A FINAL YEAR PROJECT

Submitted by:-

2010

MURSHIDABAD COLLEGE OF ENGINEERING & TECHNOLOGY

ZAID ZEESHAN 10603061030 MD. AKRAM KHAN 10603061033 RAHUL PRIYADARSHI 10603061044 SUMAN SAHA 10603061045 SOURAV SARKAR 0710601032003

UNDER THE GUIDENCE OF:-

Mr. Sandip Kundu

Department of Electronics and Communication Engineering,

M.C.E.T., Berhampore, W.B

ON

CELL PHONE CONTROLLED ROBOT

ACKNOWLEDGEMENT

We would like to express our heartiest gratitude to Mr. Sandip Kundu, Mr. Debasis Chakrabarty and Mr.

Himanshu Kumar Das for providing us with their proper guideline and supervision to perform our final year project. Then we would like to thank Mr. Subir Das, of AEIE department for assisting us during the

whole project.

We would like to thank the whole ECE Department of MCET for their continuous

cooperation and clarification of doubts while carrying out project

work.

Our special thanks goes to all the faculty members and college administration of MCET for

their assistance and encouragement.

INTRODUCTION:

Conventionally Wireless-controlled Robots use RF circuits, which have limited

working range, limited frequency range and 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 area of the service provider, no

interference with other controllers.

Although the appearance and capabilities of robot vary vastly, all robots share

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.

AN OVERVIEW:

In this project the robot, is controlled by a mobile phone that makes call to

the 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 end of the call. This is

called Dual Tone Multi Frequency (DTMF). The robot receives this DTMF tone

with the help of the phone stacked in the robot.

The received tone is processed by the microcontroller (89C51-16) with the help of

DTMF decoder (MT8870), which decodes the DTMF tone in to its equivalent binary

digit and this binary numbers are then send to the microcontroller. The

microcontroller is programmed to take a decision for any given input and outputs it

decisions to the 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 attached to the robot acts as a remote,

so this does not require any transmitter or receiver 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

called touch tone

DTMF assigns a specific frequency (consisting of two separate tones) to each

keys that it can easily be identified by the electronic circuit. The signal generated

by the DTMF encoder is the direct algebraic submission, in real time of the

amplitudes of two sine or cosine waves of different frequencies, that is pressing

5 will send a tone made by adding 1336 Hz and 770 Hz to the other end of the

mobile phone. The table below shows the corresponding frequencies of the

numbered buttons.

Frequencies corresponding to touch tone

CIRCUIT DESCRIPTION:

Figure below shows the block diagram of the circuit of this microcontroller

based robot. The important components of this robot are DTMF decoder,

Microcontroller and motor driver.

Circuit Flow Diagram

Numbered button

Tone send (as the sum)

1 1209 + 697

2 1336 + 697

3 1477 + 697

4 1209 + 770

5 1336 + 770

6 1477 + 770

7 1209 + 852

8 1336 + 852

9 1477 + 852

* 1209 + 941

0 1336 + 941

# 1477 + 941

6

8 9

0 #

4

7

*

770

697

852

941

An MT8870 series DTMF decoder is used in this circuit, which uses the digital

counting techniques to detect and decode all sixteen DTMF tone pairs into a four bit

code output. The built-in dial tone rejection circuit eliminates the need for pre-

filtering. When the input signal is 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 (pin1) through Q4 (pin14) outputs.

5

AT89C51

AT89C51 Description

The AT89C51 is a low-power, high-performance CMOS 8-bit microcomputer

with 8K bytes of Flash programmable and erasable read only memory (PEROM). The device is manufactured using Atmel‟s high-density nonvolatile memory technology and is

compatible with the industry-standard 80C51 and 80C52 instruction set and pin out. The on-chip Flash allows the program memory to be reprogrammed in-system

or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit

CPU with Flash on a monolithic chip, the Atmel AT89C51 is a powerful microcomputer which provides a highly-flexible and cost-effective solution to many embedded control applications.

