69865199 SMS Based eNotice Board for College

8/13/2019 69865199 SMS Based eNotice Board for College

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SMS based eNotice Board forCollege


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Abstract

Wireless communication has announced its arrival on big

stage and the world is going mobile. We want to control

everything and without moving an inch. This remote control

of appliances is possible through Embedded Systems. The

use of Embedded System in Communication has given rise

to many interesting applications that ensures comfort and

safety to human life.

The main aim of this project will be to design a SS driven

automatic display board which can replace the currently

used programmable electronic display. !t is proposed to

design receiver cum display board which can be

programmed from an authori"ed mobile phone. The

message to be displayed is sent through a SS from an

authori"ed transmitter. The microcontroller receives theSS# validates the sending obile !dentification $umber

%!$& and displays the desired information. Started off as an

instantaneous $ews display unit# we have improved upon it

and tried to ta'e advantage of the computing capabilities of

microcontroller. (oo'ing into current trend of information

transfer in the campus# it is seen that important notice ta'e

time to be displayed in the notice boards. This latency is not

e)pected in most of the cases and must be avoided. !t is

proposed to implement this project at the institute level. !t is

proposed to place display boards in major access points. The


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electronics displays which are currently used are

programmable displays which need to be reprogrammed

each time. This ma'es it inefficient for immediate

information transfer# and thus the display board loses its

importance. The *S based display board can be used as an

add+on to these display boards and ma'e it truly wireless.

The display board programs itself with the help of the

incoming SS with proper validation. Such a system proves

to be helpful for immediate information transfer.

The system re,uired for the purpose is nothing but a

icrocontroller based SS bo). The main components of the

'it include microcontroller# *S modem. These components

are integrated with the display board and thus incorporate

the wireless features. The *S modem receives the SS.

The -T commands are serially transferred to the modem

through -/0/. !n return the modem transmits the stored

message through the C1 port. The microcontroller

validates the SS and then displays the message in the (C2

display board. 3arious time division multiple)ing techni,ues

have been suggested to ma'e the display boards

functionally efficient. The microcontroller used in this case is

-T45s6/. otorola C784 is used as the *S modem. !n the

prototype model# (C2 display is used for simulation purpose.

While implementation this can be replaced by actually

display boards.


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The data will be displayed only after entering uni,ue pass

'ey .!n addition to that address matching is done and data

can be receive only by the dedicated receiver # and this data

is displayed on (C2.

The main focus of the thesis is on displaying information to a

dedicated (cd by the any part of world using *S networ'#

which facilitate to control any message board globally from

any location.

Introduction

The project mainly focuses on transmission of te)tual datathrough air interface by the use of *S throughasynchronous serial communication .The data will beprocessed by the microcontroller on both ends. The data willbe displayed on (cd only after entering uni,ue pass 'ey. !n

addition to that address matching is done and data can bereceived only by the dedicated receiver.-ctually what happens is# sending sms through phone hasbecome very popular and if we can use this sms to controldevices and in displaying data. !t is possible to receive ordecode the sms globally by using gsm # by the any part ofworld we can control and display data on (cd board .!n this project we not only send the data but send the datawith pass code also. Which enables us to prevent theunauthori"ed use of (cd display board and only the personwho have pass code can have access to (cd board .!mportant feature of thesis is we are using gsm networ' bywhich we can control (cd display board by the any part ofglobe. !f we must have the respected pass code. -nd thepass code is o' then the correct data is to be displayed on(C2.


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HARDWARE USED

1. 7./ 9 IS! "# C"M$"NEN!S

S"#!WARE USED1. %eil u&'ision (.)

:eil Software is used provide you with software development

tools for 4;67 based microcontrollers. With the :eil tools#

you can generate embedded applications for virtually every

4;67 derivative. The supported microcontrollers are listed in

the


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!HE"R "# "$ERA!I"N

!n this project we interfaced 4;67 microcontroller withotorola=s C784 *S mobile phone to decode the receivedmessage and do the re,uired action. The protocol used forthe communication between the two is -T command.

The microcontroller pulls the SS received by phone# decodeit# recogni"es the

obile no. and then switches on the relays attached to itsport to control the appliances. -fter successful operation#controller sends bac' the ac'nowledgement to the user=s

mobile through SS.


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A!&Co,,and set

The following section describes the -T+Command set. Thecommands can be tried out by connecting a *S modem toone of the >C=s C1 ports. Type in the test+command#adding C? @ (A %Carriage return @ (ine feed B rn& beforee)ecuting. Table gives an overview of the implemented -T+Commands in this application. The use of the commands is

described in the later sections.

-T+Command set overview

Co,,and Descri/tion

-TChec' if serial interface and*S modem is wor'ing.

-TE;Turn echo off# less traffic onserial line.

-T@C$! 2isplay of new incoming SS.-T@C>S Selection of SS memory.

-T@C*ASS string format# how theyare compressed.

-T@C*??ead new message from agiven memory location.

