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CONTENTS
Objectives
Introduction
System Hardware
Interfacing Components
The big picture – Working
Utility
Conclusion
References







OBJECTIVE
Provide a revolutionary product , A stand-alone embedded system to
Efficiently monitoring and remote controlling home appliances.
Conserve power& thereby reduces the wastage of energy.
Serve as a faithful & error free antitheft unit .





INTRODUCTION
History

Disadvantages Of The Predecessors

New Technology









HISTORY
Home automation has been an important issue throughout the last two decades.
First approach done using the electrical home wiring & outlets as a means of data communication within the home.
Other similar systems used conventional phone lines.





DISADVANTAGES OF PREDECESSORS
Communication over transmission lines reduced efficiency.
A proper remote controlling was not possible.
Data speeds were pathetic.



NEW TECHNOLOGY
Offers the facility for user to control his appliances with his cell phone.
Provides information about human presence in house, thereby working as an anti-theft device.
The user can know the status of all home appliances through an sms forwarded by the device.

SYSTEM HARDWARE
Power supply circuit
Microcontroller ATMEGA 16
Liquid Crystal Display
RS 232 converter (MAX232N)
GSM modem
PIR sensor & 555 timers


CIRCUIT BLOCK DIGRAM
POWER SUPPLY CIRCUIT
The power supply circuit converts 220v AC into 5v DC supply.
The power supply circuit contains a rectifier section & a regulator circuit.
The components included in power supply circuit are:
One step down transformer (220v– 12v)
4 diodes IN4007
Voltage regulators LM7812 & LM7805
Capacitors & resistors
Switch & LED

THE POWER SUPPLY CIRCUIT
MICROCONTROLLER ATMEGA 16
High performance, low-power CMOS 8-bit controller.
Based on enhanced RISC architecture
Key features:
Advanced RISC architecture
High Endurance Non-volatile Memory segments
Programmable serial USART
I/O and operating voltage40 pin PDIP
32 programmable I/O lines
Operating voltage 4.5v-5.5v





LCD
It displays the current status of device selected
The type of display used here is 16*2 dot matrix LCD
It consists of 8 data pins for in taking data
Pin numbers 1,2&3 are meant for vcc, ground & contrast control respectively
Pin numbers 4,5 &6 for register select, write & enable respectively



INTERFACING LCD WITH ATMEGA 16
RS 232 CONVERTER (MAX 232)
The device acts as an interface between Data terminal device(Microcontroller) & the Data communication device (Modem)
Standard voltage range of MAX 232 pins is -15v to +15v
The microcontroller transmits in RS 232 logic & this is converted into TTL by the MAX 232 IC so that serial communication between modem & microcontroller is possible

INTRFACING OF MAX232
GSM MODEM
The modem modulates & demodulates the communicating AT commands between the mobile phone & microcontroller
It can speed up the operational time with full range of Voice, Data, Fax and Short Messages
The modem consists of interfaces
i) LED Function including operating Status
ii) External antenna
iii) Serial and control link
iv) Power Supply
v) SIM card holder

THE GSM MODEM
GSM RECEIVER
PIR SENSORS & 555 TIMERS
PIR sensors (Passive Infra Red sensor) are used to detect the presence of any individual or moving object
Sensors detect the movement and give a signal to the 555 timers continuously
The timers generate an interrupt at regular intervals for the microcontroller

PIR SENSOR
INTERFACING COMPONENTS
THE FINISHED LOOK
THE CIRCUIT WORKING
Once a valid SIM card with sufficient balance is inserted into the modem, the device can be operated in the simple steps given below:
a)Switch on the modem power supply and wait for 30s for it to initialize.
b) Switch on the power supply. Look at LCD display to see what commands the microcontroller is sending to the modem to read any message in its in box.
CONTINUED….
c) Simply send the pre coded message for any of following actions
i) Switching on/off any particular device.
ii) Obtaining the status of all the devices.
d) When someone enters the room,PIR sensors detect them and automatically switches on a device. At the same time a message is received at your mobile indicating the change in status of that device.

UTILITY
The circuit can be used in:
Switch-ON, OFF or Restart some
Linux servers
ADSL modems
Printers
Door with electric Lock
Garage door
House lights
Water pumps
Block the engine of your car or your motorcycle

CONCLUSION
This device can be used to monitor home or office appliances
One can avoid unnecessary running of the devices and which in turn help to reduce energy bills
Device can also be used detect tress passers in a protected area or home or office and rise the alarm to an authorized person or group of people
REFERANCES
C S Kudarihal, P M Menghal.“Smart and Intelligent Energy Management System Using GSM Technology”., International Conference on Modeling and Simulation (MS09) India 1-3 Dec 2009
C. B. Jacobina, and E. R. C. Da Silva.“GSM interfacing of microcontroller”IEEE Trans. on Control systems, Vol. 21, No. 6, Nov. 2007, pp 1618-1627.
341-347 “AVR An introductory course” by John Morton – Newness Publication
“Programming and customizing the AVR microcontroller” by Dhananjay V Gadre – Tata McGraw Hill Publication
“Datasheet AVR ATMEGA 16”- datasheetcatalog.com