A Design Of Network Mutimedia Integrated Control System

To conveniently control the multimedia devices such as projector, computer, video presenter, DVD, sound box and screen in the multimedia room, the Multimedia Integrated Control System (MICS) emerges. The MICS can control the power supply and the operation of the multimedia devices in the integrated mode through the control panel or computer software.In the beginning, this article introduces the background and the current status of the MICS, the MICS' s structure, and the main work of this article, i. e. the control machine and control panel which is designed and developed by the author independently. Following that, this article detailedly introduces the audio/video switch circuit, VGA switch circuit, device power managing circuit and the program of the main control circuit, and presents the design of the circuit and program of the control panel, of the self-learning infrared remote control part, of the TCP/IP-RS232 part respectively.The control panel implements the keyboard control of the MICS . There are three parts in the control panel: keyboard circuit, indicator light circuit and communication circuit.The power circuit, audio/video switching circuit, VGA switching circuit, digital volume tune circuit, devices' power control circuit and communication circuit are included in the main control circuit. The operations of these circuits are all controlled using CPU. This simple main control circuit can switch the audio/video synchronously, tune the volume and control the power of devices.The function of the self-learning infrared remote control part is that it decodes the infrared remote control signal and stores the signal in the memory, and emits it to control the devices when needed. The self-learning method is that the software records the self-learninginfrared signal directly regardless its coding mode and gets back it when emitting. The emitting method is employed to create carrier wave and this method makes the circuit simply.The TCP/IP-RS232 part converts the commands in the TCP/IP format to RS232 format, and makes the whole system can be controlled based on the TCP/IP network. The SCM AT89C55 and Ethernet controller RTL8019AS are employed in this part. Based on the detailed analysis of TCP/IP protocol, the simplified TCP/IP protocol is transplanted into the AT89C55, and the detailed data structure and flow charts are presented in this article.