1.Introduction

1.INTRODUCTION

1 1. INTRODUCTION:

Cell phone operated robot is a machine that can be controlled with a mobile. In this project, the robot is controlled by a mobile phone that makes a call to the mobile phone attached to the robot. In the course of a call, if any button is pressed, a tone corresponding to the button pressed is heard at the other end of the call. This tone is called "Dual Tone Multiple- Frequency" (DTMF) tone. The robot perceives this DTMF tone with the help of the phone stacked on the robot. The received tone is processed by the microcontroller with the help of DTMF decoder. The microcontroller then transmits the signal to the motor driver ICs to operate the motors & our robot starts moving 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 controls. 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.

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

2 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.

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.

DTMF Mobile ROBO is a machine that can be controlled with a mobile . In this project, the robot is controlled by a mobile phone that makes a call to the mobile phone attached to the robot. In the course of a call, if any button is pressed, a tone corresponding to the button pressed is heard at the other end of the call. This tone is called "Dual Tone Multiple- Frequency" (DTMF) tone. The robot perceives this DTMF tone with the help of the phone stacked on the robot. The received tone is processed by the microcontroller with the help of DTMF decoder. The microcontroller then transmits the signal to the motor driver ICs to operate the motors & our robot starts moving.

Conventionally, wireless-controlled robots use RF circuits, which have the drawbacks of limited working range, limited frequency range and limited control. Use of a mobile phone for robotic control can overcome these limitations. It provides the advantages of robust control, working range as large as the coverage area of the service provider,no interference with other controllers and up to twelve controls.

3 2.

REVIEW

LITERATURE

4 2. REVIEW OF LITERATURE:

This Cellphone Operated Robot, built by Nikola Tesla in 1898, is the original prototype of all modern-day uninhabited aerial vehicles and precision guided weapons. In fact, it is among all remotely operated vehicles in air, land or sea. Powered by lead-acid batteries and an electric drive motor, the vessel was designed to be maneuvered alongside a target using instructions received from a wireless remote-control transmitter. Once in position, a command would be sent to detonate an explosive charge contained within the boat’s forward compartment. The weapon’s guidance system incorporated a secure communications link between the pilot’s controller and the surface-running torpedo in an effort to assure that control could be maintained even in the presence of electronic counter measures. During World War II in the European Theatre the U.S. Air Force with three basic forms radio-control guided weapons. In each case, the weapon would be directed to its target by a crew member on a control plane. The first weapon was essentially a standard bomb fitted with steering controls. The next evolution involved the fitting of a bomb to a glider airframe, one version, the GB-4 having a TV camera to assist the controller with targeting. The third class of guided weapon was the remote controlled B-17. It’s known that Germany deployed a number of more advanced guided strike weapons that saw combat before either the V-1 or V-2. They were the radio-controlled Herschel’s Hs293A and Ruhrstahl’s SD1400X, known as “FritzX,’ both air-launched, primarily against ships at sea. DTMF is the most common telecommunications signaling method used in Australia. DTMF stands for Dual Tone Multiple Frequency; it is used to send information through phone lines to and from local exchange. Dual Tone Multiple Frequency (DTMF) is also known as Touch-tone, Tone Dialing, VF Signaling and MF Dialing [7]. Each DTMF tone consists of two simultaneous tones (one from the high group and one from the low group), which are used to indicate which number or symbol that is press on the telephone's keypad. For example if number 5 is pressed in telephone's keypad, the tones that will hear are 1336 Hz and 770 Hz played simultaneously. Dual Tone Multiple Frequency is the basis of voice communications control. Modern telephone circuits use DTMF to dial numbers, configure telephone exchanges

