04-08-2010, 06:44 PM
This system is for GSM SMS BASED DEVICE ON-OFF CONTROL . The design portion involves mainly a GSM modem and control circuit which may consist of microcontroller and Max232N. The coding is done in Embedded C and schematic drawing and pcb designing software are utilised. Here, a Motor Starter for irrigation in Agricultural Applications is implemented using the GSM modem and many other parts.
Components used
The major parts used in the system are :
Crystal -
Microcontroller
- 89S52Atmel
Power Supply 5v DC -
7805 voltage regulator
GSM Transmitter and
Motor Starter
MAX232 - Serial Communication
11.0592MHz Receiver (MODEM).
Micro controller-AT89S52
It is a CMOS 8-bit microcontroller with 8K bytes of in-system programmable Flash memory. It is low-power, high-performance microcontroller. The other features include 1000 Write/Erase Cycles ¢ 4.0V to 5.5V Operating Range ¢ 256 x 8-bit Internal RAM ¢ 32 Programmable I/O Lines etc.
RS 232 CONVERTER (MAX 232N)
It converts serial port RS 232 to TTl compatible and vice versa.
WORKING PRINCIPLE
If the user wants to control some devices in
his house, he/she has to first send an SMS to the system specifying the operation of the device and then the system password. The GSM MODEM recieves the SMS and the microcontroller authenticates the password. The it checks whether the message was for switch ON or OFF the Motor and the relays are switched on / off accordingly.
For details regarding the block diagram, circuit, code etc, visit this link:
http://scribddoc/27317360/GSM-Based-Device-Control
http://scribddoc/23273920/Appliances-Control-Through-Sms