Wireless Notice Board using GSM and Arduino

Published  January 23, 2016   86
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Wireless Notice Board Using GSM and Arduino

Wireless notice board is very selective term for this project, as it has a very wide scope rather than just being a simple notice board. First we should understand the purpose of this project, in this system we can display a message or notice to some display device like LCD, and this message can be easily set or changed from anywhere in the world, just by using the SMS facility of your mobile handset. Whatever notice we want to display, just send the SMS of that text, with some prefix and suffix.

 

This is very useful in Hotels, Malls, college, offices and can be used anywhere, even at home. Like you can set the message like “Do not disturb” at your hotel’s room gate, can set message at your home’s door step when you are away, and of course it is used as notice board in schools, colleges, cinema halls etc. And yes, it’s just not a simple Message board, the usefulness of this project is that you can set or change the message or notice from anywhere, just sending SMS from your phone. You can also check a similar project but on a different type of display: Arduino Scoreboard using Outdoor P10 LED Matrix Display.

 

We have previously used the SMS facility of mobile phone for home security and control the home appliances remotely: PIR Sensor and GSM Based Security System and GSM Based Home Automation using Arduino

Working Explanation:

In this project, Arduino UNO is used for controlling the whole process, GSM module (SIM900A) to receive the SMS/message sent from mobile phone and LCD to display the message.

GSM Arduino and LCD for wireless notice board

We can send some message or notice like “#Circuit Digest*”, “#We Welcomes You*” through the SMS. Here we have used a prefix in the message string that is ‘#’. This prefix is used to identify the starting of the message or notice. And ‘*’ is used as suffix to indicate the end of the message or notice.

 

When we send SMS from mobile phone to GSM module then GSM receives that SMS and sends it to Arduino. Now Arduino read this SMS and extract main notice message from the received string and stores in another string.  And then sends the extracted message to 16x2 LCD by using appropriate commands.

Wireless Notice Board Using GSM Block-diagram

Further working of this system is explained in the ‘Code Description’ section below. Before we get into programming details we should know about GSM module.

GSM Module:

GSM module is used in many communication devices which are based on GSM (Global System for Mobile Communications) technology. It is used to interact with GSM network using a computer. GSM module only understands AT commands, and can respond accordingly. The most basic command is “AT”, if GSM respond OK then it is working good otherwise it respond with “ERROR”. There are various AT commands like ATA for answer a call, ATD to dial a call, AT+CMGR to read the message, AT+CMGS to send the sms etc. AT commands should be followed by Carriage return i.e. \r (0D in hex), like “AT+CMGS\r”. We can use GSM module using these commands:

ATE0 For echo off

AT+CNMI=2,2,0,0,0  <ENTER>           Auto opened message Receiving.  (No need to open message)

ATD<Mobile Number>; <ENTER>      making a call (ATD+919610126059;\r\n)

AT+CMGF=1 <ENTER>                        Selecting Text mode

AT+CMGS=”Mobile Number” <ENTER>  Assigning recipient’s mobile number

>>Now we can write our message

>>After writing message

Ctrl+Z  send message command (26 in decimal).

ENTER=0x0d in HEX

GSM-Module-SIM900A

The SIM900 is a complete Quad-band GSM/GPRS Module which delivers GSM/GPRS 850/900/1800/1900MHz performance for voice, SMS and Data with low power consumption.

 

Circuit Description:

Connections of Wireless Notice Board using GSM and Arduino are simple and shown in the figure below. Here a liquid crystal display (LCD) is used for display the “Notice” or message, which is sent though the mobile phone as SMS. Data pins of LCD namely RS, EN, D4, D5, D6, D7 are connected to arduino digital pin number 7, 6, 5, 4, 3, 2. And Rx and Tx pin of GSM module is directly connected at Tx and Rx pin of Arduino respectively. And GSM module is powered by using a 12 volt adaptor.

Arduino GSM Wireless Notice Board circuit diagram

Code Description:

The code of the program is easily understandable; the new thing here is GSN initialization function gsm_init(), which is explained in the end.