5 (switchboards) from remote locations, program certain equipment and so on. Almost any mobile phone is capable of generating DTMF, providing a connection has already been established. This is for the use of phone banking; voicemail services and other DTMF controlled applications. DTMF was designed so that it is possible to use acoustic transfer. The DTMF tones can be sent from a standard speaker and be received using a standard microphone (providing it is connected to a decoding circuit of some type). DTMF tones are simply two frequencies played simultaneously by a standard home phone/fax or mobile phone. Each key on your telephone's keypad has a unique frequency assigned to it. When any key is pressed on your telephone's keypad the circuit plays the corresponding DTMF tone and sends it to your local exchange for processing. DTMF tones can be imitated by using a White Box or Tone Dialer. It is also possible to record DTMF tones using a tape recorder or computer microphone and then played into the mouthpiece of your telephone to dial numbers. However if there is a significant amount of background sound behind the recorded DTMF tones, the tones may not work properly and cause problems when trying to dial numbers. Below is a Dual Tone Multi Frequency (DTMF) map for a 4X4-matrix keypad, the map shows each unique frequency which is assigned to each key on a standard 4X4 telephone keypad. The frequencies are exactly the same for a 3X4 matrix keypad, without the keys A, B, C and D. However, this is not a standard keypad. This keypad has 4 more keys than a standard keypad (3X4-matrix). The keys A, B, C and D are not commonly used on standard home phone/fax, office phone or payphone. Each of the keys A, B, C and D are system tones/codes and are mainly used to configure telephone exchanges or to perform other special functions at an exchange. For example, the corresponding tone/code assigned to the A key is used on some networks to move through various carriers (this function is prohibited by most carriers). Filter is one of the very important devices of this DTMF technology. When DTMF was created individual and unique frequencies were chosen so that it would be quite easy to design frequency filters and so that the tones could easily pass through telephone lines (the maximum guaranteed bandwidth for a standard telephone line extends from around 300 Hz to 3.5 kHz). DTMF was not intended for data transfer; it was designed for control signals only. With a standard DTMF encoder/decoder, it is possible to signal at a rate of

6 around 10 tones/signals per second. A standard DTMF tone should always be played for at least 50ms with a further 50ms space duration for maximum reliability. The contemporary mobile keypad is laid out in a 3x4 grid, although the original DTMF keypad had an additional column for four menu selector keys. When used to dial a telephone number, pressing a single key will produce a pitch consisting of two simultaneous pure tone sinusoidal frequencies. The row in which the key appears determines the frequency, and the column determines the high frequency. For example, pressing the key will result in a sound composed of both 697 Hz and 1209 Hz tone [8, 15]. The original keypads had levers inside, so each button activated two contacts. The multiple tones are the reason for calling the system multi frequency. These tones are then decoded by the switching center to determine which key was pressed.

Fig 2.1 Dual Tone Multi Frequency (DTMF) map.

DTMF stands for dual tone multiple frequency. DTMF is a term which used in telephone industry. DTMF generation is a composite audio signals of two tones between the frequency of 697Hz and 1633Hz. The DTMF keypad is arranged such that each row will have its own unique tone frequency and also each column will have its own unique tone. Below is a representation of the typical DTMF keypad and the associated row/column frequencies. When any of the key like "1", "2", "*", "#" etc is pressed particular code is transmitted. This

7 code is consist of two frequency among which one is higher frequency and second one is lower frequency When any DTMF code has been received at mobile phone it can be audible through speaker. So to decode this DTMF code speaker output itself can be used. Output of speaker is connected to IC MT8870 which is DTMF decoder IC. It used widely to decode DTMF code. It gives 4-bit digital output q1, q2, q3, and q4 according to the received key. Following figure shows the equivalent digital output for each key. Our main aim is to connect mobile phone's speaker output to MT8870 so for achieving this we will use aux cable which has 3.5mm male audio jack at both its end as shown in below image. 3.5mm audio jack is a TRS connector which is Tip Ring Sleeve (ground) as shown in below image. Just connect your cell phone headset (headphone) jack to the mobile phone and then mobile control electrical appliances and electrical equipment via DTMF key pad of your cell phone. Go through following images to get clear understanding.

8 3. METHODOLOGY

9 3.1 BLOCK DIAGRAM

Fig 3.1.1. Block diagram

3.2 CIRCUIT DIAGRAM

10 Fig 3.2.2. Circuit diagram

3.2.1 SIMPLIFIED CIRCUIT DIAGRAM

11 Fig 3.2.1.3. - Simplified Circuit Diagram

3.3 ACTUAL VIEW

12 Fig 3.3.4. Actual View

3.4 COMPONENTS REQUIRED

13 S.NO. COMPONENTS QUANTITY 1 MT8870 DTMF Decoder 1 2 Atmega 16 Microcontroller 1 3 L293D motor driver IC 1 4 CD7004 not gate IC 1 5 1n4007 diode 1 6 100 k resistance 2 7 10 k resistance 5 8 330 k resistance 1 9 0.47 mf capacitors 1 10 0.1 mf capacitors 1 11 22 pf capacitors 4 12 3.57 mHz crystal 1 13 12 mHz crystal 1 14 Push to ON switch 1 15 2 Geared motors (6v,50rpm) 2 16 Battery 6v 1 17 Wheels 4 18 Cellphone 2 19 Handsfree (for the phone on the rover) 1

