| As a kind of information display terminal, LED information screen is widely used on the head of the portal of the small stores, banks, small or medium-sized enterprises and so on. It is also used in buses, taxis and other movable devices. Currently, the information screen display system generally can be divided into three parts:the control terminal, the transmission medium and the display terminal. Most of the control terminal is the PC or embedded device which is high cost, and when the PC is used as the control terminal, its large volume and poor portability makes the information of the information screen system be modified impossibly in real time. The way of the transmission usually is wired or wireless, the transmission by the RS232/RS485cable increases the messy of wiring and the inconvenient of installation, the U disk as the transmission medium makes the impossible to modify the information in real time, and wireless transmission mode realized by the GSM short message or the GPRS network adds the cost of installation and use of the information screen system. Many reasons lead to the restricted of the information screen system’s popularization.Aiming at the shortcomings of the current information screen system, a method was put forward in this paper, the method is based on an integrated device which is a combination of information editing, processing and transmission, and combined with the display terminal with the function of the information receiving and display, to realize the on-line modification of the screen’s information. The method can improve the portability of the control terminal, modify the information timely, reduce the cost of the information screen, and solve the problem of the use of existing information system.Then based on the method of the screen’s information real-time modification, a screen’s information online modification system was designed and made, which consisted of the control terminal and the display terminal. The control terminal used the type of the portable and handheld structure. In the terms of hardware of the control terminal, the circuit using a SCM as the core connect flash chip was designed and made, which connected to the small LCD screen and keyboard, and connected with a wireless module, in the aspect of software of the control terminal, four programs included the Chinese character library storage, information editing module, information processing module and information sending module were designed and wrote, the function of the information editing and sending was implemented. On the display terminal’s hardware side, the circuit based on SCM was designed and made, which connected with the wireless module and information screen, in the software part, two programs included the information receiving module and information display module were designed and wrote, the function of the information receiving and display was achieved. One-to-many wireless mode was used to realize the information’s transmission between the control terminal and the display terminal, the goal of one control terminal can modify multiple display terminal’s information was achieved.Finally, the information online modification system designed and made above was assembled, and a control terminal in about size of22cm*10cm*4cm and two display terminals were got. Some tests were made on the system, and the result shows that the system can use the portable control terminal realize the function of information editing and sending. Two display terminals both can correctly judge, correctly received, and correctly display the corresponding information from the control terminal respectively. The control terminal can respectively modify the corresponding information of two display terminals in real time. From the test result, the feasibility of the method of the screen’s information online modification can be verified. Compared to the existing information system, the cost, the portability, the real-time modifying of the system got above has been improved obviously. |
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