class diagram for electronnic notice board

[Guest]

the class diagram for electronic notice board.

[anusree]

Notice board is primary thing in any institution or organization or public utility places like bus stops, railway
stations or parks. But sending various notices day to day is a tedious process. This project deals with advanced notice
board. It presents an SMS based notice board incorporating the widely used GSM to facilitate the communication of
displaying message on noticeboard via user‟s mobile phone. Its operation is based on microcontroller AT89c52
programmed in assembly language. A SIM300 GSM modem with a SIM card is interfaced to the ports of the
microcontroller with the help of AT commands. When the user sends a SMS via a registered number from his mobile
phone, it is received by SIM300 GSM modem at the receiver‟s end. SIM300 is duly interfaced 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. This
project is our experiment on real time noticing.
Keywords: SMS Notice Board, GSM MODEM SIM 300A, LCD 16x4, Microcontroller At89c52, Mobile Phone.
I. INTRODUCTION
In the last couple of decades, communication technology
has developed by leaps and bounds. The use of
“Embedded System in Communication” has given rise to
many interesting applications. Everything around us is
becoming smart such as smart phones, smart refrigerators,
so why not smart notice boards.At present, when
information has to be updated in a notice board, it has to
be done manually. To change message on display, itneeds
to change microcontroller program code again. By adding
GSM wireless communicationinterface to this system, we
can make smart noticeboard to overcome these limitations.
So we have interfaced GSM Modem with microcontroller
andimplemented a SMS transmission and reception
technique. The message on display is easily changed
bysending SMS to it. Wireless notice board is a means of
wireless data transfer for quick display of messages in real
time. Being GSM- based system, it offers flexibility to
display flash news or announcements faster than the
programmable system. GSM-based display system can be
used at other public places like schools, hospitals, railway
stations, colleges, banks etc. This system is easy, robust, to
use in normal life by anyone at anyplace with less errors
and maintenance.
II. BLOCK DIAGRAM
Fig 1. Block Diagram of GSM Notice Board System
Let us discuss the components used in the GSM Notice
Board System one by one:
1) GSM MODEM SIM 300A: Designed for global
market, SIM300 is a Tri-band GSM/GPRS engine that
works on frequencies EGSM 900 MHz, DCS 1800
MHz and PCS1900 MHz SIM300 provides GPRS
multi-slot class 10 capabilities and support the GPRS
coding schemes CS-1, CS-2, CS-3 and CS-4. SIM300
provide RF antenna interface. The SIM300 is
integrated with the TCP/IP protocol，Extended
TCP/IP AT commands are developed for customers to
use the TCP/IP protocol easily, which is very useful
for those data transfer applications.
Fig 2. Picture of GSM MODEM SIM 300A
2) MICROCONTROLLERAT89c52: The AT89C52 is a
low-power, high-performance CMOS 8-bit
microcomputer with 8Kbytes of Flash programmable
and erasable read only memory (PEROM). The device
is manufactured using Atmel‟s high-density nonvolatile
memory technology and is compatible with
the industry-standard 80C51 and 80C52 instruction
set and pin out. The on-chip Flash allows the program
memory to be reprogrammed in-system or by a
conventional non-volatile memory programmer. By
combining a versatile 8-bit CPU with Flash on a
ISSN (Online) 2278-1021
ISSN (Print) 2319-5940
International Journal of Advanced Research in Computer and Communication Engineering
Vol. 4, Issue 4, April 2015
Copyright to IJARCCE DOI 10.17148/IJARCCE.2015.4423 106
monolithic chip, the Atmel AT89C52 is a powerful
microcomputer which provides a highly-flexible and
cost-effective solution to many embedded control
applications.
Fig 3. Picture of AT89c52 µc
3) LCD DISPLAY:A liquid crystal display (LCD) is a
thin, flat display device made up of any number of
colour or monochrome pixels arrayed in front of a
light source or reflector. Each pixel consists of a
column of liquid crystal molecules suspended
between two transparent electrodes, and two
polarizing filters, the axes of polarity of which are
perpendicular to each other. Without the liquid
crystals between them, light passing through one
would be blocked by the other. The liquid crystal
twists the polarization of light entering one filter to
allow it to pass through the other.
Fig 4. Picture of LCD 16x4
4) POWER SUPPLY/ADOPTER: Power supply is the
source of electrical power. Normally any electronic
circuit uses +5v DC power for its regular working
.User can directly built +5v Dc power supply using 4
diodes, filter capacitors and regulator IC-
7805(Integrated Circuit)or can directly purchase a +5v
DC power adopter from the local market.
VI. PRE-REQUISITE
1) HyperTerminal AT+CMGD=1, AT+CMGD=2,
AT+CMGD=3.
2) Check the range accessibility of GSM modem. LED
should blink every 3 second.
3) Sender should send the message with a „*‟ at the
beginning.
4) Message should have a minimum character limit of
20.
IV. WORKING
A. Transmitting Section
Transmitting section consists of just mobile which has
inbuilt GSM modem for wireless data transfer through
GSM.
B. Receiving Section
Receiving section consists of GSM modem and
microcontroller which fetches the message and helps in
displaying on LCD.
C. Flow Chart
V. WORKING MODEL