In the program, first of all we include library for liquid crystal display (LCD) and then we defines data and control pins for LCD and some variables.

#include <LiquidCrystal.h>
LiquidCrystal lcd(7,6,5,4,3,2);

int led=13;

int temp=0,i=0,x=0,k=0;
char str[100],msg[32];

After this, serial communication is initialized at 9600 bps and gives direction to used pin. And initialize GSM Module in setup loop.

void setup() 
{
  lcd.begin(16,2);
  Serial.begin(9600);
  pinMode(led, OUTPUT);
  digitalWrite(led, HIGH);
  lcd.print("GSM Initilizing...");
  gsm_init();
  lcd.setCursor(0,0);
  lcd.print("Wireless Notice");

 For receiving data serially we use two functions, one is Serial.available which checks any serial data is coming or not and other one is Serial.read which reads the data that comes serially.

void serialEvent()
{
  while(Serial.available())
  {
    char ch=(char)Serial.read();
    str[i++]=ch;
    if(ch == '*')
    {
      temp=1;
      lcd.clear();
      lcd.print("Message Received");
      delay(1000);
    }
  }
}

After receiving data serially, we store it in a string and this string is checked for ‘#’ and ‘*’, to find the starting and ending of the Notice or message. Then finally Notice is printed on LCD using lcd.print:

void loop()    
{
  for(unsigned int t=0;t<60000;t++)
  {
    serialEvent();
  if(temp==1)
  {
    x=0,k=0,temp=0;
    while(x<i)
    {
      while(str[x]=='#')
      {
        x++;
        while(str[x]!='*')
        {
          msg[k++]=str[x++];

Initialization function ‘gsm_init()’ for GSM is important here, where firstly, GSM module is checked whether it is connected or not by sending ‘AT’ command to GSM module. If response OK is received, means it is ready. System keeps checking for the module until it becomes ready or until ‘OK’ is received. Then ECHO is turned off by sending the ATE0 command, otherwise GSM module will echo all the commands. Then finally Network availability is checked through the ‘AT+CPIN?’ command, if inserted card is SIM card and PIN is present, it gives the response +CPIN: READY. This is also check repeatedly until the network is found. This can be clearly understood by the Video below.

void gsm_init()
{
  lcd.clear();
  lcd.print("Finding Module..");
  boolean at_flag=1;
  while(at_flag)
  {
    Serial.println("AT");
    while(Serial.available()>0)
    {
      if(Serial.find("OK"))
      at_flag=0;
    }
    delay(1000);
  }
Code

#include <LiquidCrystal.h>
LiquidCrystal lcd(7,6,5,4,3,2);

int led=13;

int temp=0,i=0,x=0,k=0;
char str[100],msg[32];

void setup() 
{
  lcd.begin(16,2);
  Serial.begin(9600);
  pinMode(led, OUTPUT);
  digitalWrite(led, HIGH);
  lcd.print("GSM Initilizing...");
  gsm_init();
  lcd.setCursor(0,0);
  lcd.print("Wireless Notice");
  lcd.setCursor(0,1);
  lcd.print("    Board      ");
  delay(2000);
  lcd.clear();
  lcd.print("Circuit Digest");
  delay(1000);
  lcd.setCursor(0,1);
  lcd.print("System Ready");
  Serial.println("AT+CNMI=2,2,0,0,0");
  delay(500);
  Serial.println("AT+CMGF=1");
  delay(1000);
  digitalWrite(led, LOW);
}

void loop()    
{
  for(unsigned int t=0;t<60000;t++)
  {
    serialEvent();
  if(temp==1)
  {
    x=0,k=0,temp=0;
    while(x<i)
    {
      while(str[x]=='#')
      {
        x++;
        while(str[x]!='*')
        {
          msg[k++]=str[x++];
        }
      }
      x++;
    }
    msg[k]='\0';
    lcd.clear();
    lcd.print(msg);
    delay(1000);
    temp=0;
    i=0;
    x=0;
    k=0;
  }
  }
  lcd.scrollDisplayLeft();
}
void serialEvent()
{
  while(Serial.available())
  {
    char ch=(char)Serial.read();
    str[i++]=ch;
    if(ch == '*')
    {
      temp=1;
      lcd.clear();
      lcd.print("Message Received");
      delay(1000);
    }
  }
}

