hame appliance control using gsm

1. Objectives
 To co-ordinate appliances and other devices through Short
MessageService(SMS).
 To effectively receive and transmit data via SMS
 To eliminate the need of being physically present in any
location for tasks involving the operation of appliances
within a household/office.
 Minimize power and time wastage

2. Scope
 The scope of our project “GSM Based control system” is
immense.
 The future implications of the project are very great
considering the amount of time and resources it saves. The
project we have undertaken can be used as a reference or as
a base for realizing a scheme to be implemented in other
projects of greater level such as weather forecasting,
temperature updates, device synchronization, etc. The
project itself can be modified to achieve a complete Home
Automation system which will then create a platform for the
user to interface between himself and the household

3. Application
 Addressing medical issue
 Linking devices i.e. computer, phones, laptops, etc
 It is used to make life easier
 It is used to improve security of our home and
office
 Appliance control
 Control of doors and windows shutters
 Home entertainment system
 Security system

4. Block diagram

5. Requeriment
Hardware
 AT89C51 microcontroller
 Relay circuit
 Relay drive
 Serial communication RS 232 protocol
 GSM modem LCD
Software
 Keil software
 Flash magic
 Proteus software(simulation)

6. Literature review
GSM modem
 GSM is the most popular standard for mobile phones in the world.
It is based on TDMA (time division multiple access) technology.
 We are using the SIMCOM 900, a GSM modem . This is a powerful
GSM/GPRS Terminal with self-contained unit.
 Semen’s GSM/GPRS Smart Modem is a multi-functional, ready to
use, rugged unit that can be embedded or plugged into any
application
 The modem comprises several interfaces:
 LED Function including operating Status
 External antenna ( via SMA)
 Serial and control link
 Power Supply ( Via 2 pin Phoenix tm contact )
 SIM card holder

7. DTMF decoder MT8870
 This DTMF (Dual Tone Multi Frequency) decoder circuit identifies the dial tone
from the telephone line and decodes the key pressed on the remote telephone. Here
for the detection of DTMF signaling, we are using the IC MT8870DE which is a touch
tone decoder IC.


8. RS232 MAX232

9. Microcontroller and pin Configuration
 Features of 8051
i. RAM – 128 Bytes (Data memory)
ii. ROM – 4Kbytes (ROM signify the
on – chip program space)
iii. 32 I/O lines.
iv. Serial Port – Using UART makes it
simpler to interface for serial
communication.
v. Two 16 bit Timer/ Counter
vi. Input/output Pins – 4 Ports of 8
bits each on a single chip.
vii. Harvard Architecture – It has 16
bit Address bus
viii. 8051 can execute 1 million one-
cycle instructions per second
with a clock frequency of
12MHz

10. power supply and relay
Power supply
LED
LED
1k
- +
IN4007 * 4
GND
9-0-9Vac/1Amp
1000uF/35V
7812
POWER SUPPLY
+5V
+12V230VAC
50Hz 2.2k
7805
Relay circuit
 A relay is used to isolate one
electrical circuit from another.
 It allows a low current control
circuit to make or break an
electrically isolated high current
circuit path