Device control using Telephone

Wednesday, November 5th, 2008

Controlling devices using switches are common. From  a   few   decades  controlling devices using    remote  control   switches like infrared remote control  switch,  wireless remote control  switches,  light   activated  switches  re becoming popular. But these  technologies  have their own limitations. Laser beams are harmful to mankind. Some  technologies  like  IR  remote control are used for short distance  applications. In such case if we have   system which does not require  any  radiations  or  which is not harmful, long  remote  control  switch!!  Yes  here  is  the solution. Here I am introducing such a system which does not require any radiations, any laser beam which has no limitation of range, I mean it can be used from any distance from meters to thousand kilometers using a simple telephone line or mobile phone.

Here I am using a telephone as a media, which serves main part of this system. By using home phone as a local phone and another phone – either landline or mobile phone as a remote phone we are controlling devices.

Features:-

  1. You can control up to 10 devices. It may be any electric or electronic appliances or devices with simple to heavy appliances. Each device is given a unique code.
  2. It makes accurate switching, any false switching of device are not done.
  3. There is no risk for false switching.
  4. Your local phone (i.e., home phone or office phone) can be used for normal use by using a DPDT switch. So you need not use a separate telephone line for this device controlling.
  5. To perform any operations through remote phone line, the user needs to dial to the local telephone (to which the interfacing circuit is connected) then the respective code of the device is dialed.
  6. This circuit does not require any complex IC, so any one with little knowledge of electronics can construct this circuit, because it does not need any programmable IC’s or programming.
  7. This system detects the ringing signal from your exchange with the help of ring detector and automatically switches ON.
  8. This device saves your money. This circuit switches OFF after a time of 60 seconds (you can change this switch ON-Time which is discussed in detail in coming section).
  9. Before changing the state of the device we can confirm the present status of the device.
  10. This circuit gives an acknowledgement tone after switching ON the devices to confirm the status of the device.
  11. You can control devices from local telephone. It can also be controlled by PCO.

Taking a tour of the project:

This system uses Dual Tone Multi Frequency (DTMF) technology of our telephone set. Every telephone set will have this facility. We have two type of dialing facilities in our telephone system (i) Pulse dialing mode (ii) Tone dialing mode. Here this system works on tone dialing mode. The DTMF mode is shortly called as tone dialing mode. (Check for availability of tone dialing mode in your telephone set).

This system is divided into two sections

1: Remote Section:

It is nothing but remote telephone set which is present in the remote place. This may be your workspace (office / school) phone or mobile phone or a phone in PCO. Signals are sent through this telephone.

2: Local Control Section:

This is a control system through which you can control your appliances. This contains one telephone line and a control unit. The appliances to be controlled must be connected to telephone line through control unit .Control unit is kept with a sufficient backup.

What is DTMF?

When you press a button in the telephone set keypad, a connection is made that generates a resultant signal of two tones at the same time. These two tones are taken from a row frequency and a column frequency. The resultant frequency signal is called “Dual Tone Multiple Frequency”. These tones are identical and unique.

A DTMF signal is the algebraic sum of two different audio frequencies, and can be expressed as follows:

f(t) = A0sin(2*П*fa*t) + B0sin(2*П*fb*t) + ………..    ——->(1)

Where fa and fb are two different audio frequencies with A and B as their peak amplitudes and f as the resultant DTMF signal. fa belongs to the low frequency group and fb belongs to the high frequency group.

Each of the low and high frequency groups comprise four frequencies from the various keys present on the telephone keypad; two different frequencies, one from the high frequency group and another from the low frequency group are used to produce a DTMF signal to represent the pressed key.

The amplitudes of the two sine waves should be such that

(0.7 < (A/B) < 0.9)V               ——–>(2)

The frequencies are chosen such that they are not the harmonics of each other. The frequencies associated with various keys on the keypad are shown in figure (A).

When you send  these DTMF signals to the telephone exchange through cables, the servers in the telephone exchange identifies these signals and makes the connection to the person you are calling.

