System Design Of Temperature And Humidity Based On The MCU

Modern agricultural production is inseparable from the environmental control. in the light of the causes of greenhouse intelligent control, Based on thorough analysis about our national and abroad greenhouse intelligent control, combining intelligent sensors test with mcu control.This thesis proposes a design scheme on mcu temperature and humidity testinf system .This system adopts hierarchical, modular design.It consists of data acquisition system, mcu control system, computer monitoring system, and centers around the mcu, with many temperature, humidity sensors as measurement components. It collects and stores intelligent sensor measurement data by connecting mcu with intelligent sensors. In mcu system, some functions of the expansion storage of procedures, real-time display of data, overrun auto alarm and auxiliary data storage are realized.As the center of the monitoring computer and the intelligent sensor, mcu transmits the gathered data to monitoring computer by the means of the communication between 232 bus and monitoring computer. The monitoring computer will record, store, process and alarm the data,so that the operators can browse and record it,then take relative measures.This design has mainly done the following several works. First, it establishes the general design of the system, including the design function of the system to be completed,the technical specifications to be reached, design principles of the system, and introduces the entire system components and work principleof the systems. Secondly, it designs the hardware circuit and software design of intelligent sensors, including the introduction of the static and dynamic characteristics of sensors. The software designing of temperature measurement phase, temperature measurement principle, temperature measurement circuit and temperature measurement system of digital temperature sensor DS1820 which adopts one-wire bus technology, humidity sensor circuit of sensor HS1101, in order to prevent the distortion of humidity data gathered by mock sensor, the linear interpolation algorithm is adopted. Thirdly, it designs hardware circuit of communication interface and software system, including the introduction of adopted AT89S51 SCM, storage expansion of AT24C04 of I~2C Bus, display output of 4 digital tubes, audio alarm of overrun data, auxiliary data storage of mock SPI Bus. The last, it elaborates the working principle, designing thoughts and realizing methods of computer software system.At first, through RS-232C protocol SCM and computer are connected, and data is received and sent by serial inferface with the help of ACTIVE X programmed by serial communication in windows environment. Computer can display,store, inquire and print the data and setting as a monitor.This system integrates modern signal gathering technology, signal transmitting technology, information processing technology, combines many parameters in greenhouse environment monitoring and control theory of SCM and by many bus technologies, proposes one kind of practical feasible greenhouse environmental monitoring system. which can automatically record, storge and handle data, completely,real-time, and automaticly, and input the relative information into the computer in an effective way according to reality.Besides, it can control the monitoring system long-distace.It meets the equirement of monitoring on crop growth state completely, real-time, long-term.It can monitor and control the greenhouse environment timely and realize automation and intelligentize of temperature and humidity testing in greenhouse.