若駕駛員就坐，壓力傳感器檢測到信號，啟動系統(tǒng)并激活語音模塊，通過語音提示進行酒精檢測，此時駕駛員可進行酒精檢測。為防止駕駛員逃避檢測，設置一個話筒，當呼氣確認后，酒精傳感器開始作為呼氣判斷裝置。對探測的氣體進行檢測，并把檢測到的信號進行放大和濾波，濾波之后的信號送入A/D轉換器進行數(shù)字轉換，由單片機對此數(shù)字信號進行處理判斷，并把處理的酒精數(shù)據(jù)送至LCD1602進行

4、酒精濃度顯示，同時把處理判斷后的信號通過發(fā)射模塊發(fā)送至接收控制繼電器不起作用，語音模塊。若酒精含量正常，提示汽車可以啟動；反之，超標指示燈亮起，控制繼電器起作用，汽車制動，語音提示汽車不可以啟動，使汽車無法行駛。若駕駛員無視進行酒精檢測的提醒，強制進行點火啟動，則汽車立即處于制動狀態(tài)，汽車無法啟動。從而實現(xiàn)控制酒后駕車的功能。三 硬件設計根據(jù)系統(tǒng)結構及總體方案的設計，可以把硬件電路的設計分為手持模塊和車載安全控制模塊，具體設計如下。3.1 手持模塊電路設計3.1.1 酒精檢測模塊本模塊采用TGS2620氣敏酒精傳感器并配以濾波電路，放大電路以及A/D數(shù)字轉換電路。該傳感器 由集成的加熱器以及在

5、氧化鋁基板上形成的金屬氧化物半導體構成。當可檢知的氣體存在時，空氣中該氣體的濃度越高，傳感器的電導率就越高，使用簡單的電路就可以將這種電導率的變化變換為與氣體濃度對應的輸出信號，同時具有壽命長、功耗低、靈敏度高及后期電路簡單等優(yōu)點。一旦檢測到酒精，其輸出與濃度對應的電壓信號，此信號經(jīng)過濾波、放大后送至12位A/D轉換芯片TLC22543CN進行數(shù)字化轉換，并把數(shù)字量送到單片機進行計算并閥值判斷，檢測駕駛員呼出氣體中酒精含量是否超標。3.1.2 呼氣判斷模塊此模塊采用送話器咪頭9767，用來判斷駕駛員是否呼氣。當駕駛員呼氣時，送話器咪頭產(chǎn)生一個脈沖信號送至單片機，單片機判斷幾十元呼氣，再檢測酒精

6、探頭送來的信號；若駕駛員不呼氣，則送話器咪頭不產(chǎn)生脈沖信號，此時不檢測酒精探頭送來的信號。3.1.3 單片機模塊選用51系列的89C51單片機作為處理器，用來接收呼氣判斷信號并接收氣體中的酒精含量數(shù)據(jù)，同時送至LCD進行顯示，并生成相應的信息碼發(fā)送給發(fā)射設備。89C51是一種帶4K字節(jié)閃爍可編程可擦除只讀存儲器的低電壓、高性能CMOS8位微處理器。3.1.4 發(fā)射模塊采用PT2262芯片，該芯片為編碼芯片，其第17腳輸出經(jīng)調制的串行數(shù)據(jù)信號，當17腳為高電平期間315MHz的高頻發(fā)射電路起振并發(fā)射等幅高頻信號，當17腳為低電平期間315MHz的高頻發(fā)射電路停止振蕩，所以高頻發(fā)射電路完全受控于P

7、T2262的17腳輸出的數(shù)字信號，從而對高頻電路完成幅度鍵控（ZSK調制）相當于調制度為100%的調幅。當檢測到酒精含量超標時，發(fā)射超標碼；反之，發(fā)射不超標碼。3.1.5 液晶顯示模塊本模塊采用LCD1602進行酒精含量的顯示，1602字符型液晶是一種專門用來顯示字母、數(shù)字、符號等的點陣型液晶模塊，它由若干個5X7或者5X11等點陣字符位組成，每個點陣字符位都可以顯示一個字符，每行16個字符型液晶。3.2 車載安全控制模塊3.2.1 接收設備模塊采用PT2272芯片，該芯片是一款用以解碼的芯片。編碼芯片PT2262發(fā)出的編碼信號由地址碼、數(shù)據(jù)碼、同步碼組成一個完整的碼字，解碼芯片PT2272接

8、收到信號后，其地址碼經(jīng)過兩次比較核對后，VT腳才輸出高電平。與此同時，相應的數(shù)據(jù)腳也輸出高電平，該模塊用來接收發(fā)射模塊的信號。3.2.2 單片機采用89C51，與發(fā)射的單片機一樣，收到接收設備送來的碼，根據(jù)不同碼進行不同的操作。其控制工作指示燈、繼電器和語音模塊。3.2.3 繼電器控制模塊繼電器受51單片機的控制，相當于開關，控制制動裝置開閉、車燈的亮滅和喇叭的響與不響。3.2.4 語音模塊采用ISD4004芯片，該芯片采用CMOS技術，內含振蕩器、防混淆濾波器、平滑濾波器、音頻放大器、自動靜躁及高密度多電平閃爍存貯陳列。芯片設計是基于所有操作命令可通過串行通信接口送入。芯片采用多電平直接模擬