Fig (A): The row and column frequencies

Fig (A): The row and column frequencies

When you press the digit 5 in the keypad it generates a resultant tone signal which is made up of frequencies 770Hz and 1336Hz. Pressing digit 8 will produce the tone taken from tones 852Hz and 1336Hz. In both the cases, the column frequency 1336 Hz is the same. These signals are digital signals which are symmetrical with the sinusoidal wave.

Figure (B): A Typical frequency DTMF signal

Figure (B): A Typical frequency DTMF signal

Along with these DTMF generator in our telephone set provides a set of special purpose groups of tones, which is normally not used in our keypad. These tones are identified as ‘A’, ‘B’, ‘C’, ‘D’. These frequencies have the same column frequency but uses row frequencies given in the table in figure (A). These tones are used for communication signaling.

Figure (C): The frequency table

Figure (C): The frequency table

Due to its accuracy and uniqueness, these DTMF signals are used in controlling systems using telephones. By using some DTMF generating IC’s (UM91214, UM91214, etc) we can generate DTMF tones without depending on the telephone set.

Pages: 1 2 3 4

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Author Name :
Ranjith

Total : 132 Comments


132 Responses to Device control using Telephone

  1. santhosh

    Very good concept. I will try to do this project.

  2. ranjith

    Thank you!

  3. mojtaba zamani

    hi
    this is very good project
    thank

  4. sushmitha.k

    iam very much intrested in this project. i want to know mudh more abt this project

  5. mojtaba zamani

    hi
    please explain to me about PCO and DPDT
    thank

  6. G. Ravi Kiran

    please send me the coding of “Device control using telephone

  7. KAMTAH

    PLEASE INFORM A CIRCUIT FOR CELL PHONE – DTMF CONTROLLING DEVICES.

  8. KAMTAH

    REQUEST TO TO SEND ME A CIRCUIT TO WHICH I CAN ATTACH MY GSM/CDMA CELL PHONE TO THE CONTROL UNIT AND AND MAKE CALLS FROM ANY PHONE AND SEND DTMF TONES TO CONTROL 4 OR 8 SWICHES.

  9. zulfiqar

    i wanna know how i resemble the encoder circuit throgh my remote telephone

  10. ujjwal kohli

    please send me the coding of thi project or i want to learn how to do this !! i am very much intresten in ur project ! pleae help !!

    thnx n regard !
    ujjwal kohli

  11. paresh

    please send me complete info regarding digital ic tester &it is good to do as final year project in b.e. send more project info also.

  12. sameer

    sir have u got any projects on Cell phone controlled devices

  13. ajith

    sir i want to know more about this project ,is it work properly?plssss answer …

  14. javed

    hi
    this is very good project.
    i will use this concept in my project.

  15. nikhil

    please can u tell me how the values of R5 C5 and R6 C6 are to be given because i am right now assembling the circuit but i dont know how to address these values

  16. viral

    hello! i watn the fully detali of this project like circuit diagram, componont,discription,blockdiagram.please send me in soft copy in my mail.

  17. sarika

    can I try this project for ME level?

  18. kidist

    hi,i am very much interested in the project of controlling switch using telephone.please send me the detail information.Thank you

  19. ajith

    hai frnd
    u r doing ME ,this project is not suited 4 me level projects,try in embedded systems or in matlab field,if u want more about this project pls mail to ajith_mgkumar@rediffmail.com

  20. vinod swain

    hello sir/madam
    incredible idea. but please send detail circuit diagram and implementation technique, as i want it to submit as my final year project.
    looking forward for the response.

  21. bhavnish wadhwa

    hello!
    i want the fully detali of this project like circuit diagram, componont,discription,blockdiagram.please send me in soft copy in my mail.
    plzzz…
    i m very thankful to you…

  22. SONPREMO

    is there any law that it violate? because you are trying to connect something in the telephone line… reply asap…

  23. suni

    plz give some more projects

  24. Dakshesh

    i want know that in this project if i want to use a cellphone insted of a telephone how will it work and also how it will connect
    send me more detail about this project it’s such a nice concept withou microcontroller
    THANKS

  25. Ong

    Hi, I am using KT3170 as the Decoder. Please enlighten me on how do i connect the telephone line to KT3170?