FEATURES

• Compatible with MCS-51™ Products

• 8K Bytes of In-System Reprogrammable Flash Memory

• Endurance: 1,000 Write/Erase Cycles

• Fully Static Operation: 0 Hz to 24 MHz

• Three-level Program Memory Lock

• 256 x 8-bit Internal RAM

• 32 Programmable I/O Lines

• Three 16-bit Timer/Counters

• Eight Interrupt Sources

• Programmable Serial Channel

• Low-power Idle and Power-down Modes

INPUT DEVICE MICROCONTROLLER

(AT89C51)

MOTOR DRIVER

(L293D)

LEFT MOTOR

RIGHT MOTOR

Oscillator Characteristics

Programming the Flash

The AT89C51 is normally shipped with the on-chip Flash memory array in the

erased state (that is, contents = FFH) and ready to be programmed. The

programming interface accepts either a high-voltage (12-volt) or a low-voltage (VCC) program enable signal. The Low-voltage programming mode provides a convenient way to program the AT89C51 inside the user‟s system, while the high-

voltage programming mode is compatible with conventional third party Flash or EPROM programmers.

The AT89C51 is shipped with either the high-voltage or low-voltage programming mode enabled.

The AT89C51 code memory array is programmed byte-by-byte in either programming mode. To program any nonblank byte in the on-chip Flash Memory, the entire memory must be erased using the Chip Erase Mode.

XTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier that can be configured for use as an on-chip oscillator, as shown in

Figure 7. Either a quartz crystal or ceramic resonator may be used. To drive the device from an external clock source, XTAL2 should be left unconnected while XTAL1 is

driven, as shown.

There are no requirements on the duty cycle of the external clock signal, since the input to the internal clocking circuitry is through a divide-by-two flip-flop, but

minimum and maximum voltage high and low time specifications must be observed.

The notations are:

IC1: MT8870

IC2:- AT89C51

IC3:- L293D

IC4:- IC7805

RESISTANCES (R1 R2):- 100KΩ

RESISTANCE (R3):-330 KΩ

RESISTANCES (R4 – R8):- 10KΩ

CAPACITOR (C1):- 0.47 µF

CAPACITORS (C2,C3,C5,C6):- 22pF

CAPACITOR (C4):- 0.1µF

CRYSTAL (xtal1):-3.57Mhz

CRYSTAL (xtal2):- 12MHz

SWITCH (S1):- push to on switch

MOTORS (M1 M2):- 12V, 100 rpm

BATTERY:- 12V and

WHEELS :- 4

The circuit diagram is shown below with all necessary

connections:

THE HEX CODES:

Project_Final.asm

;CELL PHONE CONTRONLLED ROBOT

;P1.4-P1.7--->8051i/p---> Connected to DTMF o/p

;P0.0-P0.3--->8051o/p---> Connected to L293D

org 0000h

mov p1,#ffh ;Make P1 as i/p port

L1: mov a,p1

anl a,#0ffh

cjne a,#b0h,L2 ;DTMF o/p=2

mov p0,#08ah ; M1 & M2 both forward

ljmp L1

L2: cjne a,#e0h,L3 ;DTMF o/p=8

mov p0,#85h ;M1 & M2 both reverse

ljmp L1

L3: cjne a,#50h,L4 ;DTMF o/p=5

mov p0,#80h ;M1 & M2 both off

ljmp L1

L4: cjne a,#0d0h,L5 ;DTMF o/p=4

mov p0,#86h ;M1 --reverse, M2--forward

ljmp L1

L5: cjne a,#90h,L1 ;DTMF o/p=6

mov p0,#89h ;M1 --forward, M2--resverse

ljmp L1

end

THE WORKING:

In order to control the robot, you have to make a call to the phone attached

to the robot from any phone. Now the phone is picked up by the phone on the robot

through auto answer mode (which is in the phone already just we have to enable it).

Now after the circuit is ready and all hex codes are fetched we are ready to control

the robot.

No.

pressed

o/p of the DTMF

decoder

I/p to the

microcontroller

o/p of the

microcontroller

Action

performed

2 0x02 (00000010) 0xFD (11111101) 0x09 (00001001) Forward

4 0x04 (00000100) 0xFB (11111011) 0x05 (00000101) Turn left

6 0x06 (00000110) 0xF9 (11111001) 0x0A (00001010) Turn right

8 0x08 (00001000) 0xF7 (11110111) 0x06 (00000110) Reverse

5 0x05 (00000101) 0xFA (11111010) 0x00 (00000000) Brake

The figure below describes the working of the robot by cell phones with the

help of network center

Network

center

THE CONSTRUCTION:

The components listed below are used to construct this robot: the number they

are required in are written alongside them:

