14-05-2011, 10:57 AM
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SMS Based Wireless Electronic Notice Board using GSM/CDMA/3G Mobile Phone
ABSTRACT
Notice Board is primary thing in any institution / organization or public utility places like bus stations, railway stations and parks. But sticking various notices day-to-day is a difficult process. A separate person is required to take care of this notices display. This project deals about an advanced hi-tech wireless notice board.
The project is built around the ATMEGA8L micro controller from Atmel. This micro controller provides all the functionality of the display and wireless control. It also takes care of creating different display effects for given text. Display is obtained on LED Matrix Display Array on a printed circuit board. A GSM/CDMA Mobile Can is used to enter the required text or notice. The scrolling speed of the text also can be changed according to user requirement.
After entering the text the SMS is sent to the no which is connected to the LED display. At any time the user can add or remove or alter the text according to his requirement. At the receiving end the GSM modem which is connected to the Max 232 receives the message and is connected to the microcontroller ATMEGA8L. The message which is already stored in the EEPROM is displayed on the LED Matrix Display Array.
This project uses regulated 5V, 500mA power supply. 7805 three terminal voltage regulator is used for voltage regulation. Bridge type full wave rectifier is used to rectify the ac output of secondary of 230/12V step down transformer.
CHAPTER 1
INTRODUCTION
Notice Board is primary thing in any institution / organization or public utility places like bus stations, railway stations and parks. But sticking various notices day-to-day is a difficult process. A separate person is required to take care of this notices display. This project deals about an advanced hi-tech wireless notice board.
An embedded system is a combination of software and hardware to perform a dedicated task. Some of the main devices used in embedded products are Microprocessors and Microcontrollers, Microprocessors are commonly referred to as general purpose processors as they simply accept the inputs, process it and give the output. In contrast, a microcontroller not only accepts the data as inputs but also manipulates it, interfaces the data with various devices, controls the data and thus finally gives the result. As everyone in this competitive world prefers to make the things easy and simple to handle, this project sets an example to some extent.
This project is built around the ATMEGA8L micro controller from Atmel. Micro controller provides all the functionality of the display and wireless control. It also takes care of creating different display effects for given text. Display is obtained on LED Matrix Display Array on a printed circuit board. A GSM/CDMA Mobile Can is used to enter the required text or notice. The scrolling speed of the text also can be changed according to user requirement.
After entering the text the SMS is sent to the no which is connected to the LED display. At any time the user can add or remove or alter the text according to his requirement. At the receiving end the GSM modem which is connected to the Max 232 receives the message and is connected to the microcontroller ATMEGA8L. The message which is already stored in the EEPROM is displayed on the LED Matrix Display Array.
CHAPTER 2
WORKING FLOW OF THE PROJECT
2.1 BLOCK DIAGRAM
FIG: 2.1 BLOCK DIAGRAM
2.2EEPROM (ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY)
EEPROM one can select which byte to be erased, in contrast to flash, in which the entire contents of ROM are erased. The main advantage of EEPROM is that one can program and erase its contents while it is in system board. It does not require physical removal of the memory chip from its socket.
The EEPROM used in this project is 24C04 type. The ATmega8L implements 2K bytes of on-chip EEPROM for data storage and 256 bytes of RAM. The upper 128 bytes of RAM occupy a parallel space to the Special Function Registers i.e., the upper 128 bytes have the same addresses as the SFR space but are physically separate from SFR space.
FEATURES OF 24C04 EEPROM:
• 1 million erase/write cycles with 40 years data retention.
• Single supply voltage: 3v to 5.5v for st24x04 versions.
• Programmable write protection.
• Two wire serial interface, fully i2c bus compatible.
• Byte and multi byte write (up to 4 bytes).
• Page write (up to 8 bytes).
• Byte, random and sequential read modes
• Self timed programming cycle
• Automatic address incrementing
• Enhanced ESD/Latch up performances
