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Cell Phone Controlled Home Appliance circuit

Circuit Description:

Ever Imagined controlling your home appliances using your cell phone. You can find a lot of circuits for this application. But they make use of Telephone. I modified the circuit and redesigned it to make it compatible with normal cell phone headphone. Just connect the your phone headphone jack to the phone and the connections to the circuit as shown in the circuit. The relays are connected using the resistor and transistor. Use ULN2803 to reduce the circuit size and increase the performance. The connections from the output of flip-flops has to be given to the inputs of the buffer and relays has to be connected to the buffer.

Normally the tip of the headset is connected to the circuit to the 0.1uF capacitor as shown in the circuit diagram. The ground pin of headphone is connected to the ground of the circuit.

Circuit Diagram:


When you press keys in your Phone, the other person will hear some tones with respect to keys pressed. This tones are based on the DTMF technology. Data is transmitted in terms of pair of tones. The receiver detects the valid pair and gives the appropriate BCD code as the output of the DTMF decoder IC.

The output of the DTMF IC is given to the 4x16 decoder IC. We have 12 signals possible because we have 12 keys (including * and #) in mobile keypad. The decoder are outputs are then given to D flip-flops. The outputs toggle whenever a key is pressed.

In DTMF there are 16 distinct tones. Each tone is the sum of two frequencies: one from a low and one from a high frequency group. There are four different frequencies in each group.
Your phone only uses 12 of the possible 16 tones. If you look at your phone, there are only 4 rows (R1, R2, R3 and R4) and 3 columns (C1, C2 and C3). The rows and columns select frequencies from the low and high frequency group respectively. The exact value of the frequencies are listed in Table 3 below:

TABLE 3: DTMF Row/Column Frequencies
R1: ROW 0697
R2: ROW 1770
R3: ROW 2852
R4: ROW 3941
C1: COL 01209
C2: COL 11336
C3: COL 21477
C4: COL 31633
C4 not used in phones

Thus to decipher what tone frequency is associated with a particular key, look at your phone again. Each key is specified by its row and column locations. For example the "2" key is row 0 (R1) and column 1 (C2). Thus using the above table, "2" has a frequency of 770 + 1336 = 2106 Hz The "9" is row 2 (R3) and column 2 (C3) and has a frequency of 852 + 1477 = 2329 Hz.
The following graph is a captured screen from an oscilloscope. It is a plot of the tone frequency for the "1" key:

You can see that the DTMF generated signal is very distinct and clear. The horizontal axis is in samples. The frequency of the tone is about 1900 Hz - close to the 1906 Hz predicted by Table 3 (697+1209).

If you have any doubts or problems connecting the headphone to the circuit, post you comments here or mail me @

Arifuddin Sheik


Avinash Gupta said...

Hello Arif,

Avinash (from eXtreme electronics) here ...

From my Records I found that you have bought an xBoard MINI v2.0 from us. Can you showcase some of your project/experiments with it? I will pay you for that !

arifuddin said...

Definitely I am going to do that. I started posting my projects from today. I was busy with exams and holidays. I am back to my work now.

srinivas said...

hi,arif this is srinivas ,the schematic here is a very nice one ,so as a hobbyist i deciced to make one for my home appliances,bt there is a doubt in my mind,cud u plz tell me where shall i connect the pins o2 to o7 ,and N/U as well,?

jiss said...

may i know where the appliances has to be it from output pin of CD 4049 IC?

jiss said...

how can we ground the headset unable to get that...

prasenjit said...

can u send me a complete component fitted pcb with instruction it willbe a very help full project for me.

Anonymous said...

Hello Arif,

I need to buy a completed product for some farmers in my village. I want mobile to control there water pumps. Can suggest me from where I can purchase plenty of such gadgets which will work reliably.

dave said...

Home Appliances are the elecrical or mechanical devices which have been used to perform various household functions such as cooking and cleaning effectively.

yogesh said...

hey nice work
i want to make the same project can you provide me the necessary details.

yogesh said...

my emailid is

anubhav said...

hey nice work
i want to make the same project can you provide me the necessary details

Ultimate Appliances said...

Wow, Fantastic article, it’s so helpful to me, and your blog is very good,

Upright Freezers

Online electronics store said...

This is a good common sense Blog. Very helpful to one who is just finding the resources about this part. It will certainly help educate me.Online electronics store

Raviteja said...

Hi,I like to do this one as my final year project.But i am confused about the connections for headphones and cellphones.You said that the tip of the headphone is connected to the Capacitor and the ground is grounded.Then where is the cellphone connected?Please clear my doubt.

life said...

heyy i m geetika,,,,
nice project ,,,i want to make the same...
can u send me the clear circuit diagram and components required 4 this projects. and also a completely fitted picture of this project

$aveeda said...

nice project ,,,i want to make the same...
can u send me the clear circuit diagram and components required 4 this projects.
this is my mail

$aveeda said...
This comment has been removed by the author.
$aveeda said...

nice project ,,,i want to make the same...
can u send me the clear circuit diagram and components required 4 this projects.
this is my mail

shiv prasad said...

pls send me clear diagram of this project & rating of the all component used here pls email is

Er. innocent devil said...

hello arif
my name is daksh
iam a 3rd yr student
i hv thee block diagram represenation........but i dotn know exactly how to makes its circuit

can u please guide me to th point that how to find correct values of resistore and other passive divices....................

how we get to know that how much of current v need to have on particular node..........???

Anirudh Som said...

Hello Arif,
Anirudh Som (from GITAM univ)here

how do i connect my electrical appliances to the circuit.... my mail id is

sangram said...

myself sangram
i want to do this project so send me clear ckt dig mail id

sangram said...

plz do fast

Rizwan Khan said...

Asallamwalekum ARIF ,

This is RIZWAN KHAN {pursuing B.E.(Electrical & electronics)}. DTMF for cell phone cantrolled is brillient and a new softwr has been uploaded in the cell phone yet to launch to cantrol the lights from anywhere in the world. But we will be in work to have some more inovative experiment in this field. All the very best to you n your company . ALLAH HAFIZ & FACE WELL

Tittu Thomas said...

Really Helpful Post
Thank you very much.......

feel free to surf Electronics Projects and Circuits

Murali Nimmala said...

Good Work.

Vikas Gupta said...

Hello sir, i m vikas. I want to make same project (mobile controlle home appliances). Plz email me circuit layout and source code on

Himanshu Kandpal said...

helloz, i am himanshu i am doing btech in electronics and instrumentation. i want to make the same project in the last sem. so kindly send me the clear ckt diagram, components used, component fitted pcb,that will help me in making my project. my mail id is.

Jasmine Jas said...

This is the kind of products which people should buy. Amazing work of creativity.

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Visakhapatnam, Andhra Pradesh, India
I am graduate from Swarna Bharathi College of Engineering in Khammam, Andhra Pradesh, India. Currently I am doing a business. After seeing the response to my blog, I am planning to start my old electronics geek work again. Now I have got more funds and I am planning to do some creative projects. Thanks for all those who encouraged me for doing this wonderful job.