This document describes a GSM-based wireless notice board project. The system allows users to send SMS messages from mobile phones that will be displayed on an electronic notice board. It uses a SIM900 GSM modem connected to an ARM7 microcontroller via a MAX232 level shifter. The microcontroller receives messages via AT commands and displays them on an LED screen. The notice board has advantages like remote updating and access control. Potential applications include use in schools, traffic management, and public information displays.

1. SRI VENKATESWARA ENGINEERING COLLEGE
(Sponsored by exhibition society AfflIiated by JNTU Hyderabad)
Under the guidance of B.Swetha M.tech
Presented by:
K. Navya - 449
S. Harikrishna - 421
P. Ganesh - 418
N .Rajiv - 458
GSM Based Wireless Notice Board
Main project report on

2. CONTENTS
 Aim of the project
 Introduction
 Block Diagram
 GSM Modem
 AT commands
 Max 232
 LED Display
 Features of LPC 2148
 Flow Chart
 Advantages
 Disadvantages
 Conclusion
 Future scope

3. AIM OF THE PROJECT
Notice Board is primary thing in any
institution or organization or public utility places
like bus stations, railway stations and parks. But
sticking various notices day-to-day is a difficult
process.

4. INTRODUCTION
 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.
 SIM900 GSM modem with a SIM card is interfaced to the ports of the
microcontroller with the help of AT commands.
 SIM900 is duly interfaced through a level shifter IC MAX232 to the
microcontroller. The messaged is thus fetched into the microcontroller.
 It is further displayed on an electronic notice board which equipped with LED
display interfaced to microprocessor powered by a regulated power supply
from mains supply of 230 volts ac.

5. BLOCK DIAGRAM
lpc2148

6. GSM Modem
 GSM modem is the Data Communicating Equipment which is connected to terminal equipment
for data transmission and reception.
 GSM stands for Global System for Mobile Communication
 SIM stands for Subscriber identity Module
 GSM modem is controlled using AT commands
 AT stands for Attention
 Ex- AT, AT+CMGR, AT+CMGS, AT+CMGD etc.

7. SCHEMATIC DIAGRAM

8. AT Commands & Corresponding Operation
AT Commands Description
AT To check if Modem is
connected properly
ATE0 To turn echo off
ATE1 To turn echo on
AT+CMGF Set operating Mode

9. AT Commands & Corresponding Operation
AT Commands Description
AT+CMGD= <index>,
<delflag>
To delete a message
AT+CMGR= <index> To read message from an index
AT+CMGS= “contact no.” ,
TP-type address
To send message to specified
contact no.

10. MAX 232

11. MAX 232 IC
 MAX 232 that converts signals from an RS-232
serial port to signals suitable for use in TTL
compatible digital logic circuits.
 The MAX 232 is a dual driver/receiver and
typically converts the RX, TX CTS and RTS
signals.
 It changes a TTL Logic 0 to between +3 and +15
V, and changes TTL logic 1 to between -3 to -
15V, and vice versa for converting from RS232 to
TTL.

12. User wants to display a message in the led board
User sends the message from his mobile defining the
message in the code format and then to the number of
the subscriber identity module (SIM) which is inserted
in the display system MODEM.
LED DISPLAY

13. ARM7

14. ARM7
 ARM: Advanced RISC Machine
 Founded in1990, owned by Acorn, Apple and VLSI
 Most widely used 32-bit instruction set architecture
 Suitable for low power devices
 Used extensively in consumer electronics, PDA (Personal
Digital Assistant), mobile phones, computer peripherals
(hard drives & routers), music players, game consoles,
calculators, etc.,

15.  8 kb to 40 kb of on-chip static RAM and 32 kB to 512 kB of on-
chip flash memory.
 128-bit wide interface/accelerator enables high-speed 60 MHz
operation
 Operating voltage range of 3.0 V to 3.6 V
 Single 10-bit D/A converter provides variable analog output.
 Two 32-bit timers/external event counters

16. FLOW CHART

17. ADVANTAGES
 Using GSM mobile we can send message to any distant locations , from any part of the
World
 As it's a GSM wireless transmission system it has very less errors and needs less
maintenance
 Prevents unauthorized access of notice board (password)
 Multiple Users are authorized to update notices on the electronic notice board
 No printing and photocopying costs. Thus saves time, Energy and finally environment

18. DISADVANTAGES
When there is network problem
GSM doesn’t work

19. APPLICATIONS
 Educational institutions & organizations
 Managing traffic
 Advertisement Conference hall
 Bus/Railway station
 Any Public utility places

20. CONCLUSION
 We can use this Project in college Notice Board, a Professor can send message
for the immediate gathering of students at department.
 It can be used on Highways for traffic control, like traffic on one side of the road
may be blocked in view of VVIP movement or jam ahead

21. FUTURE SCOPE
 Temperature and time (RTC ) display during periods when no
messages are to be displayed
 GSM based home security system, GSM based robot control, GSM
based DC motor controller, GSM based stepper motor controller,
GSM based voting machine control et