Project Report 9-07-2013

WI-FI Based Real Time Monitoring and Control System using Power Lin e Communication

Dept of ECE, SJCE, Mysore. 1

Chapter 1

INTRODUCTION

Automation essentially involves leveraging the power of technology to reduce the

dependency on human presence and decision making for any process. It leverages

different electronic equipment (either standalone or interlinked with appropriate

applications) to control different parameters of any process. In these days of energy

scarcity, it is prudent to save energy in every way possible and is paramount to make such

systems as easy to use as possible so that people can use their appliances in a smarter way

to save energy. It also enables people to be more energy conscious by enabling them to

have a real time status of electric appliances.

Automation also helps reduce peak hour power consumption by enabling people

to turn off appliances at will remotely. This facilitates a constant power supply by having

varied pricing policies for different times of day and night. The results are exceptionally

good with the use of wireless technologies.

1.1 Objective of the Project

The main aim of the project is to design and develop an open source automation

system for controlling electrical appliances using Power Line Communication (PLC) and

monitoring the data.

The objective of this project is to design a WSN using PLC to monitor and control

the electrical appliances i.e. to inform appropriate individuals in a timely and cost

effective manner and take suitable actions. The project further deals with the detection of

temperature monitoring and controlling. This project is implemented taking an example

of the temperature detection using sensor in the places like industries, hospitals, colleges

etc. In this project, we present an automation system which is easy to implement and can

report to the user, if the value exceeds the preset limit and also enables the user to send

appropriate signals to control the appliances. Due to this flexibility of reporting, low cost

due to use of PLC and easy implementation, the automation system will be preferred.

The project describes the design for WSN response systems using Temperature

sensor. Further, it deals to design and develop the system using the embedded technology,



with the latest networking technology in the real time environment. The project will

utilize open hardware for realizing its goals.

1.2 Methodology

The main aim of the project is to design and develop an open source automation

system for controlling electrical appliances using power line communication and

monitoring the data [1]. The experimental setup is as shown in the block diagram in

Fig 1.1. Control messages are sent over Wi-Fi network from a Wi-Fi device to the PC

which then couples the messages to the power lines using the micro controller with the

serial port interface. Ubiquitous power lines are used as physical media to transmit data

over 220V/50Hz signal to control appliances/equipment and to monitor.

Fig 1.1 Block diagram of Remote Monitoring and Control System

Here we are monitoring the temperature and when this crosses the set limit the

data is sent back to the PC and this will send the data to the cell phone and the user can

get to know the temp details. The data from the microcontroller is coupled onto the power

lines using a PLC modem and DCSK (Differential Code Shift Keying) modulation

technique is employed to transmit data. The receiver unit consists of PLC modem plus

microcontroller and can be connected anywhere in the power line network. The receivers



have addresses assigned to them and only respond to the commands sent to them by the

transmitter PLC modem. The receiver unit controls the flow of electricity to the socket.

1.3 Scope of the Project

The proposed project aims at ensuring good monitoring and control of various

industrial parameters. It provides a good automation system as it sends a warning

message when the parameters exceed the preset limits. Also the system provides an easy

access to either switch on/off the device based on the value of the parameter received.

This system will be advancement in the industry, and also of low cost, since information

can be transmitted through the existing power lines without having to rewire the system.

1.4 Organization of the Report

Rest of the thesis is organized as follows.

Chapter 2 describes about the literature survey taken from the papers published in IEEE

transactions and reputed websites related to the design and implementation of Wi-Fi

based real time monitoring and control system using PLC.

Chapter 3 explains about Communication Protocols like PLC, Wi-Fi and DSSS

Modulation.

Chapter 4 describes the hardware implementation PLC Module, PIC Microcontroller

18F458, Temperature sensor, Amplifier, MAX232, ULN2003, Relay and LCD.

Chapter 5 gives the explanation of software implementation, Embedded C, MPLAB,

JAVA basics and Flowcharts.

Chapter 6 describes the results, conclusion and scope for future work.

Appendix A gives the pin description and architecture of PIC18F458 microcontroller.

Appendix B describes the information about description and other details of LM35.

Appendix C explains the details about input voltage range and features of LM324.

Appendix D gives the information about typical operating circuit and features of

MAX232.

Appendix E gives the details of ULN2003

Appendix F gives the features of PLC.



Chapter 2

LITERATURE SURVEY

2.1 A Remote Controller for Home and Office Appliances by

Telephone [5]

This paper describes the design and development of a phone -based remote

controller for home and office automation. The circuit is designed based on the Turkish

telephone standards and connected to the telephone network just like any normal

telephone sets. Any tone dialing Dual Tone Multiple Frequency (DTMF) telephone set or

hand-held tone dialer may be used to send commands to the control unit, and remotely

control a wide range of mains appliances in homes and offices. The designed circuit can

also detect user identification number for prevent non-authorized use of the control unit.

The feedback signal informs to the user about the results of commands.

2.2 Remote-Controlled Home Automation Systems with

different Network Technologies [6]

This paper describes an investigation into the potential for remote controlled

operation of home automation systems. It considers problems with their implementation,

discusses possible solutions through various network technologies and indicates how to

optimize the use of such systems. The home is an eternal, heterogeneous, distributed

computing environment (Greaves, 2002) which certainly requires a careful study before

developing any suitable Home Automation System (HAS) that will accomplish its

requirements. Nevertheless the latest attempts at introducing Home Automation Systems

in actual homes for all kinds of users are starting to be Successful thanks to the

continuous standardization process that is lowering the prices and making devices more

useful and easier to use for the end user. Even so several important issues are always to be

handled strictly before developing and installing a Home Automation System; factors like

security, reliability, usefulness, robustness and price are critical to determine if the final

product will accomplish the expected requirements.



2.3 Remote Control of Electrical Appliances via Power Line [7]

The presented work deals with problems of data transfer via power line 230 V for

the purposes of remote control electrical appliances. The devices providing relative

communication via power li

ne for a one-family house were designed and assembled. The designed devices,

namely the input-output unit, PC interface and the GSM gate, work on a bus principle.

The bus is constructed by power line 230V. The designed devices are composed of the

AVR microcontrollers and their mutual communication via power line is provided by

TDA5051AT modem. Communication protocol, with which the devices work, was

developed so that it corresponds with hardware resolution of particular devices. The

particular devices were practically implemented and their activity was tested.

2.4 Street Public Light Control and Monitoring using PLC [8]

There may be tens of thousands of street lamps in the streets and along the

highways. To inspect each lamp to check if it is working is an arduous task. Isn't it nice to

have a system, which will automatically report if a lamp in a Public Lighting System has

broken down. The infrastructure required for such self-reporting function must be very

complicated and cost prohibitively high. It is not so, if ARCHNET power line

modems are used. The ARCHNET power line modem makes use of the power cable as a

communication medium and data communication can take place between two points on a

power line without the need of a dedicated signal wires. An ARCHNET power line

modem and a sensor connected at the power source of the street lamp of a public lighting

system can sense the current flow through the lamp, thus monitoring the operation of the

street lamp. If the lamp breaks down, the modem will report the address code of the lamp

report back to the monitoring station through the power cable. At the Public Lighting

control station, a signal will flash on the screen giving the location of the street lamp.

2.5 A Practical Intelligent Home System Based on PLC [9]

This paper presents a practical, cost-effective intelligent home system based on

power line communication, in which manual keypad control, speech control and

GSM/GPRS remote control are implemented. In this system, speech control is for old

men and handicapped people who are unable to operate home appliances. A focusing



fuzzy template matching algorithm is proposed to improve the accuracy of speech

recognition under noisy background. GSM/GPRS remote control makes operation of

home appliances and home surveillance feasible anywhere. Because of the

implementation of power line communication technology, no rewiring is required, thus

making the installation of such system simple, low cost and efficient, which is favorable

for the popularization of intelligent home.

2.6 Wireless Networking for Sugar Industries through PLCC

Technique [10]

This paper discusses the new approach of parameters monitoring for drives

through Power Line Carrier Communication. Using this technique parameters likes speed,

voltage, current and power factors are monitored by using exceed power leads as a

communication media. The communication media are located in two different places for

sending and receiving the data which require existing 50Hz power line. This

communication circuit uses an asynchronous serial Communication protocol and an FSK

modulation for realizing frequency multiplexing in the power line. These monitoring

systems used for an inverter-fed induction machine are constructed using this power line

communication link. A prototype model was demonstrated satisfactory within the limited

distance.

2.7 Remote Data Acquisition Using Wireless SCADA System

[11]

This project has developed an integrated wireless SCADA system for monitoring

and accessing the performance of remotely situated device parameter such as temperature,

pressure, humidity on real time basis. For this the infrastructure of the existing mobile

network has been used, which is based on GPRS technique. Supervisory Control and Data

Acquisition (SCADA) is a field of constant development and research. This project

investigates on creating an extremely low cost device which can be adapted to many

different SCADA applications via some very basic programming and plugging in the

relevant peripherals. Much of the price in some expensive SCADA applications is a result

of using specialized communication infrastructure. The application of existing

infrastructure in the proposed scheme will reduce the cost. Additionally the generic nature

of the device will be assured.