    Also can you explain more on this paragraph “A parallel connection from the telephone line is taken and connected it to telephone interfacing circuit using a DPDT switch. When you wish this section is to be work then you switch ON the DPDT switch otherwise your telephone is used for normal calling receiving purpose.”

    Really need help on the connection. I got the circuit ready and a normal telephone set ready. But how do i connect the telephone set line to my circuit (To my KT3170)???

    Also for testing purpose, do i need to connect all output pins of IC74154 to some appliances or can i just connect few of the output pins and the rest left it unconnected.

    Looking forward for your reply, thanks a million in advance!

  26. shyam

    i want its circuit diagram

  27. megha

    i want its circuit diagram

  28. Ashish

    sir can u suggest me a circuit through which i can control a toy car using two cell phone one on the car & other on the my hand

  29. amit

    i want its circuit diagram

  30. mohamed

    send me all d information abt dis project including circuit digrams, etc..

  31. vipin

    please send me the synophsis of
    ” appliance control through mobile phone using DTMF”

  32. sidharth

    i want dis project urgently. how i can get it? pleas reply me fast as possible.

  33. shrikanth

    send that software

  34. Amarjeet

    I am very much interested in this project, if possible instead of telephone can it used with mobile, if yes what sort of changes are required. Pls send me details including components, circuit diagram , software. Pls reply immediately

  35. shweta

    plz sens me d ckt. diag. of project
    device control using mobile

  36. dishagupta

    pls send me the working of this project using microcontroller(device control using telephone)

  37. prashant tibrewal

    hi,i am very much interested in the project of controlling switch using telephone.please send me the detail information.Thank you

  38. ananyap

    please provide the circuit diagram

  39. shai kuena

    i am very interested in this so may you please provide the circuit diagram please

  40. Furqan

    i am interested in doing this project. may i please have the PCB diagram and the list of components asap. thanks.

  41. bineeta

    hello!
    i want the fully detail of this project like circuit diagram, componont,discription,blockdiagram.please send me in soft copy in my mail.as m facing interws nw..i made same projct in my final year, but nw nt able to explain it as took areadymade projct bcoz of time scarcity..
    plzzz…
    i m very thankful to you…

  42. muthu

    hi shall i do this project for my BE level pls rply me and also send me the exact details and wat will be the cost required for doing this project

  43. vinod

    I have no idea about the use of ic7 555. Can anybody help me to get out of the problem. Hoping for a reply…….vinodquilon@gmail.com

  44. Ajay

    Hi
    I need the ful detail of project(Home appliance controller using DTMF) like circuit diagram, componont list ,discription,blockdiagram,equilanant ICs list that used in this project.
    please…….. send me a soft copy in my mail as i m facing interview

    I m very thankful to you…

  45. Madhav

    hi
    I like the concept the very well.I want more information about Ckt dig, Components, synopsis of Device control using Telephone project. waiting for your reply. Thnx in adavnce.

  46. Junxplus

    Sir, pls send me a circuit diagram with complete labels on my email.

  47. sreeni

    Sir, pls send me a circuit diagram with complete labels on my email.

  48. kanchan

    respected sir,
    can i get the complete circuit diagram with neat labels and the pcb layout of this project?? plz send it to me on my email id.
    thank you.

  49. Sumesh

    Please send me the coding and circuit diagram of this project.

  50. kaustubh

    Hi
    I need the ful detail of project(Home appliance controller using DTMF) like circuit diagram, componont list ,discription,blockdiagram,equilanant ICs list that used in this project.
    please…….. send me a soft copy in my mail as i m facing interview
    I m very thankful to you…

  51. lala

    hello!
    i want the fully detail of this project like circuit diagram, component,discription,blockdiagram,equilanant ICs list that used in this project and coding.
    please……

    i m very thankful to you…

  52. Deepthy

    Great project renjith!!!

  53. abbas

    pls give circuit diagram device control through telephone. using micro controller IC. IC 89S52

  54. cossy

    pls i would like see the circuit diagram and implementation of the project

  55. raaz

    it is too good but i want some more inf

  56. kadira

    sir,m doin this project but by usin mc-8951…can u mail me details if u hav any?

