This document describes a DTMF controlled robot that can be operated using a mobile phone. It uses a DTMF decoder module connected to an Arduino microcontroller to decode tones from the phone's keypad and control a DC motor. When buttons are pressed on the remote phone, the corresponding tones are decoded to control the robot's movement - button 2 moves it forward, 8 moves it backward, 4 turns it left, and 6 turns it right. Button 5 stops it. The robot has applications in hazardous environments, search and rescue operations, and can be controlled remotely via GSM networks. Further improvements proposed include adding obstacle detection sensors and a camera for remote viewing.

1. DTMF CONTROLLED ROBOT

2. INTRODUCTION:
•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, buildings etc.
•DTMF controlled robot runs over mobile DTMF
technology that exists in dial tone.
•DTMF stands for Dual Tone Multiple Frequency.
•In simple words by adding or mixing two or more
frequencies generates DTMF tone.

3. TECHNOLOGY USED
Dual Tone Multi Frequency (DTMF):
• Dual tone multi frequency signaling is used for
telecommunication signaling over analog telephone lines.
• DTMF technology is the most useful technique at present days.
• it works on the method of digital signal processing (dsp).
• DTMF systems uses 8 different frequency signals transmitted
in pairs to represent 16 different numbers, letters or symbols.

4. What is DTMF?
• DTMF means Dual Tone Multiple Frequency
which decoder module which inturn has a
MT8870 DTMF decoder IC which decodes DTMF
tone signal to digital signal that are acceptable
for aurdino digitally.
• Here an aux wire is needed for connecting
DTMF module to phone.

5. Required Components:
1.Arduino UNO
2.DC Motor
3.Mobile Phone
4.DTMF decoder Module
5.Motor Driver L293D
6.9 Volt Battery
7.Battery Connector
8.Aux wire
9.Robot Chassis with wheel
10.Connecting wires

6. Block Diagram for DTMF Controlled Robot using Aurdino:

7. Circuit Diagram:

8. HARDWARE DESCRIPTION:
A. DTMF Decoder:
• The DTMF system generally uses eight
different frequency signals transmitted in pairs to
represent sixteen different numbers, symbols and letters.
• When someone presses any key in the key pad of the
handset, a DTMF signal generate a unique tone which
consists of two different frequencies one each of
higher frequency range (>1KHz) and
lower frequency(<1KHz) range.
• The resultant tone is the convolution of two frequencies.

9. B. Atmega328P Microcontroller:
• ATmega328P is a 32K 8-bit microcontroller.
• ATmega328P is commonly used in many projects
and autonomous systems where a simple,
low powered, low cost microcontroller is needed.
• It has 14 digital input/output pins (out of which 6 can be
exploited as PWM outputs), 6 analog input, 16 MHz crystal
oscillator.
• It has 1KB EPROM, 2KB SRAM,23 general
purpose I/O lines, 32 general purpose working
registers, three flexible timer/counters with compare
modes, internal and external interrupts.
• It has five software selectable power saving modes.
• The device operates between 1.8-5.5 volts

10. C. DC Motor Driver:
• DC motor is electromechanical device that converts
electrical energy into mechanical energy that
can be used to do many works.
• It can produce mechanical movement to move the
wheels of the robot.
• DC motor has two wires, we can say them positive
terminal and negative terminal , when these wires are
connected with power supply the shaft rotates.
• We can reverse the direction of the rotation.
• L293dchip is very safe to use for DC motor control.
• This L293D is a 16 bit chip.
• Chip is designed to control four DC motor.

11. D. MT8870 DTMF Decoder IC:
• The MT-8870 is a DTMF Receiver that integrates
both band split filter and decoder functions into a
single 18 pin DIP package.
• It is manufactured using CMOS process technology.
• The MT8870 offers low power consumption
(35mW max) and precise data handling.
• It uses digital counting techniques to detect
and decode all 16 DTMF tone pairs into a 4-bit code.

12. Working of L293D:
• The there 4 input pins for this L293D, pin 2,7 on the left
and pin 15 ,10 on the right as shown on the pin diagram.
• Left input pins will regulate the rotation of motor
connected across left side and right input for motor
on the right hand side.
• The motors are rotated on the basis of the inputs
provided across the input pins as LOGIC 0
or LOGIC 1.

13. L293D Logic Table:
Let's consider a Motor connected on left side
output pins (pin 3,6). For rotating the motor in
clockwise direction the input pins has to be
provided with Logic 1 and Logic 0
Pin 1 (Enable) Pin 2 Pin 7 Function
HIGH HIGH LOW Anticlockwise
HIGH LOW HIGH Clockwise
HIGH HIGH HIGH No Rotation
HIGH LOW LOW No Rotation
LOW X X No Rotation
Table : L293 Logic Table
Where X = HIGH/LOW

15. Working of DTMF Controlled Robot:
• DTMF controlled robot runs by some commands that are
sent 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.

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

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

18. When we press ‘4’, Robot get turn left till next command is executed.

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

20. And for stopping robot we pass‘5’.

21. APPLICATIONS:
Scientific Application:
• DTMF Robots have various scientific uses like checking of
hazardous environment , working in deep oceans ,
space exploration.
• It has various other scientific applications like research etc.
Search and Rescue:
• DTMF Robots can be used for the search process and even
for the rescue operation.
• It was once used in united states in 2008 when it was struck by
hurricanes.

22. GENERAL APPLICATION:
•This type of wireless communication (GSM) gives
the security of robots when the owner is not present.
•Operating robot from a remote place anywhere in
the world with any telecommunication device
having DTMF technology

23. FURTHER IMPROVEMENTS AND FUTURE SCOPE:
1. IR SENSOR:
• IR Sensors can be used to automatically detect & avoid obstacles
if the robot goes beyond the line of sight.
• This avoids the damage to the vehicle if we are controlling it
from a distant place.
2. ADDING A CAMERA:
• This project can be interfaced with a camera (web cam)
• So that robot can be operated beyond the line of sight
as the GSM networks have a very large range.

24. 3. PASSWORD PROTECTION:
• This project can be modified in order to password
protect the robot so that it can be operated only if
correct password is entered.
• Either cell phone can be password protected or necessary
modifications can be made in the code.
• This introduces conditioned access and increases
security to a great extent.

25. LIMITATIONS OF DTMF CONTROLLED ROBOT:
• DTMF ROBOT may not work properly if it is
operated with another mobile when there
is no signal.
• Mobiles with particular jacks can be used only.

26. CONCLUSION:
• By developing this robotic vehicle , we have overcome the
drawbacks of RF communication which have a limited range.
• where as this robot can be controlled from anywhere just using
DTMF technology.
• it provides the advantages of robust control ,working range.

27. REFERENCES:
1. http://www.8051projects.info
2. “Electronics for you” magazine , edition (2003).
3. http://www.robotplatform.com

28. THANK YOU
By
Jeevan.M
Vivek
Yashwanth