3.5 CIRCUIT DISCRIPTION

Fig. 3.1 shows the block diagram of the microcontroller-based mobile phoneoperated land rover. The important components of this rover are a 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 16 DTMF tone pairs into a 4-bit code output. The built-in dial tone rejection circuit eliminates the need for pre-filtering.When the input signal given at pin 2 (IN-) in single-ended input configuration is recognised to be

14 effective, the correct 4-bit decode signal of the DTMF tone is transferred to Q1 (pin 11) through Q4 (pin 14) outputs. Table II shows the DTMF data output table of MT8870. Q1 through Q4 outputs of the DTMF decoder (IC1) are connected to port pins PA0 through PA3 of ATmega16 microcontroller (IC2) after inversion by N1 through N4, respectively. The ATmega16 is a low-power, 8-bit, CMOS microcontroller based on the AVR enhanced RISC architecture. It provides the following features: 16 kB of in-system programmable Flash program memory with read-while-writecapabilities, 512 bytes of EEPROM, 1kB SRAM, 32 general-purpose input/output (I/O) lines and 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 single 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 two geared DC motors. Switch S1 is used for manual reset. The microcontroller output is not sufficient to drive the DC motors, so current drivers are required for motor rotation. The L293D is a quad, high- current, half-H driver designed to provide bidirectional drive currents of up to 600 mA at voltages from 4.5V to 36V. It makes it easier to drive the DC motors. The L293D consists of four drivers. Pins IN1 through IN4 and OUT1 through OUT4 are input and output pins, respectively, of driver 1 through driver 4. Drivers 1 and 2, and drivers 3 and 4 are enabled by enable pin 1 (EN1) and pin 9 (EN2), respectively. When enable input EN1 (pin 1) is high, drivers 1 and 2 are enabled and the outputs corresponding to their inputs are active. Similarly, enable input EN2 (pin 9) enables drivers 3 and 4. An actual-size, single-side PCB for cellphone-operated land rover is shown in Fig. 4 and its component layout in Fig. 5. Software description The software is written in ‘C’ language and compiled using CodeVision AVR ‘C’ compiler. The source program is converted into hex code by the compiler. Burn this hex code into ATmega16 AVR microcontroller. The source program is well commented and easy to understand. First include the register name defined specifically for ATmega16 and also declare the variable. Set port A as the input and port D as the output. The program will run forever by using ‘while’ loop. Under ‘while’ loop, read port A and test the received input using ‘switch’ statement. The corresponding data will output at port D after testing of the received data.

15 The microcontroller output is not sufficient to drive the dc motors, so current drivers are required for motor rotation. The L293D is a quad, high-current, half-h driver designed to provide bidirectional drive currents of upto600mA at voltages from 4.5V to 36V. It makes it easier to drive the dc motors. The L293D consists of four drivers. pins IN1 through IN4 and OUT1 through OUT4 are the input and output pins, respectively, of driver 1 through driver 4. Drivers 1 and 2, and driver 3 and 4 are enabled by enable pin 1(EN1) and pin 9 (EN2),respectively. when enable input EN1(pin1) is high, drivers 1 and 2 are enabled and the outputs corresponding to their inputs are active. similarly, enable input EN2(pin9) enables drivers 3 and 4. The received tone is processed by the ATmega16 microcontroller with the help of DTMF decoder MT8870. The decoder decodes the DTMF tone into its equivalent binary digit and this binary number is sent to the microcontroller. The microcontroller is preprogrammed to take a decision for any given 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 centre. The version of DTMF used for telephone tone dialing is known as ‘Touch- Tone.’ DTMF assigns a specific frequency (consisting of two separate tones) to each key so that it can easily be identified by the electronic circuit. The signal generated by the DTMF encoder is a direct algebraic summation, 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 line.