  57. sanjay

    sir i m an engineering student..
    i work on this project in my final sem..
    but because of some errors in my program my project is not run..
    will u please send me a program..
    sir,my submission will be start from 14 april…
    so,plz send me a prog. as fast as possible…
    plz sir,,,,,

  58. Rogério

    Hy -
    i want the fully detail of this project like circuit diagram, component,discription,blockdiagram,equilanant ICs list that used in this project and coding.
    please……

    i m very thankful to you…

  59. rhea

    Sir I need the circuit and components urgently I cannot find it anywhere.please help.

  60. Bernard

    Hi,
    Doing MSC project and would
    highly appreciate if you can send me the fully detail of this project
    like circuit diagram, components,description,block diagram,equivalent
    ICs list ,microproccesor used.
    Kind request

    Regards,

    Bernard

  61. Gayle Lemar

    I have visited your blog before. The more I visit, the more I keep coming back! ;-P

  62. harini

    sir,i am doing a project on this
    i need a fully detail on this project like circuit diagram, components,description,block diagram,equivalent ICs list that used in this project and coding., used.

  63. deepali

    hi, i need the coding 4 this project. pls send me the coding(program)……

  64. Umer

    Smart Idea ranjith !
    Me too working on the same concept, can do me a favour? If you can send me its block and Circuit Diagram please.
    Thanx,
    looking forward for ur positive reply ;-)

  65. rrm

    sir,
    very very thanks

    i need a fully detail on this project like circuit diagram, components,description,block diagram,equivalent ICs list that used in this project and coding., microcontrller programming for controlling devices

  66. dipty jena

    this is agood project.
    i need this project.

  67. dave

    hi…
    how to make code on PIC simulator for automated appliances
    controller using PIC16F84A

  68. dave

    please answer my question.
    how to make code on PIC simulator for automated appliances
    controller using PIC16F84A

    this is a very important project….i need your answer….

  69. krushna dongre

    this is really good project please give the detail information and circuit diagram

  70. Vamsee Priya

    Sir, please forward me the details of this project like circuit diagram and
    further description of this project !

  71. tejinder

    need a fully detail on this project like circuit diagram, components,description,block diagram,equivalent ICs list that used in this project and coding..its humble request

  72. sailendra

    sir,

    can u please provide the complete information reguarding this project. Iwould be pleased if u do so…..

  73. vaibhav miital

    sir
    i want to know fully detail of ‘dtmf based remote control using telephone ‘project like name and description,equevalent ic’s list that used in this project and coding..its humble request

  74. joginder

    i am student of ece final year,i need the details of this project for minor project.pls mail me all data of this…

  75. mans

    hi ranjith!!!!
    really a must appreciable one!!it would create immense pleasure if i could get a clear idea of how u applying the concept..

    thanking you!!
    bye!!!

  76. Rajeev Sharma

    Sir,
    I want to be a full information about this project,
    How to make a circuit and other things which can clear my doubts.

    Thank You !

  77. arjun

    Sir,
    I want to be a full information about this project,
    How to make a circuit and other things which can clear my doubts.

    Thank You

  78. Manish Goswami

    sir i want the circuit diagram of this …. in order to learn it practically
    how it works…
    i will be very much thankful to u … if u forward me the circuit diagram and
    further details on this topic….

  79. karthikeyan

    hello!
    i want the fully detail of this project like circuit diagram, component,discription,blockdiagram,equilanant ICs list that used in this project and coding.
    please……

  80. Eshwar Sondhi

    hello
    i found the project extremely innovative and interesting..i am wanting to make
    it for my college technical festival..it is just a month far from now..if you
    could just help me out i would be very grateful..i just need a few tips and the
    component list..ilive in india so advice me the appropriate devices..
    i am extremely grateful to you..i would appreciate if you could reply as soon as
    possible..
    thank you

  81. Renjith

    could you please mail me all details including circuit diagram.. i need it

  82. rakesh

    please mail me the program and detail about project

  83. harshul

    Hi
    I am doing a similar project.
    Could you please mail me the design details including circuit diagrams
    and snapshots(if available) of this project.
    It would be of great help.
    thanks

  84. kashif sohail

    I am student of electrical engineering

    (PU Lahore)Pakistan
    Kindy send me the whole information about this projects.
    I have lot of interest in it.

