SRI VENKATESWARA ENGINEERING COLLEGE (Sponsored by exhibition society AfflIiated by JNTU Hyderabad) Under the guidance of B.Swetha M.tech Presented by: K. Navya - 449 S. Harikrishna - 421 P. Ganesh - 418 N .Rajiv - 458 GSM Based Wireless Notice Board Main project report on
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SRI VENKATESWARA ENGINEERING COLLEGE(Sponsored by exhibition society AfflIiated by JNTU Hyderabad)
Notice Board is primary thing in any institution or organization or public utility places like bus stations, railway stations and parks. But sticking various notices day-to-day is a difficult process.
INTRODUCTION
It presents an SMS based notice board incorporating the widely used GSM to facilitate the communication of displaying message on notice board via user’s mobile phone.
SIM900 GSM modem with a SIM card is interfaced to the ports of the microcontroller with the help of AT commands.
SIM900 is duly interfaced through a level shifter IC MAX232 to the microcontroller. The messaged is thus fetched into the microcontroller.
It is further displayed on an electronic notice board which equipped with LED display interfaced to microprocessor powered by a regulated power supply from mains supply of 230 volts ac.
BLOCK DIAGRAM
lpc2148
GSM Modem
GSM modem is the Data Communicating Equipment which is connected to terminal equipment for data transmission and reception.
GSM stands for Global System for Mobile Communication
SIM stands for Subscriber identity Module
GSM modem is controlled using AT commands
AT stands for Attention
Ex- AT, AT+CMGR, AT+CMGS, AT+CMGD etc.
SCHEMATIC DIAGRAM
AT Commands & Corresponding Operation
AT Commands Description
AT To check if Modem is connected properly
ATE0 To turn echo off
ATE1 To turn echo on
AT+CMGF Set operating Mode
AT Commands & Corresponding Operation
AT Commands DescriptionAT+CMGD= <index>, <delflag>
To delete a message
AT+CMGR= <index> To read message from an index
AT+CMGS= “contact no.” , TP-type address
To send message to specified contact no.
MAX 232
MAX 232 IC
MAX 232 that converts signals from an RS-232 serial port to signals suitable for use in TTL compatible digital logic circuits.
The MAX 232 is a dual driver/receiver and typically converts the RX, TX CTS and RTS signals.
It changes a TTL Logic 0 to between +3 and +15 V, and changes TTL logic 1 to between -3 to -15V, and vice versa for converting from RS232 to TTL.
User wants to display a message in the led board
User sends the message from his mobile defining the message in the code format and then to the number of the subscriber identity module (SIM) which is inserted in the display system MODEM.
LED DISPLAY
ARM7
ARM7
ARM: Advanced RISC Machine Founded in1990, owned by Acorn, Apple and VLSI Most widely used 32-bit instruction set architecture Suitable for low power devices Used extensively in consumer electronics, PDA (Personal
Digital Assistant), mobile phones, computer peripherals (hard drives & routers), music players, game consoles, calculators, etc.,
FEATURES OF LPC 2148
8 kb to 40 kb of on-chip static RAM and 32 kB to 512 kB of on-