3 Main Project From Ch 1

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CHAPTER ONE

INTRODUCTION

1.1 What is SMS (Short Message Service)?

SMS is an acronym for Short Message Service. Short message service is a globally

accepted wireless service that enables the transmission of alphanumeric messages between

mobile subscribers and external systems such as electronic mail, paging and voicemail

systems [1]. It is a wonderful technology which makes it possible to send and receive

messages between mobile phones commonly called handsets. SMS first appeared in Europe

in 1992. It was included in the GSM (Global System for Mobile Communications) standards

right at the beginning. The GSM and SMS standards were originally by the European

Telecommunications Standards Institute (ETSI). Now the Third Generation Partnership

Project (3GPP) is responsible for the development and maintenance of the GSM and SMS

standards. As the name Short Message Service suggests, the one SMS message can only

contain 140 bytes (1120 bits) of data which is equivalent to 160 characters if 7-bit character

encoding is used (as in Latin characters like English alphabets), and 70 characters if 16-bit

encoding is used (as seen in non-Latin characters like Chinese which use 16-bit encoding).

SMS messages have support for international languages and works well with languages

supported by Unicode including but not limited to Arabic, Chinese, Japanese and Korea [2].

SMS messages besides text may enable transfer and reception of pictures, ringtones and so

on.

Features of SMS

The number one advantage of SMS is that it is supported by “ALL” GSM mobile

phones, and most pay plans provided by GSM carriers provide affordable plans which

include SMS service. Another distinguishing characteristic of SMS is that an active mobile

phone is able to receive or submit a short message at any time, independent of whether or not

a voice or data call is in progress. The delivery of the short message by the network is also

guaranteed by SMS. Usually, when there is temporary network failure, this failure is

identified and the short message is stored in the network until the destination becomes

available. SMS makes use of low-bandwidth message transfer. Generally, the benefits of

SMS to users are focused on convenience, flexibility and integration of messaging services

and access to data. Hence, a user should be able to use the handset as an alternative to a

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computer. One downside of the SMS technology is that one message can only carry very

limited amount of data, say 160 characters. Therefore, an extension called concatenated SMS,

sometimes called long SMS was developed. This long SMS can contain more than 160

English characters, by breaking down a long message at the sender‟s mobile phone into

smaller parts, and sending each of these parts as a single (short) SMS message. At, the

destination, the recipient‟s mobile phone will re-assemble the parts into the original long

SMS message [2].

1.2 Basic Elements In SMS Technology

1.2.1 SMS Center

The SMS center, SMSC, is used to handle the SMS operations of a wireless network. When

an SMS message is sent from a mobile phone, it goes to an SMS center first. The SMS center

then forwards the SMS message to the required destination mobile phone. An SMS message

may need to pass through more than one SMSC before getting to its final destination. It is just

like data packets pass through several routers before reaching the required destination

network in a packet switched network technology. The basic duty of an SMS center is to

route or direct the SMS messages and also to keep track and regulate the process. When the

destination is unavailable, the SMSC would usually keep the message and forward it when

the destination mobile phone becomes available. Most mobile carriers have their respective

SMS centers and respective center addresses. This address is usually configured by default in

the SIM card provided by the carrier, and typically is an ordinary phone number. It may be

reconfigured for other carriers if necessary.

1.2.2 Validity Period

There are often times when the recipient‟s mobile phone is unavailable maybe due to network

failure or low battery. The SMS message in such a case is temporarily stored in the SMS

center, and then forwarded to the destination mobile phone when it becomes available. A

time period may be specified within which the SMS message will be available in the SMSC,

before the message is deleted. Hence, after this period, the SMS message will no longer be

forwarded to the recipient‟s mobile phone even if it becomes available. This time period

within which the SMS message is valid in the SMS center and can be forwarded to the

recipient‟s phone is called the Validity Period.

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1.2.3 Message Submission Report

When an SMS leaves a sending mobile phone, it goes to the SMS center. The SMS center

usually sends back a message submission report to the sending mobile phone to ascertain

whether there are any errors such as incorrect SMS format, low account balance and so on. If

there is no such error, the SMSC sends a positive submission report to the sending mobile

phone else it sends a negative submission report to the sending mobile phone [2]. The mobile

phone then notifies the user that the message submission for sending has failed.

1.2.4 Message Delivery Report

When a sent SMS gets to the recipient‟s mobile phone, the mobile phone will send back a

delivery report to the SMS center to acknowledge receipt of such SMS and inform on any

errors if any. If there are no errors, the report sent to the SMSC would be a positive report

else it would be a negative report. If the mobile phone of the SMS sender was configured to

receive delivery reports, the SMSC would then forward that delivery report to that mobile

phone. If the SMSC does not receive the delivery report within a certain time period, it

assumes that the delivery report has been lost.

1.2.5 Home Location Register (HLR)

The home location register (HLR) is used for permanent storage and management of records.

These records include subscription periods and service profile databases. The SMS Center

checks here for routing information about the indicated subscriber.

1.2.6 Mobile Switching Center (MSC)

This determines the flexibility and switching capability of the entire system. The mobile

switching center carries out the switching requirements. It establishes control between the

SMS system and other data systems on any network.

1.2.7 Visitor Location Register (VLR)

This is similar to the Home location register but unlike the HLR, it stores temporary

information and not permanent information. It is a database consisting of temporary

information about subscribers which the Mobile Switching Center needs in order to satisfy or

service the subscribers.

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1.2.8 Mobile Station (MS)

This is a wireless terminal which has the ability to receive and send short messages as well as

other voice calls. Short message service makes use of the Mobile application part (MAP),

which defines the rules and mechanisms to be used in communication in wireless networks,

and makes use of the SS7 transaction capability application part (TCAP). The wireless

network infrastructure used in the Mobile station is based on the Signaling system No. 7

(SS7).

1.2.9 Base Station System (BSS)

This is the place where all radio-related activities or operations are carried out. The base

station system is made up of the base station controllers denoted as BSCs and the base

transceiver stations denoted as BTSs. The BSS transmit voice and data traffic between the

mobile stations.

1.2.10 Short Message Entity

This is a device which can be used to receive or send alphanumeric messages such as a

mobile phone or handset. It is the primary source and final destination of the Short Message.

1.3 Signaling Elements Used In SMS

The mobile application part (MAP) layer defines the operations necessary to support the short

message service. Bothe American and international standards bodies have defined a MAP

layer using the services of the signaling system No. 7 transaction capabilities part. The

international standard is defined by the European Telecommunication Standards Institute and

is referred to as GSM MAP, while the American Standard is referred to as IS-41 and is

published by the Telecommunication Industry Association [1]. The following MAP

operations are necessary to provide the end-to-end short message service.

1.3.1 Point-to-point Short Message Delivery

This signaling mechanism makes it possible for the SMS center to transfer short messages to

the Mobile Switching Center (MSC) which serves the addressed mobile station and in turn

attempts to deliver the message to a Mobile Station whenever it is registered. This operation

works together with the base station subsystem while the message is being forwarded from

the Mobile switching center, to the Mobile station. The outcome is either success, if the

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message is delivered or failure, if the message is not delivered. The point-to-point short

message system is made possible using Short Message Delivery Point-to-point (SMD-PP)

and forward Short message mechanisms catered for in IS-41 and GSM respectively.