MT8870 DTMF decoder 1

AT89C51 microcontroller 1

L293D motor driver IC 1

IC7805 voltage converter 1

100KΩ Resistances 2

330 KΩ Resistances 1

10KΩ Resistances 5

0.47 µF Capacitor 1

22pF Capacitors 4

0.1µF Capacitor 1

3.57Mhz Crystal 1

12MHz Crystal 1

Push-to-on Switch 1

12V, 100 rpm Geared Motors 2

12V Battery 1

Wheels 4

Cell phones 2 and

Hands free 1

Connection of the hands free with the rover:

There are two connections coming out

of the phone mounted on the rover, these

are namely (1) the tip and (2) the ring. The

jack used here is the straight one similar to

that used for iPods, but thinner one.

The tip of the jack is called the “tip”

and the rest after a black strip is called the

“ring”. So connect these two connections

with the circuit and we are done

APPLICATION

The project is not only limited to simple functioning of the robot that is

to move forward, backward, right and left, but it can also be implemented with

camera to watch what is going out in particular location of the floor in a close circuit

monitor or /and with a voice recorder to even record the conversation going on in a

room. This definitely requires a difficult circuitry. Thus it is up to the maker what

he/she wants his/her robot to be like: SIMPLE (like ours) or

SOPHISTICATED…as described further.

1) Scientific

Remote control vehicles have various scientific uses including hazardous

environments, working in deep oceans, and space exploration. The majority of the

probes to the other planets in our solar system have been remote control vehicles,

although some of the more recent ones were partially autonomous. The

sophistication of these devices has fueled greater debate on the need for manned

spaceflight and exploration.

2) Military and Law Enforcement

Military usage of remotely controlled military vehicles dates back to the first half of

20th century. Soviet Red Army used remotely controlled Teletanks during 1930s in

the Winter War and early stage of World War II.

3) Search and Rescue

UAVs will likely play an increased role in search and rescue in the United States. This

was demonstrated by the successful use of UAVs during the 2008 hurricanes that

struck Louisiana and Texas.

Thus the required connection which is to be

made with the ear piece that is the connections with

the tip and the ring is to be taken care of, because it

is this which will make the circuit to work as desired.

If the wire is not connected properly the robot will not

function.

The ring of the hands free is shown with number 1

while the tip is with number 2.

4) Recreation and Hobby

See Radio-controlled model. Small scale remote control vehicles have long been

popular among hobbyists. These remote controlled vehicles span a wide range in

terms of price and sophistication. There are many types of radio controlled vehicles.

These include on-road cars, off-road trucks, boats, airplanes, and even helicopters.

The "robots" now popular in television shows such as Robot Wars, are a recent

extension of this hobby (these vehicles do not meet the classical definition of a

robot; they are remotely controlled by a human).

FURTHER IMROVEMENTS & FUTURE SCOPE

1. IR Sensors:

IR sensors can be used to automatically detect & avoid obstacles if the robot goes

beyond line of sight. This avoids damage to the vehicle if we are maneuvering it

from a distant place.

2. Password Protection:

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 should be password

protected or necessary modification should be made in the assembly language code.

This introduces conditioned access & increases security to a great extent.

3. Alarm Phone Dialer:

By replacing DTMF Decoder IC CM8870 by a 'DTMF Transceiver IC‟ CM8880, DTMF

tones can be generated from the robot. So, a project called 'Alarm Phone Dialer' can

be built which will generate necessary alarms for something that is desired to be

monitored (usually by triggering a relay). For example, a high water alarm, low

temperature alarm, opening of back window, garage door, etc.

When the system is activated it will call a number of programmed numbers to let the

user know the alarm has been activated. This would be great to get alerts of alarm

conditions from home when user is at work.

4. Adding a Camera:

If the current project is interfaced with a camera (e.g. a Webcam) robot can be

driven beyond line-of-sight & range becomes practically unlimited as GSM networks

have a very large range.

REFERENCES:

1. Wikipedia - The free encyclopedia

2. http://www.8051projects.info/

3. http://www.instructables.com/

4. Schenker, L (1960), "Pushbutton Calling with a Two-Group Voice-

Frequency Code", The Bell system technical journal 39 (1): 235–255, ISSN

0005-8580

5. “DTMF Tester” , „Electronics For You‟ Magazine , Edition (June 2003)

6. http://www.alldatasheet.com/

7. http://www.datasheet4u.com/

8. http://www.datasheetcatalog.com/