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

16 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 algeabric 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 1336hz and 770hz to the other end of the mobile. 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 ic2 - atmega16 ic3 - l293d ic4 - cd7004 r1,r2 - 100k ohm r3 - 330k ohm r4-r8 - 10k ohm

17 c1 - 0.47 microfarad c2,c3,c5,c6 - 22 picofarad c4 - 0.1 microfarad xtal1 - 3.57 mhz xtal2 - 12 mhz s1 - push to on switch m1,m2 - 6v 50 rpm battery - 6v

3.6 COMPONENT DISCRIPTION

3.6.1 L293D IC

L293D is a dual H-bridge motor driver integrated circuit (IC). Motor drivers act as current amplifiers since they take a low-current control signal and provide a higher-current signal. This higher current signal is used to drive the motors.

L293D contains two inbuilt H-bridge driver circuits. In its common mode of operation, two DC motors can be driven simultaneously, both in forward and reverse direction. The motor operations of two motors can be controlled by input logic at pins 2 & 7 and 10 & 15. Input

18 logic 00 or 11 will stop the corresponding motor. Logic 01 and 10 will rotate it in clockwise and anticlockwise directions, respectively.

Enable pins 1 and 9 (corresponding to the two motors) must be high for motors to start operating. When an enable input is high, the associated driver gets enabled. As a result, the outputs become active and work in phase with their inputs. Similarly, when the enable input is low, that driver is disabled, and their outputs are off and in the high-impedance state.

19 Fig.3.6.1.5. L293D IC

3.6.2 CRYSTAL OSCILLATOR :

A crystal oscillator is an electronic oscillator circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a very precise

20 frequency. This frequency is commonly used to keep track of time (as in quartz wristwatches), to provide a stable clock signal for digital integrated circuits, and to stabilize frequencies for radio transmitters and receivers. The most common type of piezoelectric resonator used is the quartz crystal, so oscillator circuits incorporating them became known as crystal oscillators, but other piezoelectric materials including polycrystalline ceramics are used in similar circuits.

Quartz crystals are manufactured for frequencies from a few tens of kilohertz to hundreds of megahertz. More than two billion crystals are manufactured annually. Most are used for consumer devices such as wristwatches, clocks, radios, computers, and cell phones. Quartz crystals are also found inside test and measurement equipment, such as counters, signal generators, and oscilloscopes.

Fig.3.6.2.6 Crystal Oscillator

3.6.3 MICRO CONTROLLER :

21 A microcontroller is a single chip that contains the processor (the CPU), non-volatile memory for the program (ROM or flash), volatile memory for input and output (RAM), a clock and an I/O control unit. Also called a "computer on a chip," billions of microcontroller units (MCUs) are embedded each year in a myriad of products from toys to appliances to automobiles. For example, a single vehicle can use 70 or more microcontrollers. The following picture describes a general block diagram of microcontroller.

Fig 3.6.3.7. Microcontroller

3.6.3.1 MICROCONTROLLER (ATMEGA16) :

22 ATmega16is an 8-bit high performance microcontroller of Atmel’s Mega AVR family with low power consumption. Atmega16 is based on enhanced RISC(Reduced Instruction Set Computing, Know more about RISC and CISC Architecture) architecture with 131 powerful instructions. Most of the instructions execute in one machine cycle. Atmega16 can work on amaximum frequency of 16MHz.ATmega16 has 16 KB programmable flash memory, static RAM of 1 KB and EEPROM of 512 Bytes. The endurance cycle of flash memory and EEPROM is 10,000 and 100,000; respectively. There are 32 I/O (input/output) lines which are divided into four 8-bit ports designated as PORTA, PORTB, PORTC and PORTD. ATmega16 has various in-built peripherals like USART, ADC, Analog Comparator, SPI, JTAG etc. Each I/O pin has an alternative task related to inbuilt peripherals. 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 AT89C52 is a powerful microcomputer which provides a highly-flexible and cost-effective solution to many embedded control applications.

TRANSFERS: If the Microcontroller sets the TX Request line low a data transfer from the void packet_init(void) {UCSR0B |= _BV(RXCIE0) | _BV(RXEN0) | _BV(TXEN0); UCSR0C |= _BV(UCSZ01) | _BV(UCSZ00); UBRR0L = 51; UBRR0H = 0; UDR0 = 'S'; }