1.3.2 Routing Information Request

To send and deliver short message, the SMS center needs to obtain the necessary routing

information to determine the service Mobile switching center for the mobile station used at

the time of the delivery attempt. This is made possible by accessing information from the

Home Location Register, using the SMSrequest mechanism of IS-41 and

sendRoutingInfoForShortMsg mechanism of GSM.

1.3.3 Short Message Waiting Indication

This signaling operation is very useful and comes to play when a short message delivery

attempt to the SMS center is negative, that is, it fails. The short message waiting indication

provides a means for the SMS center to request the Home location register to add it (the SMS

center) to the list of SMS centers to be informed when the indicated mobile station becomes

accessible. This short message waiting indication is achieved using SMS notification

indicator mechanism in IS-41 and set message waiting data mechanism in GSM.

1.3.4 Service Center Alert

The service center alert functions as a means for the home location register to tell the SMS

center which has previously initiated unsuccessful short message deliver attempts to a

specific mobile station, that the mobile station is now recognized by the mobile network to be

accessible. It is made possible by the use of SMS notification mechanism in IS-41 and alert

service mechanism in GSM.

1.4 Applications and Advantages of SMS Technology

Most of the applications of SMS technologies are direct consumer applications. However,

there are also some corporate applications of SMS technologies. These applications of SMS

are detailed as follows.

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1.4.1 Simple Peer-to-peer Messaging

Most often people interact with one another using short messages usually to say hello,

arrange meetings, to pass around information and so on. Users usually find it more

convenient to use SMS than email when they need to send short quick information among

mobile users due to the fact that mobile phones most times will be close to the user, often in

his or her pocket. Hence, the recipient receives and makes use of the message within a very

short while after it is sent by the sender. This application of SMS is popular with young

people who are willing to learn how to user new technologies.

1.4.2 Provision of Information

SMS can be used to broadcast a lot of information on request to users. This information may

include share prices and quotes, scores and results from sports, weather forecasts, news

headlines, jokes and tips and many others. Usually, a user would send a request for particular

information from his or her mobile phone let‟s say health tips. This information requested (in

this case, help tips), is composed into a short message, which is delivered to the user as

requested. Also, unrequested information may also be sent to users, usually in the form of

advertisement of a product or service to be offered.

GSM carriers, companies and banks also use SMS for providing customer service

related information to their clients when necessary whether requested or not. In vehicle

positioning, Short Message Service is used to send the co-ordinates (longitude and latitude)

which correspond to a vehicle‟s location via GPS (Global Positioning System). This

integrates satellite positioning systems that tell people where a vehicle is on the surface of the

earth [3].

1.4.3 Remote Monitoring

SMS can be used to manage appliances and machines in a distant or remote environment.

This makes it possible to remotely control these appliances and machines by the use of

specific instructions place in SMS messages or to receive fault alert messages from these

appliances. The information is automatically delivered at the receiving device without any

human or physical presence. Examples of such systems are remote meter reading, remote

control of devices, fault alert systems etcetera.

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Advantages of Short Message Service

The advantages of SMS technology include but are not limited to the following:

(a) The storage and forwarding mechanism is very useful when a recipient is unavailable,

because it helps to prevent unnecessary loss of relevant information.

(b) Short Message Service provides an effective, reliable and low-cost communication

method for short message delivery.

(c) Simultaneous message delivery to multiple subscribers is possible hence one can send

short messages to more than one person at the same time.

(d) Short message service can easily be integrated with internet based (web) applications

and other data applications or systems to achieve several purposes.

Limitations of Short Message Service

Although SMS has many advantages, there still exist some limitations of its use, these

limitations include the following:

(a) The ideal message length for simple SMS text messages is 160 characters only and

nothing more.

(b) SMS ideally does not support audio or graphics; hence we have MMS which is

similar to SMS which includes the audio and graphic technologies.

(c) The storage and forwarding mechanisms of SMS although very useful, makes it

unusable for WAP applications.

(d) The signaling channel used for SMS is also used for other purposes; this somehow

reduces the message transmission data rate.

1.5 Introduction To GSM Modems

What is a GSM Modem?

GSM is an acronym for Global System of Mobile Telecommunication. A GSM modem is a

wireless modem that makes use of a GSM wireless network for its operation. A normal

wireless modem is similar to a dial-up modem. The main difference between them is that a

dial-up modem sends and receives data through a fixed telephone line while a wireless

modem sends and receives data through radio waves (wireless technology) [2].

A GSM modem may be an external device or a PC card, also called PCMCIA card.

Usually, a GSM modem is connected to a computer through a serial cable or a USB cable.

The modem in form of a PC card is designed to be used with a laptop computer and should be

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inserted into one of the PC Card slots of the laptop computer. A GSM modem requires a SIM

card from a wireless carrier or service provider in order to function just like a GSM mobile

phone. It is a hardware component that allows the capability to send and receive SMS to and

from a system. The communication with the system takes place through RS232 serial port. A

GSM modem could be the traditional PCMCIA card or a mobile phone but the use of mobile

phones limits the hardware functionality.

1.5.1 GSM Modem Versus Mobile Phone

Which is better, Mobile phone or GSM Modem? Usually, GSM modems are recommended

for use with a computer to send and receive messages. This is because some mobile phones

are limited in some ways compared to GSM modems. Some of these limitations are as

follows.

Firstly, some mobile phones (example: Sony Ericsson R380) cannot be used with a

computer to receive concatenated SMS messages. As explained earlier, concatenated

messages are those which contain more than 140 bytes of data, which is the normal capacity

for simple messages.

Secondly, many mobile phone models cannot be used with a computer to receive

Multimedia messages (MMS), (messages that include video, pictures and audio). This is

because when they receive a MMS notification, they handle it automatically instead of

forwarding it to the computer [2].

Thirdly, many mobile phones do not support some AT commands, command

parameters and parameter values. As we may think, GSM modems support a more complete

set of AT commands than mobile phones.

Also, most SMS-relying applications have to be available 24hours a day. For instance,

and SMS messaging application that provides audio downloading services as the ones used in

download of latest ringtones should always be online such that the user can never experience

downtime. If such applications use mobile phones to send and receive SMS messages, then

the mobile phones would have to be switched on all the time, which means the battery will

have to be charged all the time.

Besides the above problems, mobile phones and GSM modems are more or less the

same for sending and receiving SMS messages from a computer, or another mobile phone.

There is not much difference between mobile phones and GSM modems in terms of SMS

transmission rate, since the determining factor for the SMS transmission rate is the wireless

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network. For this project, a Sagem MyX5-2 mobile phone is used and is sufficient for the

required functionality of the system.

1.5.2 Things To Consider When Using GSM modem or Mobile Phones

For safety of the system where these devices are integrated, the following are some

precautions that should be taken.

1. Modems generate audio frequency (RF) power hence care must be taken on safety

issues related to RF interference as well as regulations of RF equipment.

2. Mobile phones should not be used in scenarios dealing with aircraft, petrol stations or

other places that may lead to hazard or where the GSM products are prohibited.

3. When integrating such system for vehicle control, check for any regulation or law

authorizing the use of GSM in vehicles in your country before installing the modem.

Also, qualified personnel should carry out the installation after consulting the vehicle

dealer for any possible interference with electronic parts/devices in the car.

