DTMF Based Home Automation


BySaddam 91

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. 


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  • Nikki Singh's picture
    Nikki Singh
    Oct 29, 2015

    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

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

    very nice project .it helps me a lot

  • Lyan Leon's picture
    Lyan Leon
    Dec 17, 2015

    what is the name of cable that connect with Android phone

  • saddam4201's picture
    Dec 18, 2015

    Aux Cable

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

    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

  • Lyan Leon's picture
    Lyan Leon
    Jan 24, 2016

    thanks guys so much

  • rushab shah's picture
    rushab shah
    Jul 19, 2017

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

  • Dharmesh yadav's picture
    Dharmesh yadav
    Jan 18, 2016


  • Arpita 's picture
    Feb 09, 2016

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

  • Abhishek's picture
    Feb 09, 2016

    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

  • Eshita's picture
    Feb 24, 2016

    For simulation of this circuit which software is more efficient?

  • saddam khan's picture
    saddam khan
    Feb 25, 2016

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

  • Ganesh Kothavale's picture
    Ganesh Kothavale
    Mar 02, 2016

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

  • Maddy's picture
    Mar 11, 2016

    yes, you can drive any AC home appliances.

  • manikanta's picture
    Mar 09, 2016

    can we use ht9170 decoder instead of mt8870?

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

    yes you can use that.

    go ahead.

  • nick's picture
    Feb 10, 2018

    hey saddam here u use uln2003 but why u use that if u connect that directly than also it work
    and i want that from pressing 1 like tv on again pressing 1 it off the tv how will i do this

  • snehal thamke's picture
    snehal thamke
    Mar 24, 2016

    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.

  • Shivam Kumar's picture
    Shivam Kumar
    Mar 30, 2016

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

  • Abhishek's picture
    Apr 02, 2016

    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.

  • Shivam Kumar's picture
    Shivam Kumar
    Apr 14, 2016

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

  • saddam khan's picture
    saddam khan
    Apr 21, 2016

    circuit is ok.

  • Amitesh Singh's picture
    Amitesh Singh
    Apr 24, 2016

    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..

  • raviraj's picture
    May 22, 2016

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

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

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

  • nosd1's picture
    Jun 21, 2016

    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

  • Rajeshwari's picture
    Jun 28, 2016

    Can u plz tel me how to connect this on pcb

  • Rajeshwari's picture
    Jun 30, 2016

    Can v operate this from any place???

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

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

  • Raghav's picture
    Jul 06, 2016

    What is Pvt and it's use

  • Sicelo's picture
    Jul 27, 2016

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

  • Avinash 's picture
    Aug 16, 2016

    what is PVT in the components given...?

  • Maddy's picture
    Oct 27, 2016

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

  • Venkat's picture
    Sep 04, 2016

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

  • Avinash 's picture
    Sep 20, 2016

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

  • Avinash 's picture
    Sep 20, 2016

    Is this requires programming

  • ramraj's picture
    Sep 30, 2016

    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

  • Abhishek's picture
    Oct 01, 2016

    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.

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

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

  • Aadesh saini's picture
    Aadesh saini
    Oct 06, 2016

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

  • ALOYSIUS's picture
    Oct 07, 2016

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

  • Maddy's picture
    Oct 07, 2016

    Yes, It will remain in the same state.

  • Sravan's picture
    Oct 13, 2016

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

  • suman's picture
    Oct 13, 2016

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

  • Maddy's picture
    Oct 27, 2016

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

  • AVINASH's picture
    Oct 21, 2016

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

  • M Prashanth's picture
    M Prashanth
    Oct 26, 2016

    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.

  • trinity's picture
    Oct 29, 2016

    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?

  • Abhimanyu's picture
    Nov 07, 2016

    Can I use 3.579mhz Crystal .plz help me immediately

  • Rahul's picture
    Nov 11, 2016

    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.

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

    can I connect DTMF IC directly to relay?

    what is a roll of driver ic?

  • Abhishek's picture
    Nov 30, 2016

    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.

  • shubham's picture
    Nov 15, 2016

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

  • Abhishek's picture
    Nov 30, 2016

    You can use only one battery as per circuit diagram.

  • shubham deore's picture
    shubham deore
    Nov 16, 2016

    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......

  • nandhu's picture
    Dec 24, 2016

    Can i use cd8870 instead of mt8870

  • MOHIT's picture
    Mar 03, 2017

    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.

  • Maddy's picture
    Mar 04, 2017

    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.

  • md riyadh's picture
    md riyadh
    Mar 16, 2017

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

  • harshal ghatole's picture
    harshal ghatole
    Mar 20, 2017

    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.

  • Abhishek's picture
    Apr 08, 2017

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

  • Harsh Patel's picture
    Harsh Patel
    Apr 06, 2017

    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.

  • rupak's picture
    Apr 26, 2017

    We can get out put with out relays

  • saloni's picture
    May 03, 2017

    how to implement this project on software, please help me

  • Mar10's picture
    May 09, 2017

    What is the name of the simulation program please ?

  • Maddy's picture
    Jul 07, 2017

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

  • shweta's picture
    May 22, 2017

    What if I use headphone jack instead of aux cable?

  • shweta's picture
    May 24, 2017

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

  • kajiru's picture
    Jun 01, 2017

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

  • Maddy's picture
    Jul 07, 2017

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

  • Indraj kumar's picture
    Indraj kumar
    Jun 27, 2017

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

  • TEAM CHATRAPATI's picture
    Jul 19, 2017

    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

  • Savani's picture
    Jul 19, 2017

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

  • kiran chavan's picture
    kiran chavan
    Aug 01, 2017

    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

  • AARADHYA's picture
    Aug 17, 2017

    is that ic pre programmed

  • Asha's picture
    Sep 10, 2017

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

  • Mintoo's picture
    Sep 22, 2017

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

  • Jmass King's picture
    Jmass King
    Oct 29, 2017

    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.

  • saqib zaman's picture
    saqib zaman
    Dec 10, 2017

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

  • anna twinkle's picture
    anna twinkle
    Jan 12, 2018

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

  • sharankumar v's picture
    sharankumar v
    Apr 30, 2018

    What is the cost of the project....???

  • Silver Jack 's picture
    Silver Jack
    May 07, 2018

    Please how do I make the phone answer when called if I'm not around to pick it?

  • Raju's picture
    Jun 23, 2018

    How much will be the cost for the project


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