DTMF Controlled Robot using Arduino

Published  August 11, 2015   62
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DTMF Controlled Robot using Arduino Uno

In present time almost all the people are familiar with robots. Robots play a very important role in human life. Robots are a machine which reduces the human efforts in heavy works in industries, building etc. and makes life easy. We are here with our next robot that is Mobile or DTMF Controlled Robot. DTMF controlled Robot runs over mobile DTMF technology that exists in Dial tone. DTMF stands for Dual Tone Multiple Frequency. There are some frequencies that we use to create DTMF tone. In simple words by adding or mixing two or more frequencies generates DTMF tone. 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 and that tone we call Dual Tone Multiple Frequency


Required Components

  • Arduino UNO
  • DC Motor
  • Mobile Phone
  • DTMF decoder Module
  • Motor Driver L293D
  • 9 Volt Battery
  • Battery Connector
  • Aux wire
  • Robot Chasis with wheel
  • Connecting wires


What is DTMF?

DTMF is a Dual Tone Multiple Frequency decoder module which has a MT8870 DTMF decoder IC which decodes DTMF tone signal to digital signal that are acceptable for arduino digitally. Here an aux wire is needed for connecting DTMF module to phone.

DTMF Module


Block Diagram for DTMF Controlled Robot using Arduino

Block Diagram for DTMF Controlled Robot using Arduino

Remote section: This section’s main component is DTMF. Here we get a tone from our cellphone by using aux wire to DTMF Decoder IC namely MT8870 which decodes the tone into digital signal of 4bit.

Control Section: Arduino UNO is used for controlling whole the process of robot. Arduino reads commands sent by DTMF Decoder and compare with define code or pattern. If commands are match arduino sends respective command to driver section.

Driver section: driver section consists motor driver and two DC motors. Motor driver is used for driving motors because arduino does not supply enough voltage and current to motor. So we add a motor driver circuit to get enough voltage and current for motor. By collecting commands from arduino motor driver drive motor according to commands.


Circuit Diagram and Working Explanation

Arduino based DTMF Controlled Robot Circuit Diagram

Circuit digram for Arduino based DTMF Controlled Robot is very similar with our other robot like PC controlled robot, Line Follower, Gesture Controlled Robot, etc.. Here one motor driver is connected to arduino for driving robot. Motor driver’s input pin 2, 7, 10 and 15 is connected at arduino digital pin number 6, 5, 4 and 3 respectively. Here we have used two DC motors to driver robot in which one motor is connected at output pin of motor driver 3 and 6 and another motor is connected at 11 and 14. A 9 volt Battery is also used to power the motor driver for driving motors. A DTMF decoder attached with this circuit and this decoder is plugged into a mobile using an aux wire for receiving command or DTMF Tone. DTMF decoder pin D0-D3 is directly connected with Arduino’s pin number 19,18,17,16. Two 9 Volt batteries are used to power the circuit in which one is used for power the motors, connected at motor driver IC pin number 8. And another battery is connected to power the remaining circuit.


Working of DTMF Controlled Robot

DTMF controlled robot run by some commands that are send via mobile phone. We are here using DTMF function of mobile phone. Here we have used the mobile phone to show working of project. One is user mobile phone that we will call ‘remote phone’ and second one that are connected with Robot’s circuit using aux wire. This mobile phone we will call ‘Receiver Phone’.   

First we make a call by using remote phone to receiver phone and then attend the call by manually or automatic answer mode. Now here is how this DTMF controlled robot is controlled by cell phone:


When we presses ‘2’ by remote phone, robot start to moving forward and moving continues forward until next command comes.

Moving forward DTMF Controlled Robot

When we presses ‘8’ by remote phone, robot change his state and start moving in backward direction until other command comes.

Moving Backward the DTMF Controlled Robot

When we press ‘4’, Robot get turn left till next command exicuted.

Turning left to DTMF controlled robot

When we press ‘6’, robot turned to right.

turning right to dtmf controlled robot

And for stopping robot we pass‘5’.

stop dtmf controlled robot


Programming Explanation

In program first of all we have defined output pins for motors and Input pins for DTMF decoder output as in INPUT for Arduino.


And then in setup set motor pin as OUTPUT and DTMF decoder output pins as INPUT.


After that we read DTMF decoder output and then compare with defined values by using “if” statement and perform relative operation.

redesign and compare

There are five conditions in this DTMF controlled Robot that are giving below:

DTMF Robot Conditions

We write program according to above table conditions.