4. If used in a car automation system, the GSM modem/mobile phone should be

connected to the vehicle‟s supply system by using a fuse-protected terminal in the

vehicle‟s fuse box.

5. To ensure longer life-span of the GSM modem/mobile phone, do not expose the

modem to extreme conditions such as high humidity or rain, high temperatures, direct

sunlight, harsh chemicals, dust or water.

6. When using modems especially traditional GSM modems, avoid disassembling or

modifying the modem, there is no user serviceable part inside the modem. In case of

problem, please contact authorized dealer.

1.6 General Concept

The principle used in this design is centered on Short Message Service (SMS). The SMS

signal is transmitted through GSM wireless network from a mobile phone which acts as a

transmitter, to another GMS mobile phone on the system itself, which acts as the receiving

modem. The receiving mobile phone converts the received signal to binary which is sent to a

microcontroller via serial communication. The microcontroller is programmed to control

some given loads based on the signal received from the transmitting mobile phone.

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1.6.1 Serial Communication

Serial transmission technology is increasingly used for the transmission of digital data. A

large number of up-to-date communications networks apply serial transmission. The

numerous applications include computer networks for numerous applications office

communications, building and manufacturing automation systems, internet and ISDN

(Integrated Services Digital Network, which is a system of digital phone connections which

has been available for over a decade. This system allows voice and data to be transmitted

simultaneously across the world using end-to-end digital connectivity).

Serial data transmission implies that one bit is sent after another (bit-serial) on a

single transmission line. Since the microprocessors in the devices process data in bit-parallel

mode, the transmitter performs parallel-to-serial single line conversion, while the receiver

performs serial to parallel conversion. [4]. See fig. 1 for more details.

Fig. 1.1 Simple 2-wire line for bit-serial transmission. [4]

As can be noted from above, serial communication is a process of sending data one bit at a

time, sequentially, over a communication channel or computer bus. This is in contrast to

parallel communication where several bits are sent as a whole, on a link with several parallel

channels. It is mostly applied for all long-haul communication and most computer networks,

where cost of cable and synchronization difficulties makes parallel communication

impractical.

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3

4

5

6

7

8

8

7 6 5 4 3 2 1

8

7

6

5

4

3

2

1

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7 6 5 4 3 2 1 8-bit unit 8-bit unit

2 lines

Transmitter Receiver

8,7,6,5

4,3,2,1

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Transmission Standards:

The various coding techniques define how the binary states are represented, that is, how the

signal states change during the transmission of a serial bit flow. These specifications are

frequently adopted by - mainly internationally standardized - transmission standards. In the

field of communications, the interface specification have been defined by the ITU

(International Telecommunication union) or adopted from other standards. Out of these

standards, the one of interest which is used frequently for computer and control applications

is the RS232 or V.24 serial interface. This is also used in this project. This is applied in point-

to-point connections between two devices. The complete specification for four-wire full-

duplex transmission as well as definitions for the handshaking line is presented in the US

standard RS232C, or in the almost identical international standard ITU-T V.24. [4].

1.6.2 Introduction to AT Commands

AT commands are instructions which are used in controlling modems. AT is the abbreviation

for „Attention’. Every command line starts with “AT” or “at”, hence modem commands are

called AT commands. Many of these commands which are used to control wired dial-up

modems, like ATD (that is, Dial), or ATA (that is, Answer), are also supported by GSM

modems and mobile phones. Besides these general command sets, GSM modems and mobile

phones support another AT command set which is specific to the GSM technology, which

includes SMS-related commands like AT+CMGS (Send SMS message), AT+CMSS (Send

SMS message from storage), AT+CMGL (List SMS messages) and AT+CMGR (Read SMS

message). The “AT” prefix informs the modem about the start of a command line. It is not

part of the AT command name in AT+CMGS, +CMGS is the actual AT command name. [2].

These commands are applied in this work for reading SMS, getting SMS notification and

more. It is used together with Assembly language coding scheme. This is used in the

programming of microcontrollers. Some tasks that can be achieved using AT commands with

a GSM modem or mobile phone are:

(i) To get basic information about the mobile phone or GSM modem. For instance, name

of manufacturer (AT+CGMI), Model number (AT+CGMM) and lots more.

(ii) To get basic information about the subscriber like MSISDN (AT+CNUM).

(iii)To get information about the mobile phone such as mobile phone activity status

(AT+CPAS), radio signal strength (AT+CSQ), battery level and battery charging

status (AT+CBC) etc.

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(iv) To establish a data connection between two peers or a connection to a remote modem

(ATD, ATA etc.).

(v) To send (AT+CMGS, AT+CMSS), read (AT+CMGR, AT+CMGL), write

(AT+CMGW) or delete (AT+CMGD) SMS messages and obtain notifications of

newly received messages (AT+CNMI).

(vi) To read (AT+CPBR), write (AT+CPBW) or search (AT+CPBF) phonebook entries.

(vii) To save and restore configurations of the mobile phone or GSM modem. For

instance, save (AT+CSAS) and restore (AT+CRES) settings related to SMS

messaging such as the SMS center address.

Usually, the mobile phone manufacturers do not implement all AT commands, command

parameters and command values in their mobile phones. Also, some AT commands require

the support of mobile network operators.

1.6.3 Microprocessors and Microcomputers

It is no exaggeration to say that microcomputers and microprocessor have revolutionized the

electronics industry and have made wonderful impacts in our lives. The development of

extremely high service Integrated Circuits has greatly reduced the sizes and costs of

microcomputers which designers routinely consider in using their power and versatility in a

wide variety of products and applications. [5]

1.7 Objective of the Project

The primary or main objective of this project is to design and fabricate a GSM based

automation system using Short Message Service (SMS) from mobile phones.

1.8 Scope of this Work

This project work entails the design and construction of an automation system using Short

Message Service (SMS). It is limited to the availability of GSM (Global System of Mobile

Telecommunication) network coverage over the area of control. The project further caters

primarily for the control of home based appliances such as light bulbs, fans.

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1.9 Significance of Project

The significance of this project is that is makes a fully integrated, versatile, intelligent home

system that eases the user‟s decision for operation of home appliances. Apart from the control

of these appliance locally or physically, the home owners are able to operate or control them

remotely while they are away from home. It will benefit the people who always leave their

home for outstation duty or those who are always travelling. It will also be helpful for a

family who are going for a long vacation especially during festivities.

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CHAPTER TWO

OVERVIEW OF HOME AUTOMATION SYSTEMS

2.1 Household Automation

Home automation is the residential extension of building automation. It is the automation of

the home, housework or household activity [6]. By definition, automation refers to the

automatic operation or control of equipment, a process, or a system without conscious

thought. It also can be defined as the use of computers to perform tasks previously performed

by people. The home automation is one that provides a comfortable and productive

environment via automated control systems such as fire safety, security and energy or

lighting management. This reflects the evolution from energy management systems in which

a central computer was used to control the building services. According to Bill Gates, home

automation is predicted to become a boom industry by technology pundits. It can provide

additional time for recreational pursuits; monetary savings through power management and

peace of mind that valued homes and contents are being monitored 24 hours a day. For

elderly or disabled people, home automation would provide them more advantage and give

them more fulfillments with their appliances since they can achieve their hearts desires with

ease.