Chapter 3

COMMUNICATION PROTOCOLS

This chapter gives the details of different communication protocols like PLC,

Wi-Fi and DSSS modulation techniques.

3.1 Power Line Communication System

Power line communication or power line carrier (PLC), also known as power line

digital subscriber line (PDSL), mains communication, power line telecom (PLT), power

line networking (PLN), or broadband over power lines (BPL) are systems for carrying

data on a conductor also used for electric power transmission.

A wide range of power line communication technologies are needed for different

applications, ranging from home automation to Internet access. Electrical power is

transmitted over long distances using high voltage transmission lines, distributed over

medium voltages, and used inside buildings at lower voltages. Most PLC technologies

limit themselves to one set of wires (such as premises wiring within a single building),

but some can cross between two levels (for example, both the distribution network and

premises wiring). Typically transformers prevent propagating the signal, which requires

multiple technologies to form very large networks. Various data rates and frequencies are

used in different situations. A number of difficult technical problems are common

between wireless and power line communication, notably those of spread spectrum radio

signals operating in a crowded environment. Potential interference, for example, has long

been a concern of amateur radio groups.

Power line communications systems operate by impressing a modulated carrier

signal on the wiring system. Different types of power line communications use different

frequency bands, depending on the signal transmission characteristics of the power wiring

used. Since the power distribution system was originally intended for transmission of AC

power at typical frequencies of 50 or 60Hz, power wire circuits have only a limited ability

to carry higher frequencies. The propagation problem is a limiting factor for each type of

power line communications.

http://en.wikipedia.org/wiki/Electric_power_transmission

http://en.wikipedia.org/wiki/Home_automation

http://en.wikipedia.org/wiki/Internet_access

http://en.wikipedia.org/wiki/Wireless

http://en.wikipedia.org/wiki/Spread_spectrum

http://en.wikipedia.org/wiki/Amateur_radio

http://en.wikipedia.org/wiki/Communications_system

http://en.wikipedia.org/wiki/AC_power

http://en.wikipedia.org/wiki/AC_power

http://en.wikipedia.org/wiki/Hertz



Data rates and distance limits vary widely over many power line communication

standards. Low-frequency (about 100–200 kHz) carriers impressed on high-voltage

transmission lines may carry one or two analog voice circuits, or telemetry and control

circuits with an equivalent data rate of a few hundred bits per second; however, these

circuits may be many miles long. Higher data rates generally imply shorter ranges; a local

area network operating at millions of bits per second may only cover one floor of an

office building, but eliminates the need for installation of dedicated network cabling.

3.1.1 ATL90 Series PLC Modem

ATL90 series Embedded PLC modem series is based on the Direct Sequence

Spread Spectrum Technology. The new technology in Power Line Carrier

Communication (PLCC) is well known for its high immunity to electrical noise persistent

in the power line. With the new solution, the form factor of the PLC modem is further

reduced and its cost lowered [2].

The Embedded PLC Modem is in the form of a ready-to-go circuit module, which

is capable of transferring data over the power cable at the low voltage end of the power

transformer of a 3-phase/ 4-wire distribution network. A pair of Embedded PLC Modems

connected on the power line can provide low speed bi-directional data communication at

a baud rate of 300/600 bps. It is built in a small form factor that can be easily integrated

into and become part of the user's power line data communication system.

3.1.2 Block Diagram of PLC Modem

The operation of the PLC Modem can be better understood by its block diagram.

Fig 3.1 shows the General Block Diagram of the ATL90 series PLC Modem.

A Power Line Communication Modem system begins with a modulated signal

entering the receiver stage, or active band pass filter where the op-amp selected for the

filter should provide low noise, low harmonic distortion, and low input bias as seen in

TI’s OPA365 or OPA353. Scaling the received signal by using a Programmable Gain

Amplifier (PGA) such as the PGA112 allows for a wide dynamic range and optimal

signal processing. It needs to connect to the input of an Analog to Digital Converter fast

and accurate enough to properly convert to a digital form for processing. This is done

http://en.wikipedia.org/wiki/Data_rate

http://en.wikipedia.org/wiki/Local_area_network

http://en.wikipedia.org/wiki/Local_area_network



thanks to the on–chip 12-bit ADC of the F28235 Delfino™ or F2802x/03x Piccolo™

microcontroller member of the scalable C2000™ 32-bit microcontroller (MCU) family.

The 12-bit ADC operates at up to 12.5 MSPS and also includes triggering

mechanisms for support of multi-frequency and phase sampling (2 sample and hold

functions). The C2000™ MCU family then enables developers to support multiple

modulations on the same hardware, thus eliminating the need to redesign the modem to

support different modulation or standards. This makes the C2000™ 32-bit MCU family a

smart and flexible platform for Power Line Communication implementation.

Fig 3.1 General Block Diagram of PLC Modem

Processed signals are injected back into the power grid by the PLC transmitter

stage that drives a high output current. The control can be done using the C2000 PWMs

support duty cycle resolution down to 150 ps to enable more control over harmonics and

reduce sample-to-output delay. The transmitter stage must be carefully designed to take

digital signals from the MCU, filter them to eliminate out of band emissions and drive the

low impedance of the AC power line. The OPA564 is a 24V, 1.5A, 17 MHz power op-

amp designed for the rigorous demands of the PLC line driver. Further improvements in

integration, performance and cost can be realized when combining the AFE031, a highly



integrated PLC Analog Front End with the C20000TM. The AFE031 integrates the

transmit filter, power amplifier, receive filter and PGA in a programmable integrated

circuit designed just for PLC.

The resulting modem MCU + AFE can directly communicate with outside

systems (both wired and wireless applications) via one of C2000TM serial interface

options including CAN, I2C, LIN, SPI or UART. TI PLC software is delivered in the

PLC Suite library and enables developers to support several modulations and standards on

one unique design. Developers can implement SFSK IEC61334, PRIME and G3

standards as well as Flex OFDM for custom OFDM implementation and is scalable for

the incoming standards.

From the power management perspective, the PLC module can take its power

from existing system DC rails or directly from the mains AC power it is communicating

over. In the case of the latter, 115V, 60Hz in the U.S. (or 230V, 50Hz in Europe and

Asia) needs to be filtered and converted to isolated DC power for the MCU, AFE and

various support components. The UCC28600 or UCC28610 Fly back Green-Mode

Controller is ideal for providing an isolated 12V or 15V DC rail that can be used directly

for the power amplifier and into a DCDC module, such as the PTH08080W, or buck

converter, such as the TPS54231, to provide low voltage (5V) PLC system rail. The

addition of a linear regulator such as the TPS79533 LDO can provide a low-noise 3.3V

rail for use by low power components such as the MCU, PGA, op amps, USB

transceivers, and any additional digital or analog components.

3.1.3 Features of PLC Modem

Some of the features of PLC modem are as follows:

Embedded ready-to-go Power Line Carrier Modem module with SMT

components.

Small form factor for easy of system integration.

Bi-directional half-duplex data communication over the mains.

Applicable to universal mains voltage and frequency up to 250V, 50 - 60 Hz.

Protocol independent, data transfer transparent to user's data terminals.

High noise immunity and reliable data communication.



Simple serial interface to user's data devices.

Built-in on board AC coupling circuit with direct connection to mains.

Built-in carrier generation and detection.

Baud rate of 300/600 bps.

Selectable TTL and RS232C level serial interface to user's data devices.

Built with industrial grade components for operation under harsh environment.

3.1.4 Applications of the PLC

Some of the important applications of the PLC are

Home Automation

Automatic Meter Reading

Process Control

Heating and Ventilation Control

Air Conditioning Control

Lighting Control

Status Monitoring and Control

Intelligent Buildings

Fire and Security Alarm System

Power Distribution Management

3.2 Wireless Communication

Wireless communication is used to transfer information over short distance of a

few meters as in TV (Tele Vision) remote control or long distance thousands of millions

of km for radio communication. The term is often shortened to wireless. It encompasses

various types of fixed, and portable two way radios, cellular telephone, Personal Digital

Assistant (PDAs) and wireless networking, other examples of wireless networking

includes GPS (Global Positioning Systems) units garage door openers, wireless computer

mouse, keyboard and handsets, satellite TV and cordless telephones. Its operation permits

service such as long range communication that is impossible or impractical to implement

with the use of wires. The term is commonly used in telecommunication industry to refer



telecommunication system for example radio transmitter and receiver, remote controllers

which use some form of energy for example radio frequency, Infrared light, laser light to

transfer information without the use of wires. Information is transferred in this manner

over both short and long distance. In our project we are using Wi-Fi as a wireless

communication.

3.2.1 Wi-Fi

Wi-Fi is a popular technology that allows an electronic device to exchange data

wirelessly using radio waves over a computer network, including high speed internet

connections.

