KUMASI TECHNICAL UNIVERSITY

FACULTY OF ENGINEERING AND

TECHNOLOGY
ELECTRICAL AND ELECTRONIC
ENGINEERING DEPARTMENT

GSM BASED ELECTRONIC NOTICE BOARD

WIRELESSLY

ABDUL RAHAMAN IBRAHIM

052230500143

SUPERVISOR
ENGINEER, SIR MAXWELL
 DECLARATION
I, ABDUL RAHAMAN IBRAHIM, a proud student of KUMASI
TECHINICAL UNIVERSIYT, pursuing my HND Level in
ELECTRICAL AND ELECTRONIC ENGINEERING, solemnly
declare that this thesis work, titled " GSM BASED ELECTRONIC
NOTICE BOARD WIRELESSLY, is the result of my original research
and has not been submitted in part or in whole for any other degree or
qualification at this university or any other institution. I have
acknowledged all sources and references used in this thesis, and all
contributions from individuals or organizations have been duly
recognized. I also affirm that the work presented herein adheres to the
ethical standards and guidelines set forth by the academic community.
I further declare that this research has been completed without any
unethical practices or misconduct, and all data, findings, and
conclusions presented are accurate to the best of my knowledge.
 DEDICATION
This thesis is dedicated to my beloved family, whose unwavering support
and sacrifices have been the cornerstone of my academic pursuits.
To my parents, your belief in my potential has been my driving force, and I
am forever grateful for your encouragement.
I dedicate this work to my thesis advisor, [ENGR, SIR MAXWELL],
whose mentorship and guidance have illuminated my path throughout this
research journey. Your patience and expertise have been instrumental in
shaping my understanding of [ELECTRICALS].
To my dear friends and companions, your camaraderie and shared
experiences have added depth and joy to my academic life. Your friendship
is cherished.
This thesis is a testament to the collective efforts and the belief of those
who have walked alongside me, and I offer it as a token of my deepest
appreciation.

ACKNOWLEDGEMENT
I extend my heartfelt gratitude to all who have contributed to my academic
odyssey. My sincere thanks go to my esteemed thesis advisor, [ ENGR,
SIR MAXWELL], for their unwavering support, mentorship, and
invaluable insights. Your guidance has been a guiding star throughout this
research endeavor.
I would also like to express my appreciation to the dedicated faculty
members at [KsTU] for their commitment to academic excellence and for
sharing their wisdom, which has enriched my learning journey.
To my family, friends, and well-wishers, your encouragement and belief in
my abilities have been a constant wellspring of motivation.
I extend my acknowledgements to all those whose scholarly works and
research have been sources of inspiration and knowledge for this thesis.
This accomplishment stands as a testament to the collective support and
belief of many, and I am profoundly grateful to each one of you.

ABSTRACT
In the last few decades, communication technology has developed by leaps
and bounds. it's already established its importance in sharing the
information to each other. Except for sharing info, it's also used for remote
mode of machines and electronic appliances.
In our daily life, we have a tendency to use several such appliances
reception, work-place and public places for our comfort and convenience.
each device needs one or the other moderately operation management that
it is a human-machine interface (HMI). Communication technology
additionally permits us to control machines. This control of appliances is
possible with wired or wireless communication interfaces embedded
among the machines. The use of "Embedded System in Communication"
has given rise to many attention-grabbing applications. One in each of
such applications is public addressing system (PAS) several corporations
are unit producing audio/video systems like public announcement system,
telecommunication equipment, programmable sign-boards etc. However,
most of these systems area unit usually hard-wired, advanced in nature and
expensive.
The key objective of this project is to develop a bulletin board that
receives associate degree displays messages from an authentic user from
anyplace among the planet victimization GSM technology. The SIM card
loaded among the GSM module fitted with the wireless board receives
messages from licensed user having a movable. The received message is
then displayed on the wireless notice board creating the complete method
simple and quick.
Table of Contents
DECLARATION........................................................................................................................2
DEDICATION............................................................................................................................3
ACKNOWLEDGEMENT.........................................................................................................3
ABSTRACT...............................................................................................................................4
CHAPTER ONE........................................................................................................................6
INTRODUCTION......................................................................................................................6
1.2 Problem statement................................................................................................................7
1.3 Proposed Solution................................................................................................................7
1.4 Key Challenges to Address..................................................................................................7
1.5 Objectives.............................................................................................................................7
1.6 Expected Impact / Significance:...........................................................................................8
1.7 Targeted Applications:..........................................................................................................8
1.8 Limitations...........................................................................................................................8
CHAPTER 2...............................................................................................................................9
LITERATURE SURVEY AND REVIEW.................................................................................9
2.1 Wireless Notice Board Based on Arduino and GSM Technology.......................................9
2.2 Wireless Electronic Notice Board Using GSM Technology................................................9
2.3 GSM Based Wireless Notice Board Using ARDUINO.....................................................10
2.4 Smart Notice Board............................................................................................................10
CHAPTER THREE..................................................................................................................11
RESEARCH METHODOLOGY.............................................................................................11
3.1 Broadcast............................................................................................................................11
3.2 GSM Modem......................................................................................................................11
3.3 SIM (Subscriber Identity Module).....................................................................................11
3.4 Arduino...............................................................................................................................12
3.5.............................................................................................................................................12
CHAPTER FOUR....................................................................................................................13
4.1 ACTUAL WORK...............................................................................................................13
4.2 Components Overview.......................................................................................................13
4.3 ARDUINO UNO................................................................................................................13
4.4 LCD....................................................................................................................................14
4.5 GSM Modem......................................................................................................................14
4.6 Specification.......................................................................................................................15
4.7 System Operation...............................................................................................................15
4.8 ANALYSIS.........................................................................................................................16
4.9 GSM MODEM...................................................................................................................16
5.0 LCD display.......................................................................................................................18
5.2 FEATURES........................................................................................................................22
5.3 How to use Arduino Board.................................................................................................22
5.4 Software Requirements......................................................................................................23
5.4 AT COMMANDS...............................................................................................................33
5.5 MODELLING....................................................................................................................34
5.6 ARCHITECTURE OF THE SYSTEM..............................................................................35
FIGURE 5.7 SCHEMATIC VIEW................................................................................36
BLOCK DIAGRAM................................................................................................................37
CIRCUIT SCHEMATIC DIAGRAM......................................................................................37
FLOW CHART........................................................................................................................39
TESTING METHOD...............................................................................................................40
1. Objective..............................................................................................................................40
2. Required Equipment and Materials......................................................................................40
3. Safety and Precaution checks...............................................................................................40
4. Test Categories and Order....................................................................................................40
5. Step by Step Procedures.......................................................................................................41
6. Expected Results and Criteria..............................................................................................41
7. Troubleshooting Guide.........................................................................................................41
WORK SCHEDULE................................................................................................................42
CHAPTER FIVE......................................................................................................................43
RESULTS, DISCUSIONS AND CONCLUSION...................................................................43
Future Scope.............................................................................................................................43
RESULTS.................................................................................................................................44
CONCLUSION........................................................................................................................46
REFERENCE...........................................................................................................................46

