A SMART & INTELLIGENT ENERGY MANAGEMENT SYSTEM USING GSM
Seminar Report
by
SAJUL BABU C
DEPARTMENT OF ELECTRONICS AND COMMUNICATION
COLLEGE OF ENGINEERRING TRIVANDRUM
THIRUVANANTHAPURAM
2010
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ABSTRACT
This circuit presented here is a home automation system which can monitor domestic devices 24/7 from anywhere, anytime the system allows the house owner to monitor and control his home appliances via his mobile phone. The design uses a GSM modem for operating different devices using just an SMS from his cell phone; also he can turn on/off those devices if he had forgot to do so. This smart system can sense human movements and react wisely such that energy conservation is made possible.
1. INTRODUCTION
Nowadays the issue of Energy Conservation is such a hot topic. So here I present a Smart & Efficient technology to control household devices. The main buzz in this topic is GSM, a recent mobile communication technology. This is a home automation system which can monitor domestic devices 24/7 from anywhere, anytime the system allows the house owner to monitor and control his home appliances via his mobile phone. The design uses a GSM modem for operating different devices using just an SMS from his cell phone; also he can turn on/off those devices if he had forgot to do so. This smart system can sense human movements and react wisely such that energy conservation is made possible.
The circuit consists of a GSM modulator, AVR microcontroller, PIR sensors and devices to be controlled. The PIR sensors sense human movements & turn off all devices when no human presence is detected. When message was sent from the mobile phone number which was already stored in modem, for eg, the message sent is “1 on”, the first device is turned on. The GSM modem is interfaced with microcontroller using RS-232 protocol using serial communication between them. The modem uses few commands (AT commands) for its various actions. If human presence is detected it switches on a predefined device and sends an intimation message to the predefined phone number, and if no human presence found ,it switches off the device.
2. FEATURES
• Efficiently monitors & remote controls home appliances
• Power wastage is reduced by proper monitoring
• Serves as a faithful & error free antitheft unit
• Multi channel access control possible
• Relatively low cost & reliability.
• User friendly
• Highly secure
2, APPLICATION
Energy wastage and security breach has become a serious issue today. So a system which can handle both these problems is something most wanted in Home Automation sector. This system can be implemented in a home, office, and museum or even in a bank for it provides greater reliability. Unlike many of its predecessors which had pathetic data speeds & poor remote controlling, the system provides an excellent innovation The circuit can be made use in switching on/off/restart some LINUX servers, in switching of ADSL modems, printers, Doors with electric lock , garage doors, house lights, water pumps, or even can be used to block the engine of your car or motor cycle. Above all it makes the human life better and easier.
Fig1: BLOCK DIGRAM
3. BLOCK DIAGRAM DESCRIPTION
The major hardware interfaces to microcontroller are LCD display, PIR sensors(Passive Infrared Sensors), modem (GSM),etc. Also the appliances are interfaced to the micro controller that is to be controlled. The design uses RS-232 protocol for serial communication between the modem and the micro controller. A serial driver IC is used for converting TTL voltage levels to RS-232voltage levels. The devices that can be interfaced to the micro controller are any 1-Φdevices. Also the corresponding driver ICs and switching circuits are used for operating devices.
When a message is sent to the number in the modem from a remote place, accordingly the devices are either on or off.
For example an SMS – “1ON” is sent, the first device is ON and similarly other operations are performed. The highlight of the design is that it can also sends a return message indicating the status of the device
Fig2:CIRCUIT DIAGRAM
Fig3:THE COMPLEATED LOOK
4. COMPONENTS
1. Power supply circuit
2. Microcontroller ATMEGA 16
3. Liquid Crystal Display
4. RS 232 converter (MAX232N)
5. GSM modem
6. PIR sensor & 555 timers
4.1. Power supply circuit
The microcontroller and other devices get their power supply fromthe power circuit as shown in fig . The power supply circuit is being used for converting 220v AC supply to 5v DC. The power supply unit has the following components:
i) One step down transformer (220v -12v)
ii) Four diodes IN4007
iii)Voltage regulators LM7812 and LM7805
v) Switch and LED
The output of transformer is 12v AC. The diodesare used for obtaining 12v pulsating DC. The voltage regulators 7805/7812 thereafter convert it into regulated 5v DC supply.
