Led Matrix

Working of  Scrolling text Message Display  Led Matrix


When power supply is turned on, a  message “FIRMCODE” is displayed on the Led Matrix. after that all text displayed is shifted from right to left , F disappear from left and S appears from right. Shifting of data  continues  till complete “FIRMCODES DEVELOPER” is displayed on LCD. After that above process is repeated again and again.

Components used

  1. LPC2148 IC
  2. 74LS138
  3. 74HC595
  4. Led Matrix
  5. Power Supply

Working of 74LS138 (3 Line to 8 Line Decoder )

74LS138 IC is 3 line to 8 line Decoder means input are three bit and output  is 8 bit. Input can be provided through A,B,C and output taken from Y0 to Y7 .Figure below explain, how  input and output are related to each other.


Working of 74HC595(Shift Register)

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The use of shift register 74HC595 minimizes the number of I/O pins required to drive the columns of the LED matrix. For driving 16 columns separately, we need 16 I/O pins of microcontroller, however, with the use of 74HC595 ICs, this number is reduced to 3. This device contains an 8-bit serial-in, parallel-out shift register that feeds an 8-bit D-type storage register. The storage register has 8 number of 3-STATE outputs. Separate clocks are provided for both the shift register and the storage register. The shift register has a direct-overriding clear, serial input, and serial output (standard) pins for cascading. Both the shift register and storage register use positive-edge triggered clocks. If both clocks are connected together, the shift register state will always be one clock pulse ahead of the storage register. The 74HC logic family is speed, function, and pin-out compatible with the standard 74LS logic family. All inputs are protected from damage due to static discharge by internal diode lamps to Vcc and ground.

Why we require 74LS138 & 74HC595 IC ?

When the project is made without these ICs then 64 pin is required  to control 7 Led Matrix and as the Led Matrix increases pin requirement is also increase. So to reduce the pin requirement these ICs are used. After using these ICs  only 6 pin is required to operate 7 Led Matrix  and if Led Matrix increases no extra pin is required, only some program change is required .


This project can be used for Advertising or for providing information at various places like schools, colleges, government offices, shops, hospitals, railway stations.

1. Circuit Diagram of Scrolling text Message Display Led Matrix using LPC2148

circuit diagram of Scrolling text Message Display Led Matrix using LPC2148

1. Program of Scrolling text Message Display Led Matrix using LPC2148



PROTEUS File for SIMULATION(Password Of RAR file is :-firmcodes.com)

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Coming soon… 


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