CHAPTER 1
 INTRODUCTION

1.1 Background
Traditional physical notice boards in institutions (e.g., schools, offices,
public spaces) suffer from critical inefficiencies:

 Require personnel to physically post/replace notices, consuming

time and resources.
 Urgent updates (e.g., schedule changes, emergencies) cannot be
broadcast instantly.
 Notices are only visible to those near the board, excluding remote
stakeholders.
 Paper-based systems incur recurring costs and environmental
impact.

Over the last two decades the use of cell phones has been rapidly
increasing. Mobile phones and the related technologies have become one
of the most important things in this modern era. This drastic use of mobile
phones gave the interesting idea of send-Ing and receiving messages and
the displaying them on digital board. The SMS (Short Message Service)
facility in mobile handset enables us to send and receive messages all
around the world by international roaming feature
The main aim of this project is to replace the conventional notice boards
by wireless digital displays driven by GSM (Global System for Mobile
communication) technology. The authenticated user on the sending end
sends SMS notice to be displayed on the board) using his mobile handset
to the SIM card loaded in the GSM module (attached to the wireless notice
board, which receives the message and passes it to the micro. controller in
the Arduino for storage and then displays the received SMS on the
wireless digital board. The SIM card at the receiving end in the GSM
module receives only those messages whose initial character is and final
is. The device can be used anywhere irrespective of the place of
deployment provided mobile network connectivity is available
 1.2 Problem statement
There is an unmet need for a real-time, wirelessly updatable notice board
that enables administrators to broadcast information remotely, instantly,
and sustainably. Existing digital solutions often rely on Wi-Fi or
Bluetooth, limiting deployment in areas with unreliable internet
infrastructure.

1.3 Proposed Solution

This project focus on designing a GSM-based Electronic Notice Board
that:
 Receives messages wirelessly via SMS from authorized users.
 Displays content instantly on an LED/LCD screen without manual
intervention.
 Operates independently of internet connectivity, leveraging
ubiquitous GSM networks.
 Ensures security through SIM-based authentication.

1.4 Key Challenges to Address

Wireless Reliability: Ensuring stable message reception in low-signal
areas.
Authorization: Restricting board access to pre-approved mobile numbers.
Power Efficiency: Minimizing energy consumption for 24/7 operation.
User-Friendliness: Enabling non-technical users to send commands via
simple SMS syntax.
Display Clarity: Optimizing screen readability for diverse lighting
conditions.

1.5 Objectives
 Develop a prototype with a GSM modem (e.g., SIM800L),
microcontroller (e.g., Arduino/ESP32), and display unit.
 Implement SMS parsing algorithms to extract/display valid
messages while filtering spam.
 Integrate authorization protocols to reject unauthorized numbers.
 Test real-world performance across varying GSM signal strengths.
  Ensure cost-effectiveness for scalable deployment.

1.6 Expected Impact / Significance:

Efficiency: Reduce notice update time from hours to seconds.
Accessibility: Broadcast critical information across multiple locations
simultaneously.
Sustainability: Eliminate paper waste and operational costs.
Emergency Response: Enable instant alerts during crises (e.g., weather
warnings, closures).

1.7 Targeted Applications:

Educational campuses, corporate offices, public transport hubs, hospitals,
and rural communities with limited internet access.

1.8 Limitations
The micro controller of a general-purpose computer permits us to theorize
on several more enhancements on this project model.
Temperature display during times whereby no message buffers, unit of
measurement empty on such theoretical improvement that's terribly
potential.
With correct use of interrupt routines, the incoming message acts as an
interrupt, the temperature display is halted and also the management low
jumps over to the specific interrupt service routine that 1st validates the
sender's variety then displays the info field.
 CHAPTER 2

LITERATURE SURVEY AND REVIEW

2.1 Wireless Notice Board Based on Arduino and GSM

Technology Arduino Nano is used to control the whole process, GSM
Module (Sim 800L).( Vikash Nagar, Satyam Diwedi, Biplav Choud-hury,
"GSM based smarthome and digital notice board", IEEE 2016.
To receive the message sent from the authenticated mobile handset and
LCD (204). To dis-play the received SMS. The Short Message Service
(SMS) technology is one the most stable mobile technologies around.
Most of our tertiary students carry mobile phones with SMS facilities and
can be used for teaching and learning

