Design and making technique of full-color LED electronic display for Metro train

The LED display on the subway is divided into two kinds: one is placed on the outside of the compartment, it is used to display the train running range, the direction of operation and the current station name, the Chinese and English compatible display, also can display other service information according to the operation needs; text display optional static, scrolling, panning, waterfall, animation and many other effects, The maximum number of displayed characters is 16x16 bitmap character 12. Another is the end of the led electronic display , placed in the car, terminal full-color LED display can be in accordance with the train operation requirements of the terminal, and real-time display of the current terminal, while also showing the current car temperature, the maximum display characters of 16x16 lattice character 8.

Full Color LED DisplayThe system consists of a single-chip microcomputer control unit and a display unit two parts, a single display unit can display 16x16 4 characters, if the production of a certain size of graphics and text LED Electronic screenSystem, as long as the use of a number of intelligent display units, the use of "building blocks" method can be achieved, the system of the display units using serial communication between the contacts. In addition to controlling the display unit and transmitting the command and signal of the host computer, the control unit is also embedded with a single-bus digital temperature sensor 18b20. Thanks to the modular design of the control circuitry, the 18B20 can be upgraded to Dallas's DS2438 and Honeywell's HIH23610 modular circuitry if humidity measurements are required. 　　In order to meet the communication needs of the vehicle, the host computer and the control unit in the vehicle are communicated by can bus. Display unit by the LED display panel and display circuit two parts, LED display panel is composed of 4 lattice module 16x64 Lattice General Intelligent display Unit, a single display unit full screen can display 4 16x16 lattice Chinese characters or symbols, the system of the display units using serial communication between the contact, So that the whole system work is coordinated and unified. The display circuit consists of two 16-pin line ports, two 74h245 tri-State bus drivers, a 74hc04d six inverter, two 74h138 eight decoders, and 8 74hc595 shift latches. The core of the control circuit is winbond high-speed microcontroller 77E58, the crystal oscillator frequency is mhz.a t29c020a for the ROM, for the storage of 16x16 lattice Chinese character library and 16x8 dot-matrix ASCII code table. A t24c020 is a ep2rom based on the I2 C serial bus, which stores pre-set statements, such as subway site names, Greetings, and so on. The internal temperature of the vehicle is measured 18b20 by a single-bus digital temperature sensor. The SJA1000 and TJA1040 are can bus controllers and transceivers, respectively.

Design and making technique of full-color LED electronic display for Metro train