3.2.2 Working of Wi-Fi

Radio waves are used for the working of Wi-Fi technology. The Wi-Fi network's

most common encryption module named as wired equivalent privacy is considered to be

the safest. The use and access to Wi-Fi network is really simple. The wireless adapter of

the computer and the wireless router play an important role in its working. The adapter

receives data from the computer in digital form. This data, after its conversion in radio

waves is sent to the router by means of an antenna. The router decodes the signal and

sends it to the internet. The process is reversed when information is sent from the internet

to a computer. The difference between the radio waves sent by Wi-Fi and those sent by

walkie-talkies and cell phones is that Wi-Fi uses high frequency waves.

3.2.3 Wi-Fi Working in Laptop or Desktop

There are three most important items which makes Wi-Fi working in laptop or

desktop. These are

Fig 3.2: Wi-Fi Working



1. Radio Signals

2. Wi-Fi Card which fits in laptop or computer

3. Hotspots which create Wi-Fi Network

Radio Signals: Radio Signals are the keys which make Wi-Fi networking possible.

These radio signals transmitted from Wi-Fi antennas are picked up by Wi-Fi receivers

such as computers and cell phones that are equipped with Wi-Fi cards. Whenever a

computer receives any signals within the range of a Wi-Fi network which is usually 300-

500 feet for antennas, the Wi-Fi card will read the signals and thus create an internet

connection between the user and the network without the use of a cord.

Access points which consist of antennas and routers are the main source which

transmit and receive radio waves. Antennas work stronger and have a longer radio

transmission with a radius of 300-500 feet which are used in public areas while the

weaker yet effective router is more suitable for homes with a radio transmission of 100-

150 feet.

Wi-Fi Cards: Wi-Fi card as being an invisible cord that connects computer to the

antenna for a direct connection to the internet. Wi-Fi cards can be external or internal,

meaning that if a Wi-Fi card is not installed in a computer, USB antenna attachment has

to be purchase and have it externally connect to USB port, or have an antenna-equipped

expansion card installed directly to the computer. For laptops, this card will be a Personal

Computer Memory Card International Association (PCMCIA) card in which you insert to

the PCMCIA slot on the laptop.

Wi-Fi Hotspots: A Wi-Fi hotspot is created by installing an access point to an internet

connection. The access point transmits a wireless signal over a short distance, typically

covering around 300 feet. When a Wi-Fi enabled device, such as a pocket PC, encounters

a hotspot, the device can then connect to that network wirelessly. Most hotspots are

located in places that are readily accessible to the public like airports, coffee shops,

hotels, book stores and campus environments. 802.11b is the most common specification

for hotspots worldwide. The 802.11g standard is backwards compatible with .11b but .11a

uses a different frequency range and requires separate hardware such as an a, a/g, or a/b/g



adapter. The largest public Wi-Fi networks are provided by private Internet Service

Providers (ISPs) that charge a fee for users to connect to the internet.

Any notebook computer with integrated wireless, a wireless adapter attached to

the motherboard by the manufacturer, or a wireless adapter such as a PCMCIA card can

access a wireless network. Furthermore, all pocket PCs or palm units with compact flash,

SD I/O support, or built-in Wi-Fi, can access hotspots. Some Hotspots require Wireless

Encryption Protocol (WEP) key to connect that is the connection is considered to be

private or secure. As for open connections, anyone with a Wi-Fi card can gain access to

that hotspot. So in order for a user to gain access to the internet under WEP, the user must

input the WEP key code.

3.2.4 Communication ranges

Wi-Fi networks have limited range. A typical wireless access point using 802.11b

or 802.11g with a stock antenna might have a range of 32m (120 ft) indoors and 95m

(300 ft) outdoors. Range also varies with frequency band. Wi-Fi in the 2.4GHz frequency

block has slightly better range than Wi-Fi in the 5GHz frequency block which is used by

802.11a. On wireless routers with detachable antennas, it is possible to improve range by

fitting upgraded antennas which have higher gain in particular directions. Outdoor ranges

can be improved to many kilometers through the use of high gain directional antennas at

the router and remote devices. Due to reach requirements for wireless LAN applications,

Wi-Fi has fairly high power consumption compared to some other standards.

Technologies such as Bluetooth designed to support wireless PAN applications

provide a much shorter propagation range of less than 10m and so in general have lower

power consumption. Other low-power technologies such as Zigbee have fairly long range,

but much lower data rate. The high power consumption of Wi-Fi makes battery life in

mobile devices a concern.

3.2.5 Advantages of Wi-Fi

Following are the advantages of Wi-Fi

1. Wi-Fi allows cheaper deployment of Local Area Networks (LANs). Also spaces

where cables cannot be run, such as outdoor areas and historical buildings, can

host wireless LANs.



2. Manufacturers are building wireless network adapters into most laptops. The price

of chipsets for Wi-Fi continues to drop, making it an economical networking

option included in even more devices.

3. Wi-Fi Protected Access encryption (WPA2) is considered secure, provided a

strong passphrase is used. New protocols for quality of service make Wi-Fi more

suitable for latency sensitive applications such as voice and video. Powers saving

mechanisms extend battery life.

3.2.6 Sockets protocol

In computer networking, an Internet socket or network socket is an endpoint of a

bidirectional inter-process communication flow across an internet protocol based

computer network, such as the internet. The Fig 3.3 below shows the socket connection.

Fig 3.3: Block Diagram Showing Communication through Sockets

The term Internet socket is also used as a name for an application programming

interface (API) for the TCP/IP protocol stack, usually provided by the operating system.

Internet sockets constitute a mechanism for delivering incoming data packets to the

appropriate application process or thread, based on a combination of local and remote IP

addresses and port numbers. Each socket is mapped by the operating system to a

communicating application process or thread.

A socket address is the combination of an IP address (the location of the

computer) and a port (which is mapped to the application program process) into a single

identity, much like one end of a telephone connection is the combination of a phone

number and a particular extension. An Internet socket is characterized by a unique

combination of the following: Local socket address, Local IP addresses and port number.

Remote socket address is used for establishing TCP sockets. As discussed in the Client-

Server section below, this is necessary since a TCP server may serve several clients

concurrently. The server creates one socket for each client, and these sockets share the

same local socket address.

http://en.wikipedia.org/wiki/Application_programming_interface

http://en.wikipedia.org/wiki/Application_programming_interface

http://en.wikipedia.org/wiki/TCP/IP

http://en.wikipedia.org/wiki/Protocol_stack

http://en.wikipedia.org/wiki/Operating_system

http://en.wikipedia.org/wiki/Process_(computing)

http://en.wikipedia.org/wiki/Thread_(computer_science)

http://en.wikipedia.org/wiki/IP_address

http://en.wikipedia.org/wiki/IP_address

http://en.wikipedia.org/wiki/Port_number

http://en.wikipedia.org/wiki/TCP_and_UDP_port



The term socket refers to an entity that is uniquely identified by the socket

number. In other sense, the socket term refers to a local socket address, i.e. a

"combination of an IP address and a port number". In the original definition

of socket given in RFC 147, as it was related to the ARPA network in 1971, the socket is

specified as a 32 bit number with even sockets identifying receiving sockets and odd

sockets identifying sending sockets. Today however, socket communications are

bidirectional. On UNIX and Microsoft Windows based operating systems the net state

command line tool may be used to list all currently established sockets and related

information.

3.3 DSSS Modulation

Direct Sequence Spread Spectrum (DSSS) as shown in Figure 3.4, is a spread

spectrum technique whereby the original data signal is multiplied with a pseudo random

noise spreading code. This spreading code has a higher chip rate (the bit rate of the

code), which results in a wideband time continuous scrambled signal.

Fig 3.4: Direct Sequence Spread Spectrum

DSSS significantly improves protection against interfering (or jamming) signals,

especially narrowband and makes the signal less noticeable. It also provides security of

transmission if the code is not known to the public. These reasons make DSSS very

popular by the military. In fact, DSSS was first used in the 1940s by the military.

DSSS can also be used as a multiple access technique, whereby several different pseudo

random spreading codes are being used simultaneously. This multiple access technique

is better known as Direct Sequence CDMA.

http://tools.ietf.org/html/rfc147

http://en.wikipedia.org/wiki/ARPANET

http://www.telecomabc.com/s/spread-spectrum.html

http://www.telecomabc.com/s/spread-spectrum.html

http://www.telecomabc.com/d/dsss.html



Chapter 4

HARDWARE IMPLEMENTATION

This chapter deals with the working principle of project and hardware description

of PIC microcontroller, PLC modem, Temperature sensor, Amplifier, MAX232, Relay,

LCD and ULN2003.

4.1 Principle of Operation

A Wi-Fi enabled device is used as means of input. A Cell phone with Wi-Fi &

Android based is used for this purpose, which provides the user with a touch screen

interface facilitating ease of use. A Wi-Fi network is first setup using a wireless router.

The PC connects to the PLC Modem through a RS232 interface. An application on the

device consists of keypad that enables us to send signals to the PC through Wi-Fi.