void gsm_init()
{
  lcd.clear();
  lcd.print("Finding Module..");
  boolean at_flag=1;
  while(at_flag)
  {
    Serial.println("AT");
    while(Serial.available()>0)
    {
      if(Serial.find("OK"))
      at_flag=0;
    }
    delay(1000);
  }

  lcd.clear();
  lcd.print("Module Connected..");
  delay(1000);
  lcd.clear();
  lcd.print("Disabling ECHO");
  boolean echo_flag=1;
  while(echo_flag)
  {
    Serial.println("ATE0");
    while(Serial.available()>0)
    {
      if(Serial.find("OK"))
      echo_flag=0;
    }
    delay(1000);
  }

  lcd.clear();
  lcd.print("Echo OFF");
  delay(1000);
  lcd.clear();
  lcd.print("Finding Network..");
  boolean net_flag=1;
  while(net_flag)
  {
    Serial.println("AT+CPIN?");
    while(Serial.available()>0)
    {
      if(Serial.find("+CPIN: READY"))
      net_flag=0;
    }
    delay(1000);
  }
  lcd.clear();
  lcd.print("Network Found..");
  delay(1000);
  lcd.clear();
}

Video

Comments

Submitted by Graham on Tue, 01/26/2016 - 21:40

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Thanks a ton, this is one of the few examples of RECEIVING a SMS that work, there are zillions of ones for sending but so few like yours

Submitted by PRINCE SANGWAN on Fri, 02/05/2016 - 01:11

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how would i intialise the the gsm module after writing the code in arduino, like how would i write those AT commands in gsm module?and would u mind sharing ur mail id for further communication?

Submitted by sachin on Mon, 02/29/2016 - 14:58

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I have modified the code attached because initially it wasn’t working.
Still it is not working i.e. the message send through gsm module is not displaying on LCD but it showing on the serial monitor.
Is there any problem in reading data serially and displaying??
According to your code the string is in # and *???
Please help me out….
Resolve the issue.

Submitted by shambel wondimnew on Sat, 04/09/2016 - 22:01

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dear pleas send me the full document for this project that i need to do the same project to my company

Submitted by Paul Bradfield on Wed, 04/20/2016 - 16:46

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Interesting reading. I want to setup wireless notice board using SMS. Can I just use a tablet to receive TXt's with a sim, instead of a GSM module & just adapt the tablet to read more as a noticeboard ?

Submitted by Tim on Wed, 08/03/2016 - 20:38

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Thanks for a brilliant tutorial, nice and easy to follow. Mine does however refuse to display long messages (I would like to display about 30/40 words) but when I try this it either freezes/doesn't display any text at all or reboots by running through the GSM initializing, ECHO off and etc. How do I get it to recieve and display longer messages?
Thanks in advance :)

Submitted by Muhammad Usman on Wed, 09/07/2016 - 20:47

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I don't know how to Thank you You really made my day...
May you get more & more success.

Submitted by Akshay yadav on Thu, 10/27/2016 - 14:51

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i m also getting the same problem ,the code just jumps to Finding module, and nothing else, may you please send me one that works well.

Submitted by curious on Sat, 11/19/2016 - 19:28

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is there something bigger than that 16*2 LCD sir/ma'am? something that can be used for larger establishments? grateful if you notice me.

Submitted by Emdaddul Bari Fahad on Wed, 12/07/2016 - 13:56

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All term has complete & shown in display, but it doesn't work for sending massese. How can i send SMS? and how can it displayed??.........Please help me...............

Submitted by Sanket on Mon, 01/16/2017 - 22:47

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Sir I have setup all the connections like yours but i only have the problem with the gsm module yhat it indicate "Finding Module.." on LCD display. Please Sir caan you please solve my problem...