Fig4:power supply circuit
4.2. Microcontroller ATMEGA 16:
The ATMEGA16 is a high performance low-power CMOS 8-bit microcontroller based on the AVR enhanced RISC architecture. By executing powerful instructions in a single clock cycle, the
ATmega16 allows the system designers to optimize power consumption versus processing speed. The imp features are listed below
a) Advanced RISC Architecture
i) 131 Powerful Instructions. Most Single clock
Cycle Execution
ii) 32x8 General Purpose Working Registers
iii) Fully Static Operation
iv) Up to 16 MIPS Throughput at 16MHz
b) High Endurance Non-volatile Memory segments
i) 16K Bytes of In-System Self-programmable Flash program memory
ii) 512 Bytes EEPROM
iii) 1K Byte Internal SRAM
iv) Write/Erase Cycles: 10,000 Flash / 100,000 EEPROM.
vi) Data retention: 20 years at 85°C/100 yearsat 25°C.
c) Programmable serial USART
d) I/O and operating voltage
i) 40 pin PDIP
ii) 32 programmable I/O lines.
iii) Operating voltage 4.5v-5.5v.
Fig5:LCD interfaced with ATMEGA16
4.2.1 Vital role of microcontroller:
The microcontroller is the heart of this circuit. It has been programmed in such a way that if any individual enters the room the sensors will detect and give an interrupt to the microcontroller, the controller then will switch on the device and give appropriate AT commands to the modem to send the alert SMS to the owner mobile.LCD is connected to microcontroller in 8 bit data mode. Before displaying anything in LCD
Microcontroller will control the LCD initialization and select the data register and command register according to the purpose. Relay and sensors are controlled by the microcontroller using single pins. Making a pin high or low would actually switch on and off the devices. Thus the microcontroller synchronizes and directs all the activities between all the hardware components such as modem, LCD, relays & sensors
Fig6:ATMEGA16 dimensions
4.3. LCD (Liquid Crystal Display):
LCD adds a lot to the application in terms of providing a useful interface for the user, debugging an application and giving it a "professional" look the most common type of LCD controller is the Hitachi 44780 that provides a relatively simple interface between a processor and an LCD.
Inexperienced designers do often not attempt using this interface and programmers because it is difficult to find good documentation on the interface, initializing the interface can be a problem and the displays themselves are expensive. Ref fig 3, LCD used has Two-line display with each line having 16 characters. There are 16 pins on the LCD. 8 pins are connected to microcontroller for data; three pins for register select, write and enable; 4 pins for input power and
ground and 1 pin for contrast control.
4.4.RS 232 CONVERTER (MAX 232N):
This is the device, which is used to convert TTL/RS232 vice versa. The IC used is MAX 232N.AVR The main role of the RS232 chip is to convert the data coming for the 12-volt logic to 5 volt logic and from 5 volt logic to 12 volt logic
Fig7:RS232 interfaced with ATMEGA16
4.4.1. RS-232Protocol:
RS-232 was created for one purpose, to interface between Data Terminal Equipment (DTE) and Data Communications Equipment (DCE) employing serial binary data interchange. So as stated the DTE is the terminal or computer and the DCE is the modem or other communications device.
4.4.2. Voltage range:
The standard voltage range on RS-232 pins is 15Vto +15V.This voltage range applies to all RS-232signal pins. The total voltage swing during signal transmission can be as large as 30V. In many cases,
RS-232 ports will operate with voltages as low as_5V to +5V. This wide range of voltages allows for better compatibility between different types of equipment and allows greater noise margin to avoid interference. Because the voltage swing on RS-232 lines is so large, the RS-232 signal lines generate a significant amount of electrical noise. It is important that this signal does not run close to high impedance microphone lines or audio lines in a system. In cases where you must run these types of signals nearby one another, it is important to make sure that all audio wires are properly shielded
4.4.3. Vital role of RS232 Converter (Max 232n) :
RS 232 Converter is an IC to convert the TTL voltage levels into RS 232 level and vice versa, Maxim Corporation develops this chip. In this case MODEM is communicating with the microcontroller through a serial port; the microcontroller will send the commands to the modem through RS 232. Thus to make the modem compatible with the microcontroller for serial communication we are using the RS232 converter.
