基于单片机的心率设计 - 图文

宁波理工学院

毕业设计（论文）

题 目 心率监测系统设计

姓 名 陈园园 学 号 3070431071 专业班级 07通信工程3班 指导教师 应蓓华 分 院 信息工程与工程分院 完成日期 2011年6月1日

摘 要

心率是指单位时间内心脏跳动的次数,一般指每分钟的心跳次数,是临床常规检查的生理指标。心率监测系统在我们的日常生活中已经得到了非常广泛的应用。在医学上，通过测量人的心率，便可初步判断人的健康状况。本课题设计完成了一个基于51单片机的心率监测系统。系统以AT89C51单片机为核心，以红外发光二极管和光敏三极管为传感器，利用单片机系统内部定时器来计算时间，由光敏三极管感应心跳脉冲，单片机通过脉冲累加得到心脏跳动次数，在数码管上显示心跳次数和时间。系统实现了心率的实时监测与显示、定时测量以及报警提醒等功能。实验结果表明，系统工作正常，测量灵敏度高，实现了设计功能。

关键词：心率监测；AT89C51单片机；光电传感器

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Abstract

Heart rate generally refers to the number of heart beats per minute. It is one of the physiological indexes in clinical routine examination. The heart rate monitoring system has been widely used in our daily life. In medicine, it can preliminarily determine the health status by measuring heart rate. This paper proposes a new system based on a single-chip microcomputer and two sensors of an infrared light emitting diode and a photo transistor. The sensors detect heart beating and the single-chip microcomputer gets the frequency by accumulating the times of heart beating. The time is obtained by the inner timer of the single-chip microcomputer. This system can not only display the heart rate, the test time online, but also give alarming as a reminding when the heart rate is not normal. The test result shows that the system works well with high sensitivity and short delay. It has realized the functions of design.

Keywords: Hearting rate monitoring；AT89C51 single-chip microcomputer；Photoelectric sensor

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目 录

摘 要 ............................................................................................................................... I Abstract ........................................................................................................................... II 第1章 1.1 1.2 第2章 2.1 2.2 第3章 3.1 3.23.33.4 3.5 3.6 3.7 3.8 第4章 4.1 4.2 4.3 第5章 5.1 第6章 6.1 6.2 6.3 概述 ................................................................................................................. 1

选题的背景和意义 ......................................................................................... 1 心率监测系统的发展与应用 ......................................................................... 2 心率监测系统结构 ......................................................................................... 3

系统结构 ......................................................................................................... 3 工作原理 ......................................................................................................... 3 硬件系统设计 ................................................................................................. 5

控制器 ............................................................................................................. 5

3.1.1 AT89C51 简介 ............................................................................. 5 3.1.2 AT89C51 的特点 ......................................................................... 5 3.1.3 AT89C51 的结构 ......................................................................... 5

心率信号取样 ................................................................................................. 7

3.2.1 光电传感器的原理 ....................................................................... 7 3.2.2 光电传感器的结构 ....................................................................... 8 3.2.3 光电传感器检测原理 ................................................................... 8 3.2.4 信号取样电路 ............................................................................... 9

信号放大电路 ............................................................................................... 10

3.3.1 LM324放大器 ............................................................................ 10 3.3.2 低通放大电路 ............................................................................. 10

波形整形电路 ............................................................................................... 12 单片机控制电路 ........................................................................................... 14 LED显示电路 .............................................................................................. 14

3.6.1 LED的结构及工作原理 ............................................................ 15 3.6.2 LED数码管的显示方式 ............................................................ 16

报警电路 ....................................................................................................... 16 硬件系统原理 ............................................................................................... 17 软件系统设计 ............................................................................................... 18

主程序流程 ................................................................................................... 18 中断程序流程 ............................................................................................... 18 显示程序流程 ............................................................................................... 19 系统干扰分析及处理措施 ........................................................................... 20

干扰分析 ....................................................................................................... 20

5.1.1 环境光干扰及处理措施 ............................................................. 20 5.1.2 电磁干扰及处理措施 ................................................................. 20 5.1.3 测量过程中运动噪声干扰及处理措施 ..................................... 21

系统测试结果 ............................................................................................... 22

硬件调试 ....................................................................................................... 22 系统测试 ....................................................................................................... 24 误差分析 ....................................................................................................... 24

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