DTMF Based Home Automation System

We use many different types of communication in control applications to control home appliances, industrial appliances, and other type of automation. There are two types of communication that is we generally use - one is wired and other one is wireless. In wireless communication we transmits signal wirelessly, like using radio frequency (RF) and in wired communication in which we uses wires like copper wire. In this project “DTMF Based Home Automation System” we are going to control our home appliances wirelessly. Other important feature of this project is, that we are not going to use any microcontroller in it.


Required Components

  1. MT8870 DTMF Decoder                 -1
  2. ULN2003                                              -1
  3. Relay 5 volt                                         -3
  4. Bulb with holder or LED                 -3
  5. Connecting wires
  6. Bread board                                       -2
  7. Aux Wire                                             -1
  8. 9 volt battery                                     -2
  9. PVT or Terminal Block                      -4
  10. 100K Resistor                                     -2
  11. 330K resistor                                      -1
  12. 0.1 uf Cap                                            -2
  13. 22 pF cap                                             -2
  14. 3.57 Mhz Crystal                               -1
  15. Mobile phone                  
  16. LEDs                                                       -3
  17. 1K resistor                                           -6
  18. 7805                                                       -1


Circuit Concept and Working

DTMF controlled home appliances project works over mobile DTMF technology that exists in Dial tone. DTMF stands for Dual Tone Multiple Frequency. There are some frequencies that we used to create DTMF tone. In simple words by adding or mixing two or more frequencies generates DTMF tone (Also check: DTMF Based Robot using Arduino). These frequencies are given below:

DTMF Frequencies

In Given figure we can see two groups of different frequencies. When one upper and one lower frequencies mixed then a tone is created that tone we calls Dual Tone Multiple Frequency. In this project we control ac appliances by pressing dial pad keys like 1, 2, 3, 4, 5 and more.

Block Diagram for DTMF Based Home Automation

Here we have connected a cell phone using aux wire to the DTMF decoder circuit. Before explaining the further working of project we need to know about the output of DTMF decoder for every key pressed.

Output of DTMF Decoder

Now understand working according to given table.

In circuit diagram at Q1 LIGHT is connected, at Q2 FAN is connected and at Q3 TV is connected through relay driver IC. We have left Q4. Now when we press key 1 at the dial pad of mobile phone DTMF decodes this tone and generates a digital output given in table. Now According to given output in table Q1 is HIGH and Q1 is connected with light so LIGHT turned ON. If we want turned OFF the LIGHT, we need to press key number 8. Because in the output of key8, Q1, Q2 and Q3 LOW and Q4 are HIGH and we have not used Q4. So it doesn’t matter that Q4 is HIGH or LOW. But our operation has been performed because Q1 is LOW in key 8’s output and rest of appliances not affected. Now is we want to turned on FAN so we need to press key2 because by pressing key2 only Q2 is activated and rest of output are remain same. Now if we to OFF the FAN then we need to press key8 again like before for as LIGHT. Now if we want to TV so we need to press key4 and for tuning it OFF we need to press 8 like before. Now suppose we want to turned ON all of the appliances so we need to press key7 (see table) and for turning OFF all key8 (see table).


Now if we need to ON LIGHT and FAN so we need to press key3 (see table). And now we want to ON TV so we need to press key 7 not key4. Because we should keep remain turn ON previous appliances. Now if we want to turn OFF only LIGHT so we need to press key6. Because we should again to keep remain turn ON the previous appliances except LIGHT.


So we can control each of the appliances according to table output.


Circuit Diagram and Explanation

DTMF Based Home Automation Circuit Diagram

Circuit diagram for DTMF controlled home automation project is shown above. In this circuit we have used a DTMF decoder namely MT8890 IC which converts dial pad tone into the four bit digital output. LIGHT, FAN and TV are connected to Q1,Q2 and Q3 of DTMF decoder IC through a relay driver namely ULN2003. 5 volt SPDT 3 relays are used for controlling LIGHT, FAN and TV.


