introduction
LED billboards are public-facing information display terminals with a wide range of civilian and commercial values. Now most of the information displayed on LED billboards is pre-cured in the system, which loses the real-time nature of the information, especially for the user to replace the display content; a few LED billboards are directly connected to the microcomputer, and the information is transmitted by the microcomputer. This kind of system solves the problem of information refreshing, but because of the wired connection, it restricts the randomness of the system placement, especially for the advertising company for multi-region and multi-client, which brings a lot of inconvenience to the real-time update and maintenance of the system. This paper proposes a new scheme for remote control of LED billboards by hand-held transmitters, which realizes flexible changes to the contents and display modes of billboards, and is very convenient to use. The program uses a PC as the host computer, and both the transmitter and the receiver are based on the single-chip microcomputer, which has a high performance-price ratio.
1, system solution
1.1 Wireless remote control
Wireless remote control refers to the realization of non-contact remote control of the controlled target, and is widely used in industrial control, aerospace and home appliances. Wireless remote control and wireless transmission systems increase freedom of movement compared to wired and infrared devices. As a result, wireless remote control devices and wireless transmission systems are increasingly used in the industrial field. The advantage of the relative cable connection is that the installation cost is low (no wiring, no underground engineering, no cable trough), which increases flexibility and reduces maintenance costs.
In order to achieve the purpose of remote control, the information and control commands that need to be displayed must be transmitted to the display terminal LED screen by wireless transmission. Commonly used wireless transmission methods are: sound waves (ultrasonic waves), light waves (infrared rays) and electric waves. Considering that the wave transmission has the following advantages:
1) The transmission distance is much farther than the other two;
2) The available components are rich in variety, performance is also good, and the price is cheap;
3) The technology is more mature.
Therefore, the system uses radio wave transmission. That is, information is transmitted between the handheld transmitter and the receiver by radio waves.
The performance of the high-frequency wireless transmitting and receiving module directly affects the remote control distance and communication quality. After multiple investigations and demonstrations, the system adopts an integrated transmitting and receiving module. Its main advantage is good frequency consistency and freedom from debugging.
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