These signals are sent to PLC modem. When a user presses a particular number,

specific messages are sent over the Wi-Fi network to the PLC modem through PC .

PLC modem transmits data signals through the existing power lines to the other side

PLC Modem.

Fig 4.1 Block diagram of Wi-Fi based real time Monitoring and Control system

Using PLC.



PLC modem sends this data signals to the PIC Microcontroller. The

microcontroller converts these messages into simple control signals. The commands sent

by the microcontroller to switch ON/OFF an appliance are not sent directly to the

appliance, but rather these commands are broadcasted over the power lines using a

PLC transmitter. The microcontroller sends data to the PLC modem using UART

protocol. Each end appliance has a PLC receiver plus microcontroller combination to

listen to these commands, if the commands are intended to the corresponding appliance;

it switches ON/OFF the appliance. Fig 4.1 shows the block diagram of Wi-Fi based real

time Monitoring and Control system using PLC.

On the other hand if the parameters of a particular appliance exceed a threshold

or preset limit then the microcontroller sends data signal to the PLC modem using

UART Protocol. The PLC modem on the other side receives this signal through the

existing Power lines. These signals are sent to the PC through RS232 interface. PC will

send information to the cell phone via Wi-Fi for monitoring parameters. Here we are

monitoring the temperature and when this crosses the set limit the data is sent back to the

PC and this will send the data to the cell phone through Wi-Fi and the user can get to

know the temperature details.

4.2 Hardware Description

The following sections briefly describe the hardware components used in this project.

4.2.1 PLC Modem ATL90115-1

The ATL90115 series Embedded PLC Modem is a ready to go circuit module,

which is capable of transferring data over the power cable at the low voltage end of

the power transformer of a 3-phase/ 4-wire distribution network. Fig 4.2 shows PLC

Modem ATL90115-1 used in the project.

Fig 4.2 PLC Modem ATL90115-1



A pair of Embedded PLC Modems connected on the power line can provide low

speed bi-directional data communication at a baud rate of 300 bps. It is built in a small

form factor that can be easily integrated into and become part of the user's power line data

communication system. The PLC modem is based on the Direct Sequence Spread

Spectrum Technology, which ensures high noise immunity and reliable data

communication.

Fig 4.3 ATL90115-1 Application Diagram

Application Diagram for the single phase of the ATL90115 is shown in Fig 4.3.

This PLC Module provides bi-directional half-duplex data communication over the mains

of any voltage up to 250V AC, and for frequency of 50 or 60 Hz. It does not require any

protocol to function and therefore is protocol independent.

Data flow through PLC modem as if it is a channel and therefore it is transparent

to the Data Devices. As a result, with user’s proper addressing and communication

protocol, multiple units can be connected to the mains without affecting the operation of

one another. There is no hassle of building interface circuits. It has a built-in onboard AC

coupling circuit, which allows direct and simple connection to the mains. Interface to

user’s data devices is a simple data -in and data-out serial link. Power to the PLC Modem

circuit module is a single +12v DC supply.

4.2.2 PIC Microcontroller

The microcontroller used for his system is PIC 18F458. Fig 4.4 shows PIC18F458

Pin details. The PIC families of microcontrollers are developed by microchip Technology

Inc [3].

Features

The CPU uses Harvard architecture with separate program and variable (data) memory



interface. This facilitates instruction fetch and the operation on data accessing of variables

simultaneously. Basically, all PIC microcontrollers offer the following features:

RISC instruction set

On-chip timer with 8 bit prescaler

Power on reset

Watchdog timer

Power saving SLEEP Mode

Direct, indirect and relative addressing modes

External clock interface

RAM data memory

EPROM Program memory

Some devices offer the following additional features:

Analogue input channels

Analogue comparators

Additional timer circuits

EEPROM data memory

Flash EEPROM program memory

External and timer interrupts

USART serial interface

Internal oscillator

Pin Description:

PIC18F458 is a 40 pin microcontroller. It has 5 ports Port A, port B, port C, port D, port E.

All the pins of the ports for interfacing input output devices.

Port A [Analog]: It consists of 6 pins from A0 to A5

Port B [Interrupt]: It consists of 8 pins from B0 to B7

Port C [serial communication]: It consists of 8 pins from C0 to C7

Port D [LCD]: It consists of 8 pins from D0 to D7



Port E [Enable]: It consists of 3pins from E0 to E2

The rest of the pins are mandatory pins these should not be used to connect input/output

devices.

Pin 1 is MCLR (master clear pin) also referred as reset pin.

Pin 13, 14 are used for connecting the crystal oscillator to generate a frequency of about

20MHz.

Fig 4.4 PIC 18F458 Pin Details

4.2.2.1 Analog to Digital converter (ADC):

External signals are usually fundamentally different from those the

microcontroller understands (zero and one); so that they have to be converted in order the

microcontroller can understand them.

An analog-to digital converter is an electronic circuit which converts continuous

signals to discrete digital numbers. This module is therefore used to convert some analog

value into binary number and forwards it to the CPU for further processing. In other

words, this module is used for input pin voltage measurement (analog value). The result

of measurement is a number (digital value) used and processed later in the program.



The Analog-to-Digital (A/D) Converter module has five inputs for the

PIC18F2X8 devices and eight for the PIC18F4X8 devices. This module has the

ADCON0 and ADCON1 register definitions that are compatible with the PICmicro®

mid-range A/D module. The A/D allows conversion of an analog input signal to a

corresponding 10-bit digital number.

4.2.2.2 UART

A universal asynchronous receiver/transmitter, abbreviated UART, is a type of

"asynchronous receiver/transmitter", a piece of computer hardware that translates data

between parallel and serial forms. For serial data transfer UART is often used because of its

simple design. Serial transmission is commonly used with modems and for non-networked

communication between computers, terminals and other devices. There are two primary

forms of serial transmission Synchronous and Asynchronous.

The device changes parallel information to serial, which can be sent on

communication line. The UART usually does not directly generate or receive the external

signals used between different items of equipment. Separate interface devices are used to

convert the logic level signals of the UART to and from the external signaling levels.

External signals may be of many different forms. Examples of standards for voltage

signaling are RS-232, RS-422 and RS-485 from the EIA. In UART we are using a standard

protocol i.e. RS-232.

4.2.2.3 Liquid Crystal Display

A liquid crystal display is a thin, flat display device as shown in Fig 4.5 is made

up of many number of color or monochrome pixels arrayed in front of a light source or

reflector and it consumes very low power which makes it user compatible. Each pixel of

LCD consists of a column of liquid crystal molecules suspended between two transparent

electrodes, and two polarizing filters, the axes of polarity of which are perpendicular to

each other.

The liquid crystal twists the polarization of light entering through one filter to

allow it to pass through the other filter. For an 8-bit data bus, the display requires a +5V

http://en.wikipedia.org/wiki/RS-232



http://en.wikipedia.org/wiki/Electronic_Industries_Alliance



supply and 11 I/O lines. When the LCD display is not enabled, data lines are tri-state and

they do not interfere with the operation of the microcontroller.

Fig 4.5 Pin Details of 16x2 line LCD

There are three signals in the LCD: Enable, Read/Write and Register select.

1. Enable (E): This line allows access to the display through R/W and RS lines.

When this line is low, the LCD is disabled and when it is high, the LCD checks

the state of the two control lines and responds accordingly.

2. Read/Write (R/W): This line determines the direction of data between the LCD

and microcontroller and when it is low, data is written to the LCD. When it is

high, data is read from the LCD.

3. Register Select (RS): With the help of this line, the LCD interprets the type of data

on data lines and when it is low, an instruction is being written to the LCD. When

it is high, a character is being written to the LCD.



4.2.3 RS232

RS232 (Recommended Standard 232) is the traditional name for a serial binary

single ended data and control signal connecting between a DTE (Data Terminal

Equipment) and a DCE (Data Circuit terminating Equipment) this defines each device

which wires will be sending and receiving each signal.

Table 4.1 RS232 Logic Levels

RS232 Line Type & Logic Level RS232 Voltage TTL Voltage

to/from MAX232

Data Transmission (Rx/Tx) Logic 0 +3 V to +15 V 0 V

Data Transmission (Rx/Tx) Logic 1 -3 V to -15 V 5 V

Control Signals

(RTS/CTS/DTR/DSR) Logic 0 -3 V to -15 V 5 V

Control Signals

(RTS/CTS/DTR/DSR) Logic 1 +3 V to +15 V 0 V

4.

The standard defines the electrical characteristics and timing of signals, the

meaning of signals, and the physical size and pin out of connectors. The RS232 standard

defines the voltage levels that corresponding to logical one and logical zero levels for the

data transmission and the control signal lines. The Table 4.1 shows the RS232 logic

levels.

Fig 4.6 RS232 Pin Diagram

The standard specifies a maximum open circuit voltage of 25 V, signal levels of

+/- 5 V, +/-10 V, +/- 12 V, and +/- 15 V are all commonly seen depending on the power

supplies available within device. Fig 4.6 shows the 9 pin configuration of RS232. The

standard defines the electrical characteristics and timing of signals, the meaning of

signals, and the physical size and pin out of connections. RS232 drivers and receivers



must be able to withstand indefinite short circuit to ground or to any voltage level up to

+/- 25 V. Both synchronous and asynchronous transmissions are supported.