For demonstration of this project we have connected three LEDs at relay instead AC appliances. And we have also used 9 volt dc battery instead 220VAC for driving LEDs. 


Comments (86)

  • Nikki Singh's picture
    Nikki Singh

    Will this project work if I will make a call at the receiver and then during call,press the buttons from the transmitter side. Please help me by explaining the working of each and every component. I beg u plz help me

    Oct 29, 2015
  • Abhishek's picture

    Yes, it should work during the call.

    Nov 14, 2015
  • Lyan Leon's picture
    Lyan Leon

    very nice project .it helps me a lot

    Nov 25, 2015
  • Lyan Leon's picture
    Lyan Leon

    what is the name of cable that connect with Android phone

    Dec 17, 2015
  • saddam4201's picture

    Aux Cable

    Dec 18, 2015
  • Lyan Leon's picture
    Lyan Leon

    how can i know the aux cable is worked or not, i juz cut my earphone to test it but it didn't work
    plz suggest me

    Dec 20, 2015
  • Lyan Leon's picture
    Lyan Leon

    thanks guys so much

    Jan 24, 2016
  • rushab shah's picture
    rushab shah

    Is your project working? If yes, then would you mind contacting us. we really need your help. Contact us on teamchatrapati@gmail.com

    Jul 19, 2017
  • Dharmesh yadav's picture
    Dharmesh yadav


    Jan 18, 2016
  • Arpita 's picture

    How have you connected the aux cable to the dtmf decoder chip? please help me.

    Feb 09, 2016
  • Abhishek's picture

    You need to cut the one end of AUX cable and take out its wires, and connect them to breadboard. Check this Article for Aux cable connections: Small Loudspeaker

    Feb 09, 2016
  • Eshita's picture

    For simulation of this circuit which software is more efficient?

    Feb 24, 2016
  • saddam khan's picture
    saddam khan

    by using four 4 or 5 push buttons you can simulate it at proteus.

    Feb 25, 2016
  • Ganesh Kothavale's picture
    Ganesh Kothavale

    can we drive a electric fan working on ac power supply at home using this circuit?how can we do this?please help us.

    Mar 02, 2016
  • Maddy's picture

    yes, you can drive any AC home appliances.

    Mar 11, 2016
  • manikanta's picture

    can we use ht9170 decoder instead of mt8870?

    Mar 09, 2016
  • saddam khan's picture
    saddam khan

    yes you can use that.

    go ahead.

    Mar 09, 2016
  • snehal thamke's picture
    snehal thamke

    here in dis components list they have mentioned about PVT, I just wanted to know what is PVT and what are its uses and application.

    Mar 24, 2016
  • Shivam Kumar's picture
    Shivam Kumar

    Sir, what is the use of the other 4 led(3 red and 1 yellow), would u plz explain?

    Mar 30, 2016
  • Abhishek's picture

    These are indication LEDs, when we connect the actual AC appliances in places of 3 LEDs at the Right side, then these LEDs work as indicators.

    Apr 02, 2016
  • Shivam Kumar's picture
    Shivam Kumar

    All the led's are not going off after pressing 8,( my circuit is correct)??

    Apr 14, 2016
  • saddam khan's picture
    saddam khan

    circuit is ok.

    Apr 21, 2016
  • Amitesh Singh's picture
    Amitesh Singh

    Can we control home appliances using dtmf tone, through wifi lan connection...if yes then please send me a solution, that how it will work..

    Apr 24, 2016
  • raviraj's picture

    sir can i use cd 8870 ic for this ckt ?? is their any change in ckt diagram

    May 22, 2016
  • Naresh Jeevaalaggan's picture
    Naresh Jeevaalaggan

    please let me know the use of ULN2003 driver in this project?

    May 22, 2016
  • nosd1's picture

    Can you please help me understand how this is a wireless solution?? The mobile is connected to the circuit through the AUX cable as I see it. I would really like a wireless version of this. Thank You

    Jun 21, 2016
  • Rajeshwari's picture

    Can u plz tel me how to connect this on pcb

    Jun 28, 2016
  • Rajeshwari's picture

    Can v operate this from any place???

