Wireless Electronic Notice Board using GSM

We know the importance of notice boards in public places like railway stations, bus stations and airports. But changing notices day-to-day is a difficult task. This article explains you how to design a Wireless Electronic Notice Board using GSM technology. The project displays the data on LCD whatever we sent from the mobile.

There are many wireless communication technologies like Bluetooth, RF Communication, ZigBee, etc. but GSM Technology based communication allows long range, reliable and secure communication.

Wireless Electronic Notice Board using GSM

The Wireless Electronic Notice Board using GSM project, as the name suggests, is built around GSM Technology as mobile phones (that communicate through GSM Technology) have become very abundant, cheap and easy to use.

NOTE: We need a Mobile Phone to send the Message (Notice) and a GSM MODEM to receive that notice.

Related Post: RFID Based Attendance System using Microcontroller

Construction and Output Video 

Circuit Principle

When we send the message from the mobile, the GSM Modem which is connected to the Microcontroller and the display unit, will receive the message. Now, the microcontroller reads the message from the GSM Modem and displays it on LCD.

When user sends the message from the mobile, GSM modem sends the below command serially to indicate that a new message is received.

+CMTI: “SM”,3

In the above command, number “3” indicates the location of the new message i.e. it is the third message in the inbox. Now you need to read this unread message to display on LCD. The command to read the message from GSM modem is

AT+CMGR=3

Here, the number “3” indicates the location of the message to be read. After giving this command to the GSM module, it will send the below command serially.

+CMGR: “REC UNREAD”,”MD-WAYSMS”,,”13/05/20,15:31:48+34″

Electronics Hub

In the above command, “REC UNREAD” indicates that message is unread message, “MD-WAYSMS” indicates sender mobile number or name, 13/05/20 indicates the date, 15:31 indicates time and Electronics hub is the content of the message.

From the above command we need to extract message (Electronics Hub) sent by the user to display it on the notice board (LCD).

Circuit Diagram of Wireless Electronic Notice Board using GSM

Components for Wireless Electronic Notice Board using GSM 

Hardware Requirements

• 8051 Microcontroller (AT89C51)
• 8051 Programming board (Programmer with cable)
• 8051 Development Board
• SIM 900A GSM MODEM (GSM Module)
• SIM Card (for inserting in GSM Modem)
• A mobile phone with a SIM Card already inserted
• 16 x 2 LCD Display
• 10 KΩ Potentiometer
• Connecting wires
• Power Supply
• If 8051 Development Board is not available, then you need the following components
  • 2 x 10 KΩ Resistors (1/4 Watt)
  • 2 x 33pF Ceramic Disc type Capacitors
  • Push Button
  • 10µF / 16V Capacitor (Polarized)
  • 0592 MHz Quartz Crystal

Software Requirements

• Keil µVision IDE (for writing the program and generating .hex file)
• Willar Software (for burning the .hex file in to the microcontroller)
• Proteus (for circuit diagram and simulation)

Circuit Design

The above circuit of the Wireless Electronic Notice Board using GSM consists of 8051 Microcontroller, GSM Module (Modem) and 16 x 2 LCD. Here, the 16 x 2 LCD is used to display message and is used in 8 – bit mode. Means, we need 8 data lines to display the data. The data lines of the LCD Display are connected to PORT1 Pins. The control pins RS, RW, and E pins are connected to P3.6, GND and P3.7 pins respectively.

The GSM Module is directly connected to the microcontroller as the logic levels of both the GSM Modem and Microcontroller are already matched in the GSM Module Board. If there is no level converter on the board, then we need to use MAX232 level converter as a mediator between Controller and GSM to transfer the data.

To know more details about max232 refer Max232 Datasheet

In order to communicate with the GSM Modem, we need to send some AT commands using serial communication (UART protocol). Here, GSM SIM 900A module is used. This module requires 9600 baud rate.

To know more details about GSM go through the article GSM Interfacing with 8051 Microcontroller

Circuit Algorithm

1. Initialize the LCD and UART protocol
2. Check for the command +CMTI: “SM”,3 (Location number) to know whether the new message is received or not.
3. If you receive the command, then store message location number.
4. Now read that particular location and extract the body of the message.
5. Display the message on LCD.

Use below code to display message on LCD wirelessly using GSM

while (rx_data() ! = 0x0d);
while (rx_data() ! = 0x0a);
if (rx_data() == ‘+’)
{
if (rx_data() == ‘C’)
{
if (rx_data() == ‘M’)
{
if (rx_data() == ‘T’)
{
if(rx_data()==’I’)
{
while (rx_data() != ‘,’);
a = rx_data ();
delay_ms (10);
tx_string (“at”);
tx_data (0x0d);
tx_data (0x0a);
tx_string (“at + cmgf =1”);
tx_data (0x0d);
tx_data (0x0a);
tx_string (“at + cmgr =”);
tx_data (a);
tx_data (0x0d);
tx_data (0x0a);
while (rx_data() ! = 0x0a);
while (rx_data() != 0x0a);
while (rx_data() ! = 0x0a);
for (i=0; i<15; i++)
{
read [i]= rx_data();
}
lcd_stringxy(1,0,read);
delay_ms (5000);
}
}
}
}
}

Circuit Simulation Video

How to Operate Wireless Electronic Notice Board using GSM?

1. Write the program to the wireless electronic  notice board using Keil software
2. Now burn the program to the microcontroller with the help of hardware programmer and Willar Software.
3. Give the connections as per the circuit diagram.
4. Use power supply circuit to provide 5V DC to the microcontroller
5. Insert the SIM (Subscriber Identity Module) to the GSM module.
6.  Now switch on the supply
7. Send SMS to the GSM module using other mobile
8. Now you can see the same message on LCD.

Circuit Advantages

• No need of any complex wires to display the message on LCD as it is wireless.
• Consumes less power and easy to operate.
• The circuit is portable.

Circuit Applications

• Used in bus stations, railway stations, parks, etc. to display the messages wirelessly
• This Project can also be used in colleges and organizations.

Circuit Limitations

• Display unit must have the network to receive the message wirelessly
• As there is no password any one can send the message to display.

Download Project Code