4.2.4 MAX232

The MAX232 from maxim was the first IC which is one package contains

the necessary drivers and receivers, to adapt the RS232 signal voltage levels to TTL logic.

It became popular, because it just needs +5 V and generates the necessary RS232 voltage

levels. The pin configuration of MAX232 is shown in Fig 4.7. In serial communication

the line that is used to transmit data is called Tx and the line used to receive data is called

Rx. The PIC Microcontroller uses TTL level for logic that is a 1 is a 5 V and 0 is 0 V but

RS232 standard uses different scheme for logic level, so we need a level converter in

between. The data is ready to be fed to a standard serial port of PC. All good development

boards have an on board level converter. The MAX 232 IC is a industry standard chip for

the purpose of level conversion between RS232 and TTL signals. Serial cable has been

used to connect the MAX232 to PC.

Fig 4.7 Pin Configuration of MAX232

Serial cable has male and female DB9 connector. Pin 13 and 8 of MAX232 have

been connected to DB9 port in order to transfer information to the computer. Pins 12 and

9 on the MAX232 have been connected to PIC, port C pin C6 and C7 in order to transfer

information signals to PIC. The voltage supply of 5V for Max232 can be achieved

through the schematic circuit which has standard capacitance.

Voltage Levels

It is helpful to understand what occurs to the voltage levels. When a MAX232 IC

receives a TTL level to convert, it changes a TTL Logic 0 to between +3 and +15 V, and

changes TTL Logic 1 to between -3 to -15 V, and vice versa for converting from RS232



to TTL. The different voltage levels as shown in Table 4.1 of RS-232 and TTL voltage to

and from MAX232. This can be confusing when one realize that the RS-232 Data

Transmission voltages at a certain logic state are opposite from the RS-232 Control Line

voltages at the same logic state.

For data transmission lines TXD, RXD and their secondary channel equivalents

logic one is defined as a negative voltage and the signal condition is called marking.

Logic zero is defined as positive and the signal condition is termed spacing. Control

signals are logically inverted with respect to what one sees on the data transmission lines.

When one of these signals is active, the voltage on the line will be between +3 to +15

volts and the inactive state for these signals is the opposite voltage condition, between −3

and −15 volts. The voltage levels are higher than logic levels typically used by integrated

circuits, special intervening driver circuits are required to translate logic levels and also

protect the device's internal circuitry from short circuits or transients.

4.2.5 LM35 Temperature Sensor

The LM35 series are precision integrated circuit temperature sensor is shown in

the Fig.4.8 whose output voltage is linearly proportional to the Celsius temperature. The

LM35 thus has an advantage over linear temperature sensors calibrated in Kelvin, as the

user is not required to subtract a large constant voltage from its output to obtain

convenient Centigrade scaling. The LM35 does not require any external calibration or

trimming to provide typical accuracies of ±1⁄4°C at room temperature and ±3⁄4°C over a

full −55 to +150°C temperature range. Low cost is assured by trimming and calibration at

the wafer level.

Fig 4.8 Temperature Sensor LM35

LM35 can be applied easily in the same way as other integrated circuit

temperature sensors. It can be glued or cemented to a surface and its temperature will be

within about 0.01°C of the surface temperature. This presumes that the ambient air

LM

35

Vcc O/P Gnd



temperature is almost the same as the surface temperature; if the air temperature were

much higher or lower than the surface temperature, the actual temperature of the LM35

would be an intermediate temperature between the surface temperature and the air

temperature. The copper leads are the principal thermal path to carry heat in the devices,

so its temperature might be close to the air temperature than to the surface temperature.

The LM35’s low output impedance, linear output, and precise inherent calibration make

interfacing to readout or control circuitry especially easy. It can be used with single

power supplies, or with plus and minus supplies.

As it draws only 60 μA from its supply, it has very low self heating, less than

0.1°C in still air. The LM35 is rated to operate over a −55° to +150°C temperature range,

while the LM35C is rated for a −40° to +110°C range. The LM35 series is available

packaged in hermetic TO-46 transistor packages, while the LM35C, LM35CA, and

LM35D are also available in the plastic TO-92 transistor package. To minimize this

problem, the wiring to the LM35 as it leaves the devices, held is at the same temperature

as the surface of interest. The easiest way to do this is to cover up these wires with a bead

of epoxy, which will insure that the leads and wires are all the same temperature as the

surface and that the LM35’s temperature is not affected by the air.

The LM35 can be applied easily in the same way as other integrated-circuit

temperature sensors. It can be glued or cemented to a surface and its temperature will be

within about 0.01°C of the surface temperature. If the air temperature were much higher

or lower than the surface temperature, the actual temperature of the LM35 die would be at

an intermediate temperature between the surface temperature and the air temperature.

This is especially true for the TO-92 plastic package, where the copper leads are the

principal thermal path to carry heat into the device, so its temperature might be closer to

the air temperature than to the surface temperature. Alternatively, LM35 mounted can be

inside a sealed end metal tube and is then dipped into a bath or screwed into a threaded

hole in a tank. The LM35 and accompanying wiring and circuits must be kept insulated

and deep, to avoid leakage and corrosion. This is especially true if the circuit coatings and

varnishes such as epoxy paints or dips often used are to insure that moisture cannot

corrode the LM35 or its connections.



4.2.6 LM324 Operational Amplifier

The LM324 series are low cost, quad operational amplifiers with true differential

inputs. They have several distinct advantages over standard operational amplifier types in

single supply applications. The quad amplifier can operate at supply voltages as low as

3.0V or as high as 32V with quiescent currents about one fifth of those associated. The

common mode input range includes the negative supply, thereby eliminating the necessity

for external biasing components in many applications. The output voltage range also

includes the negative power supply voltage.

In the linear mode, the input common mode voltage range includes ground and the

output voltage can also swing to ground, even though operated from only a single power

supply voltage. The unity gain crossover frequency and the input bias current are

Temperature compensated. LM324 has large dc voltage gain up to 100 dB, wide

bandwidth is about 1MHz. It has Wide power supply range Single supply 3Vdc to 30Vdc

and Low input biasing current and offset voltage. True Differential input stage is

considered, and is internally compensated.

The LM324 consists of four independent, high-gain, internally frequency-

compensated operational amplifiers designed specifically to operate from a single power

supply over a wide range of voltages. The LM324 series is made using four internally

compensated, two stage operational amplifiers. Another feature of this input stage is that

the input common mode range can include the negative supply, in single supply

operation, without saturating either the input devices or the differential to single ended

converter.

Fig 4.9: Pin Description of LM324



Pin description of LM324 is as shown in Fig 4.9. The first stage consists of

differential input devices Q20 and Q18 with input buffer transistors Q21 and Q17 and the

differential to single ended converter Q3 and Q4. The first stage performs not only the

first stage gain function but also performs the level shifting and transconductance

reduction functions. By reducing the transconductance, a smaller compensation capacitor

can be employed, thus saving chip area. The transconductance reduction is accomplished

by splitting the collectors of Q20 and Q18.

4.2.7 ULN2003

The ULN2003 is a high voltage and high current Darlington transistor array. It

consists of seven NPN Darlington pairs that feature high voltage output with common

cathode clamp diodes for switching inductive loads. The collector current rating of a

single Darlington pairs is 50 mA. The Darlington pairs can be paralleled for higher

current capability. Applications include relay drivers, hammer drivers, lamp drivers,

display drivers and logic buffer. Fig 4.10 shows the pin configuration of ULN2003.

Fig 4.10 Pin Diagram of ULN2003

The key features of ULN2003 are 500 mA rated collector current (single output),

high voltage output, and output clamp diodes and input compatible with various type of

logic and relay driver applications. A Darlington pairs consists of two transistors which

are connected in series, output of one transistor drives the other transistors. The

amplification done at one transistor is enhanced by other transistor. Fig 4.11 shows

Darlington pairs.

The seven NPN Darlington connected transistors in these arrays are well suited for

driving lamps, relays, or printer hammers in a variety of industrial and consumer



applications. Their high breakdown voltage and internal suppression diodes insure

freedom from problems associated with inductive loads. Peak inrush currents to 500 mA

permit them to drive incandescent lamps. The ULx2003A with a 2.7 kΩ series input

resistor is well suited for systems utilizing a 5.0 V TTL or CMOS Logic.

Fig 4.11 Darlington pairs

4.2.8 Relay

Relay is an electrically operated switch which is as shown in Fig 4.12. The current

flowing through the coil of the relay creates a magnetic field which attracts a lever and

changes the switch contacts.

Fig 4.12 Circuit diagram of a Relay



The coil current can be on or off so relays have two switch positions and they are

double throw (changeover) switches. Relays allow one circuit to switch a second circuit

which can be completely separate from the first.

