毕业论文：基于单片机的电话自动拨号报警器.doc

毕 业 论 文（设 计） 届 专业 班级 题 目 基于单片机的自动拨号报警器的设计 二О 年 月 日 内 容 摘 要 随着社会的发展，人们的活动、居住区域越来越大，安全问题越显重要。简洁、经济型报警器成为家庭所需。 本设计就是以AT89C51单片机作为电话自动拨号报警器的控制核心。首先，通过报警检测电路中二氧化碳传感器检测空气中的二氧化碳浓度来确定是否发生火灾，若二氧化碳浓度超过预先设定的浓度基准值就产生一个报警信号，单片机检测到该报警信号后，立即控制摘机电路摘机并从E2PROM存储器CAT24C021中取出预先存储的电话号码，再通过双音多频发送电路编码产生双音频信号，完成自动拨号功能。 本系统采用HD7279控制键盘及数码管显示，完成电话号码的输入和显示功能，还采用了双音多频收发芯片MT8880来进行编码产生双音频信号，再通过音频放大器LM386 来完成双音频信号的功率和幅度的放大 。 本设计涉及到了单片机开发、程序设计、传感器设计及应用、现代通信技术、自动控制技术等等，并将它们有机地结合在一起。这对于交叉学科的研究将起到很大的作用。 关键： AT89C51 自动拨号 报警 DTMF Abstract Along with the development of the society,peoples activity and the district for living became more and more big,so the problem of safe also became more and more important . The alarm device which is simple and economic became needed for the family. In this design,AT89C51 microprocesser is adopted as the control unit,the smoke sensor is used to tell whether fire happens according to the detected smoke density.if this density extend the one which is set in advance, the product will produce a alarm signal.when the alarm signal is sent to the microprocesser, the microprocesser will control the circuit to take off the telephone,and access the telephone number which is memoried in the CAT24C021 in advance.,then control the circuit of DTMF to dial the telephone number.thus,the function of auto-dial is then finishend. This alarm device concludes a chip of HD7279 for entering ang displaying the telephone number,and a chip of MT8880 which is adoped as dialling and receiving the signal of DTMF,then via the audio power amplifier for enlarging the signal power. A spread field of science and technology such as SCM exploitation,programming,the design and apply of sensors,modern communicate technology and control technology are involved in this research,ang are combined together organically. This will rise very important function for the study of cross. Key word： AT89C51 Auto-Dial Alarm DTMF 目 录 第1章 前言 1 第2章 电话自动拨号报警器的总体设计 2 2.1电话自动拨