2.2 Wireless Electronic Notice Board Using GSM Technology The

main aim of this article is to design a SMS driven automatic display toolkit
which may re-place the currently used programmable electronic display.
it's proposed to style receive cum display toolkit which may be
programmed from a licensed mobile.( Tsinghua, and Beijing, China "A
Remote data acquisition system based on SMS". Systems, Man and
Cybernet-ics, 2004 IEEE International Conference Volume: 7) The
message to be displayed is distributed through an SMS from a licensed
trans-Mitter. The toolkit receives the SMS, Validates the sending Mobile
Identification Number (MIN) and displays the required information after
necessary code con versions.( Dawood. R. Muchallil)

2.3 GSM Based Wireless Notice Board Using ARDUINO

By referring this journal, we are able to acknowledge of a GSM receiver
and LCD which might be programmed from a certified computer. It
receives the SMS, and displays the specified information after necessary
code conversion ( M. Abila Mary, B. Pavithra, R.Sangeetha,
Prof.T.C.Subbu Lakshmi, "GSM Based Wireless Notice Board Using
ARDUINO ). It can function a board and display the important notices
instantaneously thus avoiding the latency. GSM based device is simple to
expand and allows the user to display units at any time and at any location
within the campus.

References:
[1] Fizza Hamid & Nusrat Hamid Shah, "Wireless notice board based on
Arduino and GSM technology", International Journal of Engineering
Sciences & Research Technology February, 2018, Electronics and
Communication Engineering, CGCTC, Jhanjeri.

2.4 Smart Notice Board

In this journal the foremost operation relies on micro controller AT89C52
pro-grammed in computer software. A SIM300 of GSM modem is
interfaced to the ports of the micro controller. It's further displayed on an
electronic bulletin board which equipped with LCD display interfaced to
microprocessor

Reference
[1] Bhumi Merai, Rohit Jain, Ruby Mishra, "Smart Notice Board",
International Journal of Advanced Research in Computer and
Communication Engineering Vol. 4. Issue 4, April 2015. Bachelor of
Engineering. Electronics and Telecommunication, Atharva College of
Engineering, Mumbai, India.

CHAPTER THREE

RESEARCH METHODOLOGY

3.1 Broadcast
A term to explain communication where a chunk of knowledge is
distributed or transmitted from one point to all other points. There is just
one sender, but the information is simultaneously sent to all or any
connected receivers. In networking, a distinction is made between
broadcasting and multi casting. Broadcasting sends a message to every-
one on the network whereas multi casting sends a message to a pick list of
recipients.

3.2 GSM Modem

The GSM Modem, works by accepting any GSM network operator SIM
card acts just like an itinerant with its own unique telephone number. The
advantage of this modem is that its RS232 pin is often wont to
communicate and develop embedded application. For this purpose, it can
be connected to a PC port directly or to the other micro controller. The
GSM modem acts as a highly flexible plug and its direct and simple
integration to RS232 applications plays a major role.

3.3 SIM (Subscriber Identity Module)

SIM stands for Subscriber Identity Module. it's a chip on small card which
consists of user's information and phone book. The SIM is inserted during
a slot available on the GSM Modem. A SIM card contains a singular serial
number (ICCID), International Mobile Subscriber Identity (IMSI) number,
security authentication and ciphering in-formation. It also stores temporary
information associated with the local network, an inventory of the services
the user has access to, and two passwords: a personal identification
number (PIN) for ordinary use, and a private unblocking code (PUK) for
PIN unlocking. The SIM used in this project is SIM900A.
 3.4 Arduino

The micro controller employed in this proposed system is Arduino UNO,

which is based on ATmega328P. it's 14 digital input/output pins (of which
6 are often used as PWM outputs), 6 analog inputs and a 16 MHz quartz. It
also consists of a USB connection, an influence jack, an ICSP header and a
button. the most operation of the Arduino is to read the SMS received from
the GSM module, extract the most message from the received string and
store it in another string. This project aims at integrating the expansiveness
of a wireless cellular network and the easy information transfer through
the SMS with the coverage of campus display boards. It can even be a
modest effort to comprehend the entire potential of public display boards
in instantaneous information broadcast in swift response to events of
interests.

RESEACH DESIGN IDEATION

3.5

SEARCH FOR
MATEIALS CONSTRUCTION TESTING

CHAPTER FOUR
 4.1 ACTUAL WORK

An embedded system is a consists of hardware and software and perhaps

other mechanical parts designed to perform a selected function. An SMS
sent from a portable to GSM modem is received by the GSM modem and
stores it through AT commands. Using Arduino, it's possible to retrieve the
stored message in GSM and display it on a LED dis-play using embedded
programming languages. Short information is often sent from a portable as
SMS and made display until the following one

4.2 Components Overview

This particular system uses the following components.

4.3 ARDUINO UNO

could be a microcontroller board supported by 8-bit ATmega328P micro

controller. together with ATmega328P, it consists of other components like
oscillator, serial communication, transformer, etc. To support the micro
controller, Arduino Uno has 14 digital input/output pins (out of which 6
are often used as PWM outputs), 6 analog input pins, a USB connection,
an influence barrel jack, an ICSP header and a push.

4.4 LCD

The GSM based CDS uses an LCD for displaying the text data. It is 16-
character x 2-line display module. But in practice, it should be replaced by
the large multi-line, multi color commercial display units.
 4.5 GSM Modem

A GSM modem may be a wireless modem that works with a GSM (Global
System for Mobile communication) wireless network.
A wireless modem behaves sort of a dial-up modem. The most difference
between them is that a dial-up modem sends and receives data through a
set telephone line while a wireless modem sends and receives data through
radio waves. sort of a GSM portable, a GSM modem requires a SIM card
so as to work.

