摘要:自行车的发明与使用至今已有近两百年的历史。经过不断的改良与发展，各式各样的自行车出现在众人眼前。而随着时代的发展，自行车已经从基础的代步工具演变为人们娱乐休闲的选择之一。因此人们也希望自行车的功能越来越多，越来越强大。自行车速度里程表这一辅助工具便是随着人们的需要发展出来的。其功能也从单一的测速以及显示里程发展到人体状态检测等丰富功能。本论文主要阐述了一种基于霍尔元件的里程表的设计,它以STC89C52单片机作为核心，霍尔传感器收集脉冲测速，并能够用LCD显示出实时的速度及已经行驶过的路程。

　　　文章介绍了里程表的硬件设计及软件设计。硬件部分利用霍尔元件测脉冲信号送入单片机系统，信号经过处理后显示出来。软件部分用C语言编程。

关键词  单片机；里程/速度；霍尔元件；C语言

Abstract:The invention and the use of the bicycle has been nearly two hundred years in history. Through continuous improvement and development，various kinds of bikes have came in the sight of the people.But with the development of The Times, bicycle has evolved from the basic transport tool for people to entertainment and leisure choices. So people also hope that the function of the bicycle is becoming more and more stronger. The auxiliary tool of bicycle speed odometer is developed with the needs of the people. Its function has developed from a single speed measuring and display mileage to various functions such as inspect the status of the human body. This thesis mainly expounds the design of a kind of odometer which based on the hall sensor. The bicycle speed odometer uses STC89C52 single chip microcomputer as the core, hall sensors to collect pulse velocity, and be able to use the LCD to show the real-time speed and the distance that has drived down. 

　　　This paper introduces the odometer in the hardware design and software design. Hardware part uses hall sensor to measure the pulse signal and sends to the microcontroller system, then the processed signal is displayed. Software part uses C language to programe.

Key words  single chip microcomputer  Range/speed  Hall element  C language

　　　本课题的主要任务是设计制作一个自行车里程速度计，能自动显示自行车行驶的总里程与行车速度。并且在设计中加入了超速报警模块，本装置设定了两个报警速度，分别为8M/s和10M/s。两个报警值可以单独切换。当超速时，可以发出声光报警，提醒骑行者减速，以减少发生危险的机率，保证生命安全。本设计是以单片机为处理核心元件，利用霍尔传感器将车轮的转数参数转换为电脉冲输出，送入到单片机进行处理。里程及速度的测量是经过单片机的定时/计数器测出总的脉冲，再经过单片机计算得出。其结果通过LCD显示器显示出来。本文主要介绍了自行车里程表的设计思想，电路原理，方案论证以及元件的选择等内容，整体上分为硬件设计和软件设计。

　　　本文首先对课题的任务进行了硬件及软件方案的设计；然后具体的介绍了传感器的选择，单片机的选择，以及显示电路的设计；继而介绍了软件程序的编写；最后进行了仿真中问题的分析与解决，最后对本次设计进行了总结。