ELECTRONICS NOTICE BOARD

In the day to day life, we have the importance of the notice boards in the public places like the railway stations, bus stop, airports. But to change the notices every single day is a difficult task. This article explains you to design a wireless electronic notice board with the help of the GSM technology. This project displays the data on the LCD whatever we sent from the mobile.

 

PRINCIPLE


When we send the particular message from the mobile, the GSM modem which is then arranged at the display unit will receives the message. Now the controller can read the message from the GSM modem and then displays in on LCD.

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

  • +CMTI: “SM”,3

In the following above command number 3 indicates that the location of the new message. Now you need to read this unread message to display this message on LCD. The command to read the following message from GSM modem is

  • at+cmgr=3

Here the number 3 indicates that the location of the message to be read. After giving this command to the GSM module send the below command serially.

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

 

CIRCUIT DESIGN


notice-board

 

COMPONENTS


  • AT89C51 controller
  • AT89C51 Programming board
  • Single pin connecting wires
  • 16*2 LCD
  • 10k (1/4 watt) resistor
  • MAX232 level converter
  • 12MHz crystal
  • DC battery or 12V,1A adaptor
  • 5V power supply circuit
  • 0.1uF ceramic capacitors – 4
  • 33pF capacitors – 2
  • 10uF electrolytic capacitor
  • GSM sim 300 module
  • Programming cable

 

SOFTWARE


  • Keil compiler
  • Proteus
  • Flash magic

 

CODES


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);

}

}

}

}

}

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