#define m11 3
#define m12 4
#define m21 5
#define m22 6

#define D0 19
#define D1 18
#define D2 17
#define D3 16

void forward()
   digitalWrite(m11, HIGH);
   digitalWrite(m12, LOW);
   digitalWrite(m21, HIGH);
   digitalWrite(m22, LOW);

void backward()
   digitalWrite(m11, LOW);
   digitalWrite(m12, HIGH);
   digitalWrite(m21, LOW);
   digitalWrite(m22, HIGH); 

void left()
   digitalWrite(m11, HIGH);
   digitalWrite(m12, LOW);
   digitalWrite(m21, LOW);
   digitalWrite(m22, LOW);

void right()
   digitalWrite(m11, LOW);
   digitalWrite(m12, LOW);
   digitalWrite(m21, HIGH);
   digitalWrite(m22, LOW);

void Stop()
   digitalWrite(m11, LOW);
   digitalWrite(m12, LOW);
   digitalWrite(m21, LOW);
   digitalWrite(m22, LOW);

void setup() 
  pinMode(D0, INPUT);
  pinMode(D1, INPUT);
  pinMode(D2, INPUT);
  pinMode(D3, INPUT);

  pinMode(m11, OUTPUT);
  pinMode(m12, OUTPUT);
  pinMode(m21, OUTPUT);
  pinMode(m22, OUTPUT);

void loop() 

  int temp1=digitalRead(D0);
  int temp2=digitalRead(D1);
  int temp3=digitalRead(D2);
  int temp4=digitalRead(D3);
  if(temp1==0 && temp2==1 && temp3==0 && temp4==0)

  else if(temp1==0 && temp2==0 && temp3==1 && temp4==0)

  else if(temp1==0 && temp2==1 && temp3==1 && temp4==0)

  else if(temp1==0 && temp2==0 && temp3==0 && temp4==1)

   else if(temp1==1 && temp2==0 && temp3==1 && temp4==0)


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Submitted by Wes on Sat, 12/19/2015 - 22:26


Interesting project. However, there seems to be a big gap in the area of getting the audio signal from the cell phone to the DTMF module. " an aux wire is needed" does not explain much.

Submitted by usman iqbal on Sun, 12/20/2015 - 02:16


plz i need a clear image of circuit diagram pins connection to arduino

Submitted by khaja vali on Fri, 01/01/2016 - 22:28


Dtmf contolled robot with microcontroller, dtmf -dual tone muliti-frequency

Submitted by rishu on Fri, 01/29/2016 - 21:02


can u tell me whole procedure of how to burn code in arduino uno.....thnks
what library files u added while coding for dtmf decoder

Submitted by naveen on Fri, 03/11/2016 - 22:34


i didnt get where aux wire got connected .it is not even shown in circuit diagram

Submitted by sushil kr.singh on Thu, 04/21/2016 - 11:36


No need of programming for dtmf ic .So feed yr program in ardino (burner port).

Submitted by MENA on Fri, 08/26/2016 - 19:14


i cant find DTMF module in shops in my city ,, but there is MT8870 ic only ,, can i use it only ??? ,, or it should be programmed first ???

Submitted by Pravin Subhash… on Wed, 08/31/2016 - 12:24


I have one question in my mind.. You are using analog pins A2 - A5. and in void loop you are reading data digitally.. how is it possible? Analog pin only takes analog input and dtmf module decodes input digitally. So digital data should be read by Arduino.
I am also failing to drive the motors as per this information mentioned by you... please give me directions. my all connections are well checked as per your instructions.Please help us...

Submitted by poojashree.s on Thu, 02/02/2017 - 21:22


can i directly do the coding in turbo 7...ll it directly save in arduino...r shld i any other procedure for that...could you plz guide me

Submitted by Ajith Kumar K on Thu, 03/02/2017 - 19:04


You are saying that the output of dtmf module is digital, but how you are connecting it with analog pins of arduino??

Submitted by Rohit on Tue, 04/04/2017 - 00:12


i want to make the calling using sim900A module as well as control using dtmf command set.
since i tried using AT+DDET=1 but my module showing error. could you advice me.

Submitted by karthik on Sat, 04/08/2017 - 11:56


#define D0 19
#define D1 18
#define D2 17
#define D3 16 in this code u r defining the pins as 16,17,18,19 where r those pins in audrino..help me to understand

Submitted by Manish singh on Wed, 04/19/2017 - 22:55


how to connect aux cable with DTMF and mobile phone. and which type of cell phone use for this project .

Submitted by Makwana Prashant on Sat, 07/29/2017 - 19:24


How to use in project of DC motor ? How many Voltage in DC Motor ?

Submitted by Ahad on Sat, 08/19/2017 - 02:07


I want to get vedio feedback from attached Android mobile phone to calling Android mobile phone, by using skype vedio call. Is it possible, if i use seme circuit diagram and same ardiuno code?? Plz replay.. its very urgent.

Submitted by STEPH on Sun, 02/04/2018 - 16:25


I have some questions:

1. Do we use a 3.5mm TRS Aux cable to connect the DTMF Module to the Receiver phone?
2. Will this project work with this MT8870 Module?
3. Can you please explain "attend the call by manually or automatic answer mode" in more detail?
I'm using a Samsung S6 for the remote phone. Would a Nokia 130 work ok for the receiver phone?
Thank you.

1. You can use 3.5mm Aux cable

2. Yes it will

3. There is an android phone which can automatically answer calls, install it and your phone will answer the call automatically then you can use the DTMF to navigate 

Submitted by Mahadev on Sat, 05/05/2018 - 23:51


All those r very gud concepts but hw I can download the PDF of particular projects????

Submitted by praveen on Fri, 08/31/2018 - 15:47


i have given all the connections..still the motor has not get power supply.....
i am using l298n driver .....we have give the connections for enable or it will work without enable connections..?