琼州学院本科毕业论文 (设计)
ABSTRACT
In life, we often use to electric fan. For example, in the hot summer people use electric fan to cool; in industrial production, large-scale machinery use electric fan for cooling. But when the environmental temperature changes, artificial hard to timely control the speed of the fan, is also very difficult to effectively utilize valuable resources. With the development of technology of temperature control, temperature control technology has been fully meet the modern daily life and production requirements, emerge as the times require temperature-controlled electric fan has gradually entered people's life. Temperature control electric fan according to the ambient temperature automatic regulating electric fan start / stop and speed, in real life use, temperature-controlled electric fan not only can save valuable resources, also brings great convenience for people's life and production.
Temperature control fan in modern society production and people's daily life have a wide range of applications, Such as industrial production of large mechanical cooling system of fan, now notebook computer on a wide range of application of intelligent CPU fan. This paper introduces the design of MCU based temperature control fan system, using SCM as the controller, use of temperature sensor DS18B20 as a temperature acquisition component, and according to the collected temperature, through a Darlington reverse driving fan motor driver ULN2803. According to the detected temperature and a set temperature to achieve system comparison of fan motor for automatic start and stop, and according to temperature changes automatically change the fan motor speed, at the same time with the LED eight digital tube display the detected temperature and a set temperature. The preset temperature set by two independent buttons to achieve, The one increase the preset temperature, and the another one reduced the preset temperature.
Key words: single chip microcomputer; DS18B20; temperature control; fan
琼州学院本科毕业论文 (设计)
目 录
第一章 前 言 ................................................................................................................ 1 第二章 整体方案设计 .................................................................................................. 2
2.1 系统整体的设计 .............................................................................................. 2 2.2方案论证 ........................................................................................................... 2
2.2.1 温度传感器的选择 ................................................................................ 3 2.2.2 控制核心的选择 .................................................................................... 3 2.2.3 温度显示器件的选择 ............................................................................ 4 2.2.4 调速方式的选择 .................................................................................... 4
第三章 各单元模块的硬件设计 .................................................................................. 6
3.1 系统器件简介 .................................................................................................. 6
3.1.1 DS18B20单线数字温度传感器简介 .................................................... 6 3.1.2 达林顿反向驱动器ULN2803简介 ..................................................... 6 3.1.3 AT89C52单片机简介 ............................................................................ 7 3.1.4 LED数码管简介 .................................................................................... 9 3.2电路设计 ......................................................................................................... 10
3.2.1 开关复位与晶振电路 .......................................................................... 10 3.2.2 独立按键连接电路 .............................................................................. 11 3.2.3 数码管显示电路 .................................................................................. 12 3.2.4 温度采集电路 ...................................................................................... 13 3.2.5 风扇电机驱动与调速电路 .................................................................. 14 3.2.6 电路总图 .............................................................................................. 15
第四章 软件设计 ........................................................................................................ 17
4.1 程序设置 ........................................................................................................ 17
4.1.1 主要程序代码 ...................................................................................... 18 4.2 用Keil C51 编写程序 .................................................................................. 20 4.3 用Proteus进行仿真 ...................................................................................... 21
4.3.1 Proteus简介 .......................................................................................... 21 4.3.2 本设计基于Proteus的仿真 ................................................................ 22
琼州学院本科毕业论文 (设计)
第五章 系统调试 ........................................................................................................ 26
5.1 软件调试 ........................................................................................................ 26
5.1.1 按键显示部分的调试 .......................................................................... 26 5.1.2 传感器DS18B20温度采集部分调试 ................................................ 26 5.1.3 电动机调速电路部分调试 .................................................................. 27 5.2 硬件调试 ........................................................................................................ 27
5.2.1 按键显示部分的调试 .......................................................................... 27 5.2.2 传感器DS18B20温度采集部分调试 ................................................ 27 5.2.3 电动机调速电路部分调试 .................................................................. 28 5.3 系统功能 ........................................................................................................ 28
5.3.1 系统实现的功能 .................................................................................. 28 5.3.2 系统功能分析 ...................................................................................... 28
第六章 结束语 ............................................................................................................ 30 参考文献 ...................................................................................................................... 31 附 录 ............................................................................................................................ 32 致 谢 ............................................................................................................................ 34
琼州学院本科毕业论文 (设计)
第一章 前 言
在现代的生活和生产中，电风扇被广泛的使用，发挥着举足轻重的作用，如夏天人们使用的散热风扇、工业生产中大型机械中的散热风扇以及现在笔记本电脑上广泛使用的智能CPU风扇等。而随着温度控制技术的发展，为了降低风扇运转时的噪音以及节省能源等，温度控制风扇越来越受到重视并被广泛的应用。在先阶段，温控风扇的设计已经有了一定的成效，可以使风扇根据环境温度的变化进行自动无极调速，当环境温度升高到到一定时能自动启动风扇，并随着环境温度的升高自动加快风扇的转速，当环境温度降到一定时能自动停止风扇的转动，实现智能控制。
本文设计了由ATMEL公司的8052系列单片机AT89C52作为控制器，采用DALLAS公司的温度传感器DS18B20作为温度采集元件，并通过一个达林顿反向驱动器ULN2803驱动风扇电机的转动。同时使系统检测到的环境温度以及系统预设的温度动态显示在LED数码管上。根据系统检测到的环境温度与系统预设温度的比较，实现风扇电机的自动启动与停止以及转速的自动调节。
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第二章 整体方案设计
第二章 整体方案设计
2.1 系统整体的设计
本设计的整体思路是：利用温度传感器DS18B20检测环境温度并直接输出数字温度信号给单片机AT89C52进行处理，在LED数码管上显示当前环境温度值以及预设温度值。其中预设温度值只能为整数形式，检测到的当前环境温度可精确到小数点后一位。同时采用PWM脉宽调制方式来改变直流风扇电机的转速。并通过两个按键改变预设温度的大小，一个提高预设温度，另一个降低预设温度。系统结构框图如图2-1所示。
温度显示 DS18B20 独立按键 AT89C52 PWM驱动电路 直流电机 复位 晶振
图2-1 系统构成框图
2.2方案论证
本设计需要实现风扇直流电机的温度控制，使风扇电机能根据环境温度的变化自动启动和停止以及转速的自动调节，需要比较高的温度变化分辨率以及稳定可靠的换挡停机控制部件。
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