Design And Implementation Of Intelligent Fume Hood Control System

In recent years,chemical laboratory safety accidents occur frequently,experimental safety issues have aroused widespread concern of the whole society.Fume hoods are indispensable laboratory equipment in chemical laboratory and closely related to experimental safety.Its role is to exhaust the unpleasant,toxic or corrosive harmful gases produced in experiments from the room.At present,the fume hoods commonly used exhaust gases with the fixed air volume,which is of less safety and inconvenient to use with a single function.In order to improve the safety of fume hoods and make it convenient for experimental personnel to use,this paper designs the intelligent fume hood control system.The system consists of fume hood control terminal and remote monitoring platform.Fume hood control terminal includes embedded computer(raspberry pie),measurement subsystem,control subsystem and human-computer interaction subsystem.The measuring subsystem is composed of a human body sensing sensor,a distance measuring sensor and a speed measuring module,intending to complete the measurement of the working parameters.The control subsystem is composed of a window motor,an exhaust fan,an alarm module and an LED light bar.The interactive subsystem consists of LCD touch screen and camera,which is used to achieve human-computer interaction.Raspberry is used to coordinate the work of subsystems,and exchange data with the remote monitoring platform through the network.The remote monitoring platform is developed by HBuilder development tools and PHP language,and use MySQL database to save data.The system has the window automatic lift,cover wind speed control,system parameter display,alarm,continuous exhaust,picture collection,remote monitoring and other functions.Among them,the cover wind speed control and remote monitoring function are the core function of the system and the embodiment of intelligent control of fume hood.According to the open height of the window,the system real-time adjusts the exhaust air volume of fume hood,and then maintains the stability of the wind speed.The system uses the thyristor to control the exhaust fan speed and then adjust the exhaust volume,and applies PID algorithm to accelerate the adjustment process and improve system stability.Remote monitoring function is an important innovation of the system.After logging on to the remote monitoring platform through browser,the experimenter can remotely monitor and control fume hood.After system development is complete,system test is carried out.Test results show that the system functions is normal and the system is running stable.The system has the advantages of simple operation,be convenient to use,saving energy,strong expansibility and good stability.It effectively changes the status of the existing fume hood which has a single function and poor security.