9、量存儲技術，每個采樣值直接存貯在片內閃爍存貯器中，因此能夠非常真實、自然地再現(xiàn)語音、音樂、音調和效果聲，避免了一般固體錄音電路音量化和壓縮造成的量化噪聲和“金屬聲”。采樣頻率可選4.0、5.3、6.4、8.0kHz，頻率越低，錄放時間越長，而音質則有所下降，片內信息存于閃爍存貯器中，可在斷電情況下保存100（典型值），反復錄音10萬次。采用ISD4004語音芯片作為語音模塊核心部分，當壓力傳感模塊感應有人時，發(fā)出酒精檢測提示音；當酒精含量超標時，發(fā)出禁止行車警告音；當酒精含量未超標時，發(fā)出允許行車提示音。四 軟件設計軟件部分根據(jù)總體方案設計，可劃分為手持模塊和車載安全控制模塊兩個部分，各模塊均

10、采用模塊化編程。五 結束語本文介紹了車載酒精檢測的新思路，討論了新型酒精檢測及其控制系統(tǒng)的設計與實現(xiàn)。鑒于設計者的能力和水平及電子產(chǎn)品的開發(fā)不斷進行，針對此系統(tǒng)的優(yōu)化和擴展還有比較復雜的問題需要進一步的探討和研究。參考文獻1 華成英.信號運算符和過濾器.模擬電子技術基本教程，2006:257-268.2 曾興雯，劉乃安，陳健.頻率調制和解調.高頻電路原理與分析，2006：232-267.3 邱關源，羅先覺.對含理想運放的擴音器的分析.電路，2009：120-123.4 張先庭，向瑛，王忠，周傳璘.單片機原理、接口與C51應用程序設計，2011：189-206.5 白中英.數(shù)字系統(tǒng)的基本模型.數(shù)

11、字邏輯與數(shù)字系統(tǒng)，2008：157-162.6 閻石.模擬數(shù)字轉換.數(shù)字電子技術基礎，2007:506-545.7 高西全，丁玉梅.模擬信號的數(shù)字化處理.數(shù)字信號處理，2011:21-29.Based on single chip microcomputer intelligent vehicle alcohol detection and control system designAbstract: this paper introduces a kind of controller based on single-chip low-power alcohol detection, the

12、controller adopts the alcohol sensor, pressure sensor, voice alarm, electronic lock and auto vehicle alcohol detection and safety control system. The system can be divided into two parts: one for handheld detection part, another for the control part, installed in the car, so as to realize intelligen

13、t vehicle alcohol detection and safety control. Due to the function of the system has high sensitivity and low power consumption, thus has high practical value.Key words: alcohol detector; Pressure sensor; Voice alarm; An on-board1.IntroductionIn recent years, traffic accidents caused by drunk drivi

14、ng frequently occurred, caused huge losses to drivers themselves and others, as a result, the detection and management of drunken driving to become indispensable link. But using ordinary monitoring and management become essential link. But using the ordinary monitoring mode, mainly is the drivers co

15、nsciousness and the traffic police spot checks, on the one hand, spend a lot of energy but the efficiency is extremely low; On the other hand, drunk driving cause traffic accident remains high. Although the national in May last year implemented a lines of drunk driving penalties, but the drunk drivi

16、ng accidents still happen.To this end, the author studies the intelligent alcohol detection and voice alarm circuit system, effectively implements a simple circuit. , in a nutshell, is when the alcohol concentration to set in the drivers breath gas concentration of alcohol, can voice prompt, and for

17、ce to cut off the car power bus, make its cant start the car. This design on the basis of the general social phenomenon and the previous design, with classmates, guidance of the teachers careful discussion, on the basis of the original design into our design ideas, design method of integration we ba

18、sically hardware circuit can realize to our satisfaction. Such maximum limit and reduce the phenomenon of drunk driving, as far as possible to reduce the traffic police work, improve the work efficiency of the traffic police at the same time.2.The system structure and the overall scheme designThe co

19、ntrol system mainly by single chip microcomputer as the core, the detection circuit, control circuit, display circuit, voice circuit, and adopts the method of forced the driver out, to determine whether drivers to drink. Specific work process is: the first pressure sensor is used to detect the press

20、ure, if the driver sat, pressure sensor detects the signal, startup system and activate the voice module, through the voice prompt alcohol detection, drivers alcohol detection can be performed at this time. In order to prevent the pilot to escape detection, set up a microphone, exhale when confirmed

21、, alcohol sensor began to exhale as judging device. To test the detection of gas, and the detected signal is amplified and filter, filter after into the A/D converter to convert the digital signal, the digital signal by single-chip microcomputer for processing, and processing of data sent to the LCD