The concept of automation has existed for many years. It began with a student

connecting two electric wires to the hands of an alarm clock in order to close a circuit of a

battery and light bulb. Later, companies developed automated systems of their own to control

alarms, sensors, actuators and video cameras and in so doing, created the first automated

buildings [7].The term “intelligent systems” or “intelligent home” followed. Due to the

obvious advantages of these systems, their influence on the conventional home was

predictable and finally, in 2988, the term domotics was coined. Domotics is the application of

computer and robot technologies to domestic appliances. Domotics is a portmanteau word

formed from „domus‟ (a Latin word which means house) and „robotics‟. A modern definition

of Domotics could be the interaction of technologies and services applied to different

buildings and structures with the purpose of increasing security, comfort, communications

and energy savings [7].

At the beginning, automated devices were independent or, sometimes grouped in

small independent systems. The idea of giving them some operability among each other using

a common language keeps developing, consequently following such idea; the first Home

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automation systems (HASs) appeared bringing a new concept of a home network full of

possibilities. However, there were also some new factors to bear in mind. A strong reason for

Home automation systems are becoming popular because they are so many attractive features

that can easily lure companies to enter quickly into this emerging market. HASs also

represent a great research opportunity in creating new fields in engineering, architecture and

computing [7]. It should be noted that these new technologies are still in their early stages

with a lack of robust standards creating compatibility issues affecting their reliability.

Another problem is that these systems are not always fully accepted by final users, especially

the old and disables, which even need it the most. As an example, one effort to make these

systems usable and affordable by any user helped the use of old, cheap and simple

technologies like the X-10 protocol to transfer data in the home-network. Relatively, this

approach created low cost HASs.

There are many recent tendencies to integrate various kinds of embedded devices and

consumer appliances into software systems, tendencies that have emerges from the ideas of

pervasive computing. This evolution offers many useful possibilities in Domotics. Lately, it

is being proved that Domotics has many interesting fields, and among them, using remote-

controlled Home automation systems to control the home network is one of the most

challenging. The possibility of having ubiquitous access to many devices within a building at

anytime from anywhere, resolves many of the problems that users often face when they

return home, saving significant amount of time. It also notably increases the security in any

kind of building and it may even provide a backup control system for local system

breakdowns [7]. This access could be achieved from many different digital devices and it is

known that the network hierarchy has been rapidly moving lower in the chain towards

smaller and more personal devices [8]. Considering these latest tendencies, everything points

at prompt remote control standardization in home networks.

Recently, with the explosive growth of the internet and telecom technology, home

automation is experiencing an accelerating growth based on different kinds of residential

network. There exist several types of transmission media for residential installations such as

radio and microwave etc. Compared to many other methods of transmission, the GSM

wireless transmission has a good advantage in setting up a home automation system without

installation of many additional devices, with relatively low cost.

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2.2 GSM Control Systems

(i) GSM/Mobile/Cell phone based device monitoring and control system: This system

monitors and controls any digital or analog devices from a cell phone. It can be used to

control up to 16 electrical devices. With the circuit, it is possible to switch ON or OFF, or

restart some Linux servers, modems, printers, door and electrical locking devices, irrigation

pump, garage door, house lights, water pumps. As every automation system, it makes human

life easier and better.

(ii) GSM Based Automation Irrigation Water Controller System: This system is designed

to send SMS alerts whenever the electrical power status changes to ON or OFF. The mobile

phone can be used to switch ON or OFF the water pump from any location in the world.

(iii) GSM based remote monitoring and control of digital energy meter: This is useful for

remote meter reading. It is such that the power supply can be disconnected in an event of

non-payment of electric bill.

(iv) GSM Based Highway vehicle traffic monitoring system: The purpose of this project is

to monitor the vehicles moving on highways at remote locations. It counts the number of

vehicles passing on both directions using infrared and laser sensor system. It makes use of a

microcontroller to store the vehicle count. The information can be sent periodically or by

demand to the user via SMS.

(v) Ezy Switch: This can be used to remotely control and monitor your heating, security

systems and domestic/commercial appliance. Ezy switch is a simple switch control design

that connects to electrical devices. It your equipment can be switched ON or OFF, it can be

controlled from a mobile phone with Ezy switch. It can take up to 8 monitored devices and 4

power controlled devices. It can be integrated in domestic systems, security systems (for

controlling alarms, light sensors), heating and ventilation systems, agriculture (to remotely

control milk sheds, water pumps, monitor fuel tanks and irrigation equipment. The block

diagram of the Ezy switch system is as shown on the following page. [9]

(vi) Control of Remote Domestic System Using Dual Tone Multi Frequency (DTMF):

This method uses a system of control using Dual tone Multi Frequency from mobile phones.

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It makes use of a mobile phone to transmit the DTMF signals and a receiver to receive them.

A decoder typically IC 8870 is used to decode the DTMF signals and then pass them to a

microcontroller which is interfaced with the necessary loads. The block diagram of this

system is given below.

Fig. 2.1: Block Diagram of DTMF Remote Control System [10]

2.3 Smart Homes Today

The “smart” concept has become a marketing catchword, still employed today, to sell a wide

range of products; hence we have smart phones, smart cameras, smart design and lots more.

However, sometimes marketing buzzwords alone cannot guarantee the sell. Xanadu was the

first example of a mass-produced smart home. It was built throughout the 1980s in the US

around the original EPCOT idea; these houses were commercially built dwellings that made

extensive use of smart home technologies. The Xanadu home had a computer that monitored

and controlled all its systems, the kitchen, living room, bathrooms, and bedrooms with all of

them having their own electrical and electronic devices to control the appliances present in

the house. [11]. The house was eloquently described as Xanadu: The Computerized House of

Tomorrow and its peculiar appeal were set by the advert: a house with a brain, where every

room adjusts automatically to match your changing moods.

Tansmitter (mobile phone)

Receiver (mobile phone)

Channel

Condenser Microphone

Audio amplifier

Decoder IC 8870

Microcontroller

Relay – to control devices

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Fig. 2.2: Picture of a Xanadu House [11]

As the time moved on, and most of the houses were still unsold, the technology contained

soon became obsolete. The Xanadu houses started being demolished to make space for more

“commercially viable” projects and by October 2005, they were all gone. Even with the

commercial setback, the concepts of the Xanadu homes were sound and a combination of

elements such as computers, robotics and artificial Intelligence (AI) were to push the Smart

Home concept further, even if sometimes only in research laboratories [11]. Several ideas

provided great indication that the technology may have been finally mature enough to deliver

commercially viable solutions for instance, a device named Waldo, which interfaced with an

Apple computer, could use voice recognition and speech synthesis technology to control

appliances.

Today, several projects funded by universities and the industries alike are still

investigation the possibilities that smart homes can offer. Some of the projects based on

Smart Homes are enumerated as follows:

(a) CISCO Internet Home – This project aims at investigating the benefits of a high-

speed, always available internet connection which will enable an array of consumer

devices and appliances in the home. It was developed in conjunction with leading

19

consumer companies. It further demonstrates how the internet can enhance daily

living for consumers in the home and communities, for the future.

(b) MIT House – This is led by a multi-disciplinary team composed by architects,

computer experts, engineers and behavioral scientists who investigate key issues and

what services could be offered in the home of the future. The main focus of this is on

the design of the home and its related technologies, products and services, in order to

see how they can evolve to meet the opportunities and challenges in the new home.