In this project, we must take under consideration the actual fact that the
modem re-quires a wired connection at one end and wireless at the
opposite. We use SIM900A and SIM900A modem is made with dual band
GSM/GPRS based SIM900A modem from SIMCOM, it works on
frequencies 900/1800 MHz SIM900A can search these two bands
automatically. The frequency bands may also be set by AT commands. The
band ratio is configurable from 1200-115200 through AT commands. The
GSM/GPRS mo.-dem has internal TCP/IP stack to enable you to attach
with internet via GPRS. SIM900A is an ultra-compact and reliable
wireless module. this can be a whole GSM/GPRS mod-ule a really. SMT
type and designed with a very powerful single-chip processor integrating
AMR926EJ-S core, allowing you to learn from small dimensions and cost-
effective solutions. The use of AT commands in computers is to control the
modems. GSM modems and dial up modems both support a common set
of standard AT commands. GSM modem can be used just like a dial up
modem. In addition to the standard AT commands the GSM modems
support's an extended set of AT commands. These extended AT commands
are defined in the GSM modem.

4.6 Specification

1. 20x4 I2C LCD

2. LEDs
3. 5V Buzzer
4. 1000μF capacitor and some other capacitors
5. 10KΩ Resistor and others
6. Arduino Nano
7. GSM Module (SIM800L)
8. Power Supply (12V, 2A)
9. 2 LM7805 Voltage Regulator
10. Big Veroboard
11. casing
12. Lead
13. 2 Jumper wires

4.7 System Operation

The operation of the system is incredibly simple. Sending message
from any of the remote area to the distant located e-notice board
using GSM (Global System for Mobile communication) mobile. For
sending the text message from remote area we want to interface the
movable with GSM Modem. For developing a number of GSM
based applications we want to own some commons peripherals
including GSM MODEM, SIM, ARDUINO, LCD (Liquid crystal
display), power supply and also some connecting wires. Moreover,
GSM based applications may well be easily developed and enhanced
thanks to easily accessibility of components in local markets at very
pocket friendly prices.

4.8 ANALYSIS

4.9 GSM MODEM

A GSM modem could be a wireless modem that works with a GSM
(Global System for Mobile communication) wireless network. A
wireless modem behaves sort of a dial-up modem. the most
difference between them is that a dial-up modem sends and receives
data through a set telephone line while a wireless modem sends and
receives data through radio waves. sort of a GSM portable, a GSM
modem requires a SIM card from a wireless carrier so as to work.
GSM sim 900 Modem can accept any GSM network operator SIM
card and act rather like a portable with its own unique number.
Advantage of using this modem is going to be that you simply can
use its RS232 port to speak and develop embedded applications.

Applications include SMS Control, data transfer, device and login

may be developed easily. The modem can either be connected to PC
port directly or to any Arduino. It may be accustomed send and
receive SMS or make/receive voice calls. It may also be utilized in
GPRS mode to attach to internet and do many applications for data
logging and control. In GPRS mode you'll also hook up with any
remote FTP server and upload files for data logging. This GSM
modem may be a highly flexible plug and play quad band GSM
modem for direct and simple integration. Supports features like
Voice, SMS,
GSM MODULE
Data/Fax, GPRS and integrated TCP/IP stack. Computers use AT
commands to manage modems. Both GSM modems and dial up modems
support a typical set of normal AT commands.

GSM modem can be used like a dial-up modem. In addition to the

standard AT commands the GSM modems support an extended set of AT
commands. These AT commands are defined in the GSM standards, With
the extended AT commands, various

things can be done:

1. Sending SMS messages.

2. Monitoring the signal strength.

3. Monitoring the charging status and charge level of the battery.

4. Reading, writing and searching phone book entries.

5. Reading, writing and deleting SMS messages.

5.0 LCD display

One of the most common devices attached to an 8051 is an LCD display.
Some of the most common LCD connected to the 8051 are 16x2 and 20x2
displays. This means 16 characters per line by 2 lines and 20 characters per
line by 2 lines, respectively. In recent years the LCD is finding widespread
use replacing LEDs. This is due to the following reasons:

1. Declining of prices
2. Ability to display numbers, characters and graphics.

3. Incorporation of a refreshing controller into the LCD.

4. Ease for programming.

Fortunately, a really popular standard exists which allows us to speak with

the over-whelming majority of LCDs irrespective of their manufacturer.
the quality is stated 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. The 44780 standard requires 3
control lines furthermore as either 4 or 8 I/O lines for the information bus.
The user may select whether the LCD is to control with a 4-bit data bus or
an 8-bit data bus. If a 4-bit data bus is employed the LCD would force a
complete of seven data lines (3 control lines plus the 4 lines for the
information bus). If an 8-bit data bus

is employed the LCD would force a complete of 11 data lines (3 control

lines plus the 8 lines for the information bus).

Important Signals

The following pins are very important for LCD's while programming

Enable (EN)
The EN is known as "Enable". This control line is used to tell the LCD that
you are sending the data. To send data to the LCD, your program should
make sure this line is low (0) and then set the other two control lines
and/or put data on the data bus. When the other lines are completely ready,
bring EN high (??) and wait for minimum amount of time required by the
LCD datasheet (this varies from one LCD to another LCD), and it end by
bringing it low (0) again.

Register Select (RS)

The RS line is that the "Register Select" line. When RS is low (0), the
information is to be treated as a command or special instruction (such as
clear screen, position cursor, etc.). When RS is high (1), the information
being sent is text data which should be displayed on the screen. as an
example, to display the letter "T" on the screen you'd set RS high.