4.5. GSM modem:
Siemens’s GSM Smart Modem is a multi-functional, ready to use, rugged unit that can be embedded or plugged into any application. The Smart Modem can be controlled and customized to various levels by using the standard AT commands. The modem is fully type-approved, it can speed up the operational time with full range of Voice, Data, Fax and Short Messages. Description of the interfaces: The modem comprises several interfaces:
i) LED Function including operating Status
ii) External antenna
iii) Serial and control link
iv) Power Supply ( Via 2 pin Phoenix tm contact)
v) SIM card holder
4.6. PIR Sensors and 555 timers:
PIR sensors (Passive Infra Red sensor) are used to detect the presence of any individual. Sensors are used to detect the movement and give a signal to the 555 timers continuously. The timers generate the 555 timers continuously. The timers generatean interrupt at regular intervals for the microcontroller. On receiving the interrupt the microcontroller acts accordingly. After the description of the components now it issuitable to give the final circuit diagram as displayed below some important pin connections of microcontroller are listed below:
a) The devices are connected at pins A.3, A.4, A.5 and A.6.
b) PIR sensors are connected at pins C.0, C.1, C.2 and C.3.
c) All 8 pins of PORT B are connected to the data lines of the LCD.
d) pins A.0, A.1 and A.2 are used for providing select, enable and write signals to the LCD.
e) Pins D.1 and D.0 are connected to the modem through MAX232 for the purpose ofserial communication.
The hardware connections were completed as per the circuit diagram and explanation given earlier.
5 CIRCUIT ASSEMBLING
5.1. Setting the baud rate:
The next most important step was to set up a suitable baud rate for the transmission of commands to the modem. The baud rate was selected to be 9600 bits per second which is the universally accepted and the maximum offered by the modem used. The selected baud rate (BAUD)along with the frequency of the oscillator (FOSC)used is fed to the MYUBRR register of microcontroller as per the following formula MYUBRR = FOSC/16/BAUD – 1MYUBRR is a special internal register which needs to be loaded with the baud rate and frequency of the oscillator before setting up the serial transmission.
5.2.Establishing serial communication:
As shown in diagram pin D.0 is used for receiving and D.1 is used for transmitting the bits to the modem. The status of this data transfer is displayed in the status registers UCSRA, UCSRB and UCSRC (Universal Status and Control Register)These are 8 bit registers and each bit conveys some specific information about the status of task on serial. The details are as per the apex ‘D’. Thus these registers are used while programming for indicating the receipt of some message from the modem as also for transmitting the commands to the same.
5.3.Establishing the display:
The LCD is connected as per the fig 3. It is controlled by the microcontroller through LCD commands. The important LCD commands used are listed as per the apex. The LCD differentiates between a data and a command through its select pin. If the microcontroller makes the select pin low then it assumes the bits on its data lines as a command and performs suitable action such as clear screen, cursor blinking etc. However if the microcontroller makes the select pin high then the LCD displays the bits that it receives on its data lines.
5.4.Interfacing of the sensors:
The sensors continuously generate a signal on detecting any movement. This signal is then fed to the 555 timer which generates an interrupt for the microcontroller informing it of the detection. The timer after a specified interval once again checks for the sensors to generate a suitable interrupt. Thus the microcontroller receives interrupts from the timer only at specified intervals. This is done because the processing speed of the microcontroller is not sufficient to accept continuous signal from
The sensors. Interfacing the devices: The pins of the microcontroller are connected to ULN 2003 as shown in fig 6. This IC converts 5v from the microcontroller to 12v signal for the operation of relays In the above diagram the devices have been represented by the LED. However in place of these LED’s SPDT relays switches have been placed. The devices are in turn connected to the relay switches. Thus the activation of the relay activates the device.ULN2003A apart from the above function also protects the microcontroller from any reverse high voltage flow from the devices.
5.5.Using the System:
Once a valid SIM card with sufficient talk time is inserted into the modem the device can be operated in the following simple steps.
a) Switch on the modem power supply and wait for30s for it to initialize.
b) Switch on the power supply of the device. Look at the LCD display to see what commands the microcontroller is sending to the modem to read any message in its in box.