(c) Microsoft Research EasyLiving – This Started in 1998, EasyLiving is a project

funded by Microsoft research, and it is about creating an intelligent environment that

will make computing more accessible and more pervasive that today‟s desktop

computer. Its goal is to develop prototype architecture and technologies for building

intelligent systems and environments which facilitate people interaction with other

people, computers and other devices.

(d) UMASS intelligent home project – This project from University of Massachusetts

makes use of simulations of agent-based intelligent systems that also use robotics in a

domestic context.

(e) Adaptive House - This project, led by University of Colorado, is to develop a smart

home system that programs itself by observing the lifestyle and desires of the

inhabitants, and by learning to anticipate and accommodate their needs.

(f) Duke Smart home Program – This is Duke University‟s dynamic „living laboratory‟

environment that contributes to the innovation and demonstration of future residential

building technology. The pivoting concept of this project is the belief that smart

homes can improve the quality of life for people of all ages and incomes.

(g) Aware Home Research Initiative (AHRI) – This is an interdisciplinary research

project held at Georgia Tech and is aimed at addressing the fundamental technical,

design and social challenges presented by such questions by using off-the-shelf and

state-of-the-art technologies.

(h) CENELEC Smart Housev - Funded by the European Committee for Electro Technical

Standardization (CENELEC), the aim of this project is to grow and sustain

convergence and interoperability of systems, services and devices that will provide

citizens with access to increased functionality, accessibility, reliability and security

that a Smart House, with common and open architectures, can deliver [11]

20

2.4 SMS Mobile Control System Architecture

The receiver phone is integrated with a microcontroller (eg. PIC16F873A, AT89C52)

which receives SMS message from the transmitter mobile phone and sends a command to

control the output. The system utilizes a low cost microcontroller that is currently available in

the market, and the system makes use of both hardware and software to give required results.

The sequence of events that takes place for the working of the system is as follows:

(a) The remote user sends text messages (SMS) including the necessary commands to the

receiver mobile phone.

(b) The receiver mobile phone receives messages sent from transmitter mobile phone.

(c) The receiver mobile phone decodes the received message and sends the commands to

the microcontroller.

(d) The microcontroller acts on the received commands to control the needed outputs.

Such a system uses the following technologies:

Cellular phone, Networks and Communication Protocols: The widely available networks

are based on GSM. GSM provides a wide coverage area existing in many countries and

locations of the world and can be utilized more cost-effectively for such system. The

communication protocols which can be used include Dual Tone Multi Frequency, DTMF,

Short Message Service, SMS etc. SMS is the most efficient communication protocol. A

mobile phone or cellular device is necessary to create and transmit SMS or DTMF.

I/O Interfaces between Microcontroller and devices: Serial or parallel I/O ports will be

considered for to connect the GSM mobile phone receiver and the Microcontroller. Using the

microcontroller, a control circuit will be implemented to control the electrical appliances such

as lighting points, fans and many others. The Figure 4 below gives the general architecture of

a mobile control system using SMS, to control devices like Air conditioner, lighting points

and security devices.

21

Fig. 2.3: Block Diagram of System [9]

2.4.1 Microcontroller System

The microcontroller is a microcomputer with provisions for input and output

embedded in it. It has all the components of a microprocessor packaged or embedded on a

single chip. It consists of timers, Analog to Digital converters (ADCs), Universal

Synchronous Asynchronous Receiver Transmitter (USART) and others. It is an 8-bit device

with a flash memory which can be erased and rewritten hence it is called Electrically

Erasable Programmable Read Only Memory (EEPROM). The instruction set varies from

microcontroller to microcontroller. The three major features of the controller are:

(a) To receive instructions and decode them to give device address and command for the

device, then send corresponding signals to the driver circuit or actuator.

(b) To ensure dual independent action – device ON or OFF.

(c) To provide feedback status of any device or devices under control whether ON or

OFF.

2.5 Market for Remote Control Systems/Smart Homes

The 20th

century introduced a dramatic revolution in domestic technology which

culminated with the emergency of the remote controlled or smart home concept. However, in

many cases, the research carried out for smart home systems has been focusing more on the

technical possibilities with little consideration of the social aspects or the actual needs of the

22

potential user [11]. Hence these systems seem to be stuck in the early adopter phase of

Roger‟s technology Adoption lifecycle.

Fig. 2.4: Roger’s Technology Adoption Lifecycle [11]

A survey carried out for the UK-based Joseph Rowntree Foundation in 2000 reported that we

may be close to a change of attitude where home remote control systems or smart home

systems may soon become popular and widespread. Many of the people interviewed stated

their interest for a technology that would save time and effort in their home. The research

further outlined concerns about how complicated such a system might still be to operate. It

was also suggested that the young people would be more in favour of such technology that

elderly people, due to their degree of familiarity with modern computer systems [11].

A similar study identifies other types of users who could benefit from this technology.

Similar studies identify other types of user who could benefit from home remote

control systems and smart systems. The relatively recent concept of networking opens new

opportunities for professionals to work from their homes. These individuals may spend more

time in their homes and become more interested in taking advantage of the potential benefits

of the home automation or smart systems.

2.5.1 Potential Benefits

The ability to monitor and control all the devices in the home from a central location

can introduce time-saving benefits. Furthermore, over half of the participants of a survey

reported that they would welcome a new technology that would save time and effort in their

homes [11]. An effective smart home or home remote control system may be able to make

23

complex decisions that are likely beyond the technical expertise of the inhabitants of the

house, for example, an expert system built into a smart home system could contain a detailed

knowledge of thermal systems, of human physiology and other house installations and be

able to determine the optimal choice of temperature and humidity based on the information

received by the thermometers and humidity sensors located inside and outside the house. It is

anticipated that smart homes of the future will be able to integrate all heating, air

conditioning, lighting, home entertainment, and security systems together. Although safety,

security and centralized control are the main requirements, the result of this integration

together with modern networking technology, will open new possibilities that may not exist

today. The able represents the following areas where home remote control may exist today.

Table 2.1: Examples of Smart Home appliances [11]

AREA EXAMPLES

Welfare Health and monitoring, remote diagnosis, remote personal trainer

Entertainment Music television and video downloading

Environment Remote control of lighting, heating/air-conditioning, energy

usage and costs.

Safety Alerting of problems eg. Gas leaks and so on.

Communication Video phone, calendar reminders, communication inside and

outside home

Appliances Self-diagnosis or problems, and assistance in their operations,

automated food ordering.

Studies have demonstrated how mobile phones and short message service (SMS) messages

have become a popular way to keep in touch and how this can increase the sense of safety

and connectedness among family members [11]. These benefits may be further expanded by

integrating this mobile communication network now composed also by other devices and

hand-held computers.

Finally, smart home and remote control systems can increase the quality and facilitate

the life of people with disabilities. Today‟s digital controls and communication systems can

already allow health and support services to carry out routine diagnostics, monitoring and

basic services while allowing the person to remain comfortably at home.