Read/Write (R/W)
The RW line is known as the "Read/Write" control line. When RW is low
(0), the information on data bus is being written to the LCD. When RW is
high (??), the program is effectively querying (or reading) the LCD. Only
one instruction ("Get LCD status") is a read command. All the others are
written commands-so RW will almost always be low. Finally, the data bus
consists of 4 or 8 lines (depending on the mode of operation selected by
the user). In the case of an 8-bit data bus, the lines are referred to as DB0,
DB1, DB2, DB3, DB4, DB5, DB6, and DB7.
Above is that the quite simple schematic. The LCD panel's Enable and
Register Select is connected to the Control Port. The Control Port is an
open collector / open drain output. While most Parallel Ports have internal
pull-up resistors, there's some which don't. Therefore, by incorporating the
2 10K external pull up resistors, the circuit is more 18 portables for a
wider range of computers, a number of which can don't have any internal
pull up resistors. We make no effort to put the info bus into reverse
direction. Therefore, we hard wire the R/W line of the LCD panel, into
write mode. this can cause no bus conflicts on the info lines. As a result,
we cannot read back the LCD's internal Busy Flag which tells us if the
LCD has accepted and finished processing the last instruction. This
problem is Overcome by inserting known delays into our program.

The 10k Potentiometer controls the contrast of the LCD panel. Nothing
fancies here. like all the examples, I've left the facility supply out. you'll be
able to use a bench power supply set to 5v or use an onboard +5 regulator.
Remember some de-coupling capacitors, especially if you've got trouble
with the circuit working properly.

5.1 ARDUINO NANO/UNO

Arduino Uno may be a micro controller board supported 8-bit
ATmega328P micro con-troller. together with ATmega328P, it consists
other components like oscillator, serial communication, transformer, etc. to
support the micro controller. Arduino Uno has 14 digital input/output pins
(out of which 6 may be used as PWM outputs), 6 analog input pins, a USB
connection, an influence barrel jack, an ICSP header and a button.
 ARDUINO UNO

5.2 FEATURES
1. Microcontroller is ATmega328
2. Operating Voltage is 5V
3. Supply Voltage (recommended) is 7-12V
4. Maximum power supply voltage (not recommended) is 20V
5. Digital I/O Pins are 14 (of which 6 provide PWM output)
6. Analog Input Pins are 6
7. DC Current for I/O Pin 40 mA
8. DC Current for 3.3V Pin 50 mA
9. Flash Memory 32 KB (ATmega328) of which 0.5 KB used by
bootloader
10. SRAM 2 KB (ATmega328)
11. EEPROM 1 KB (ATmega328)
12. Clock Speed is 16 MHz

5.3 How to use Arduino Board

The 14 digital input/output pins are used as input or output pins by using
pin Mode (), digital Read () and digital Write () functions in Arduino
programming. Each pin operates at 5V and might provide or receive a
maximum of 40mA current, and has an inside pull-up resistor of 20-50 K
Ohms which are disconnected by default. Out of those 14 pins, some pins
have specific functions as listed below:
Serial Pins 0 (Rx) and 1 (Tx):
Rx and Tx pins were used to receive and transmit TTL serial data. These
pins are connected with the corresponding ATmega328P USB to TTL
serial chip. External Interrupt Pins 2 and 3:
These pins can be configured to trigger an interrupt on a low value, rising
or falling edge, or a change in value.
PWM Pins 3, 5, 6, 9 and 11:
These pins provide an 8-bit PWM output by using analog Write ()
function.
SPI Pins 10 (SS), 11 (MOSI), 12 (MISO) and 13 (SCK):
These pins are used for SPI communication.
In-built LED Pin 13:
This pin is connected with a built-in LED, when pin 13 is HIGH-LED is
on and when pin 13 is LOW, LCD is off.
Along with 14 Digital pins, there are 6 analog input pins, each of which
offer 10 bits of resolution, i.e. 1024 different values. They measure from 0
to five volts but this limit is often increased by using AREF pin with
analog Reference () function. Analog pin 4 (SDA) and pin 5 (SCA) also
used for TWI communication using Wire library.
Arduino Uno has a couple of other pins as explained below:
AREF: It is Used to provide reference voltage for analog inputs with
analog Reference () function.
Reset Pin: When this pin LOW, resets the micro controller.

5.4 Software Requirements

Programming Arduino
Once Arduino IDE is installed on the pc, connect the board with computer
using USB cable. ( D. Sunitha, V. C. Patil, H. N. Manjula and S. Jebakani,
"Digital notice board using Smart Phones- Speech Recognition Voice
command," 2018) Now open the Arduino IDE and choose the right board
by selecting Tools Boards>Arduino Uno, and then choose the correct Port
by selecting Tools>Port. Arduino Uno is programmed using Arduino
programming language based on Wiring. To get it started with Arduino
Uno board, blink the built-in LED and then load the example code by
selecting Files>Examples>Basics>Blink. Once the example code (also
shown below) is loaded into your IDE, click on the 'upload' button on the
top bar. Once the upload is finished, you can see the Arduino's built-in
LED blinking. Below is the example code for blinking:
#include <SoftwareSerial.h>
#include <LiquidCrystal_I2C.h>
// Initialize SoftwareSerial for SIM800L (RX, TX)
SoftwareSerial sim800l(11, 10); // RX = 11, TX = 10
// Initialize LCD (I2C address 0x27, 20 columns, 4 rows)
LiquidCrystal_I2C lcd(0x27, 20, 4);
// Pin definitions for LEDs and buzzer
#define GREEN_LED 7
#define RED_LED 6
#define BUZZER 9
// Buffer to store SMS message
String smsBuffer = "";
unsigned long lastScrollTime = 0;
unsigned long lastBlinkTime = 0;
unsigned long lastErrorTime = 0;
const int SCROLL_DELAY = 500; // Scroll speed in milliseconds
const int BLINK_INTERVAL = 200; // Normal blink interval for green
LED
const int URGENT_BLINK_INTERVAL = 100; // Faster blink for urgent
messages
bool greenLedState = false;
bool isScrolling = false;
bool isUrgent = false;
// Custom character for heart symbol
uint8_t heart[8] = {
0b00000,
0b01010,
0b11111,
0b11111,
0b01110,
0b00100,
0b00000,
0b00000
};
void setup() {
// Initialize pins
pinMode(GREEN_LED, OUTPUT);
pinMode(RED_LED, OUTPUT);
pinMode(BUZZER, OUTPUT);
digitalWrite(GREEN_LED, LOW);
digitalWrite(RED_LED, LOW);
digitalWrite(BUZZER, LOW);
// Start serial communication for debugging
Serial.begin(9600);
delay(1000);
// Start communication with SIM800L
sim800l.begin(9600); // Try 115200 if 9600 doesn't work
delay(1000);
// Initialize LCD
lcd.begin();
 lcd.backlight();
lcd.createChar(0, heart); // Define heart symbol as custom character 0
lcd.setCursor(0, 0);
lcd.print("Initializing...");