For example a low voltage battery circuit can use a relay to switch a 230V AC

mains circuit. There is no electrical connection inside the relay between the two circuits;

the link is magnetic and mechanical. The relay's switch connections are usually labeled C,

NC and NO.

C indicates Common, always connected; it is the moving part of the switch. NC

indicates Normally Closed, C is connected to this when the relay coil is off. NO indicates

Normally Open, C is connected to this when the relay coil is on. As shown in the in Fig

4.12, coil of a relay passes a relatively large current , typically 30mA for a 12V relay, but

it can be as much as 100mA for relays designed to operate from lower voltages. Most ICs

(chips) cannot provide this current and a transistor is usually used to amplify the small IC

current to the larger value required for the relay coil. The coil will be obvious and it may

be connected either way round. Relay coils produce brief high voltage 'spikes' when they

are switched off and this can destroy transistors and ICs in the circuit. To prevent damage

a protection diode must be connected across the relay coil.



Chapter 5

SOFTWARE IMPLEMENTATION

This chapter briefs about the different software tools used in the project like

MPLAB, Java basics and flowchart of the program.

5.1 Embedded C

The C programming language is the most popular programming language for

programming embedded systems. C is a general purpose, block structured, procedural,

imperative computer programming language developed in 1972 by Dennis Ritchie at the

Bell Telephone Laboratories for use with the UNIX operating system. Although C was

designed for implementing system software, it is also widely used for developing

application software. C is a high level programming language that is portable across many

hardware architectures. This means that architecture specific features such as register

definitions, initialization and start up code must be made available to our program via the

use of libraries and include files.

C remains a very popular language for microcontroller developers due to the code

efficiency and reduces overhead and development time. C offers low-level control and is

considered more readable than assembly. Many free C compilers are available for a wide

variety of development platforms. The compilers are part of an IDEs with ICD support,

breakpoints, single –stepping and an assembly window. The performance of C compilers

has improved considerably in recent years, and they are claimed to be more or less as

good as assembly. Most tools now offers options for customizing the compiler

optimization. Additionally, using C increases portability, since C code can be compiled

for different types of processors.

5.2 MPLAB IDE

MPLAB IDE is a Windows based IDE for the Microchip Technology

Incorporated PIC microcontroller families. MPLAB IDE allows writing, debugging and

optimizing PIC microcontroller application for firmware product designs. IDE is

abbreviated as Integrated Development Environment. It includes a text editor, simulator

and project manager. It runs under Microsoft Windows 3.1x, Windows 95/98, Windows



NT or Windows 2000. It provides function that allows creating and editing source files,

group files into projects, debugging source code and debugs executable logic using this

simulator. MPLAB IDE allows creating and editing source code by providing full feature

text editor. Further, it can easily debug source code with the aid of a Build Results

window that displays the errors found by the compiler, assembler and linker when

generating executable files. A Project Manager allows to group source files, pre-compile

object files, libraries and link script files into a project format. The MPLAB IDE also

provides feature rich simulator environment to debug the logic of executable. Source

code, program memory and absolute listing windows allow viewing the source code and

its assembly level equivalent separately and together. It has the ability to step through

execution or apply Break, Trace, Standard or Complex trigger points.

A MPLAB desktop contains the major elements like menu across the top lines,

tool bar below the menu, workspace in which various files, windows, and dialogues can

be displayed and a status bar at the bottom. The status bar includes information about how

the system is currently configured. A project in MPLAB is the group of files needed to

build an application along with their associations to various build tools. The source nodes

are typically assembly source files, C source files, Precompiled object files, libraries and

linker scripts.

5.3 Java

Java is a general purpose, object oriented programming language developed by

Sun Microsystems of USA in 1991.Originally called Oak by James Gosling, one of the

inventors of the language; Java was designed for the development of software for

consumer electronic devices like TVs, VCRs, toasters and such other electronic machines.

This goal had a strong impact on development team to make the language simple,

portable and highly reliable. The most striking feature of the language is that it is

platform-neutral language.

Java is a pure object-oriented language. Object-oriented programming is an

approach that provides a way of modularizing programs by creating partitioned memory

area for both data and functions that can be used as templates for creating copies of such

modules on demand. Some of the features of object-oriented paradigm are Emphasis is on

data rather than procedure, Programs are divided into Objects, Data structures are

designed such that they characterize the Objects. Methods operate on the data of an object



or tied together in the data structure. Data is hidden and cannot be accessed by external

functions. Objects may communicate with each other through methods. New data and

methods can be easily added whenever necessary. Java is a first programming language

that is not tied to any particular hardware or operating system. We can call Java as a

revolutionary technology because it has brought in a fundamental shift in how we develop

and use programs. The inventors of Java wanted to design a language which could offer

solutions to some of the problems encountered in modern programming.

They wanted the language to be not only simple, portable and highly reliable, but

also compact and interactive. The inventors describe Java with following attributes.

Usually a computer language is either compiled or interpreted. Java combines both these

approaches thus making java a two stage system. First Java compiler translates source

code into what is known as byte code instructions, next Java interpreter generates

machine code that can be directly executed by the machine that is running Java program.

Java programs can be easily moved from one computer system to another, anywhere and

anytime. Java ensures portability in two ways. First, Java compiler generates byte code

instructions that can be implemented on any machine. Secondly, the size of the primitive

data types is machine data types are machine independent.

Almost everything in Java is an object. All program code and data reside within

objects and classes. Java comes with an extensive set of classes, arranged in packages that

we can use in our programs by inheritance. The object model in Java is simple and easy to

extend. Java performance is impressive for an interpreted language mainly due to the use

of intermediate byte code. Java architecture is also designed to reduce overheads during

runtime.

5.4 JCreator

JCreator is a powerful IDE for Java. JCreator is the development tool for every

programmer that likes to do what he does best: programming. It is faster, more efficient

and more reliable than other Java IDE’s. Therefore it is the perfect tool for programmers

of every level, from learning programmer to Java-specialist. JCreator provides the user

with a wide range of functionality such as: Project management, project templates, code-

completion, debugger interface, editor with syntax highlighting, wizards and a fully

customizable user interface. With JCreator you can directly compile or run your Java



program without activating the main document first. JCreator will automatically find the

file with the main method or the html file holding the java applet, and then it will start the

appropriate tool. JCreator is written entirely in C++, which makes it fast and efficient

compared to the Java based editors/IDE.

5.5 Android

Android is a mobile operating system that is based on a modified version of

Linux. It was originally developed by a startup of the same name, Android, Inc. In 2005,

as part of its strategy to enter the mobile space, Google purchased Android and took over

its development work (as well as its development team). The Android code was released

under the open-source Apache License, which means that anyone who wants to use

Android can do so by downloading the full Android source code. Moreover, vendors

(typically hardware manufacturers) can add their own proprietary extensions to Android

and customize Android to differentiate their products from others. This simple

development model makes Android very attractive and has thus piqued the interest of

many vendors.

The main advantage of adopting Android is that it offers a unified approach to

application development. Developers need only develop for Android, and their

applications should be able to run on numerous different devices, as long as the devices

are powered using Android. In the world of smart phones, applications are the most

important part of the success chain. Device manufacturers therefore see Android as their

best hope to challenge the onslaught of the iPhone, which already commands a large base

of applications.

Eclipse is a highly extensible multi-language software development environment

that supports application development of all sorts. Eclipse can be used to write and test

the developed applications using a wide variety of languages, such as Java, C, C++, PHP,

Ruby, and so on. Because of its extensibility, new users of Eclipse often feel inundated

with the IDE. The Android Platform takes advantage of several mechanisms designed to

protect the privacy and security of Android users, as well as the operating system. These

methods include the Android security architecture, application certificate and application

permissions.



5.6 Hyper Terminal

Hyper Terminal is a communication program that is included with Windows and

allows a user to call a remote computer via modem and transfer files. Here Hyper

Terminal is used to send and receive characters over the serial port using AT

commands. The following sequence shows how to create a connection. Hyper Terminal is

usually found in 'Start | All Programs | Accessories | Communications' Click on

HyperTerminal. If you have never run HyperTerminal before it will ask for your location

and area code this will not be needed for our application but enter this information

anyway to get the software to start. Fig 5.1 shows the connection description for hyper

terminal. Hyper Terminal will begin by asking for the connection description in the

connection description dialog box, enter a name and choose an icon for the connection.

Then click the OK button. In the connect-to dialog box, choose the COM port for GSM

modem to combo box. The illustration is shown in an example, choose COM1 if mobile

phone or GSM modem is connecting to the COM1 port. Then click the OK button. The

Properties dialog box comes out. Enter the correct port settings for your mobile phone or

GSM mode.

Fig 5.1 Connection Description of Hyper Terminal

The example uses a baud rate of 9600 so select '9600' in the 'Bits per second' drop

down box, and select 'None' in the Flow control drop down box. The other settings



should be the defaults. Then click the OK button. To find the correct port settings that

should be used with your mobile phone or GSM/GPRS modem, consult the manual of

your mobile phone or GSM/GPRS modem. Type AT in the main window. A response OK

should be returned from the mobile phone or GSM/GPRS modem .If the command OK

returns, it means your mobile phone or GSM/GPRS modem is connected successfully.

