2. ABSTRACT
• It presents an SMS based notice board incorporating the widely used GSM to
facilitate the communication of displaying message on notice board via user’s mobile
phone.
• SIM300 GSM modem with a SIM card is interfaced to the ports of the microcontroller
with the help of AT commands.
• SIM300 is duly interfaced through a level shifter IC MAX32 to the microcontroller.
The messaged is thus fetched into the microcontroller.
• It is further displayed on an electronic notice board which equipped with LCD display
interfaced to microprocessor powered by a regulated power supply from mains
supply of 230 volts ac.
5. 8051 MICROCONTROLLER
• Microcontroller is a small computer on a single integrated circuit containing a
processor core, memory and programmable I/O peripherals.
• The 8051 microcontroller has Harvard architecture with RISC (Reduced
Instruction Set Computer) concept.
• The 89C51RB2/RC2/RD2 device contains a non-volatile 16kB/32kB/64kB Flash
program memory that is both parallel programmable and serial In-System and
In-Application Programmable.
• 8051 has 8-bit ALU which can perform all the 8-bit arithmetic and logical
operations in one machine cycle. The ALU is associated with two registers A &
B special function registers.
6. FEATURES
• 4 KB on chip program memory (ROM or
EPROM)).
• 128 bytes on chip data memory (RAM).
• 8-bit data bus
• 16-bit address bus
• 32 general purpose registers each of 8 bits
• Two -16 bit timers T0 and T1
• Five Interrupts (3 internal and 2 external).
• Four Parallel ports each of 8-bits (PORT0,
PORT1, PORT2, PORT3) with a total of 32
I/O lines.
• One 16-bit program counter and One 16-
bit DPTR ( data pointer)
• One 8-bit stack pointer
• One Microsecond instruction cycle with
12 MHz Crystal.
• One full duplex serial communication
port.
7. GSM MODEM
• GSM Modem can accept any GSM network operator SIM
card and act just like a mobile phone with its own unique
phone number. Advantage of using this modem will be
that you can use its RS232 port to communicate and
develop embedded applications.
• The modem can either be connected to PC serial port
directly or to any microcontroller. It can be used to send
and receive SMS or make/receive voice calls.
• It can also be used in GPRS mode to connect to internet
and do many applications for data logging and control.
• This GSM modem is a highly flexible plug and play quad
band GSM modem for direct and easy integration to RS232
applications.
8. LCD
• LCD-Liquid Crystal Display is an electronic device for displaying text or characters. We are using 16x2 LCD. It
represents 16 characters and 2 line display.
• LCD’s are economical and easily programmable and can easily display special and custom characters.
• In recent years the LCD is finding widespread use replacing LED’s. This is due to the following reasons
1. Declining prices
2. Ability to display numbers, characters and graphics.
3. Incorporation of a refreshing controller into the LCD.
4. Ease of programming.
The standard is referred to as HD44780U, which refers to the controller chip which receives data from an
external source (in this case, the 8051) and communicates directly with the LCD.
9. MAX 232
• converts signals from an RS-232 serial port to
signals suitable for use in TTL compatible digital
logic circuits.
• The MAX232 is a dual driver/receiver and
typically converts the RX, TX, CTS and RTS
signals.
• The MAX232(A) has two receivers, and two
drivers .
DB9 Connector
• The DB9 connector is an analog 9-pin plug of the
D-Sub miniature connector family (D-Sub or Sub-
D).
• The DB9 connector is mainly used for serial
connections, allowing for the asynchronous
transmission of data as provided for standard
RS-232 (RS-232C).
12. APPLICATIONS
• The big shops and the shopping centers use digital displays now.
• Also, in trains and buses the information like platform number,
ticket information is displayed in digital boards.
• In any institution or organization or public utility places like bus
stops, railway stations or parks
13. CONCLUSION
• The display boards are one of the major communications medium for mass
media.
• Local language can be added as a variation in this project. This can be
achieved by using graphics and other decoding techniques. Also we realize
that this project saves time, energy and hence environment. Cost of printing
and photocopying is also reduced as information can be given to a large
number of people from our fingertips.
• Thus we can conclude that this project is just a start, an idea to make use of
GSM in communications to a next level.