// Configure SIM800L for SMS

bool initSuccess = true;
initSuccess &= sendATCommand("AT", 1000, true); // Check if module
is responding
initSuccess &= sendATCommand("AT+CMGF=1", 1000, true); // Set
SMS to text mode
initSuccess &= sendATCommand("AT+CNMI=2,2,0,0,0", 1000, true); //
Set SMS notification mode
lcd.clear();
lcd.setCursor(0, 0);
if (initSuccess) {
lcd.print("Ready for SMS");
// Startup feedback: red LED flashes, buzzer plays jingle
for (int i = 0; i < 3; i++) {
digitalWrite(RED_LED, HIGH);
digitalWrite(BUZZER, HIGH);
delay(100);
digitalWrite(RED_LED, LOW);
digitalWrite(BUZZER, LOW);
delay(100);
}
digitalWrite(BUZZER, HIGH);
delay(200);
digitalWrite(BUZZER, LOW);
 } else {
lcd.print("SIM800L Init Failed");
errorFeedback();
}
}
void loop() {
// Check if data is available from SIM800L
if (sim800l.available()) {
String response = sim800l.readString();
Serial.println("SIM800L Response: " + response); // Debug full
response
// Check if the response contains an SMS notification
if (response.indexOf("+CMT:") != -1) {
// Extract SMS content (skip header line)
int smsStart = response.indexOf("\n", response.indexOf("+CMT:")) +
1;
smsBuffer = response.substring(smsStart);
smsBuffer.trim();
// Replace <3 with heart symbol (custom character 0)
smsBuffer.replace("<3", String(char(0)));
// Replace non-displayable characters with ?
for (int i = 0; i < smsBuffer.length(); i++) {
if (smsBuffer[i] < 32 || smsBuffer[i] > 126) {
if (smsBuffer[i] != 0) { // Allow custom heart character
smsBuffer[i] = '?';
}
}
}
 // Check for urgent message
isUrgent = smsBuffer.indexOf("URGENT") != -1 ||
smsBuffer.indexOf("urgent") != -1;

// Print SMS content to Serial Monitor

Serial.println("Received SMS: " + smsBuffer);

// Display SMS on LCD with word-wrapping

displaySMS(smsBuffer);
// SMS received feedback: green LED blinks, buzzer beeps
for (int i = 0; i < 2; i++) {
digitalWrite(GREEN_LED, HIGH);
digitalWrite(BUZZER, HIGH);
delay(isUrgent ? 150 : 100);
digitalWrite(GREEN_LED, LOW);
digitalWrite(BUZZER, LOW);
delay(isUrgent ? 150 : 100);
}
if (isUrgent) {
digitalWrite(BUZZER, HIGH);
delay(150);
digitalWrite(BUZZER, LOW);
}
}
}
// Handle scrolling for long messages
if (smsBuffer.length() > 60) {
 if (millis() - lastScrollTime >= SCROLL_DELAY) {
scrollSMS(smsBuffer);
lastScrollTime = millis();
// Scrolling feedback: soft buzzer tick
digitalWrite(BUZZER, HIGH);
delay(50);
digitalWrite(BUZZER, LOW);
}
isScrolling = true;
digitalWrite(GREEN_LED, HIGH); // Green LED on during scrolling
} else {
isScrolling = false;
// Blink green LED for new SMS (faster for urgent)
if (millis() - lastBlinkTime >= (isUrgent ?
URGENT_BLINK_INTERVAL : BLINK_INTERVAL)) {
greenLedState = !greenLedState;
digitalWrite(GREEN_LED, greenLedState);
lastBlinkTime = millis();
}
}
// Retry initialization if error persists
if (millis() - lastErrorTime >= 5000 && digitalRead(RED_LED)) {
lcd.clear();
lcd.setCursor(0, 0);
lcd.print("Retrying Init...");
setup(); // Re-run setup to retry initialization
}
 // Forward Serial input to SIM800L for debugging
if (Serial.available()) {
sim800l.write(Serial.read());
}
}

bool sendATCommand(String command, int delayMs, bool debug) {

sim800l.println(command);
delay(delayMs);
bool success = true;
if (debug && sim800l.available()) {
String response = sim800l.readString();
Serial.println("AT Command: " + command + " | Response: " +
response);
if (response.indexOf("OK") == -1) {
lcd.clear();
lcd.setCursor(0, 0);
lcd.print("Check SIM800L");
success = false;
errorFeedback();
lastErrorTime = millis();
}
}
return success;
}

