Device control using Telephone
by Ranjith | 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:-
- 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.
- It makes accurate switching, any false switching of device are not done.
- There is no risk for false switching.
- 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.
- 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.
- 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.
- This system detects the ringing signal from your exchange with the help of ring detector and automatically switches ON.
- 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).
- Before changing the state of the device we can confirm the present status of the device.
- This circuit gives an acknowledgement tone after switching ON the devices to confirm the status of the device.
- 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
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
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
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.
December 17th, 2008 at 5:17 pm
Very good concept. I will try to do this project.
December 17th, 2008 at 5:18 pm
Thank you!
December 18th, 2008 at 4:17 am
hi
this is very good project
thank
December 19th, 2008 at 3:18 pm
iam very much intrested in this project. i want to know mudh more abt this project
December 23rd, 2008 at 5:43 pm
hi
please explain to me about PCO and DPDT
thank
December 30th, 2008 at 12:22 pm
please send me the coding of “Device control using telephone
January 4th, 2009 at 2:05 pm
PLEASE INFORM A CIRCUIT FOR CELL PHONE – DTMF CONTROLLING DEVICES.
January 4th, 2009 at 2:09 pm
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.
January 12th, 2009 at 11:20 pm
i wanna know how i resemble the encoder circuit throgh my remote telephone
January 17th, 2009 at 11:18 am
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
January 28th, 2009 at 6:04 pm
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.
February 1st, 2009 at 5:43 am
sir have u got any projects on Cell phone controlled devices
March 3rd, 2009 at 6:30 pm
sir i want to know more about this project ,is it work properly?plssss answer …
March 28th, 2009 at 3:48 pm
hi
this is very good project.
i will use this concept in my project.
April 2nd, 2009 at 3:09 pm
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
July 28th, 2009 at 4:02 pm
hello! i watn the fully detali of this project like circuit diagram, componont,discription,blockdiagram.please send me in soft copy in my mail.
July 31st, 2009 at 6:50 pm
can I try this project for ME level?
August 3rd, 2009 at 1:01 pm
hi,i am very much interested in the project of controlling switch using telephone.please send me the detail information.Thank you
August 5th, 2009 at 8:18 pm
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
August 12th, 2009 at 12:41 am
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.
August 19th, 2009 at 1:19 am
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…
August 21st, 2009 at 10:02 am
is there any law that it violate? because you are trying to connect something in the telephone line… reply asap…
August 26th, 2009 at 12:52 pm
plz give some more projects
August 26th, 2009 at 1:14 pm
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
September 1st, 2009 at 11:51 am
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!
September 16th, 2009 at 1:25 pm
i want its circuit diagram
September 25th, 2009 at 10:45 am
i want its circuit diagram
October 3rd, 2009 at 11:48 am
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
October 3rd, 2009 at 11:50 am
i want its circuit diagram
October 13th, 2009 at 8:21 am
send me all d information abt dis project including circuit digrams, etc..
October 30th, 2009 at 1:20 pm
please send me the synophsis of
” appliance control through mobile phone using DTMF”
November 2nd, 2009 at 10:22 pm
i want dis project urgently. how i can get it? pleas reply me fast as possible.
November 9th, 2009 at 4:04 pm
send that software
November 12th, 2009 at 5:38 pm
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
November 12th, 2009 at 8:34 pm
plz sens me d ckt. diag. of project
device control using mobile
November 26th, 2009 at 9:22 pm
pls send me the working of this project using microcontroller(device control using telephone)
December 2nd, 2009 at 9:31 am
hi,i am very much interested in the project of controlling switch using telephone.please send me the detail information.Thank you
December 6th, 2009 at 9:37 pm
please provide the circuit diagram
December 9th, 2009 at 1:58 pm
i am very interested in this so may you please provide the circuit diagram please
December 11th, 2009 at 12:29 pm
i am interested in doing this project. may i please have the PCB diagram and the list of components asap. thanks.
December 14th, 2009 at 3:29 pm
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…
December 18th, 2009 at 3:08 pm
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
December 24th, 2009 at 7:32 pm
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
December 27th, 2009 at 6:29 pm
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…
December 30th, 2009 at 3:40 pm
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.
January 24th, 2010 at 5:16 pm
Sir, pls send me a circuit diagram with complete labels on my email.
January 28th, 2010 at 3:15 pm
Sir, pls send me a circuit diagram with complete labels on my email.
January 28th, 2010 at 9:03 pm
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.
February 1st, 2010 at 11:03 pm
Please send me the coding and circuit diagram of this project.
February 2nd, 2010 at 1:45 pm
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…
February 6th, 2010 at 6:32 am
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…
February 14th, 2010 at 11:55 am
Great project renjith!!!
February 14th, 2010 at 4:10 pm
pls give circuit diagram device control through telephone. using micro controller IC. IC 89S52
February 20th, 2010 at 7:24 am
pls i would like see the circuit diagram and implementation of the project
March 11th, 2010 at 12:17 pm
it is too good but i want some more inf