-T@C*SSend message to a givenrecipient.

-T@C*2 2elete message.

Status 0A!

The -T command is a status re,uest used for testing if acompatible modem is connected and that the serial interfaceis wor'ing properly.


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-T command and possible responses

Co,,and Res/onse Co,,ent

-T 1:

Connected

and wor'ing

E??1?

Serial line1:# modemerror

Ec2o off 0A!E)

The -TE; command is used to configure the

communication. Dy default# *S modems are set to echoany received command bac' with an ac'nowledgement. -ne)ample of this is shown below.-Trn Command sent tomodem-Trn1:rn ?esponse from modemwith echo enabled

-fter sending -T# the modem replies with -Trr1:rn.With echo off# -TE;# the modem would have answered

rn1:rn when e)ecuting -T.The echo off command will reduce traffic on the serial line.The -TE7 command will enable echo again.

-TE; command and possible responses

Co,,and

Res/onse0ec2o

off Co,,ent

-TE;1: Echo off

E??1?Could not turnecho off

Ne- Message Indication 0A!3CNMI


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-T@C$! configures how the modem signals arrival of newmessages to the connected terminal device and how theyare stored in the modem. This feature is useful when it

comes to reading new messages. !nstead of polling themodem periodically for arrival of new messages# -T@C$!can tell when a new message has arrived. The -3? will catchsuch indication# and set a flag. This ensures that the modemonly ta'es up C>F resources when necessary.

-T@C$! command and possible responses


-T@C$!BGmodeH7#GmtH/#GbmH0#GdsHI#GbfrH6 1: ode set

E??1?Error# could not setsuch mode.

N"!E4

7. GmodeH integer type9 how messages are buffered.

/. GmtH integer type9 indication of new SS# set to 7.

0. GbmH integer type9 $ot in use.

I. GdsH integer type9 $ot in use.

6. GbfrH integer type9 $ot in use.

What values GmodeH# GmfH# GbmH# GdsH and GbfrHcould ta'e will be different from modem to modem. Thisshould be tested off line with modem connected to the >C.-n e)ample is given below9


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$otes9

7. G7H string type9 emory from which

messages are read and deleted.

/. G/H string type9 emory to which messagesare written and sent.

0. G0H string type9 emory in which receivedmessages are stored# if forwarding to pc is notset.

GusedH integer type9 is number of messages

currently in ).GtotalH integer type9 is total number of messagelocations in ).

Message for,at0A!3CM5#

The -T@C*A command is used to set input and outputformat of SS messages. Two modes are available9

K >2F mode9 reading and sending SS is done in a specialencoded format.

K Te)t mode9 reading and sending SS is done in plain te)t.

>2F mode is described later in section /./. This compressedformat saves message payload and is default on mostmodems. >2F mode is implemented in the source code forthis application note# it is possible to use te)t mode toreduce code footprint if the connected modem supports this.!n te)t mode header fields as sender address# messagelength# validation period etc. can be read out in plain te)ttogether with the sent message. >lease consult *S



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-T@C>SBG7H7#G/H/#G0H0

@C>S9Gused7H#Gtotal7H#Gused/H#Gtotal/H#Gused0H#Gtotal0H

rr1:rn

emoryconfigured1:

@CSE??1? Error

$otes9

7. G7H string type9 emory from whichmessages are read and deleted.

/. G/H string type9 emory to which messagesare written and sent.

0. G0H string type9 emory in which receivedmessages are stored# if forwarding to pc is notset.

GusedH integer type9 is number of messagescurrently in ).GtotalH integer type9 is total number of messagelocations in ).

Message for,at0A!3CM5#

The -T@C*A command is used to set input and outputformat of SS messages. Two modes are available9

K >2F mode9 reading and sending SS is done in a specialencoded format.

K Te)t mode9 reading and sending SS is done in plain te)t.

>2F mode is described later. This compressed format savesmessage payload and is default on most modems. >2Fmode is implemented in the source code for this application


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note# it is possible to use te)t mode to reduce code footprintif the connected modem supports this.!n te)t mode header fields as sender address# messagelength# validation period etc. can be read out in plain te)t

together with the sent message.

for more about reading messages in te)t mode. This is notthe main target for this application.. -T@C*A command and possible responses

Co,,and Res/onse Co,,ent-T@C*ABGmodeH7 1: ode selected

E??1? Error

$otes9

7. GmodeH integer type9 ; is >2F mode# 7 is te)tmode.

Read Message0A!3CM5R

The -T@C*? command is used to read a message from a

given memory location. E)ecution of -T@C*? returns amessage at Ginde)H from selected memory G7H %See section/.7.I for memory setup&. The status of the message and theentire compressed message %>2F& is returned. To get anyuseful information out of the compressed message it shouldbe decompressed. The >2F format and the compression anddecompression is described in section /././.!able *&6. -T@C*? command and possible responses

Co,,and Res/onse Co,,ent-T@C*?BGinde)H7

@C*?9GstatH/#GalphaH0#GlengthHI rn pduH6

essageread 1:

@CS E??1?Error# $osuch inde)


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Notes4 7. Ginde)H integer type9 ?ead message fromlocation Ginde)H.