Microcontroller to the FRPC2 will be initiated. Similarly the FRPC2 will pull RX Request low when it requires transferring data to the Microcontroller. The transfer protocol is fully asynchronous, i.e. the Microcontroller may service another interrupt and then continue with the FRPC2 transfer. It is desirable that all transfers are completed quickly since the radio transceiver is disabled until either the Microcontroller to the FRPC2 or the FRPC2 to the Microcontroller transfer is completed. Typically a Microcontroller can transfer a 60 byte packet to / from the FRPC2 in under 1ms. 3.5.3 TRANSMIT When a data packet is received from the Microcontroller, the packet - preamble, frame sync byte and an error check sum are appended by the FRPC2’s internal function. For mark such as space balance, the packet is then coded and transmitted. In 6ms of

23 TX air time (60 byte data @ 160kb/s + 1.25ms preamble), a full 60 byte packet can be transmitted Collision avoidance (Listen before transmit) functions can be enabled to prevent loss of packets. Data packets may be sent with either normal or extended preamble. Extended preamble is used if the remote FRPC2 is in power save mode. Extended preamble length can be changed in the EEPROM memory.

RECEIVE: On detection of preamble from the radio receiver, the FRPC2 will phase lock, decode and error check the incoming synchronous data stream. If it is successful, the data is then placed in a buffer and the RX Request line is pulled low to signal to the Microcontroller that a valid packet waits to be uploaded to the Microcontroller.

3.6.4 MT8870 DTMF DECODER :

24 The MT8870 is a complete DTMF receiver integrating both the band split filter and digital decoder functions. The filter section uses switched capacitor techniques for high and low group filters; the decoder uses digital counting techniques to detect and decode all 16 DTMF tone-pairs into a 4-bit code. External component count is minimized by on chip provision of a differential input amplifier, clock oscillator and latched three-state bus interface.

This circuit detects the dial tone from a telephone line and decodes the keypad pressed on the remote telephone. The dial tone we heard when we pick up the phone set is call Dual Tone Multi-Frequency, DTMF in short. The name was given because the tone that we heard over the phone is actually make up of two distinct frequency tone, hence the name dual tone. The DTMF tone is a form of one way communication between the dialer and the telephone exchange. A complete communication consist of the tone generator and the tone decoder. In this article, we are use the IC MT8870DE, the main component to decode the input dial tone to 5 digital output. These digital bits can be interface to a computer or microcontroller for further application eg. remote control, phone line transfer operation, LEDs, etc.

25 Fig 3.6.4.8. DTMF decoder

3.6.5 DC MOTOR :

26 A DC motor is a class of electrical machines that converts direct current electrical power into mechanical power. The most common types rely on the forces produced by magnetic fields. Nearly all types of DC motors have some internal mechanism, either electromechanical or electronic, to periodically change the direction of current flow in part of the motor. Most types produce rotary motion; a linear motor directly produces force and motion in a straight line. DC motors were the first type widely used, since they could be powered from existing direct-current lighting power distribution systems. A DC motor's speed can be controlled over a wide range, using either a variable supply voltage or by changing the strength of current in its field windings. Small DC motors are used in tools, toys, and appliances. The universal motor can operate on direct current but is a lightweight motor used for portable power tools and appliances. Larger DC motors are used in propulsion of electric vehicles, elevator and hoists, or in drives for steel rolling mills. The advent of power electronics has made replacement of DC motors with AC motors possible in many applications. A coil of wire with a current running through it generates an electromagnetic field aligned with the center of the coil. The direction and magnitude of the magnetic field produced by the coil can be changed with the direction and magnitude of the current flowing through it.

Fig.3.6.5.9 DC Motor

A simple DC motor has a stationary set of magnets in the stator and an armature with one more windings of insulated wire wrapped around a soft iron core that concentrates the magnetic field. The windings usually have multiple turns around the core, and in large