void errorFeedback() {
// Error feedback: red LED on, buzzer error tone
 digitalWrite(RED_LED, HIGH);
digitalWrite(BUZZER, HIGH);
delay(500);
digitalWrite(BUZZER, LOW);
}
void displaySMS(String message) {
lcd.clear(); // Clear the LCD
// Word-wrap the message for up to 3 lines (60 chars total)
int len = message.length();
int line = 0;
int pos = 0;
String lineText = "";
while (pos < len && line < 3) {
// Read up to 20 characters or until a space
int endPos = pos + 20;
if (endPos > len) endPos = len;
// Find last space before or at 20 chars
int lastSpace = -1;
for (int i = pos; i < endPos; i++) {
if (message[i] == ' ') lastSpace = i;
}
// Decide where to break the line
int breakPos = endPos;
if (lastSpace != -1 && lastSpace > pos) {
breakPos = lastSpace;
}
// Extract line text
 lineText = message.substring(pos, breakPos);
lcd.setCursor(0, line);
lcd.print(lineText);
Serial.println("Line " + String(line) + ": " + lineText); // Debug
pos = breakPos + 1; // Skip the space
line++;
// Handle case where no space was found
if (lastSpace == -1 && pos < len) {
pos = endPos; // Break at 20 chars if no space
}
}
}
void scrollSMS(String message) {
static int scrollPos = 0;
int len = message.length();
// Display scrolled portion with word-wrapping
int pos = scrollPos;
for (int line = 0; line < 4; line++) {
int endPos = pos + 20;
if (endPos > len) endPos = len;
// Find last space before or at 20 chars
int lastSpace = -1;
for (int i = pos; i < endPos; i++) {
if (message[i] == ' ') lastSpace = i;
}
// Decide where to break the line
int breakPos = endPos;
 if (lastSpace != -1 && lastSpace > pos) {
breakPos = lastSpace;
}
// Extract and display line
String scrollText = message.substring(pos, breakPos);
lcd.setCursor(0, line);
lcd.print(" "); // Clear line
lcd.setCursor(0, line);
lcd.print(scrollText);
Serial.println("Scroll Line " + String(line) + ": " + scrollText); // Debug
pos = breakPos + 1; // Skip the space

// Handle case where no space was found

if (lastSpace == -1 && pos < len) {
pos = endPos;
}
}
// Update scroll position
scrollPos++;
if (scrollPos + 80 > len) scrollPos = 0; // Loop back for 4 lines
}

5.4 AT COMMANDS
AT commands are accustomed control modems. AT is that the abbreviation
for Attention. These commands come from Hayes commands that were
utilized by the Hayes smart modems. The Hayes commands started with
AT to point the eye from the modem. The dial up and wireless modems
(devices that involve machine to machine communication) need AT
commands to interact with a computer. These include the Hayes command
set as a subset, together with other extended AT commands. AT commands
with a GSM/GPRS modem or mobile phone can be used to access the
following information and services:
1. Information and configuration pertaining to mobile device or modem
and SIM card.
2. SMS services.
3. MMS services.
4. Fax services.
5. Data and Voice link over mobile network.
The Hayes subset commands are called as basic commands and the
commands specific to GSM network are called as the extended AT
commands.

5.5 MODELLING
An embedded system could be a combination of hardware and software
and maybe other mechanical parts designed to perform a selected function.
Theoretically an SMS sent form a itinerant to GSM (Global System for
Mobile communication) modem is received by the GSM and stores it
through AT commands. Using Arduino, it's possible to retrieve the stored
message in GSM and display it on an LCD display using embedded
programming languages. Short information will be sent from an itinerant
as SMS and made display until the following one.

SYSTEM MODELS
The User interacts with the system by sending a message to system for it
to display.
Once the system receives the message it verifies the user identification
(MIN) together with his number. If the validation proves to be authentic
the message is stored and pro-cedes to display the message. Denial of
authentication (wrong MIN) leads to discarding the message. Admin is
granted with the responsibility of addition to the authenticated list, deletion
of users from the list and it also has the flexibility to vary the access code
(MIN).

DATA FLOW DIAGRAM

The flow starts by initializing the ports of components. LCD is enabled
and also the baud is about. The program module points out the AT
commands that needs to be executed by the GSM (Global System for
Mobile communication). When micro reads these AT commands, it's sent
to the GSM module where the commands are processed. The updating of
messages is checked and if the sender is valid the messages are stored per-
formed. Once the operations are performed the acknowledgement is
shipped. within the worst-case scenario if there are not any new messages
the loop of checking for brand new messages continues until the new one
arrives. The SMS is deleted from the SIM when it's read, thus making
room for the subsequent SMS. the key constraints Incorp-rated are the
utilization of "* because the termination character of the SMS and also the
display of 1 SMS as a time. By introducing the concept of wireless
technology within the Field of the communication we are able to make our
communication more efficient and faster, with greater efficiency

5.6 ARCHITECTURE OF THE SYSTEM

The constituent parts involved in the process are
1. Mobile phone
2. GSM (Global System for Mobile)
3. Arduino board
4. LCD display

Architecture of the system consists of Arduino which involves within the

operation and validation. Regulated supply is to power up the entire circuit
components. GSM (Global System for Mobile communication) modem
stores any message received by the user, any operation performed by the
GSM is because of the AT commands initiated by the Arduino. Arduino
forwards the message to the LCD. LCD receives the message and might
display only 16*2 characters at a time. Mobile is that the user that starts
the interaction with GSM by sending a message This is proposed to
implement this project at the institute level. it's proposed to put display
boards at major access points. These include canteens, entrance gate,
hostel area etc. But the GSM (Global System for Mobile communication)
based display toolkit will be used as an add-on to those display boards and
make it truly wireless. The display panel programs itself with the
assistance of the incoming SMS with proper validation. The valid senders
may include the Director, Deans and Registrars.

