Description in detail: It mainly consist of following blocks
1. 5 x 7 Matrix LEDs: We have to display characters in the messages, for this purpose we are going to use 5 X 7 matrix of LEDs. A single matrix consists of 5 columns and 7 rows. We have used 5mm Red LEDs. The actual physical diamension of single matrix is 10 cm by 8 cm.
2. Control Unit: This unit is used to select the matrices sequentially, control unit gets input from Microcontroller and then gives output to individual matrix. Only one matrix is selcted at a time so as to display a character.
3. Microcontroller: This is the CPU (central processing unit) of our project. We are going to use a microcontroller which belongs to the 8051 family. The various functions of microcontroller are like
I. Reading input from Keypad and store it into EEPROM II. Sending data to Data bus so that it displays characters on the Matrix. III. Storing the data into EEPROM memory and display it later using Matrix. IV. Sending the data to the computer using serial port
4. EEPROM: We are going to use EEPROM memory, it is Electrically erasable programmable read only memory. It stores the data even if power supply is disconnected. This is used to the characters which has to be displayed on the Matrix display.
5. PC Interfacing: We are going to use max 232 IC for pc interfacing, the values of message to be diplayed on Matrix LEDs will be sent to PC.
6. Keypad: Various operations of keypad are as following,
I. Start / Stop display.
II. Select message to be displayed.
III. Send/Receive data to Computer

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