24

CHAPTER THREE

DESIGN CONSIDERATIONS

3.1 System Specification

The digital IC used in the design and implementation of GSM based automation

system using SMS is AT89C51 microcontroller. The voltage requirement for it is +5v. This

+5v is supplied to the controller from the power supply unit with a 7805 regulator IC. For the

12v d.c relay that is used in the output interface, the voltage required to switch it is +12v and

this is tapped from the unregulated voltage of the power supply. The alternative to this way is

to connect another 12 volts regulator at the input of the unregulated voltage to get exactly 12

volts. Other components used are ULN2003A (output driver), BC337 (transistor), Sagem

mobile phone (receiver). Each of them requires +5v d.c to function. The step-down

transformer that is used for the power supply is 240v a.c to 12v a.c with the current rating of

800mA. The system‟s main features are summarized in table 2.

Table 3.1: System’s main features

ITEM CONTENT

Controller IC AT89C51 microcontroller

Text Format Alphanumeric

Power supply 11-20V d.c/220V a.c

Receiver modem Sagem phone

The hardware subsystem is made up of the input interface, the output interface, the

feedback and the control system.

3.1.1 The Input Interface: The input interface comprises of a GSM mobile phone as

transmitter and a GSM mobile phone as receiver, with the GSM network coverage acting as

the bridge between them, and the serial connection between the receiver mobile phone and

the microcontroller.

The ready indicator indicates when the system is ready to receive signals after

initialization.

25

Choice of GSM Network/Mobile Phone

The GSM network was used as the medium and the Sagem phone for the following reasons:

(a) The GSM network has wide coverage over several locations

(b) Most GSM mobile phones have the ability to send and receive short messages (SMS)

which is very important for this system.

(c) The chosen sagem phone is easily made to be compatible with RS232 standard serial

connection and is capable of sending and receiving attention (AT) commands.

(d) The GSM network is relatively fast and reliable.

Choice of Microcontroller (AT89C52)

The microcontroller has the following desirable features:

(a) It supports multilevel programming

(b) It has fast response time

(c) It has 32 input/output ports.

(d) It has serial communication capability

(e) It has enough memory space (4k)

(f) It is cheap and easily available

(g) It has relatively low power consumption.

3.1.2 The Output Interface

The output interface is made up of the ULN2003A driver and the necessary relay devices

rated 12volts each. The loads to be controlled or operated by the system are 4 loads.

26

Fig. 3.1: Section showing the output devices

Fig. 3.2: Output Section showing ULN2003A coupled to the output devices

27

Choice of 240V/10A Relay.

The load rating is 100w, 220v. But power, P = I x V - - (i)

Thus current, I = P/V = 100/220 = 0.45A

Thus the relay meets the current and voltage requirement of the load

Choice of Transistor BC337

The resistance of relay coil = 400Ω (given)

From Ohm‟s law, V = IR, - - - - - (ii)

where I = current, R = Resistance,

Hence, Current, I through the coil = V/R = 12/400 = 30mA

The transistor BC337 can handle this current very well (its hfe = 200 typical)

From kickoff‟s voltage law:

Vcc – IbR2 – Vbe = 0 - - - - - (iii)

For silicon transistors, Vbe = 0.7v

5 – 0.7 = IbR2, 4.3 = IbR2

But Ib = Ic/hfe - - - - - - (iv)

Where Ic = transistor collector current=800mA

And emitter forward current gain, hfe = 200

Ib = 0.8/200 = 0.004A

R2 = 4.3/Ib = 4.3/0.004

R2=1kΩ

Choice of the Freewheel Diode, 1N4001

The free wheel diode D1 protects the transistor from inductive click of the relay. The peak

inverse voltage of 1N4001 = 50v. These are well above 30mA and 12v.

28

3.2 The DC Power Supply

The block diagram of the power supply is shown in figure 5.

Fig. 3.3. Block Diagram Of The Power Supply

3.2.1 Power Supply Requirements

For one to determine the power supply requirements of the entire system, it is necessary to

analyse the current and voltage requirement of the loads and various components used in the

systems design. This will also aid in calculation of entire power requirement of the system.

Table 4.7 shows load , current and power analysis of of the system

Table 3.2 load, current and power analysis of the system.

S/N Component Voltage

Requirement,

V(volt)

Current

Requirement,

I(mA)

Power

Requirement

V x I(mW)

3 AT89C52 5 20mA x 22=

440

2200

5 12v relay 12 30 360

6 Sagem 5 30 150

Step down

transformer

Rectification

Filteration

Regulation

Regulated

output

voltage

29

Phone

10 LEDs 5 10 50

11 Loads 220ac 0.455ac 400w

Maxmum dc

Voltage = 12v

Ac voltage

= 220v(typical)

Total dc

Current

= 510mA

Total dc power

Consumption

= 2705mW.

Total ac power

Consumption

=400W

From the calculations above in Table 3.2, the powe supply must have the following

specification:

i d.c current of 510mA

ii d.c voltage of 12v and 5v.

iii a.c voltage of 220v

iv a.c current of 0.455amp

Transformer Consideration

240/12v, 510mA step down transformer is required. The transformer that is next to 240/12v,

500mA, is 240/12v, 800mA.

Rectifying Diodes Consideration

The rectifier diodes must be able to withstand 510mA and inverse voltage of 12v. IN4001 is

chosen because it has forward current of of 1amp and peak inverse voltage (PIV) of 50v.

Filter Capacitor Consideration

It can be shown that for a full wave bridge rectifier that

dV = load current(I)/2fc, where

dV = ripple voltage

30

f = frequency of the mains supply = 50Hz

C= capacitance of the filter capacitor

Now, let dV be 3v,

Then C = I/(2fdV) - - - (v)

= 0.51/(2 x 50 x 3) =~ 1700uF.

A standard value that is closest to this value is 2200uF.

The capacitor must be able to withstand 2times of the transfomer voltage,

i.e 2 x 12 = 24v.

Thus we 2200uF,25v capacitor

Regulator Consideration

The system requires regulated 5v and unregulated 12v. The current requirement is not more

than 1amp. Thus 7805(5v regulator), will serve the purpose.

31

Fig. 3.4 Circuit diagram for Remote Control

RECEIVER PHONE

4B

5B

6B

7B

P3.0

P3.1

RECEIVER PHONE

P1.0

P1.1

P1.2

P1.3

AT89C52

4C

5C

6C

7C

COM

L1

L2

L3

L4

12v

12v

12v

12v

RL1

RL2

RL3

RL4

+Vcc

1k

1k

1k

1k

GSM NETWORK

31

40

Vcc

12v

1k

Vcc

P3.2

32

3.3 The Software Subsystem

3.3.1 Algorithm:

Step 1: Start

Step 2: Phone Initialization and ready indicator

Step 3: Check phone for any received SMS

Step 4: If new SMS is received, goto step 5, else goto step 3.

Step 5: Identify loads to be switched OFF/ON, and perform required option.

Step 6: Verify that the required operation is performed, if yes, goto step 7, if no, goto step 5.

Step 7: End and go back to step 1.

From the algorithm, the flow chart was developed as shown in Fig. 3.5

33

See appendix I for Assembly code.

Fig. 3.5 Flow chart of the switching

Start

Initialize the System

Check for any received SMS

Is there Any

SMS?

Identify the loads to be operated and

perform the action

Has the action

been performed?

End

NO YES

NO YES

34

CHAPTER FOUR

CONSTRUCTION PROCEDURES

4.1 Purchasing and Preparation of Components

To implement this project, a market survey had to be carried out to ascertain the availability

and affordability of the components and materials. Furthermore, component cost estimate

was done before any purchases were made so as to guide against unnecessary purchase and

waste of resources. As part of the other components to be purchased, two SMS enabled

mobile phones; an RS232 standard serial cable and 2 SIM cards were also purchased.