After successful connection of GSM /GPRS modem with PC, you are ready to run this

application.

The attached project is downloaded and the application is run. The communication

using the Hyper Terminal is done by selecting the Hyper Terminl window and the file

name is entered to save the file,using the settings options COM Port,baud rate and

configuration settings is done.After all the settings the commands are sent to build

communication between modem and the PIC Microcontroller. Fig 5.2 shows the Hyper

Terminal Window for port selection. The connect to screen now appears, select the com

port that the USB to TTL cable has been asssigned from the connect using drop down list

and click OK. Next the port properties dialog box appears the example uses the baud rate

of 9600 so select 9600 in the bits per second and select none in the flow control.

Fig 5.2 Port Settings in Hyper Terminal



5.6 Flowchart of the Project

Y

N

N

Y

Y

N

Y

N

Y

N

Fig: 5.3 Flowchart of the Project

Start

Initialize PIC

Initialize ADC and

Read Temperature

Values

IF

Temp

> 40

Display “Temp High”

and send character

‘A’ to PLC

Display

“Temp Normal “

Stop

RCV_ISR

INT_RDA

Return

Value

=1

If

Value

=2

If

Value

3

If

Value

=4

Bulb Switch ON

Bulb Switch OFF

Bulb

Fan Switch ON

Fan

Fan Switch OFF



5.7 Flowchart for Android Application

N

Y

N

Y

Fig 5.4 Flowchart of Android Application

Start

Enter the Wi-Fi

router IP

addresses

Send messages to hardware for

Fan ON, Fan OFF, Light ON and

Light OFF.

Hardware Receives

messages

Disconnect from hardware

Stop

If

Connection

established

IF data

received from

PC=’A’

Display “Temp Limit

Crossed”



Figure 5.3a shows the flow chart of the project. On power ON, the

Microcontroller, ports, registers, ADC and LCD connected to the Microcontroller are

initialized. The temperature value sensed by the sensor is read by the ADC of the

microcontroller. The microcontroller checks whether the temperature value is greater than

40. If it is true, the microcontroller displays “Temp High” in the LCD. If the condition is

false then the microcontroller displays “Temp Normal” and sends a character ‘A’ to PLC.

Figure 5.3(b) shows the flowchart in the case of an interrupt. The ISR checks if

the value received is ‘1’. If the condition is true, then a control signal to switch on the

bulb is sent. If the condition is false, check if value is ‘2’. If it is true, Bulb is switched

off; else check if value received is ‘3’. If it is true Fan is switched on. If the condition is

false, the ISR checks if the value is ‘4’. If it is true, Fan is switched off. If not true, the

ISR is terminated and execution returns to the main program

Figure 5.4 shows the flowchart of Android Application. On opening the

application in the cell phone, it requests for the IP address of the router to establish

connectivity between the cell and the PC .On successfully connected with the PC ,the

Android application checks if the data received from PC is ‘A’. If it is true, then a

message “Temp limit Crossed” is displayed in the cell. Then the application continues

with the other routines like sending messages to turn ON/OFF the Fan and Bulb

controlled by the microcontroller.



Chapter 6

RESULTS, CONCLUSION AND FUTURE WORK

This chapter provides details about the results obtained from the work done,

conclusion, future work and enhancement.

6.1 Results

This project is mainly designed for the purpose of monitoring and controlling various

electrical appliances based on the temperature value sensed from a remote location. The user

can know the status of the temperature from anywhere in a large building without requiring

him to be present at the location for monitoring and controlling, in the real time

environment. This status information will be in the form of Text message. The status of the

appliances whether the Light ON/OFF and Fan ON/OFF is displayed in the user’s mobile.

Depending on the status of the temperature in the field, the user can again control the status

of the devices by sending commands from his mobile. These monitoring and controlling can

be done by pressing the GUI buttons in the Android, Wi-Fi based mobile. The signals are

communicated through the Wi-Fi, PC and through power line, to the device section. This

will reduce the requirement of external communication media or wiring. Fig 6.1 shows the

snapshot of hardware unit.

Fig: 6.1 Snapshot of Hardware Unit.



Figure 6.2 shows the snapshot requesting the IP Address of the router.

Fig: 6.2 Snapshot requesting the IP Address of the router.



Fig 6.3 shows that Wi-Fi connectivity has been established between users mobile and the

PC. PC is connected to the PLC modem via RS232 cable.

Fig: 6.3 Snapshot showing Wi-Fi connectivity.



Fig: 6.4 Snapshot of GUI created in the Mobile

Fig 6.4 shows GUI buttons that enable the user to turn ON/OFF the Bulb and Fan.

Fig: 6.5snapshot showing the Temperature limit crossed.

Figure 6.5 shows the temperature limit crossed.



Figure 6.6 shows Transmitter Section.

Fig: 6.6 Snapshot showing the Transmitter Section

Fig: 6.7 Snapshot of showing Rreceiver section.

Figure 6.7 shows snapshot of Receiver Section.



6.2 Conclusion

The system was extensively tested for various conditions/cases in the laboratory

such as AC power, UPS and no power and practical conditions were simulated

artificially; for example resetting automatically from no power state. The system uses

Power Line as a physical media for communication in spite of no activity on the Power

Line data was being transferred reliably. This system has the potential to reduce the

response time in a cost effective way. The system is robust and efficient methods can be

incorporated to validate the threats in the Industry by adding some additional options to

the sensors. This system at the moment will be focusing on multiple aspects of the

emergency detection which are fire, short circuit and gas leaks which occurs mostly in

many industries, severe weather changes in the campus.

6.3 Scope for Future Work

The project can be enhanced by using 32 bit ARM controller to monitor and control

more parameters. In our project PLC Modem processes with a Baud rate of 300 bps. The

processing speed can be increased by using latest PLC Modems with 9600 Baud rate. PC

can be replaced by RTOS based systems. Implementation of PLC-Zigbee Hybrid

combination could further enhance the functionality of the system.



AUTHORS PUBLICATION

This work has been selected for Paper presentation in 2nd

INTERNATIONAL

CONFERNCE ON INNOVATIONS IN ELECTRONICS & COMMUNICATION

ENGINEERING [ICIECE – 2013] on 08-09 August 2013, organized by department of

Electronics & Communication, Guru Nanak Institute of Technology, Ibrahimpatnam,

Hyderabad, A.P, India.



BIBLIOGRAPHY

[1] Chia-Hung Lien,Ying-Wen Bai, Hsien-Chung Chen and Chi-Huang Hung:“Home

Appliance Energy Monitoring and Controlling Based on Power Line Communication”,

978-4244-2559-4/09/$25.00©2009 IEEE

[2] Yitran ATL90115 Power Line Communication Modem Data Sheet

[3] Microchip PIC18FXX8 Data Sheet.

[4] Shwehdi.M.H.; Khan,A.Z; "A power line data communication interface using spread

spectrum technology in home automation," Power Delivery, IEEE Transactions on,

vol.11, no.3, pp.1232-1237, July1996.doi:10.1109/61.517476

[5] A Remote Controller for Home and Office Appliances by Telephone-Consumer

electronics, IEEE, 1998.

[6] Remote-Controlled Home Automation Systems with Different Network Technologies-

Centre for Applied Internet Research (CAIR), University of Wales, NEWI, Wrexham,

UK

[7] Remote Control of Electrical Appliances via Power Line- XIX IMEKO World

Congress fundamental and Applied Metrology September 6−11, 2009, Lisbon, Portugal

[8] Street Public Lighting Control and Monitoring using PLC

[9] A Practical Intelligent Home System Based on PLC -Power electronics systems and

applications, 2006 ICPESA`06 2nd

International conference dated on 12-14 Nov 2006

[10] Wireless Networking for Sugar Industries through PLCC Technique- International

Journal of Recent Trends in Engineering, Vol 2, No. 6, November 2009

[11] Remote Data Acquisition Using Wireless –SCADA System.

[12] Power Line Communication Based Automation System using a Hand held Wi-Fi

device.

WEB REFERENCES

http://www.cscjournals.org/csc/manuscript/Journals/IJE/volume3/Issue1/IJE-24.pdf

http://www.archnetco.com/english/product/lamp.htm

http://www.cscjournals.org/csc/manuscript/Journals/IJE/volume3/Issue1/IJE-24.pdf

http://www.archnetco.com/english/product/lamp.htm



APPENDIX A

18F458 PIC Microcontroller

Appendix A includes the PIC 18f458 architecture and features. Fig 1 shows the

Architecture of PIC18458. It consists of RISC instruction set, single cycle execution and

Harvard architecture.

