毕业设计—温湿度显示仪表设计.docVIP

（ 摘 要 温度、湿度监测在人们现实生活生产中应用已日渐广泛，在发电厂、纺织、食品、医药、仓库、农业大棚等众多的应用场所，对温度、湿度参量的要求都非常严格，因此能否有效对这些领域的温、湿度数据进行实时监测是一个必须解决的重要前提。 本设计采用单片机作为控制核心，对温度进行采集。通过将值转换为电量输出由ADC0809实现模拟信号的数字化同时，外接可编程接口芯片实现温度值的切换显示；可以利用小键盘设定温度的最大值和最小值，超过最大值或低于最小值报警。Abstract Temperature and humidity is monitoring in the practical application of life and production, it has become increasingly widespread in the plant, textile, food, medicine, warehouses, agricultural sheds and many other places the application of temperature, humidity parameter requirements are very strict, it is effective in those areas of the temperature and humidity data for real-time monitoring is a need to address an important prerequisite. The designs choose Atmel AT89C51 as the core control of temperature and humidity for acquisition. Through capacitive humidity of Acquisition and humidity conditioning circuit humidity value will be converted into Output voltage ，this Voltage signals are converted to digital signal with ADC0809 ， Temperature Acquisition choose Selection of a single temperature sensor DS1820, it use to digital temperature of acquisition and digital signal directly into the MCU. Meanwhile, Add-8155 programmable interface chip linking small keyboard and LED display circuit use to temperature and humidity value of the switching display,The design also provides alarm system, we can use a small keyboard settings, temperature and humidity of maximum and minimum. When the temperature and humidity in excess of the maximum or below the minimum will be issued at the buzzer alarm. The design also provide an expanded RAM can be expanded to use up system. Keywords : DS1820; AT89C51; A/D conversion; RAM；Humidity capacitance ；ADC0809 目录 摘要 I abstract II 目录 III 图表清单 V 第一章 绪论 1 1.1 问题的提出 1 1.2 温湿度数据采集与监测技术的发展历程 1 1.3 温湿度测量的分析 2 1.4本课题的主要内容 3 第二章 硬件电路设计 4 2.1硬件电路设计原则 4 2.2 硬件设计思路 4 2.3总体设计框图 5 2.4 单元电路设计 5 2.4.1 AT89C51单片机 5 2.4.2湿度采集及调理电路 10 2.4.3单线数字温度传感器DS1820 13 2.4.4 模数转换电路 18 2.4.5 键盘及数码管显示电路 21 2.4.6 I/O口扩展电路 22 2.4.7 外