FIGURE 5.7 SCHEMATIC VIEW

BLOCK DIAGRAM
CIRCUIT SCHEMATIC DIAGRAM
FLOW CHART
 TESTING METHOD

1. Objective
Verify reliable powering, SMS reception, Arduino message parsing, LCD
updates, indicator behavior, and overall system robustness.

2. Required Equipment and Materials

• Assembled device (Arduino Nano, SIM800L, LCD with I²C, LEDs,
buzzer, regulator).
• Mobile phone (same network as SIM800L).
• Bench power supply (0–12V, ≥2A).
• Multimeter, oscilloscope (optional).
• USB-to-TTL adapter (optional).
• Active SIM card with SMS.
• Jumper wires, tools, log sheet.

3. Safety and Precaution checks

• Ensure correct polarity and voltage before powering.
• Set current limit (~1A initially).
• Verify no short circuits.
• Use insulated work surface.

4. Test Categories and Order

1. Power checks
2. GSM module operation
3. UART communication
4. SMS receive & processing
5. LCD display update
6. LEDs & buzzer
7. End-to-end test
8. Stress & robustness tests
9. Final acceptance & log

5. Step by Step Procedures

• Power: Verify regulator 5V output under load.
• GSM: Insert SIM, check AT response, confirm registration.
• UART: Verify communication at 9600 baud.
• SMS: Send messages, check parsing & LCD update.
• LCD: Confirm text clarity and I²C address.
• Indicators: Test LED/buzzer on SMS.
• Integration: Send multiple SMS for stability.
• Robustness: Test recovery from brown-out, bursts, network loss.

6. Expected Results and Criteria

• Power: 5.0V ±0.1V.
• GSM: AT → OK, registration <60s.
• SMS: >95% correct display within 10s.
• Indicators: LED/buzzer trigger correctly.
• Robustness: System recovers from glitches.

7. Troubleshooting Guide
• No power, Check regulator.
• GSM not responding, Check SIM, antenna.
• Garbled UART, Check baud/wiring.
• LCD garbage, Verify I²C wiring.
• SMS parsing fails, Confirm text mode (AT+CMGF=1).
 WORK SCHEDULE
Days Date Time (hours Description
work)
Monday 7th July 2025 8:30am to Drawing a plan
1:00pm for the project
List of items,
that will be
need
Tuesday 15th July 2025 10:00am to Oder the list of
12:09pm items, that have
been listed
Wednesday 16th July 2025 9:30am to Visited the lab
2:30pm workshop (To
design some
part of the
project
Thursday 17th July 2025 9:00am to Try to check or
1:30pm test each
component, that
was ordered
Friday 25th July 2025 7:00am to Try to assemble
12:10pm the GSM
Notice Board
Saturday 26th July 2025 8:00am to Check the
3:00pm connection after
assembling the
project
Monday 24th July 2025 1:00pm to The final test
2:30pm was done on
this day. The
test was
successful
 CHAPTER FIVE

RESULTS, DISCUSIONS AND CONCLUSION

Future Scope
The use of Arduino in spot of a general-purpose computer allows us to
speculate on many further improvements on this project prototype.
Temperature display in periods wherein no message buffers are empty is
one such theoretical improvement that's very possible.
The ideal state of the Arduino is when the indices or space for storing
within the SIM memory are empty and no new message is there to display.
With proper use of interrupt routines, the incoming message acts as an
interrupt, the temperature display is blocked and also the control flow
jumps over to the particular interrupt subprogram which first validates the
sender's number so displays the knowledge field.
Another very interesting and significant improvement would be to
accommodate multiple receiver modems at the various positions during a
geographical region carrying duplicate SIM cards. With the assistance of
principles of TDMA (Time Division Multiple Access) technique, we will
favor to simulcast and/or broadcast crucial notifications. After a display
receives the valid message through the modem and displays it, it with-
draws its identification from the network & synchronously another nearby
modem signs itself into the network and starts to receive the message. The
message is broadcast by the mobile switching center for a nonstop
fundamental quantity during which as many possible display modems
catch the message and display it as per the constraint of vali-dation. These
limitations are removed by the employment of upper end micro
controllers. higher end Arduinos and extended RAM.

Multilingual display may be another added variation of the project. The

display boards are one in every of the only most vital media for
information transfer to the greatest number of end users. this may make
sure the increase within the number of informed users. Graphical display
may be considered as a protracted term but achievable and target able
output. The prototype may be implemented using commercial display
boards. during this case, it can solve the matter of instant information
transfer within the campus.

RESULTS

TYPING MESSAGE IN MOBILE MESSAGE RECIEVE

MESSAGE DISPLAY
 CONCLUSION
The prototype of the GSM (Global System for Mobile communication)
based display toolkit was actively designed. This prototype has
competence to be integrated with a board thus making it truly operated in
mobile. The toolkit accepts the SMS, stores it, validates it and then
displays it within the LCD module. The SMS is deleted from the SIM
whenever it's read, thus making room for the next SMS. the most
constraints incorporated are the employment of because the termination
character of the SMS and thus the display of 1 SMS as a time.

By introducing the concept of wireless technology within the Field of the

communication we are able to make our communication more efficient and
faster, with greater efficiency, we are able to display the messages with
less errors and maintenance. this technique is utilized in college, school,
offices, railroad terminal and commercial additionally as personal used.
The above technical paper explains how we are able to develop
additionally as modify voice control Android based wireless bulletin
board.

The wireless GSM technology utilized in the projected project to display

messages on the board is efficient, reliable, and faster with minimal errors.
it's cost-effective system, requires little maintenance, and is simple to
handle and use. It fills the role of conventional and old notice boards that
need papers to write down the messages. this point consuming and tedious
work has been replaced by wireless display board. From small institutions
to big organizations, the digital bulletin board is improving their
popularity.

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