Design Of Internet Of Things Based On VLC-PLC And Its Application In Access Control

With the rapid development and large-scale application of the Internet of Things,the traditional single communication technology can no longer meet the needs of the Internet of Things.A combination of two or more technologies is targeted for use as a communication technology for intelligent terminals in the Internet of Things Become inevitable.This project will use both Visible Light Communication(VLC)and Power Line Communication(PLC)as the communication technology of the Internet of Things,as an extension and supplement of the existing Internet of Things communication technology.This topic combines VLCPLC and access control technology to design an access control system based on VLC-PLC.The main work of the paper is as follows:(1)The application scenarios of Bluetooth,Zig Bee,Wi Fi,NB-Io T,VLC,PLC and other communication technologies commonly used in the Internet of Things are analyzed,as well as their respective advantages and disadvantages.In order to solve the problems of electromagnetic interference,short communication distance,and information security of wireless radio frequency communication,a combination of Visible Light Communication and Power Line Communication is proposed as one of the communication technologies of the Internet of Things.The channel access mechanisms commonly used in power line channels such as CSMA,CSMA / CD,CSMA / CA,and TDMA are comparatively analyzed,and a channel access mechanism suitable for the small-scale Internet of Things is designed.(2)Complete the design of the hardware circuit of the access control system.Including the design of power supply circuit,LED drive circuit based on embedded optical key,design of light signal receiving,processing circuit,power line module in optical door lock,design of smoke detection circuit in fire alarm,etc.(3)Based on the hardware circuit,by designing the corresponding software,the functions of each module of the access control system are realized.Based on the embedded optical key,the user’s legitimacy is verified through fingerprint identification,the key information is encrypted with 128 bit-AES,and the LED is driven to send the optical key.The optical door lock completes the demodulation and decryption of the optical key,and controls the stepper motor to unlock.The smoke alarm monitors the smoke concentration in real time.When it detects that the smoke concentration exceeds the standard,it sends an unlocking instruction to the light door lock through the power line module.(4)Design a light key APP based on an Android phone,and use the flash of the Android phone to send the optical key.