27 motors there can be several parallel current paths. The ends of the wire winding are connected to a commutator. The commutator allows each armature coil to be energized in turn and connects the rotating coils with the external power supply through brushes. (Brushless DC motors have electronics that switch the DC current to each coil on and off and have no brushes.)The total amount of current sent to the coil, the coil's size and what it's wrapped around dictate the strength of the electromagnetic field created. The sequence of turning a particular coil on or off dictates what direction the effective electromagnetic fields are pointed. By turning on and off coils in sequence a rotating magnetic field can be created. These rotating magnetic fields interact with the magnetic fields of the magnets (permanent or electromagnets) in the stationary part of the motor (stator) to create a force on the armature which causes it to rotate. In some DC motor designs the stator fields use electromagnets to create their magnetic fields which allow greater control over the motor. At high power levels, DC motors are almost always cooled using forced air. Different number of stator and armature fields as well as how they are connected provides different inherent speed/torque regulation characteristics. The speed of a DC motor can be controlled by changing the voltage applied to the armature. The introduction of variable resistance in the armature circuit or field circuit allowed speed control. Modern DC motors are often controlled by power electronics systems which adjust the voltage by "chopping" the DC current into on and off cycles which have an effective lower voltage. Since the series-wound DC motor develops its highest torque at low speed, it is often used in traction applications such as electric locomotives, and trams. The DC motor was the mainstay of electric traction drives on both electric and diesel- electric locomotives, street-cars/trams and diesel electric drilling rigs for many years. The introduction of DC motors and an electrical grid system to run machinery starting in the 1870s started a new second Industrial Revolution. DC motors can operate directly from rechargeable batteries, providing the motive power for the first electric vehicles and today's hybrid cars and electric cars as well as driving a host of cordless tools. Today DC motors are still found in applications as small as toys and disk drives, or in large sizes to operate steel rolling mills and paper machines. Large DC motors with separately excited fields were generally used with winder drives for mine hoists, for high torque as well as

28 smooth speed control using thyristor drives. These are now replaced with large AC motors with variable frequency drives. If external power is applied to a DC motor it acts as a DC generator, a dynamo. This feature is used to slow down and recharge batteries on hybrid car and electric cars or to return electricity back to the electric grid used on a street car or electric powered train line when they slow down. This process is called regenerative braking on hybrid and electric cars. In diesel electric locomotives they also use their DC motors as generators to slow down but dissipate the energy in resistor stacks. Newer designs are adding large battery packs to recapture some of this energy.

3.6.6 RESISTORS :

29 A resistor is a two-terminal electronic component that produces a voltage across its terminals that is proportional to the electric current through it in accordance with Ohm's law: V=IR .The unit of is resistor ohm (symbol: Ω) commonly used multiples and submultiples in electrical and electronic usage are the milliohm (1x10-3), kilohm (1x103), and megohm (1x106).

Fig .3.6.6.10 Resistor

A resistor implements electrical resistance as a circuit element. Resistors act to reduce current flow, and, at the same time, act to lower voltage levels within circuits. In electronic circuits resistors are used to limit current flow, to adjust signal levels, bias active elements, terminate transmission lines among other uses.

High-power resistors that can dissipate many watts of electrical power as heat may be used as part of motor controls, in power distribution systems, or as test loads for generators. Resistors may have fixed resistances that only change a little with temperature, time or operating voltage. Variable resistors can be used to adjust circuit elements (such as a volume control or a lamp dimmer), or as sensing devices for heat, light, humidity, force, or chemical activity.

30 Resistors are common elements of electrical networks and electronic circuits and are ubiquitous in electronic equipment. Practical resistors as discrete components can be composed of various compounds and forms. Resistors are also implemented within integrated circuits. Resistors act to reduce current flow, and, at the same time, act to lower voltage levels within circuits. In electronic circuits resistors are used to limit current flow, to adjust signal levels, bias active elements, terminate transmission lines among other uses. Resistors are also implemented within integrated circuits. The value of a resistor can be measured with an ohmmeter, which may be one function of a multimeter.

Practical resistors have a series inductance and a small parallel capacitance; these specifications can be important in high-frequency applications. In a low-noise amplifier or pre-amp, the noise characteristics of a resistor may be an issue. The temperature coefficient of the resistance may also be of concern in some precision applications.

The unwanted inductance, excess noise, and temperature coefficient are mainly dependent on the technology used in manufacturing the resistor. They are not normally specified individually for a particular family of resistors manufactured using a particular technology. A family of discrete resistors is also characterized according to its form factor, that is, the size of the device and the position of its leads which is relevant in the practical manufacturing of circuits using them.

Practical resistors are also specified as having a maximum power rating which must exceed the anticipated power dissipation of that resistor in a particular circuit: this is mainly of concern in power electronics applications. Resistors with higher power ratings are physically larger and may require heat sinks. In a high-voltage circuit, attention must sometimes be paid to the rated maximum working voltage of the resistor. While there is no minimum working voltage for a given resistor, failure to account for a resistor's maximum rating may cause the resistor to incinerate when current is run through it.