4.2 Installation and Soldering

The components were arranged in compliance with the circuit diagram of the system, and

installed on the Vero board. The pins were well put through the pin holes on the board to

avoid mechanical faults. A soldering iron and soldering lead was used to solder the pins to

the board and to another pin contact where necessary. Care was taken while soldering the

components so as not to short any of them or over heat them.

The SIM cards were installed in the two mobile phones by taking off the back panel

of the phone, removing the battery and placing the SIM in the slot provided. The RS232 cable

was used to connect the SMS-receiving mobile phone to the microcontroller.

The test loads (4 loads) were placed on a separate wooden board and wired together,

and a supply from the ULN2003a feeds these loads. As is the case in this project, the circuit

board containing the loads could be disconnected for movement purposes (transfer of the

device from one location to another), and re-connected when necessary.

4.3 Assembly Coding

To successfully write a code for any design, it is necessary to first create an algorithm and

flowchart to guide the working principles of the system or design. This project is not

different. A flowchart was drawn to analyze the working of the system, and this flowchart

was used to code the working of the microcontroller based on the received signals or SMS

transmitted from the external mobile phone(s) to the receiving mobile phone, which connects

to the microcontroller. This idea can be coded using several programming language apart

from Assembly language. It depends on the proficiency of the designer in the chosen

35

language. For this design, assembly language was used because the designer is fairly

proficient in it, and it is more commonly used for similar designs.

After the code was written, it was burnt to the EEPROM of the microcontroller

through a development board connected to a PC, running a software application known as an

Integrated Development Environment (IDE). The IDE is used to assemble and burn the code

to the EEPROM.

4.4 Testing

The entire system has to be tested after all the installation and soldering has been done, to

ensure that it is functioning as required. For this design, all the inherent parts of the circuit

performed consistently. Also, the test yielded the following results based on the program of

control that was written.

Table 4.1 Results of System Test

CODE SENT LOAD 1 LOAD 2 LOAD 3 LOAD 4

*1*# ON OFF OFF OFF

*2*# ON ON OFF OFF

*3*# ON ON ON OFF

*4*# ON ON ON ON

*5*# OFF ON ON ON

*6*# OFF OFF ON ON

*7*# OFF OFF OFF ON

*8*# OFF OFF OFF OFF

The 4 loads are supplied from the 4 supply lines from the ULN2003a driver.

As we can see from table 4.1 above, the first 4 codes sent from the transmitter mobile

phone(s) are used to switch on loads 1, 2, 3 and 4 respectively, and the last 4 SMS codes are

used to switch off loads 1, 2, 3 and 4 respectively. We can also induce from the table above

that we cannot control two devices at once using this design. When we switch loads 1 ON

(*1*#), and then send a code to switch loads 2 ON (*2*#), loads 2 comes ON but loads 1 still

remains ON, till we send a separate code to switch it OFF (*5*#). In the same way, when we

send a code to switch a particular load OFF, if there were any other loads ON, they will

36

remain ON till we switch them OFF by sending codes separately. Only the one whose code

we specify is switched OFF.

In summary, the home automation system on test performed exceptionally well to its

accuracy and capability. However, we can control only one supply line (from the ULN2003a)

at a time. In the case of this design, each of these supply lines is connected to 1 load.

37

CHAPTER FIVE

SUMMARY AND CONCLUSION

5.1 Summary

Automation systems generally play important roles in our society. This remote control

of home appliances (4 light bulbs) studied in this work is just one of such systems. It provides

a means whereby an individual or certain group of individuals can control a domestic system

using the Short Message Service (SMS) generated from a mobile phone which (the SMS), is

transmitted to the receiver mobile phone connected to the domestic system. This control

method uses commercial mobile communication networks as the path of data transmission.

SMS based remote control for home appliances are important for the human generation,

because mobile technology is used very often these days. The SMS based remote control for

home appliances is easy to implement so that an electrical device can be switched ON/OFF

via SMS. In a simple automation system as this one, where the internet facility and even PC

are not provided, one can use mobile phones which are simple and cost effective.

Alternatively, we can use DTMF (Dual tone Multi-Frequency) instead of SMS to

achieve the same or better results. This is based on the ability of some mobile phones to

generate signals which have horizontal and corresponding vertical frequencies on each key.

Hence, when these keys are pressed, the combination of the vertical and horizontal

frequencies are sent to the device, which incorporates a DTMF decoder, to decode the signals

to decipher which key or keys were pressed on the phone, and pass this information to a

controller to perform the required operation.

This system is limited to the area of coverage of the carrier network used for the SIM

card attached to the receiving mobile phone connected to the microcontroller. Also, due to

this design, the loads can only be controlled 1 at a time separately.

5.2 Advantages of Such System

(a) Convenience: SMS technology is easy to use and learn and can be accessed easily

when needed as long as there is GSM coverage over that area.

(b) Accessibility: Instructions can be sent to the microcontroller to be controlled and

monitored from any location provided there is existence of an active GSM network

from anywhere in the world.

38

(c) Portability: A microcontroller can be controlled and monitored from any GSM phone

that supports SMS. Considering the fact that most GSM phones support SMS, the

system is therefore highly portable.

(d) Saves Time: An SMS bases remote monitoring system saves time as the user is not

required to gain access to an internet connection or make a direct contact with the

system, hence the stress of moving to and from the device to operate it is cut off hence

time is saved.

(e) Cheapness: SMS services are generally cheap and are sometimes provided for free (at

least for certain periods) by service providers. Furthermore, most service providers do

not charge users for receiving SMS.

Applications

This system with a little modification in the design can be adapted for the following

applications.

i. Combination lock

ii. Home security system

iii. Mobile/wireless Robot control

iv. Wireless Radio control

v. Remote switches

5.3 Recommendation

This project aimed at implementing a remote method of controlling home appliances and was

successful. However, they are some recommendations which should be considered for future

related works.

(a) Inclusion of feedback mechanism from the device, so that the user knows that the

command he or she sent has successfully reached the device and the required

operation has been performed, not just relying on the delivery report from the carrier

network which does not give feedback on whether the required operation has been

effected.

(b) Inclusion of a charging system within the device itself so that the battery of the

receiving mobile phone attached to the device can be charged at regular intervals to

enhance availability of the system.

39

5.4 Conclusion

This project presents a method to control domestic loads using SMS generated and

transmitted from a mobile phone and received by another mobile phone connected to the

remote system. This control method makes use of commercial career networks as the path of

data transmission. Mobile phones have become an indispensable part of our life. This system

mainly uses a microcontroller and a cellular phone for its operations, and can be used as a test

bed for any application that requires on-off switching based systems. Wireless controlled

home appliances in the comforts of any environment will without doubt improve our way of

living.