Fig.1 Architecture of PIC 18f458 Microcontroller



High-Performance RISC CPU:

Linear program memory addressing up to2 Mbytes

Linear data memory addressing to 4 Kbytes

Up to 10 MIPS operation

DC – 40 MHz clock input

4 MHz-10 MHz oscillator/clock input with PLL active

16-bit wide instructions, 8-bit wide data path

Priority levels for interrupts

8 x 8 Single-Cycle Hardware Multiplier

Peripheral Features:

High current sink/source 25 mA/25 mA

Three external interrupt pins

Timer0module: 8-bit/16-bit timer/counter with 8-bit programmable prescaler

Timer1module: 16-bit timer/counter

Timer2module: 8-bit timer/counter with 8-bit period register (time base for PWM)

Timer3module: 16-bit timer/counter

Secondary oscillator clock option – Timer1/Timer3

Advanced Analog Features:

10-bit, up to 8-channel Analog-to-Digital Converter module (A/D) with:

Conversion available during Sleep

Up to 8 channels available

Analog Comparator module:

Programmable input and output multiplexing

Comparator Voltage Reference module

Programmable Low-Voltage Detection (LVD) module:

Supports interrupt-on-Low-Voltage Detection

Programmable Brown-out Reset (BOR)

CAN bus Module Features:

Complies with ISO CAN Conformance Test

Message bit rates up to 1 Mbps



Conforms to CAN 2.0B Active Spec with:

9-bit Identifier Fields

8-byte message length

3 Transmit Message Buffers with prioritization

2 Receive Message Buffers

Fig 2 Pin Diagram of PIC 18F458



APPENDIX B

LM35 Temperature Sensor

The LM35 series are precision integrated circuits temperature sensors, whose

output voltage is linearly proportional to the Celsius temperature. Fig 3 shows LM35

precision grade temperature sensor. The LM35 has an advantage over linear temperature

sensors calibrated in degree Kelvin. The user is not required to subtract a large constant

voltage from its output to obtain convenient centigrade scaling. A Thermistor responds to

temperature change by changing the resistance, but its response is not linear. The

complexity associated with writing software for such a non-linear devices has lead many

manufacturer to market a linear temperature sensor. Simple and widely used temperature

sensor includes the LM35 series from National Semiconductor Corporation.

Fig 3 LM35 Pin Description

It can be used with single power supply or with plus or minus supplies. As it

draws only 60 µA from its supply, it has very low self heating, less than 0.1°C in still air.

The LM35 is rated to operate over -55°C to +150°C temperature range, while LM35 is

rated for a -40°C to +110°C range. The LM35 does not require any external calibration

or trimming to provide typical accuracies of 1/4°C at room temperature and 3/4°C

over a full -55 to +150°C temperature range. Low cost is assured by trimming and

calibration at the wafer level. The LM35’s low output impedance, linear output and

precise inherent calibration makes interfacing to readout or control circuitry especially

easy. The inherent strength of the LM35 sensor over other currently available temperature

sensors is that it is not susceptible to large errors in its output from low level leakage

currents. Low cost and high accuracy are maintained. LM35 has very less self heating.



APPENDIX C

LM324 Operational Amplifier

The amplifier used in this project is LM324 which is shown in Fig 4 [7]. It is a

Quad Operational Amplifier which consists of four independent, high gains; internally

frequency compensated operational amplifiers which were designed specifically to

operate from a single power supply over a wide voltage range. Operation from split

power supplies is also possible so long as the difference between the two supplies is 3

volts to 32 volts. Application areas include transducer amplifier, DC gain blocks

Summing Amplifiers, multivibrators, oscillators and all the conventional OP Amp circuits

which now can be easily implemented in single power supply systems.

Fig 4 Input Voltage Range

LM323 eliminates need for dual supplies and it is four internally compensated op

amps in a single package, allows directly sensing near ground. LM324 is compatible with

all forms of logic. The graph shows input voltage range of LM324.



APPENDIX D

MAX 232 Level Converter

The MAX232 from maxim was the first IC which is one package contains the

necessary drivers and receivers, to adapt the RS232 signal voltage levels to TTL logic. It

became popular, because it just needs +5 V and generates the necessary RS232 voltage

levels. In serial communication the line that is used to transmit data is called Tx and the

line used to receive data is called Rx. The PIC Microcontroller uses TTL level for logic

that is a 1 is a 5 V and 0 is 0 V but RS232 standard uses different scheme for logic level,

so we need a level converter in between.

Fig 5: Max 232 Pin Diagram

The data is ready to be fed to a standard serial port of PC. All good development

boards have an on board level converter. The MAX 232 IC is a industry standard chip for

the purpose of level conversion between RS232 and TTL signals. Serial cable has been

used to connect the MAX232 to PC. Serial cable has male and female DB9 connector. Pin

13 and 8 of MAX232 have been connected to DB9 port in order to transfer information to

the computer. Pins 12 and 9 on the MAX232 have been connected to PIC, port C pin C6

and C7 in order to transfer information signals to PIC. The voltage supply of 5V for

Max232 can be achieved through the schematic circuit which has standard capacitance.



APPENDIX E

ULN2003

The ULN2003 is a high-voltage and high-current Darlington transistor array. It

consists of seven NPN Darlington pairs that feature high-voltage with common cathode

clamp diode for switching inductive loads. The collector-current rating of a single

Darlington pair is 500mA. The Darlington pairs may be paralleled for higher current

capability. The ULN2003 has become the primary choice to control the external

components. It is cheap, effective, and requires no operating voltages other than the

common ground.

Fig 6 : LOGIC DIAGRAM Fig:7 SCHEMATIC (EACH DARLINGTON PAIR)

Pin Configuration of ULN2003

Pins 1:7 are inputs, while pins 10:16 are high-current sink drivers. Between the

I/Os is an independent Darlington pair (the ‘Darlington pair’ behaves like a single

transistor with a high-current gain). When a input is driven high, the corresponding output

will basically become an earth. Alternately, when the input pin is low the output pin

adopts high impedance. This allows external high-current circuits to be driven by small



micro-controllers. These are seven channels ready to be used, and as mentioned earlier,

the ULN2003 can sink up-to 500mA between all the channels. For inductive loads, such

as motors and relays, pin 9 is connected to the loads positive to shunt counter-

electromotive force safety. That is, if the motor was connected to +12V and pin 16 of the

ULN2003, then pin 9 would be connected to the same +12V source as the motor.

Applications include relay drivers, hammer drivers, lamp drivers, display drivers

(LED gas discharge), line drivers, and logic buffers. The pin configuration of ULN2003 is

as shown in fig. ULN2003 has output current of 500mA featured with high sustained

voltage output of 50V min. The inputs are compatible with various types of logic.

Features

Output current (single output) 500 mA Max.

High sustaining voltage output 50v Min.

Output clamp diodes

Inputs compatible with various types of logic

Package type : DIP-16pin



APPENDIX F

PLC MODEM

The ATL90115 series Embedded PLC Modem is a ready-to-go circuit module,

which is capable of transferring data over the power cable at the low voltage end of the

power transformer of a 3-phase/ 4-wire distribution network. A pair of Embedded PLC

Modems connected on the power line can provide low speed bi-directional data

communication at a baud rate of 300 bps. It is built in a small form factor that can be

easily integrated into and become part of the user's power line data communication

system. The PLC modem is based on the Direct Sequence Spread Spectrum Technology,

which ensures high noise immunity and reliable data communication.

The modules provide bi-directional half-duplex data communication over the

mains of any voltage up to 250V AC and for frequency of 50 or 60 Hz. It does not require

any protocol to function and therefore is protocol independent. Data flow through PLC

modem as if it is a channel and therefore it is transparent to the Data Devices. As a result,

with user’s proper addressing and communication protocol, multiple units can be

connected to the mains without affecting the operation of one another. There is no hassle

of building interface circuits. It has a built -in on board AC coupling circuit, which allows

direct and simple connection to the mains. Interface to user’s data devices is a simple

data-in and data-out serial link. Power to the PLC Modem circuit module is a single +12V

DC supply.

Applications of the Power Line Modem include status monitoring, control and

data communication of devices connected on the power line, such Home Automation,

Lighting Control, HVAC control, Low Speed Data Networks, Automatic Meter Reading,

Signs and Information Display, Fire and Security Alarm.

Features

Embedded ready-to-go Power Line Carrier Modem module with SMT

components

Small form factor for easy of system integration

Bi-directional half-duplex data communication over the mains

Applicable to universal mains voltage and frequency up to 250v, 50 – 60 Hz



ATL90115-3 applicable to 3-phase 4-wire network of up to 460VAC phase to

phase

Protocol independent, data transfer transparent to user’s data terminals

High noise immunity and reliable data communication

Simple serial interface to user’s data devices

Built-in on board AC coupling circuit with direct connection to mains

Built-in carrier generation and detection

Multiple units can be connected to the power line of the distribution transformer

Baud rate of 300 bps

Selectable TTL and RS232C level serial interface to user’s data devices

Built with industrial grade components for operation under harsh environment

Complies with EN50065-1: 2001

ATL90115 Data port Pin out assignment



ATL90115 Application Diagram

Fig: 8 Application diagram

Specifications

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Project Report 9-07-2013

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