Submitted by madhuri on Sat, 01/28/2017 - 19:39

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Thanks a lot
But after making all connections I could see only finding module on LCD and could not see any thing further could you help me out

Submitted by Raj on Wed, 02/01/2017 - 14:42

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Hi saddam, Great work. i'm an electronics enthusiast and try to build circuits and write codes. Every thing seems to be gud but the msg sent to the sim is not getting displayed on the screen. Pls suggest what can i do next.

Submitted by babith on Mon, 02/13/2017 - 21:43

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is that the code is correct .... have you cheacked it ? if anyone changed the code pls comment .... also give your correct mail id pls

Submitted by prathima on Thu, 03/23/2017 - 22:54

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code is showing some warnings in gsm_init()

if(Serial.find("OK"))

if(Serial.find("+CPIN: READY"))

Submitted by SHaheer on Fri, 03/31/2017 - 10:44

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hey maddy
I have connected and write code on arduino as per this website . after running Lcd MONITER SHOWS"Circuit digest System ready.But when i send messages it shows same. that means message is not displaying ,or it may not receving.Can you help me ? is there anything that i have to modified these code ? hoping a convenient reply from you.

Submitted by thirupathi on Sat, 04/01/2017 - 12:23

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code is showing some warnings in gsm_init()
if(Serial.find("OK"))
if(Serial.find("+CPIN: READY"))

Submitted by Shahzaib Bijapure on Thu, 11/02/2017 - 13:14

In reply to by Akash

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Akash i m alsi getting the same , ditto error on compilation , if u have alredy found the solution please send

Submitted by kishan on Wed, 05/10/2017 - 10:47

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sir hw does the program read the balance in sim, and how to recharge it again, or how to check bal in it
can we contact you sir pls,,we r doing this proj as our final yr project, please help us out
even if you are charging money for its okay, please help us out

Submitted by Atikah Shukri on Thu, 09/14/2017 - 11:10

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hello sir, i really adore with your project , may i get help from you because i make this project too as my final year project . Hope can hear from you soon . i do really need your help sir. Please sir

Submitted by Samruddhi chitnis on Sat, 09/23/2017 - 22:01

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sir i want to know about the code actually i am not getting that whether the message recieved is stored in str[i++] or is it in x or is x and i the same

Submitted by mayank pingale on Sat, 02/17/2018 - 14:01

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How can i contact you personally ?
Wants to know how to connect led board with aurduino.(but led board is home made by mi connecting all led in series)

Submitted by Ganu on Thu, 04/19/2018 - 19:49

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The module is working on lcd interface but the message send by the mobile phone is not received and displayed. I used the same code specified. Please help me out of it to get the output

Submitted by razu ahmed on Wed, 05/30/2018 - 11:35

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some people facing same problem...like me ..display showing nothing just showing Module fund...nothing else.....can you tell me what is the solution for this problem.

Submitted by Pounrajan on Mon, 09/10/2018 - 16:16

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sir i need one help..
how to print the message in second line...
i will send the message only in first line but not display in second line..
how can resolve it...

C:\Users\tumma\Documents\Arduino\notice_board\notice_board.ino: In function 'void gsm_init()':

C:\Users\tumma\Documents\Arduino\notice_board\notice_board.ino:92:26: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]

       if(Serial.find("OK"))

                          ^

C:\Users\tumma\Documents\Arduino\notice_board\notice_board.ino:109:26: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]

       if(Serial.find("OK"))

                          ^

C:\Users\tumma\Documents\Arduino\notice_board\notice_board.ino:126:36: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]

       if(Serial.find("+CPIN: READY"))

                                    ^

Sketch uses 4134 bytes (12%) of program storage space. Maximum is 32256 bytes.
Global variables use 614 bytes (29%) of dynamic memory, leaving 1434 bytes for local variables. Maximum is 2048 bytes.

i got these errors while compiling . can someone tell how to solve these errors,

Sir I have setup all the connections like yours but i only have the problem with the gsm module that it indicate "Finding Network.." on LCD display and it is stuck on that loop nothing happened after. Please Sir can you please solve my problem or assist me in resolving this problem

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