/. GstatH9 integer type9 Status of message inmemory9 ?E-2# F$?E-2# SE$T and F$SE$T.

0. GalphaH integer type9 anufacturer specificfield. $ot used.

I. GlengthH integer type9 (ength of compressedmessage.

6. GpduH string type9 Compressed message.

Send Message0A!3CM5S

This command enables the user to send SS messages.

Section /./.0 describes how to build such messages. Low toinclude user defined te)t and recipient telephone number.-fter the user defined fields are set# the message can becompressed and sent using the -T@C*S command. -ne)ample usage of -T@C*S is given in section /./.0.

!able -T@C*S command and possible responses


-T@C*SBGlengthH7

C?/

GpduH 0 ctrl+MI

1: essage sent

@CSE??1? Command error


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Notes4 7. GlengthH integer type9 (ength of message.

/. C? B Carriage return

0. GpduH string type9 Compressed message

I. Ctrl+M9 Command terminator. -SC!! character/8 %dec&.

Delete Message 0A!3CM5D

This command is used to delete a received stored messagefrom G7H %See Table /+6&.!able. -T@C*2 command and possible responses

This concludes the presentation of the implemented -T+Command set. ore commands are discussed in ETS!standard *S ;N.;6# and proposed as a reference whenwor'ing with applications interfacing *S compatiblemodems together with manufacturer=s datasheet.


-T@C*2BGinde)H71:

essagedeleted

E??1? Command error

$otes9 7. Ginde)H integer type9 !nde) of message todelete.

$DU for,at e7/lained

There are two ways of sending and receiving SS messages9by te)t mode and by >2F %>rotocol 2escription Fnit& mode.


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Dy default most phones and modems are setup to send SSmessages using a special compression format %>2F+mode&.Some modems supports te)t+mode# in which any informationand the message itself can be read as plain te)t. $ote

however that not all phones and modems support te)t+mode.

DESCRI$!I"N "# $R"8EC!

Interfacing of ,obile /2one -it2 9)+14

We used a hands+free to ta'e out the signal from mobile

phone to transmit it to microcontroller. The operatingvoltage of mobile is 0.0 3 and provides 0.N volt at logic 7and ; v at logic;. To ta'e it to the level e,ual ofmicrocontroller we used a) /0/ !C. !t can sense inputvoltage lower than /3.


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MA: *(*4

The -/0/ is a dual driverreceiver that includes acapacitive voltage generator to supply E!-+/0/ voltage levelsfrom a single 6+3 supply. Each receiver converts E!-+/0/inputs to 6+3 TT(C1S levels. These receivers have atypical threshold of 7.0 3 and a typical hysteresis of ;.6 3#and can accept O0;+3 inputs. Each driver converts

TT(C1S input levels into E!-+/0/ levels.

$in Diagra,


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logic diagra, 0/ositi;e logic

1. $"WER SU$$4

$o-er su//l


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Lere in our application we need a 6v 2C power supply forall electronics involved in the project. This re,uires stepdown transformer# rectifier# voltage regulator# and filtercircuit for generation of 6v 2C power. Lere a brief

description of all the components are given as follows9

#uture "f $ro=ect

The use of microcontroller in place of a general purpose

computer allows us to theori"e

on many further improvements on this project prototype.

Temperature display during

periods wherein no message buffers are empty is one such

theoretical improvement that

is very possible. The ideal state of the microcontroller is

when the indices or storage

space in the S! memory are empty and no new message is

there to display. With proper

use of interrupt routines the incoming message acts as an

interrupt# the temperature

display is halted and the control flow jumps over to the

specific interrupt service routine

which first validates the sender=s number and then displays

the information field. -nother

very interesting and significant improvement would be to

accommodate multiple receiver

12ES at the different positions in a geographical area

carrying duplicate S! cards.


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With the help of principles of T2- techni,ue# we can

choose to simulcast and or

broadcast important notifications. -fter a display board

receives the valid message

through the 12E and displays it# it withdraws its

identification from the networ' P

synchronously another nearby 12E signs itself into the

networ' and starts to receive

the message. The message is broadcast by the mobile

switching center for a continuoustime period during which as many possible display board

12ES catch the message

and display it as per the constraint of validation.

ultilingual display can be another added variation of the

project. The display

boards are one of the single most important media for

information transfer to the

ma)imum number of end users. This feature can be added

by programming the

microcontroller to use different encoding decoding schemes

in different areas as per the

local language. This will ensure the increase in the number

of informed users. *raphical

display can also be considered as a long term but achievable

and target able output. S


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technology along with relatively high end microcontrollers to

carry on the tas's of

graphics encoding and decoding along with a more

e)pansive ban' of usable memory can

ma'e this tas' a wal' in the par'

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69865199 SMS Based eNotice Board for College

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