  85. ashish

    sir,
    kindly send me the complete information of this project using microcontroller 89C51 including circuit diagram and coding.please send me on the above mentioned email as soon as possible.

  86. avaya

    i want the circuit diagram\

  87. prashant

    hi sir
    i m doing a home automation useing dtmf 8870
    we r useing ic 89c52 but it is not work
    properly shopkeeper sed ic is faulty repls the ic
    program ic cost Rs.1000 but i dont have that mach
    rupees so help me
    ihave program but i want in hex file

    include c:\PROGRAM\8051\LCD_LIB.LIB
    include c:\PROGRAM\8051\24C04.LIB
    include c:\PROGRAM\8051\Reg51.LIB

    Cls
    Upperline
    Lcd ” WEL COME TO ”
    Lowerline
    Lcd “DTMF HOME CO”

    Wait 3

    Main:

    Reset Oh

    Cls
    Upperline
    Lcd “DTMF HOME CO. SYS.”
    Lowerline
    Lcd ” WAIT FOR RING ”

    Ringc = 0

    While Ringc < 7
    Ringdetect , 0 , Ringcount , Sub
    Wend

    Cls:Upperline : Lcd "Line Pickedup"
    Set Oh
    Wait 1

    Password:
    Cls : Upperline : Lcd " ENTER YOUR "
    Lowerline : Lcd " PASSWORD "

    Cstart:

    For Count = 1 To 6
    IF Std = 1 THEN
    Portval = P1
    Waitms 100

    Cls : Lcd Text
    Next

    If Text = Password Then Goto Wait4cmd
    If Text Password Then GOTO MAIN

    End If

    Wait4cmd:
    Cls : Lcd ” ENTER COMMAND ”

    For Count = 1 To 3

    IF Std = 1 THEN
    Portval = P1
    Waitms 100
    Next
    Goto Check

    Check:

    Select Case Text

    Case “123″ : Goto R_eeprom

    Case “456″ : Goto Change_password

    Case “789″ : Goto Relay_stat

    Case “*0#” :
    Lowerline
    Lcd “Line Disconnect”
    Wait 2 : Goto Mainloop

    Case “*1*” :
    Set P0.4
    Lowerline
    Lcd “Relay 1 ON”
    Wait 1

    Case “*2*” :
    Set P0.1
    Lowerline
    Lcd “Relay 2 ON”
    Wait 1

    Case “*3*” :
    Set P0.2
    Lowerline
    Lcd “Relay 3 ON”
    Wait 1

    Case “*4*” :
    Set P0.3
    Lowerline
    Lcd “Relay 4 ON”
    Wait 1

    Case “*5*” :
    Set P0.0
    Lowerline
    Lcd “Relay 5 ON”
    Wait 1

    Case “*6*” :
    Set P0.5
    Lowerline
    Lcd “Relay 6 ON”
    Wait 1

    Case “*7*” :
    Set P0.6
    Lowerline
    Lcd “Relay 7 ON”
    Wait 1

    Case “*8*” :
    Set P0.7
    Lowerline
    Lcd “Relay 8 ON”
    Wait 1

    Case “#1#” :
    Reset P0.4
    Lowerline
    Lcd “Relay 1 OFF”
    Wait 1

    Case “#2#” :
    Reset P0.1
    Lowerline
    Lcd “Relay 2 OFF”
    Wait 1

    Case “#3#” :
    Reset P0.2
    Lowerline
    Lcd “Relay 3 OFF”
    Wait 1

    Case “#4#” :
    Reset P0.3
    Lowerline
    Lcd “Relay 4 OFF”
    Wait 1

    Case “#5#” :
    Reset P0.0
    Lowerline
    Lcd “Relay 5 OFF”
    Wait 1

    Case “#6#” :
    Reset P0.5
    Lowerline
    Lcd “Relay 6 OFF”
    Wait 1

    Case “#7#” :
    Reset P0.6
    Lowerline
    Lcd “Relay 7 OFF”
    Wait 1

    Case “#8#” :
    Reset P0.7
    Lowerline
    Lcd “Relay 8 OFF”
    Wait 1

    Case Else :
    Cls
    Lcd “INVALID COMMAND”
    Lowerline
    Lcd “TRY AGAIN” : Wait 2
    Goto Wait4cmd