    Jun 30, 2016
  • Odin Olaya's picture
    Odin Olaya

    What PVT stands for and how it is used. in the diagram it is not shown though. thanks

    Jun 30, 2016
  • Raghav's picture

    What is Pvt and it's use

    Jul 06, 2016
  • Sicelo's picture

    Just interested in this project and wanna know like how much does it cost, like the entire project

    Jul 27, 2016
  • Avinash 's picture

    what is PVT in the components given...?

    Aug 16, 2016
  • Maddy's picture

    PVT is Terminal Block, Green color block adjacent to each Relay (see picture), to secure wires with screws.

    Oct 27, 2016
  • Venkat's picture

    Can we make circuit in pcb board? And can we use tv on output side instead of led

    Sep 04, 2016
  • Avinash 's picture

    What is the PVT mentioned in the list of apparatus..?

    Sep 20, 2016
  • Avinash 's picture

    Is this requires programming

    Sep 20, 2016
  • ramraj's picture

    Hi sir can I use it for 440 volts ac supply or if not please tell me that what can I use for 440 volts ac motor start with push button please help me

    Sep 30, 2016
  • Abhishek's picture

    You can use the same circuit but you have to replace the Relay for handling 440 v, the relay used in this circuit can handle upto 250v.

    Oct 01, 2016
  • Aadesh saini's picture
    Aadesh saini

    I need full circuit diagram, what are component is used full details .plz replay soon as possible. I want urgent

    Oct 01, 2016
  • Aadesh saini's picture
    Aadesh saini

    what are the function of pin number 5&6 of IC MT8870?

    Oct 06, 2016
  • ALOYSIUS's picture

    sir; wat happen
    to the cct wen i dropped d cal.. will the cct stil b active

    Oct 07, 2016
  • Maddy's picture

    Yes, It will remain in the same state.

    Oct 07, 2016
  • Sravan's picture

    Can we use TRIAC instead of 5v relay in this circuit?

    Oct 13, 2016
  • suman's picture

    Many people keep asking whats pvt .no one answered that. Someone please tell what does pvt stand for atleast??!

    Oct 13, 2016
  • Maddy's picture

    PVT is Terminal Block, Green color block adjacent to each Relay (see picture), to secure wires with screws.

    Oct 27, 2016
  • AVINASH's picture

    thank you ..this project really worked well.....

    Oct 21, 2016
  • M Prashanth's picture
    M Prashanth

    I know its a lot to ask but Can you send me the final project Report of this it'll be really helpful and Thank you very much the project is really Great and its working Perfectly.

    Oct 26, 2016
  • trinity's picture

    I want to control the appliances wirelessly (using another phone to control the whole circuit). can any one help me out with the necessary things to add?

    Oct 29, 2016
  • Abhimanyu's picture

    Can I use 3.579mhz Crystal .plz help me immediately

    Nov 07, 2016
  • Rahul's picture

    I made this circuit on pcb as per diagram but it's not working.
    led 1,2,3 is continuously on and IC MT8870 is heating more.
    please let me know what should I do?
    I am waiting your response.

    Nov 11, 2016
  • shubham deore's picture
    shubham deore

    can I connect DTMF IC directly to relay?

    what is a roll of driver ic?

    Nov 11, 2016
  • Abhishek's picture

    Relay should be used with a driver circuit of Transistor and diode to make it work properly, check here for more detail. And ULN2003 IC has inbuilt darlington transistor pairs and other circuitry to drive relay.

    Nov 30, 2016
  • shubham's picture

    why another 9v battery is used at relay? is it must to connect ?

    Nov 15, 2016
  • Abhishek's picture

    You can use only one battery as per circuit diagram.

    Nov 30, 2016
  • shubham deore's picture
    shubham deore

    circuit is working but when I press 2 or 3 it will turn on one relay ,then if I press 4 or 5 button it will on 2nd relay, at a time all 3 relay r not conducting plz help me fast

    plz reply......