40

APPENDIX A

Assembly Program

; The software for sms_device control

;Daniel Abara

; June 14, 2011, 12:26AM

; message format: *message*#

;MESSAGE MUST BE AT LEAST 4 DIGITS

; ON LOAD1=*1*#

; ON LOAD2=*2*#

; ON LOAD3=*3*#

; ON LOAD4=*4*#

; OFF LOAD1=*5*#

; OFF LOAD2=*6*#

; OFF LOAD3=*7*#

; OFF LOAD4=*8*#

; PHONE_NUM EQU=30H-3FH

org 00h

jmp start

load1 bit p3.2

load2 bit p3.3

load3 bit p3.4

load4 bit p3.5

LED EQU P1

message equ 5Ah

;&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

ORG 23H

LJMP TAKE_ACTION

;&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

Org 30h

start: SETB load1 ; off all loads

SETB load2

SETB load3

SETB load4

MOV R5,#8

MOV A,#0FFH

INIT: CPL A

MOV P1,A

CALL wait

DJNZ R5,INIT

mov scon,#50h ;configure the serial port mode

mov TMOD,#20h ;setting the serial port to receive data

41

mov TH1, #-24 ;setting the baud rate to 1,200

setb TR1 ;enable timer1

CALL WAIT5_SECS

CALL ONESEC

CALL ONESEC

CALL ONESEC

CALL WAIT

CALL WAIT

CALL WAIT

;*******************************************

clr RI

CLR TI

MOV IE,#10010000b ;ENABLE SERIAL INTERUPT

wait_4_msg:CPL P3.7 ; LED BLINK

CALL WAIT

jmp wait_4_msg

TAKE_ACTION:CLR IE.7 ; DIS ENABLE INTERRUPT

call ONESEC

call SEND_READ_COMMAND

CALL ONESEC

CALL READ_SMS

CALL ONESEC

CALL DEL_MSG

CALL ONESEC

MOV A,MESSAGE

IDENTIFY_MSG:

ON_LOAD1:CJNE A,#'1',ON_LOAD2

MOV A,#1

CPL A

MOV LED,A

LJMP SWITCH_ON_LOAD1

ON_LOAD2:CJNE A,#'2',ON_LOAD3

MOV A,#2

CPL A

MOV LED,A


ON_LOAD3:

CJNE A,#'3',ON_LOAD4

MOV A,#3

CPL A

MOV LED,A


42

ON_LOAD4:CJNE A,#'4',OFF_LOAD1

MOV A,#4

CPL A

MOV LED,A


OFF_LOAD1:CJNE A,#'5',OFF_LOAD2

MOV A,#5

CPL A

MOV LED,A

LJMP SWITCH_OFF_LOAD1


MOV A,#6

CPL A

MOV LED,A



MOV A,#7

CPL A

MOV LED,A


OFF_LOAD4:CJNE A,#'8',IGNORE

MOV A,#8

CPL A

MOV LED,A


IGNORE: MOV LED,#00

CALL WAIT5_SECS

CLR RI

CLR TI

CALL WAIT5_SECS

CLR RI

CLR TI

CALL WAIT5_SECS

CLR RI

CLR TI

SETB IE.7

RETI

SWITCH_ON_LOAD1:CLR LOAD1

CALL WAIT5_SECS

CLR RI

CLR TI

CALL WAIT5_SECS

CLR RI

43

CLR TI

CALL WAIT5_SECS

CLR RI

CLR TI

SETB IE.7

RETI


CALL WAIT5_SECS

CLR RI

CLR TI

CALL WAIT5_SECS

CLR RI

CLR TI

CALL WAIT5_SECS

CLR RI

CLR TI

SETB IE.7

RETI


CALL WAIT5_SECS

CLR RI

CLR TI

CALL WAIT5_SECS

CLR RI

CLR TI

CALL WAIT5_SECS

CLR RI

CLR TI

SETB IE.7

RETI


CALL WAIT5_SECS

CLR RI

CLR TI

CALL WAIT5_SECS

CLR RI

CLR TI

CALL WAIT5_SECS

CLR RI

CLR TI

SETB IE.7

RETI

SWITCH_OFF_LOAD1:SETB LOAD1

CALL WAIT5_SECS

CLR RI

CLR TI

44

CALL WAIT5_SECS

CLR RI

CLR TI

CALL WAIT5_SECS

CLR RI

CLR TI

SETB IE.7

RETI


CALL WAIT5_SECS

CLR RI

CLR TI

CALL WAIT5_SECS

CLR RI

CLR TI

CALL WAIT5_SECS

CLR RI

CLR TI

SETB IE.7

RETI


CALL WAIT5_SECS

CLR RI

CLR TI

CALL WAIT5_SECS

CLR RI

CLR TI

CALL WAIT5_SECS

CLR RI

CLR TI

SETB IE.7

RETI


CALL WAIT5_SECS

CLR RI

CLR TI

CALL WAIT5_SECS

CLR RI

CLR TI

CALL WAIT5_SECS

CLR RI

CLR TI

SETB IE.7

RETI

WAIT5_SECS:mov r7,#36

mov r6,#40

45

mov r5,#176

waita_: djnz r5,waita_

djnz r6,waita_

djnz r7,waita_

ret

;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%

;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%

SEND_READ_COMMAND:clr TI

READuu: clr A

movc A,@a+dptr

CJNE A,#'#',READ_COMMAND_

clr RI

RET

READ_COMMAND_:MOV SBUF,A

JNB TI,$

CLR TI

INC DPTR

JMP READuu

;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%

READ_SMS:MOV R0,#30h

MOV R1,#00

clr RI

mov r1,#00h

GO_AHEAD:JNB RI,$

clr p3.4

clr RI

MOV A,SBUF

MOV @R0,A

inc R1

CJNE R1,#46,GO_AHEAD

MOV @R0,A

INC R0

GO_AHEAD2:JNB RI,$

clr RI

MOV A,SBUF

MOV @R0,A

INC R0

CJNE R0,#5BH,GO_AHEAD2

RET

SEND_PHONE_NUM:

;&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

MOV DPTR,#PHONE_NUM

SEND: clr A

movc A,@a+dptr

CJNE A,#'#',SMSG2

JMP CONT

46

SMSG2:MOV SBUF,A

JNB TI,$

CLR TI

INC DPTR

JMP SEND

;&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&7

clr TI

CONT: MOV R0,#30H

XXXh: MOV A,@R0

CJNE R0,#40H,PHONE_NO

MOV A,#13

MOV SBUF,A

JNB TI,$

CLR TI

RET

PHONE_NO:MOV SBUF,A

JNB TI,$

CLR TI

INC R0

JMP XXXh

DEL_MSG:clr TI

MOV DPTR,#MEM_MSG

Muu: clr A

movc A,@a+dptr

CJNE A,#'#',DEL_MEM_

RET

DEL_MEM_:MOV SBUF,A

JNB TI,$

CLR TI

INC DPTR

JMP Muu

wait: mov r3,#8

mov r2,#8

mov r1,#236

waita: djnz r1,waita

djnz r2,waita

djnz r3,waita

ret

onesec:MOV R2,#90

MOV R1,#162

on_e: DJNZ R1,on_e

DJNZ R2,on_e

NOP

RET

INIT_MSG:DB'AT+CMGF=1',13,'#'

NEW_MSG:DB'AT+CNMI=1,1,1,1,1',13,'#'

47

PHONE_NUM:DB'AT+CMGS=#'

MEM_SIM:DB'AT+CPMS="SM"',13,'#'

MEM_MSG:DB'AT+CMGD=1,4',13,'#'

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

end

3 Main Project From Ch 1

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Transcript of 3 Main Project From Ch 1