The document summarizes a student project to create a cellphone-operated land rover. A group of students designed a robot that can be controlled by dialing the mobile phone attached to the robot. When buttons are pressed on the calling phone, it sends dual-tone multi-frequency (DTMF) tones that are received and decoded by a microcontroller on the robot. The microcontroller then controls motors to move the robot forward, backward, or turn based on the decoded DTMF tones. The project uses a DTMF decoder chip, microcontroller, and motor driver circuit to enable remote control of the robot using a standard mobile phone as the controller.

1. CELLPHONE
OPERATED LAND
ROVER
UDIT VERMA
ANISH MISHRA
LAKSHIT ARNEJA
SANJAY TALUKDAR
Department of Electrical & Electronics Engineering
Skyline Institute of Engineering & Technology
Greater Noida
2009

2. 2
CERTIFICATE
This is to certify that the project work entitled “Cellphone
Operated Land rover” submitted by
 Udit Verma - 0515321054
 Anish Mishra - 0515321007
 Lakshit Arneja - 0515321028
 Sanjay Talukdar – 0515321047
In partial fulfillment of the requirements of the degree of Bachelor
of Technology in Electrical & Electronics Engineering, embodies
the work done by them under my supervision.
Signature of Guide Signature of HOD
Submitted for the project viva held on ………………………
Internal Examiner External Examiner

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ACKNOWLEDGEMENTS
This project involved the collection and analysis of information
from a wide variety of sources and the efforts of many people
beyond us. Thus it would not have been possible to achieve the
results reported in this document without their help, support and
encouragement.
We would like to express our gratitude to the following people for
their help in the work leading to this report:
Project supervisor: for their useful comments on the subject matter
and for the knowledge I gained by sharing ideas with them.
Mr. S. M. Khan; Project Coordinator: for organizing and
coordinating the BTech Projects 2009.

4. 4
INTRODUCTION
Conventionally, Wireless-controlled robots use RF circuits, which
have the drawbacks of limited working range, limited frequency
range and the limited control. Use of a mobile phone for robotic
control can overcome these limitations. It provides the advantage
of robust control, working range as large as the coverage area of
the service provider, no interference with other controllers and up
to twelve controllers.
Although the appearance and the capabilities of robots
vary vastly, all robots share the feature of a mechanical, movable
structure under some form of control. The Control of robot
involves three distinct phases: perception, processing and action.
Generally, the preceptors are sensors mounted on the robot,
processing is done by the on-board microcontroller or processor,
and the task is performed using motors or with some other
actuators.

5. 5
PROJECT OVERVIEW
In this project the robot, is controlled by a mobile phone that
makes call to the mobile phone attached to the robot in the course
of the call, if any button is pressed control corresponding to the
button pressed is heard at the other end of the call. This tone is
called dual tone multi frequency tome (DTMF) robot receives this
DTMF tone with the help of phone stacked in the robot. The
received tone is processed by the atmega16 microcontroller with
the help of DTMF decoder MT8870 the decoder decodes the
DTMF tone in to its equivalent binary digit and this binary number
is send to the microcontroller, the microcontroller is
preprogrammed to take a decision for any give input and outputs
its decision to motor drivers in order to drive the motors for
forward or backward motion or a turn.
The mobile that makes a call to the mobile phone stacked in the
robot acts as a remote. So this simple robotic project does not
require the construction of receiver and transmitter units.
DTMF signaling is used for telephone signaling over the line in the
voice - frequency band to the call switching center. The version of
DTMF used for telephone dialing is known as touch - tone.
DTMF assigns a specific frequency (consisting of two separate
tones) to each key s that it can easily be identified by the electronic
circuit. The signal generated by the DTMF encoder is the direct al-
gebric submission, in real time of the amplitudes of two sine
(cosine) waves of different frequencies, i.e., pressing 5 will send a
tone made by adding 1336 Hz and 770 Hz to the other end of the
mobile. The tones and assignments in a dtmf system shown below

6. 6
BLOCK DIAGRAM

7. 7
CIRCUIT DESCRIPTION
Figures show the block diagram and circuit diagram of the
microcontroller- based robot. The important components of this
robot are DTMF decoder, Microcontroller and motor driver.
An MT8870 series dtmf decoder is used here. All types of the
mt8870 series use digital counting techniques to detect and decode
all the sixteen DTMF tone pairs in to a four bit code output. The
built -in dial tone rejection circuit eliminated the need for pre-
filtering. When the input signal given at pin2 (IN-) single ended
input configuration is recognized to be effective, the correct four
bit decode signal of the DTMF tone is transferred to Q1 (pin11)
through Q4(pin14) outputs.
The atmega 16 is a low power, 8 bit; cmos microcontroller based
on the AVR enhanced RISC architecture. It provides the following
feature: 16kb of in system programmable flash memory with read
write capabilities, 512bytes of EEPROM, 1KB SRAM, 32 general
purpose input/output lines. 32 general purpose working registers.
All the 32 registers are directly connected to the arithmetic logic
unit, allowing two independent registers to be accessed in one
signal instruction executed in one clock cycle. The resulting
architecture is more code efficient. Outputs from port pins PD0
through PD3 and PD7 of the microcontroller are fed to inputs IN1
through IN4 and enable pins (EN1 and EN2) of motor driver
L293d respectively, to drive geared motors. Switch S1 is used for
manual reset.
The notations are:
 ic1 - MT8870 DTMF decoder
 ic2 – Atmega16 AVR microcontroller
 ic3 - L293D motor driver
 ic4 – 74LS04 NOT gate

8. 8
 r1,r2 - 100k resistances
 r3 - 330k resistances
 r4-r8 - 10k resistances
 c1- 0.47 micro farat capacitor
 c2,c3,c5,c6 - 22pfarat capacitor
 c4 - 0.1micro farat capacitor
 xtal1 - 3.57 mhz crytal
 xtal2 - 12mhz crystal
 s1 - push to on switch
 m1,m2 - 6v 50rpm motor
 batt- 6v
CIRCUIT DIAGRAM

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