基于单片机控制的金属探测器系统的设计

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摘要 
本文介绍的是基于单片机控制的金属探测器系统的设计过程和工作原理．这个系统是以AT89C51单片机为核心,首先由555定时器构成多谐振荡器产生脉冲信号送入探测线圈以形成交变磁场,然后经过线性霍尔器件UGN3503将磁场变化转换为电压信号的变化,经过放大电路和峰值检测电路,经数模转换之后输入到单片机中,由单片机对数据进行软件滤波之后,与基准值比较之后,判断是否存在金属和报警显示．系统的软件部分采用汇编语言编写，其中采用了软件滤波替代常用的硬件滤波电路，提高系统的抗干扰的能力．此外还对金属探测器的灵敏度和稳定性产生影响的因素进行探讨和分析． 
本文首先在绪论中对课题的背景和意义作了简单介绍。在第二章论述系统设计的理论依据，传感器的相关的知识等总体设计过程．第三章着重描述了系统硬件电路设计包括各个模块的设计和功能以及整机的工作原理和工程描述,在第四章中介绍了软件的总体设计和子程序的编写。最后在结论中简单介绍了主要的设计指标和设计的体会和本设计的优缺点。 

关键词：　 单片机，A/D转换，传感器，探测线圈 
Abstract
This article introduces the design process and the working principle of a metal detector system which bases on the technology of one-chip computer This system is take the one-chip computer AT89C51 as a core. .First it produces the pulse signal by the multivibratorwhich is consisted of 555 timer and send in the detecting coil to form the alternating magnetic field, then it asopts UGN3503 linear half-effect as prode to the magnetic field change into the voltage signal change,after enlargement electric circuit and peak value examination electric circuit,the signal be treated to send into ADC0809 modulus converter change moduluses, then the digital signal after the modulus converter is changed is sent into AT89C51one-chip computers afterwards, after the digital filter, AT89C51one-chip computers afterwards compares the data to the reference voltage and judges whether to have detected the metal and alarm. The system software adopts the assembly language to be written, and use the software digital filter to substitute hardware filter circuit, enhancing the system ability of antijamming. In addition,this article also disscusses the influence factor to the metal detector sensitivity and the stability . [资料来源：THINK58.com]
This article first has made the simple introduction in the introduction to the topic background and the significance. In second chapter it elaboration the theory basisof system design, the related knowledge of sensor and the system design processes.In third chapter it described the system hardware circuit design e including each module design and the function as well as the complete machine principle of work and the description of complete machine, the software system design and the subroutine compilation are introduced in the fourth chapter. Finally we introduces the main design target , the design experience and the advantage and disadvantage of the design.
Keywords：　technology of the one-chip computer , A/D change, sensor,search coil 
目录 
摘要 错误！未定义书签。 
Abstract II [资料来源：http://think58.com]

1. 绪论 4
1.1 引言 4
1.2 课题的背景和意义 4 [资料来源：www.THINK58.com]

2. 系统的总体概述 5
2.1 探测金属的理论依据 5
2.2 系统中传感器UGN3503简介 6

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3. 系统硬件电路设计 11
3.1 中央处理器8051 11
3.2 硬件电路设计 14
3.2.1 线圈振荡电路 14
3.2.2 数据采集电路 15
3.2.3 模数转换电路 17
3.2.4显示报警电路 22
3.2.5 电源电路 22 [版权所有：http://think58.com]

4. 系统软件的设计 25
4.1 软件设计思想 25
4.2 数字滤波算法说明 25
4.3 系统主程序的功能 26
4.4 子程序的模块设计 28
5. 主要技术指标……………………………………………………………..31
5.1 工作频率………………………………………………………………31 
5.2 灵敏度分析……………………………………………………………31
5.3 稳定性分析 [版权所有：http://think58.com]

结 论 32
致 谢 33
参考文献 34 [来源：http://www.think58.com]

1.绪论 
1.1 引言 
随着电子技术的进步，金属探测器从电子管，晶体管乃至集成电路，有了更新换代的发展，其应用敢为几乎扩大到各个领域，对工业生产和人身安全起着重要的作用。目前，随着科学技术的不断发展，犯罪分子和恐怖分子也利用高新技术制造新式的武器，爆炸物等。各个 国家也对安检阅越来越重视。 
金属探测仪作为重要的安全检查设备，已被广泛的应用与社会的生产和生活的诸多领域，如大型的运动会，展览会，工业部门等。都用金属探测器来对过 [来源：http://think58.com]