毕业设计（论文）--基于89c51单片机的粮仓温湿度检测系统(有程序).doc

毕业设计（论文） 基于单片机的温湿度测系统设计方案基于单片机的温湿度测系统设计方案主要由温度、湿度采集、AD转换、控制、显示部分组成采用单片机为控制中心该芯片具有4KB的快擦写可编程/擦除只读存储器EEPROM、256 KB片内RAM、3个16位定时计数器、个中断源，无需进行系统扩展既可满足任务要求，能较大幅度提高系统的性价比。温湿度传感器dht11传感器，性价比高该系统除了能显示温湿度以外，还能设置温湿度报警阈值。关键词：Barn temperature monitoring system Abstract The graduation project is based on the single chip design temperature and humidity monitoring system, mainly by temperature, humidity acquisition, AD conversion, microprocessor control, digital display, usb connector composed of six parts. The design of the control center using 89c51 microcontroller, the chip has 4KB of flash programmable / erasable read only memory EEPROM, 256 KB on-chip RAM, 3 16-bit timer counters, six interrupt sources, both without the need for system expansion to meet mission requirements, can greatly improve the systems cost. The temperature and humidity sensor I use is dht11, he cost effective. DHT11 digital temperature and humidity sensor is a calibrated digital signal output with the temperature and humidity combined sensor. Its application-specific digital modules acquisition and temperature and humidity sensor technology, to ensure that products with high reliability and excellent long-term stability. Sensor includes a resistive element and a sense of wet NTC temperature components, and with a high-performance 8-bit microcontroller connected. So the product has excellent quality, fast response, anti-interference ability, high cost performance advantages. In addition the system in addition to showing the outside temperature and humidity, but also set the temperature and humidity alarm threshold. Keywords：Temperature and humidity;89c51 microcontroller;dht11 Sensor1 绪论 1.1 选题背景 近几年据海关统计结果显示，我国粮食进出口同比均呈下降趋势，我国粮食供求开始进入紧平衡阶段。在粮食供给能力逐渐弱化的情况下，我们必须注意到贮存粮食的科学性和有效性。贮粮仓库的现代管理也是当前粮食系统改造的重大项目之一。而在粮仓管理过程当中，最重要的是控制仓内的温度和湿度，温湿度会直接影响粮食的贮存量。2℃ 湿度检测范围： 20%-90%RH 检测精度：5%RH 显示方式： 温度：四位显示 湿度：四位显示 报警方式： 三极管驱动的蜂鸣音报警2 设计方案 温湿度监测系统要满足以下条件：能完成数据采集和处理、显示、串行通信、输出控制信号等多种功能。由数据采集、数据调理、单片机、等4个大的部分组成。该测控系统具有实时采集（检