    End Select

    Goto Wait4cmd

    Sub Write_eeprom(adres As Word , Value As Byte)
    I2cstart
    I2cstop
    Waitms 10
    End Sub

    Sub Read_eeprom(adres As Word , Value As Byte)
    I2cstart
    I2cstop
    End Sub

    Change_password:
    Cls
    Lcd “Change Password” : Wait 2 :

    For Count = 1 To 6
    IF Std = 1 THEN
    Portval = P1
    Waitms 100
    Lcd Text
    Next

    Lowerline
    Lcd “Press # 2 confirm”
    IF Std = 1 THEN
    Portval = P1
    Waitms 100

    Call Write_eeprom(4 , X)
    Call Write_eeprom(5 , X)
    Call Write_eeprom(6 , X)
    Call Write_eeprom(7 , X)
    Call Write_eeprom(8 , X)
    Call Write_eeprom(9 , X)
    Lcd “New Code”
    Lowerline
    Lcd “Accepted”
    Wait 2
    Goto Password_lookup
    Else
    Lcd “Wrong Selection”
    Lowerline
    Lcd “Try again !”
    End If
    Text = “”

    R_eeprom:
    Password =
    Call Read_eeprom(4 , Value)
    Call Read_eeprom(5 , Value)
    Call Read_eeprom(6 , Value)
    Call Read_eeprom(7 , Value)
    Call Read_eeprom(8 , Value)
    Call Read_eeprom(9 , Value)
    Wait 4
    Text = “”
    Goto Wait4cmd

    Ingcount:
    Ringc = Ringc + 1
    Lowerline
    Lcd “Ringcount ” ; Ringc
    Return

    Write_password2eeprom:
    Call Write_eeprom(4 , 1)
    Text = “”
    Cls : Lcd “WRITE 2 EEPROM” : Wait 2 :
    Goto Main

  88. prashant

    my id is pmojar@gmail.com

  89. ashis

    sir,
    i need the complete circuit diagram of remote section and local control section with proper theory.please send it to me
    as soon as pssible.my email id is (ashishdi106@gmail.com)

  90. anand

    sir,
    i want to do this project using 89c51 microcontroller.kindly send me the circuit diagram of local control section using 89c51 with proper details.
    my email id is sw83992@gmail.com

  91. shan

    i want the fully detail of this project like circuit diagram, component,discription,blockdiagram,equilanant ICs list that used in this project and coding.
    please……

  92. neo0786

    sir,
    i like to do this as my project for final year project.so kindly sent me the circuit diagrams and other details about it.please!!!!

  93. Fannie

    Hi,i would like to that project for my final year ,so i want full details of this project and the program code.Thanks in advance.

  94. mustafa khalid

    hello !! how r u doing ??
    acctly i love ur project …and m thinking that m gonna do it as a final project for me at uni !!
    please give me full details ??

  95. B.Janarthanan

    Respected sir,
    I have to complete the project named ‘device control using telephone network’….I need report about that as well as software coding in ‘c’…..
    Am looking for your positive reply………

  96. B.Janarthanan

    Respected Sir,
    If you have source code for device control using telephone,send it to me…………….

  97. vikash

    sir,

    kindly send me the complete information of this project using microcontroller 89C51 including circuit diagram and coding.please send me on the above mentioned email as soon as possible.

  98. JAGDISH

    I am 3rd year ece student and want to make this project.
    can you give me the programing details of this project.

  99. BenR

    pliz! if you could kindly forward me the details to this project, like component values, circuit diagram and the program using C. im looking forward to your kindly reply, thank you.

  100. Noel

    hi can u plz send d ful details and circuit diag of d proj as soon as possibl. thank u..