Most axial resistors use a pattern of colored stripes to indicate resistance, which also indicate tolerance, and may also be extended to show temperature coefficient and reliability class. Cases are usually tan, brown, blue, or green, though other colors are

31 occasionally found such as dark red or dark gray. The power rating is not usually marked and is deduced from the size. The failure rate of resistors in a properly designed circuit is low compared to other electronic components such as semiconductors and electrolytic capacitors. Damage to resistors most often occurs due to overheating when the average power delivered to it greatly exceeds its ability to dissipate heat specified by the resistor's power rating. This may be due to a fault external to the circuit, but is frequently caused by the failure of another component in the circuit connected to the resistor.

32 3.6.7 CAPACITORS :

Capacitor is passive electronic component consisting of a pair of conductors separated by a dielectric. When a voltage potential difference exists between the conductors, an electric field is present in the dielectric. This field stores energy and produces a mechanical force between the plates. An ideal capacitor is characterized by a single constant value, capacitance, which is measured in farads. The capacitance is greatest when there is a narrow separation between large areas of conductor, hence capacitor conductors are often called plates, referring to an early means of construction. When there is a potential difference (voltage) across the conductors, a static electric field develops across the dielectric, causing positive charge to collect on one plate and negative charge on the other plate. Energy is stored in the electrostatic field. An ideal capacitor is characterized by a single constant value, capacitance, measured in farads. This is the ratio of the electric charge on each conductor to the potential difference between them.

Capacitors are widely used in electronic circuits for blocking direct current while allowing alternating current to pass, in filter networks, for smoothing the output of power supplies, in the resonant circuits that tune radios to particular frequencies, in electric power transmission systems for stabilizing voltage and power flow, and for many other purposes.

An ideal capacitor is characterized by a single constant value for its capacitance. Capacitance is expressed as the ratio of the electric charge Q on each conductor to the potential difference V between them. The SI unit of capacitance is the farad (F), which is equal to one coulomb per volt (1 C/V). Typical capacitance values range from about 1 pF

(10−12 F) to about 1 mF (10−3 F).

33 Fig.3.6.7.11 Capacitor

The capacitance is greater when there is a narrower separation between conductors and when the conductors have a larger surface area. In practice, the dielectric between the plates passes a small amount of leakage current and also has an electric field strength limit, known as the breakdown voltage. The conductors and leads introduce an undesired inductance and resistance.

Capacitors are widely used in electronic circuits for blocking direct current while allowing alternating current to pass. In analog filter networks, they smooth the output of power supplies. In electric power transmission systems, they stabilize voltage and power flow. The capacitance of certain capacitors decreases as the component ages. In ceramic capacitors, this is caused by degradation of the dielectric. The type of dielectric, ambient operating and storage temperatures are the most significant aging factors, while the operating voltage has a smaller effect. The aging process may be reversed by heating the component above the Curie point. Aging is fastest near the beginning of life of the component, and the device stabilizes over time. Electrolytic capacitors age as the electrolyte evaporates.

34 In contrast with ceramic capacitors, this occurs towards the end of life of the component. Temperature dependence of capacitance is usually expressed in parts per million per °C. It can usually be taken as a broadly linear function but can be noticeably non-linear at the temperature extremes.

The temperature coefficient can be positive or negative, sometimes even amongst different samples of the same type. In other words, the spread in the range of temperature coefficients can encompass zero. Capacitors, especially ceramic capacitors, and older designs such as paper capacitors, can absorb sound waves resulting in a microphonic effect. Vibration moves the plates, causing the capacitance to vary, in turn inducing AC current.

Some dielectrics also generate piezoelectricity. The resulting interference is especially problematic in audio applications, potentially causing feedback or unintended recording. In the reverse microphonic effect, the varying electric field between the capacitor plates exerts a physical force, moving them as a speaker. This can generate audible sound, but drains energy and stresses the dielectric and the electrolyte, if any.

35 3.6.8 LIGHT EMITTING DIODE :

A light-emitting diode (LED) is a semiconductor diode that emits light when an electrical current is applied in the forward direction of the device. LEDs are widely used as indicator lights on electronic devices and increasingly in higher power applications such as flashlights and area lighting LEDs present many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved robustness, smaller size, faster switching, and greater durability and reliance.