    Nov 16, 2016
  • nandhu's picture

    Can i use cd8870 instead of mt8870

    Dec 24, 2016
  • MOHIT's picture

    How to prevent calls from other mobile and mall functioning of DTMF decoder as any one can dial mobile connected to circuit. I want exclusive control with only specific mobile.

    Mar 03, 2017
  • Maddy's picture

    Easiest way is to use exclusive sim card for that mobile, otherwise you need use some microcontroller and GSM module to filter the incoming mobile number.

    Mar 04, 2017
  • md riyadh's picture
    md riyadh

    I can control it from anywhere. Another mobile calls.?

    Mar 16, 2017
  • harshal ghatole's picture
    harshal ghatole

    Sir,it says,that whenever we forget to switch off the appliances,that time this circuit is used.But sir,in video,we have to keep on our appliances and off,when phone call is dialled.but when switch is already on,and if we want to switch off the appliance,then how we do that?.because,if we off the switch during phone call,after phone call ends,the appliances will remain on.so,the purpose is not achieved.please please tell me.

    Mar 20, 2017
  • Abhishek's picture

    If you switch off the appliance from the mobile then it will remain off, whether the main switch is on

    Apr 08, 2017
  • Harsh Patel's picture
    Harsh Patel

    I made this circuit on PCB it can not working. At the time of starting when i connect the supply directly 12 and 13 pin LED is start to glow without any given input. please help sir.

    Apr 06, 2017
  • rupak's picture

    We can get out put with out relays

    Apr 26, 2017
  • saloni's picture

    how to implement this project on software, please help me

    May 03, 2017
  • Mar10's picture

    What is the name of the simulation program please ?

    May 09, 2017
  • Maddy's picture

    Please read the above comments before posting, your question might have already answered.

    Jul 07, 2017
  • shweta's picture

    What if I use headphone jack instead of aux cable?

    May 22, 2017
  • shweta's picture

    can i use any smartphone or is it necessary to use any specific phone to interface?

    May 24, 2017
  • kajiru's picture

    sir is it a must to have relays between the leds and the ic mt8870?

    Jun 01, 2017
  • Maddy's picture

    No, you can use Transistors to trigger LEDs. Relays are for the purpose of switching AC appliances.

    Jul 07, 2017
  • Indraj kumar's picture
    Indraj kumar

    Hello guys
    I complete made this circuit but auxaux wir how to connect??????

    Jun 27, 2017
  • TEAM CHATRAPATI's picture

    We've been trying really hard to run this project. Can anyone please help me out in any which way? If yes, then kindly contact us on teamchatrapati@gmail.com

    Jul 19, 2017
  • Savani's picture

    What is the use of crysal oscillator. In the circuit ??

    Jul 19, 2017
  • kiran chavan's picture
    kiran chavan

    Sir,i want to control the tubelight & fan which is operates on 230v-50hz power supply.can i use this ckt fr this .if yes ,what modefication is needed to do in ckt .plz reply

    Aug 01, 2017
  • AARADHYA's picture

    is that ic pre programmed

    Aug 17, 2017
  • Asha's picture

    Is we need to store program in mt8870 or it is already pre program ....how we can store .....plz explain every step

    Sep 10, 2017
  • Mintoo's picture

    We implemented the circuit but the leds remain on once we connect the battery..plzz help

    Sep 22, 2017
  • Jmass King's picture
    Jmass King

    Hello Sir.
    I want to implement this project by using At328 microcontroller, can you help me how the circuit diagram will look like?,
    Please,help me.

    Oct 29, 2017
  • saqib zaman's picture
    saqib zaman

    1. Is this all the circuit you got ??
    2. Does it has any coding or not?
    3. Did anyone has tried that?

    Dec 10, 2017
  • B.Aswinth Raj's picture
    B.Aswinth Raj

    There is no coding required, it should work as demonstarted 

    Dec 11, 2017
  • anna twinkle's picture
    anna twinkle

    plz help mee
    i cannot get the output when we dial the number on the phone
    its not working

    Jan 12, 2018

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