  101. ashwini barapatre

    Sir,

    I m interested in doing this project so can u plz send me all the details like circuit diagram, component used ,description and block diagram.Hoping for your reply as early as possible.

    Thank you

  102. Shefali Kalia

    sir,
    i am interested in doing this project so can u please send me all the details like circuit diagram,component used and block diagram.waiting for your reply.
    Thank You

  103. RabiRathina

    sir,
    I am interested in this project. can you send me the details please.

    Thank you

  104. kapil desai

    I m interested in doing this project so can u plz send me all the details like circuit diagram, component used ,description and block diagram.Hoping for your reply as early as possible.

    Thank you

  105. ajil olickal

    I m interested in doing this project so can u plz send me all the details like circuit diagram, component used ,description and block diagram.Hoping for your reply as early as possible.
    Thank you

  106. karthi

    I m interested in doing this project so can u plz send me all the details like circuit diagram, component used ,description and block diagram.Hoping for your reply as early as possible.
    Thank you

  107. Yogesh varma

    Can u plz send me detail of d project with ckt diagram as soo as possible

  108. mukesh garg

    can u plz tell me further addition in dis project ……i need to hav bigger project so i want to hav additon in it

  109. khushi

    sir plz send d block diagram of device control using mobile not by telephone

  110. kirtish

    please send me the complete details with the block diagrames i am highly intrested.

  111. angelito domingo

    please send me also the complete details of this system please.. i want to do this for our final project in school.. please send to my email giodale_18@yahoo.com thank you very much……

  112. shahab

    By using this project i want to construct the personally branched telephone exchange (PBEX) .SO PLEASE PROVIDE further information about this project circuit diagram and coding as soon as possible on my mail.iwill be very thankful to you.

  113. Lino Skeldon

    Thank you for a very informative writeup. in my experience things are slighly more complicated than you make them seem. time will tell, but the problem is I do not have enough time. it is good to know we are not alone in the struggle. but you might want to reconsider some fragments in your post. after all, if it can do all that, why do we even need the rest anylonger? just a bit. take care

  114. abinash

    plz send me the project code…..

  115. manjunath

    ur project is awesome still i need more information about it pls send the code also…..

  116. peter gichuki

    please send me more detail am very interested
    in this project

  117. santosh

    u r project is very intresting …i would like to do this ….sir plz send the entire controlling circuit description to my mail..plzzzzzz

  118. belias

    kindly send me the complete information of this project using microcontroller 89C51 including circuit diagram and coding.please send me on the above mentioned email as soon as possible. Thanking you I remain

  119. hira mustafa

    kindly send me complete detail including schemetic .

  120. Norrey

    Nice project. Am gonna try it out.

  121. ravi

    sir,
    I m interested in doing this project so can u plz send me all the details like circuit diagram, component used ,description and block diagram.Hoping for your reply as early as possible.
    Thank you

  122. DANIYAL ANSARI

    PLS SEND ME THE CODING

  123. madhuri

    sir can u send the the circuitdiagram and more details about project

  124. adesh

    sir,
    I m interested in doing this project so can u plz send me all the details like circuit diagram

  125. aravind narayan

    your project is very good. but i don’t like that. so never repeat it again.
    .

  126. resham

    Hi
    I need the ful detail of project(Home appliance controller using DTMF) like circuit diagram, componont list ,discription,blockdiagram,equilanant ICs list that used in this project.
    pls send me all the details 2 my is as soon as u can
    i will be highly obliged
    thanks in advance
    its very important
    pls send the details as soon as u can.

  127. resham

    pls send the compltete ckt diagram using ic89c51,ic8870,ic uln2003,ic7806,regulatorls,relays and mobile phone connector
    thanx

  128. raju.s

    hello!
    i want the fully detail of this project like circuit diagram, component,discription,blockdiagram,equilanant ICs list that used in this project and coding.
    please……
    i m very thankful to you…

  129. sathya

    sir,pls give full circuit diagram for using my prjct

  130. mahroof

    sir pls give the code for this project

  131. mahroof

    pls send the code for this project in my mail pls pls……..

  132. lakshmi

    salaam namasthe, what is the specification of the pcb to be used. pls help. thanks in advance

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