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Password Protected 20X4 Alphanumeric LCD and SIM800 GSM/GPRS Modem based SMS Controlled Wireless Digital Notice Board with Mobile Number Authentication using ATmega32-II

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In this project, we will learn how to make a Password Protected 20X4 Alphanumeric LCD and SIM800 GSM/GPRS Modem based SMS Controlled Wireless Digital Notice Board with Mobile Number Authentication using AVR ATmega32 Microcontroller-II. Here, we will receive notice board content wirelessly through SMS using SIM800 GSM/GPRS modem and ATmega32 microcontroller and we will display the notice board content in a 20X4 Alphanumeric LCD. But before the notice can be displayed in the 20X4 alphanumeric LCD, a password  needs to be sent by SMS to gain access of the digital notice board and SMS received from one particular mobile number are valid and processed by the digital notice board and others are discarded. This digital notice board can display only 160 characters only.

When the SIM800 GSM/GPRS modem power is turned on, the ATmega32 microcontroller reads the initial status data sent by the SIM800 GSM/GPRS modem through USART protocol. After reading the status data, the ATmega32 microcontroller processes the SIM800 GSM/GPRS modem status data and displays the status of the modem and SIM in the alphanumeric LCD. If SIM card is not present, then "Plz Insert SIM" is displayed, if SIM card is present and modem is ready, then "SIM800 is Ready" is displayed and for other conditions, "SIM800 Error" is displayed in the alphanumeric LCD.

Now, when the SIM800 GSM/GPRS modem is ready, the LCD displays "Send Password:" in it. The digital notice board treats all SMS received as password SMS till the correct password SMS is not received. Once correct password SMS is received and password is authincated, all SMS received after password SMS are treated as notice SMS. When the SIM800 GSM/GPRS modem receives any SMS, it sends new SMS notification to the ATmega32 microcontroller. But if the ATmega32 microcontroller receives some other notification(other then SMS like Call and others), then "Unknown Error" is displayed in the  alphanumeric LCD. The ATmega32 microcontroller reads the new SMS notification. After reading the SMS notification, ATmega32 microcontroller checks whether password authentication is pending or over. If password authentication is pending, then "PasswordRecieved" is displayed in the LCD display. Then, the ATmega32 microcontroller reads the SMS and if it reads the SMS successfully, then it will compare the mobile number from where SMS is received with the stored mobile number else it will display"Empty location" when the read memory location is empty and "Error" when there is error in reading the SMS. Now, if the mobile numbers matches, then "Valid Number" is displayed in the alphanumeric LCD and the message of the SMS(received password) is compared with set password else "Invalid Number" is displayed in the alphanumeric LCD and SMS is discarded. The mobile number of the received SMS is compared with the stored mobile number each time the digital notice board receives any SMS and SMS received from valid mobile number are processed by the ATmega32 microcontroller and others are discraded. If the SMS is received from a valid mobile number, then it will compare the content of the SMS with the stored password. If the received password and the set password are same, then "Correct Password" is displayed in the alphanumeric LCD else "Re-send Password" is displayed in the LCD. Apart from display in LCD, the status of the password comparision is sent as SMS(Correct Password or Wrong Password) to the mobile number from which the password SMS is received. The digital notice board will request user to send password SMS till the correct password is sent. Once correct password is sent, the digital notice board will request the user to send notice SMS and the LCD displays "Send Notice" in its 1st row. The digital notice board waits for the notice SMS to display the notice in the 20X4 alphanumeric LCD.

When the SIM800 GSM/GPRS modem receives any SMS after password authentication, it sends new SMS notification to the ATmega32 microcontroller. The ATmega32 microcontroller reads the new SMS notification and displays "New Notice" in the alphanumeric LCD. But if the ATmega32 microcontroller receives some other notification(other then SMS like Call and others), then "Unknown Error" is displayed in the  alphanumeric LCD.  After receiving new SMS notification, the ATmega32 microcontroller will read the SMS from the SIM800 GSM/GPRS modem memory. If it reads the SMS successfully, then it will compare the mobile number from where SMS is received with the stored mobile number else it will display"Empty location" when the read memory location is empty and "Error" when there is error in reading the SMS. When the notice SMS is read successfully, the ATmega32 microcontroller compares the mobile number from where SMS is received with the stored mobile number, if the mobile numbers matches then "Valid Number" is displayed in the alphanumeric LCD and the message of the received noticel SMS is displayed in the alphanumeric LCD else "Invalid Number" is displayed in the alphanumeric LCD and SMS is discarded. The mobile number of the received SMS is compared with the stored mobile number each time the digital notice board receives a SMS and SMS received from valid mobile number are processed by the ATmega32 microcontroller and others are discraded. When the notice SMS is read successfully, the ATmega32 microcontroller displays the 1st 160 characters of the notice SMS in the 20X4 Alphanumeric LCD. But, since the 20X4 alphanumeric LCD can display a maximum of 80 characters in it at ant instant of time, so 160 characters are displayed in slots of 80 characters. Initially, 1st 80 charactes are displayed, then next 80 charactes are displayed. There is delay of 2s between display of each 80 characters. In this way, 160 characters are displayed in 2 slots with a time gap of 2s between each slot. The above process contiues and the notice is displayed continuously in the 20X4 alphanumeric LCD.

Now, send different SMS to the SIM800 GSM/GPRS modem of the Digital Notice Board from different mobile number and check mobile number authentication, password authentication and see the notice in the 20X4 Alphanumeric LCD.

Softwares Required

Hardwares Required

Name / Unit Price Quantity Total Price
AVR Trainer Board-100 with ATmega32
Rs. 730.00
1pc
Rs.730.00
AVR USB Programmer
Rs. 350.00
1pc
Rs.350.00
SIM800 GSM/GPRS Modem
Rs. 1500.00
1pc
Rs.1500.00
JHD204A 20X4 Alphanumeric LCD Green
Rs. 400.00
1pc
Rs.400.00
12V, 2A SMPS Adaptor
Rs. 170.00
1pc
Rs.170.00
10 to 10 FRC Female to Female Connector
Rs. 15.00
2pc
Rs.30.00
1 to 1 Connector-Female to Female
Rs. 4.00
18pc
Rs.72.00
TOTAL Rs.3252.00

Circuit Diagram

Circuit_Diagram_of_Password_Protected_20X4_Alphanumeric_LCD_and_SIM800_GSM_GPRS_Modem_based_SMS_Controlled_Wireless_Digital_Notice_Board_with_Mobile_Number_Authentication_using_AVR_ATmega32_Microcontroller-II.png

Video

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