# Mobile Controlled Robotic Car Using Arduino and DTMF

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## Introduction: Mobile Controlled Robotic Car Using Arduino and DTMF

Hello guys!

This is my first project on instructables, hope u will enjoy this.

This project is about how you can control a robotic car using cell phone and how you can control that car from anywhere in the world.

## Step 1: Components

1. IC’s:

· 7805

· MT 8870 / HT 9170 B

· MH 7404 (hex inverter)

· L293D / L298 (motor driver)

2. Arduino Uno

3. 9 V battery

4. 100 k ohm resistor x2

5. 330 k ohm resistor x1

6. 22 pF capacitor x2

7. 10 micro F capacitor x2

8. 3.579 MHz crystal

9. Audio Jack

10. DC motors x2

11. Mobile phone

## Step 2: DTMF Signal:

DTMF (dual tone multi frequency) is the signal to the phone company that you generate when you press an ordinary telephone's touch keys.

With DTMF, each key you press on your phone generates two tones of specific frequencies. So that a voice cannot imitate the tones, one tone is generated from a high-frequency group of tones and the other from a low frequency group.

## Step 4: Circuit Explanation:

MT 8870 or HT9170 B takes the DTMF signal from the cell phone and decode that signal into a binary code, that signal cannot be processed directly into the Arduino Uno (microcontroller), if u do so your signal will loss. That’s why a hex inverter IC is utilized to convert its logic and powered the signal. The output of hex inverter can be processed into Arduino Uno and u can now program the circuit.

You can also control your car by making a call from other phone, and by pressing buttons from other phone. Make sure that you have activated keypad sounds.

## Step 5: Arduino Code:

int x,y,z,t;

int a=3;

int b=4;

int c=5;

int d=6;

int e=7;

int f=8;

int g=9;

int h=10;

void setup() {

// put your setup code here, to run once:

pinMode(a,INPUT);

pinMode(b,INPUT);

pinMode(c,INPUT);

pinMode(d,INPUT);

pinMode(e, OUTPUT);

pinMode(f,OUTPUT);

pinMode(g,OUTPUT);

pinMode(h,OUTPUT);

Serial.begin (9600);

}

void loop() {

// put your main code here, to run repeatedly:

Serial.print(x);

Serial.print(y);

Serial.print(z);

Serial.println(t);

delay(1000);

if (x==1 && y==0 && z==1 && t==1)

{digitalWrite(e,HIGH);

digitalWrite(f,LOW);

digitalWrite(g,HIGH);

digitalWrite(h,LOW);}

if (x==1 && y==1 && z==1 && t==0)

{digitalWrite(e,LOW);

digitalWrite(f,HIGH);

digitalWrite(g,LOW);

digitalWrite(h,HIGH);}

if (x==1 && y==1 && z==0 && t==1)

{digitalWrite(e,LOW);

digitalWrite(f,LOW);

digitalWrite(g,HIGH);

digitalWrite(h,LOW);}

if (x==1 && y==0 && z==0 && t==1)

{digitalWrite(e,HIGH);

digitalWrite(f,LOW);

digitalWrite(g,LOW);

digitalWrite(h,LOW);}

if (x==0 && y==0 && z==1 && t==1)

{digitalWrite(e,LOW);

digitalWrite(f,LOW);

digitalWrite(g,LOW);

digitalWrite(h,LOW);}}

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## Questions

plz send hiw to connect this connection i connected but output is not come

everything is working except motor ive given connection properly

what might be the problem

you show in video that you attached mobile phone with wire. Is it possible we run robot through wireless with mobile phone? please reply

6 replies

i attached mobile with wire because DTMF signal is controlling the robot.

yes it is possible to control without wire by using bluetooth module (HC-05).

I check all connection and it all right. After it I check 9170B ic with led's and then send mobile signal but the led's not glowing according to the binary code, I use 20Mhz crystal oscillator What should I do please tell me?

so i will change the coding or not?

You don't need to change anything, just make sure there is no loose connection.

sadeem, the pinout of l293d in the circuit diagram u posted in this site is different from what i got from google.so is it a mistake? or may i stick on to ur diagram????????? please reply.................