22、1602 alcohol alcohol concentration showed that at the same time, the treatment after the judgment signal by emitting module sending and receiving control relay doesnt work, the voice module. If alcohol is normal, prompt car can be started; On the other hand, the excessive light is lit up, control re

23、lay, automobile brake, voice prompt car cant start, is unable to drive the car. If the driver to ignore for the detection of alcohol to remind, to enforce the ignition starts, the car immediately in the braking state, the car wont start. So as to realize the function of control driving under the inf

24、luence of alcohol.3. Hardware designBased on the system structure and the overall scheme design, can be divided into hand-held module and the hardware circuit design of on-board security control module, design details are as follows.3.1 holding a module circuit design3.1.1 alcohol detection moduleTh

25、is module USES TGS2620 alcohol gas sensitive sensor and filter circuit, amplifying circuit and A/D digital conversion circuit. Integration of the sensor by the heater and the alumina of metal oxide semiconductor is formed on the substrate. When there is gas detector, the higher the concentration of

26、the gases in the air, the higher the conductivity sensor, using a simple circuit can change with the conductivity of the gas concentration of the corresponding output signal, and has long service life, low power consumption, high sensitivity and late simple circuit etc. Concentration of alcohol once

27、 detected, the output and the corresponding voltage signal, the signal after filtering and amplification to 12 bits A/D conversion chip TLC22543CN to digital conversion, and the digital quantity to single chip microcomputer to calculate and threshold judgment, whether the detection of alcohol conten

28、t in the drivers breath gas exceeds bid.3.1.2 expiratory judgment moduleThis module USES the microphone microphones, 9767, which is used to determine whether the driver out. When the driver exhale, microphone microphones to generate a pulse signal sent to the single-chip microcomputer, exhale, MCU t

29、o judge a few yuan to detect alcohol from probe signal; If the driver fails to exhale, the microphone microphones do not produce the pulse signal, while the signal from alcohol detection probe.3.1.3 MCU moduleChoose 51 series of 89 c51 single chip as the processor, used to receive a breath alcohol i

30、n judge signal and receives gas content data, at the same time sent to the LCD display, and generate the corresponding information code sent to the transmitting equipment. With a 4 k byte flash is 89 c51 is programmable to erase the read only memory (ROM) of low voltage, high performance CMOS8 bit m

31、icroprocessor.3.1.4 launch moduleUSES PT2262 chip, this chip for encoding chip, its 17 feet by the modulation of the serial data output signal, when 17 feet for high level during the high frequency of 315 MHZ transmission circuit of high frequency signals, such as vibration and launch when 17 feet f

32、or low level during the high frequency of 315 MHZ transmission circuit to stop oscillation, so high frequency circuit is completely controlled by the launch of PT2262 17 feet output digital signals, thus for high frequency circuit to complete the amplitude keying (ZSK modulation) equal to 100% of th

33、e modulation of amplitude modulation. When detected, over the legal alcohol limit, emission standard code; On the other hand, the launch is not overweight.3.1.5 liquid crystal display moduleThis module adopts the LCD1602 to alcohol, according to a 1602 character LCD is a kind of special used to disp

34、lay the letters, Numbers, symbols, such as the point of formation of LCD module, it consists of a number of 5 x7 or x11 dot matrix characters such as composition, each dot matrix characters can display a character, line 16 character LCD.3.2 vehicle safety control module3.2.1 receiving device moduleU

35、sing PT2272 chip, the chip is a to decoding chip. Encoding chip PT2262 encoding signals by the address code, data, synchronization code to form a complete code word, after decoding chip PT2272 receives the signal, its address code after two comparison, after checking VT feet to output high level. At

36、 the same time, the corresponding data foot also output high level, the module is used to receive signals launch module.3.2.2 microcontrollerUsing 89 c51, the launch of the single chip microcomputer, and receive from receiving equipment code, according to the different code for different operation.

37、Its control work lights, relays and voice module.3.2.3 relay control moduleRelay controlled by 51 single chip microcomputer, is equal to the switch, brake control opening and closing, destroy the light of lights and horn ring and not ring.3.2.4 voice moduleThe ISD4004 chip, the chip USES the CMOS te

38、chnology, embedded oscillator, prevent blur filter, smoothing filter, audio amplifier, since the action mania and high-density multilevel flash storage display. Chip design is based on all commands into through serial communication interface. Chip adopts multilevel direct analog storage technology,

39、each sampling value directly storage in glint on chip memory and therefore able to reproduce the very real, natural voice, music, tone and sound effect, avoids the general solid quantitative and compressed sound recording circuit caused by the quantization noise and metal. Sampling frequency optiona

40、l 4.0, 5.3, 6.4, 8.0 kHz, the lower the frequency, the longer the playback time, and the sound quality is declined, glint on chip information stored in memory and may be retained in the case of power cuts 100 (typical), the tape 100000 times over and over again. The ISD4004 voice chip as the core voice module, when the pressure sensor module induction someone sends an alcohol test sound; When alcohol content exceeds bid, a ban on driving warning sound; When alcohol content was not overweight, driving prompt