An interesting project that can be done using Microcontroller is a LED message scroll er. It teaches you a quite lot of things. So I decided to make one. I made the hardware design modular and cascadeble That means the whole display is made up of several 15×7 modules. Each module has everything to drive 15×7 led matrix which includes a ULN2003 row driver IC and two shift register IC to drive the 15 columns. Data is loaded serially into the 15 columns. and multiplexing is done along the row.
The 15×7 Smart LED Board.
The Controller Board.
Any cheap AVR MCU like a ATmega8 can be used to control this board (also up to 4 such boards which give a total of 60px by 7px display). We are using our low cost development board as the controller to the LED matrix board. This board can be purchased at a price as low as Rs. 249 including the MCU ! So wiring this project is a matter of ten minutes !
Connecting The Display Module with Devboard.
PIN No | PIN Name | Devboard PIN |
1 | GND | GND |
2 | N/C | |
3 | +5V IN | +5V out |
4 | N/C | |
5 | Serial Data In | PB0 |
6 | ST_CP | PB2 |
7 | SH_CP | PB1 |
8 | ROW A | PD0 |
9 | ROW B | PD1 |
10 | ROW C | PD2 |
11 | ROW D | PD4 |
12 | ROW E | PD5 |
13 | ROW F | PD6 |
14 | ROW G | PD7 |
Program
The program is written in C language and compiled using the free GNU C compiler for AVR Platform. The Project manager is AVR Studio 4. More information on how to install and use these software tool please see the following article.
For more detail: AVR ATmega8 Project LED Moving Message Display using ATmega8 microcontroller
