The document describes a home automation project that allows users to remotely control home appliances via SMS messages sent to a microcontroller. The transmitting end is a cell phone that can send SMS messages. The receiving end includes a microcontroller, GSM module, relays and other components to receive SMS commands and control appliances. The system uses AT commands to send and receive SMS messages to remotely control devices like heaters and security systems. Future enhancements proposed include adding timers, sensors and hidden cameras for improved security and automation.

1. SUBMITTED BY,
M.ARUN KUMAR (05E111)
T.S.HARISHANKAR (05E122)
S.VEDAPRAKASH (05E166)
III B.E EEE

2. why this project ?
 The present days many houses are secure less
and all appliances are operated manually.
 The objective of this project is to enable users to
remotely control their home appliances and
systems using a cell phone-based interface via a
simple SMS .
 Over the last decade, this problem has been
overcome by using the Internet and through
power-line modems.

3. DESCRIPTION
 TRANSMITTING END
 ANY TYPE OF CELL PHONE THAT CAN SEND AND
RECEIVE SMS.(GSM/CDMA)
 RECEIVING END
 “GSM” CELLPHONE SUPPORTING BASIC AT
COMMANDS
 MICROCONTROLLER
 MAX 232
 RS232 INTERFACE
 POWER SUPPLY
 VOLTAGE REGULATOR
 RELAYS
 KEYPAD AND LCD DISPLAY

4. Wireless?
 Rf?
Short range
Signal get weaken
 Ir?
Short range
Straight path
 Bluetooth?
Short range
No authentication

5. Wireless?
 Wifi?
Need of hot spots
Internet connection
a separate dedicated system
Expensive

6. Wireless - GSM
 Global system of mobile communication
 Available in all parts of the world
 No distance limit
 Needs only a dedicated GSM cellphone
and a interface cable
 Minimum power consumption
 Not expensive
Because we use the SMS for communicating

7. controller?
 A PC?
Expensive
Power consumption is more
 A Microprocessor?
Needs External RAM,TIMER,ROM…..
Serial Interfacing is difficult
 A FPGA?
Expensive
Programming is difficult

8. A Microcontoller
 It has in built RAM,ROM,TIMER….
 Serial interfacing is easy
 Programming is easy
 Power consumption is minimum
 cheap
 Does not occupy much space

9. SOFTWARE
 LABview?
Very expensive
Need of external interfacing device ,DAC
and a PC.
 PLC
Expensive
It has only 8 i/o ports

10. KEIL
 This software is used to program the
microcontroller
 This software uses “C”compiler.
 Easy programming
 Not expensive (freeware is available)
 Needs only a programmer (to burn a
ROM)

11. PROJECT
DESCRIPTION
 ATMEL MICROCONTROLLER SERIES:
89C51 Family
 TECHNOLOGY: CMOS
 FEATURES:
 4K Bytes of In-System Reprogrammable Flash Memory
 Fully Static Operation: 0 Hz to 24 MHz
 Three-Level Program Memory Lock
 128 x 8-Bit Internal RAM
 32 Programmable I/O Lines
 Two 16-Bit Timer/Counters
 Six Interrupt Sources
 Programmable Serial Channel
 Low Power Idle and Power Down Modes

12. MAX232
 It is a dual driver/receiver.
 A capacitive voltage generator to supply RS-232
voltage levels from a single 5-V supply.
 Each receiver converts RS-232 inputs to 5-V
TTL/CMOS levels.
 Each driver converts TTL/CMOS input levels into
EIA-232 levels.
 This chip is used to do the level shifting & it is
required to send data serially to a cell phone which
requires voltage levels as per RS232 standard.

13. RS232 STANDARD
 RS232 is an interface cable used for serial
communication.
 9-pin (DB9) connector cable.
 Voltage level:
+12v(logic 0)
-12v(logic1)
 the signal encoding used here is NRZ-L
 It uses only two levels.

14. AT COMMANDS
 A GSM cellphone is a wireless modem
 The instructions used for controlling the mobile
phone or GSM/GPRS modem are called AT
commands.
 One use of the AT commands is to control the
sending and receiving of SMS messages.

16. Important AT command
 ATD To dial a voice call from the modem.
 AT+CLIR For calling line Identification Restriction.
 AT+CNMI To set the mode of the mobile.
 AT+CMGR To read the message at particular
location.
 AT+CMGD To delete the received message
 AT+CMGS To send the message.
 AT+CMGF To change the message format to PDU
or Text mode.
 AT+CMGL To see all the list of messages.

17. WORKING:
STEP1: the command AT is sent through the microcontroller from SBUF register.
STEP2: “AT+CMGF=1” is sent to set the mobile phone in text mode.
STEP3: AT+CPMS=”ME” command selects the phone memory.
STEP4: AT+CNMI=1,2,0,0,0 this command will read the message in the first index of the
phone memory and delete it after reading it.
STEP5: when a new message says “HEATER ON” is sent from our mobile this is
delivered to the microcontroller directly in this text format.
+CMGL:1,"RECREAD","+85291234567",,"06/11/11,00:30:29+32"
HEATER ON.
STEP6: SBUF register will receive this message. Through our
program the carriage return is sensed and the content of the message
is received.
STEP7: this string received is compared with the already stored string. If this match occurs
the corresponding subroutine is invoked and the corresponding port pin is made “1”.
STEP8: this port is connected to a relay and through this the HEATER is switched ON.

18. SECURITY SYSTEMS
 The security system that is used includes an electronic
keypad that comprises of 8 keys numbering (0-7).
 In the residence absence, When a person enters/types
the home code . This code will be sent to the owner’s
cell phone number through the microcontroller.
 If the code is correct command “OPEN DOOR” is sent.
 The microcontroller will interpret this command and
opens the door. If the code is wrong the door will not
be opened.
 All the above authentication process is done by
separate subroutine in our program. This subroutine is
invoked when the keypad is activated.

19. APPARATUS COST
S.NO
1. Microcontroller(AT 89C51) 60
2. MAX232 30
3. CELL PHONE(NOKIA 3220) 1500
4. SERIAL (F BUS) 160
5. PCB DESIGN 500
6. LCD DISPLAY 100
7. KEYPAD 50
8. POWER SUPPLY 80+3+12+2
TOTAL 2500

20. FUTURE ENHANCEMENT
 CONTROL ENHANCEMENT:
 Timer control:
○ Immersion Heater:
 A timer in microcontroller is used to set the time after it gets
switched off.
○ Motor Pump
 After a period of time, the motor gets switched off & sends a
message like "motor is switched off, tank is filled. “
 Parameter control:
○ Temperature setting in a heater
○ Setting temperature in air conditioners:
 Sensing the temperature, convert into digital signals and using
8255 PPI send info to 89c51.

21.  SECURITY ENHANCEMENT
 Sensors:
○ When a moving object is sensed, all the hidden cameras would get
switched ON.
 Hidden Cameras:
○ Taking photographs & sending via MMS.
 Energy Meter:
○ When speed of rotation exceeds, it will intimate certain devices to turn
OFF.
 Sound Meter:
○ When a sound is sensed, it would send message.