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 any individual enters the room in your absence the PIR sensors detect the same and automatically switch on the device. At the same time a message is received at your mobile indicating the change in status
5.6.Usage of this circuit:
With this circuit you can switch-ON, OFF or Restart some Linux servers, ADSL modems, Printers, Door with electric Lock, Garage door, House lights, Water pumps, electric sunshade, Block the engine of your car or your motorcycle, at the steal case and much more. The purpose of this circuit is to make the human life better and easier.
6. PROGRAMME CODE
include <P89V51Rx2.H> // header file
include<string.h>
voidinit (void); // prototype declaration void Uart_gsm (void);
void delay(unsigned char); void Recievedata(); void gsminit(void); void gsmcmdsend(unsigned char *); unsigned char Rx_data(void);
sbit device1=P0^0;
sbit device2=P0^1;
unsigned char message[11]; unsigned char count;
unsigned char code password1[10]="device1 on"; // Commands for controlling devices unsigned char code password2[11]="device1 off"; unsigned char code password3[10]="device2 on"; unsigned char code password4[11]="device2 off";
void main() { // port initialization init(); Uart_gsm(); // serial port initialization gsminit(); Recievedata(); // for recieving the data from modem }
voidinit(void) {
P0=0x00; }
voidUart_gsm(void) { TMOD = 0x20; TH1 = -3; SCON = 0X50; TR1 = 1; } void Recievedata() {
while(1) {
while(Rx_data()!='+'); // chacking message format
while(Rx_data()!='C');
while(Rx_data()!='M');
while(Rx_data()!='T');
while(Rx_data()!=':');
while(Rx_data()!='"');
while(Rx_data()!='\n');
for(count=0;count<11;count++) // storing msg in a buffer {
message[count]=Rx_data();
if(message[count]=='\r')
break; } message[count]='\0';
if(strncmp(message,password1,10)==0)
// comparing message with password to make a action on device
{
device1=1;
}
if(strncmp(message,password2,11)==0) {
device1=0;
}
if(strncmp(message,password3,10)==0)
{
device2=1;
}
if(strncmp(message,password4,11)==0) {
device2=0;
}
}
}
// TO RECIEVE SERAIL DATA unsigned char Rx_data(void) { RI=0; while(RI==0); return(SBUF); }
void delay(unsigned char x) { unsigned inti,j; for(i=0;i<x;i++) for(j=0;j<2000;j++); }
voidgsminit(void) {
// AT COMMANDS unsigned char gsm_cmd1[]="AT"; unsigned char gsm_cmd2[]="ATE0"; unsigned char gsm_cmd3[]="AT&W"; unsigned char gsm_cmd4[]="AT+CMGF=1"; unsigned char gsm_cmd5[]="AT+CNMI=2,2,0,0,0"; gsmcmdsend(gsm_cmd1); gsmcmdsend(gsm_cmd2); gsmcmdsend(gsm_cmd3); gsmcmdsend(gsm_cmd4); gsmcmdsend(gsm_cmd5); }
void gsmcmdsend(unsigned char *cmd) // FUCNTON TO ININTILIZE AT COMMANDS FOR MSG { unsigned char i; for(i=0;*cmd!='\0';i++) { SBUF=*cmd; while(TI==0); TI=0; cmd++; } delay(2); SBUF=0x0A; while(TI==0); TI=0; SBUF=0x0D; while(TI==0); TI=0; while(RI==0); RI=0; }
7.a. CONCLUSION
Smart and Intelligent Energy Management System Using GSM Technology circuit is tested in the laboratory and found working very satisfactorily. This device can be used to monitor home or office appliances and one can avoid unnecessary running of the devices and which in turn help to reduce energy bills. Secondly the 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’s.
7.b, UTILITY
The circuit can be made use in switching on/off/restart some LINUX servers, in switching of ADSL modems, printers, Doors with electric lock , garage doors, house lights, water pumps, or even can be used to block the engine of your car or motor cycle. Above all it makes the human life better and easier.
9. REFERENCES:
• CS Kudarihal P M Menghal, “Smart and Intelligent Energy Management System UsingGSM Technology” ,International Conference on Modelling and Simulation (MS09) India 1-3 Dec 2009, pg no 208
• Alexander M.Haimovich, Takizawa and Tetushi Ikegami,”Applied Home Automation using AVR”,IEEE ACTIVE SYSTEM MAGAZINE,pp.116-123,January 2009.
• “Datasheet AVR ATMEGA 16”-datasheetcatalog.com