However, they are relatively expensive and require more precise current and heat management than traditional light sources. LEDs are available in red, orange, amber, yellow, green, and blue and white. Blue and white LEDs are much more expensive than the other colors. The color of an LED is determined by the semiconductor material, not by the coloring of the 'package'. LEDs are available in a wide variety of sizes and shapes. An LED must have a resistor connected in series to limit the current through the LED otherwise it will burn out almost instantly. Nonetheless these diodes are very useful as light emitters in visual display units and in optically coupled circuits. They are used in arrays of different types for displaying alphanumeric (letters and numbers) or supplying input power to lasers or for entering information into optical computer memories and for numeral displays in hand-held or pocket calculators.

Fig.3.6.8.12 Light Emitting Diode

36 A light-emitting diode (LED) is a two-lead semiconductor light source. It is a basic pn- junction diode, which emits light when activated. When a fitting voltage is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence, and the color of the light (corresponding to the energy of the photon) is determined by the energy band gap of the semiconductor. An LED is often small in area (less than 1 mm2) and integrated optical components may be used to shape its radiation pattern.

37 3.6.9 DIODE : In electronics, a diode is a two-terminal electronic component that conducts electric current in only one direction. The term usually refers to a semiconductor diode, the most common type today. This is a crystalline piece of semiconductor material connected to two electrical terminals. A vacuum tube diode is a vacuum tube with two electrodes: a plate and a cathode. The most common function of a diode is to allow an electric current to pass in one direction (called the diode's forward direction) while blocking current in the opposite direction (the reverse direction). Thus, the diode can be thought of as an electronic version of a check valve. This unidirectional behavior is called rectification, and is used to convert alternating current to direct current, and to extract modulation from radio signals in radio receivers.

Fig.3.6.9.13 Diode Reversed Biased

38 3.6.10 VOLTAGE REGULATOR :

A voltage regulator is designed to automatically maintain a constant voltage level. A voltage regulator may be a simple "feed-forward" design or may include negative feedback control loops. It may use an electromechanical mechanism, or electronic components. Depending on the design, it may be used to regulate one or more AC or DC voltages.

The Digital board can use any power supply that creates a DC voltage between 6 and 12 volts. A 5V voltage regulator (7805) is used to ensure that no more than 5V is delivered to the Digital board regardless of the voltage present at the J12 connector (provided that voltage is less than 12VDC).

Fig. 3.6.10.14 Voltage Regulator

Electronic voltage regulators are found in devices such as computer power supplies where they stabilize the DC voltages used by the processor and other elements. In automobile alternators and central power station generator plants, voltage regulators control the output of the plant. In an electric power distribution system, voltage regulators may be installed at a substation or along distribution lines so that all

39 customers receive steady voltage independent of how much power is drawn from the line. The regulator functions by using a diode to clamp the output voltage at 5VDC regardless of the input voltage - excess voltage is converted to heat and dissipated through the body of the regulator. If a DC supply of greater than 12V is used, excessive heat will be generated, and the board may be damaged. If a DC supply of less than 5V is used, insufficient voltage will be present at the regulator output. It is mainly used in the circuit to maintain the exact voltage which is followed by the power supply. A simple voltage regulator can be made from a resistor in series with a diode. Due to the logarithmic shape of diode V-I curves, the voltage across the diode changes only slightly due to changes in current drawn or changes in the input. When precise voltage control and efficiency are not important, this design may work fine.

Feedback voltage regulators operate by comparing the actual output voltage to some fixed reference voltage. Any difference is amplified and used to control the regulation element in such a way as to reduce the voltage error. This forms a negative feedback control loop; increasing the open-loop gain tends to increase regulation accuracy but reduce stability. There will also be a trade-off between stability and the speed of the response to changes. If the output voltage is too low (perhaps due to input voltage reducing or load current increasing), the regulation element is commanded, up to a point, to produce a higher output voltage–by dropping less of the input voltage (for linear series regulators and buck switching regulators), or to draw input current for longer periods (boost-type switching regulators); if the output voltage is too high, the regulation element will normally be commanded to produce a lower voltage.

However, many regulators have over-current protection, so that they will entirely stop sourcing current if the output current is too high, and some regulators may also shut down if the input voltage is outside a given range. Voltage regulators or stabilizers are used to compensate for voltage fluctuations in mains power. Large regulators may be permanently installed on distribution lines. Small portable regulators may be plugged in between sensitive equipment and a wall outlet.

Automatic voltage regulators are used on generator sets on ships, in emergency power supplies, on oil rigs, etc. to stabilize fluctuations in power demand. For example, when a

40 large machine is turned on, the demand for power is suddenly a lot higher. The voltage regulator compensates for the change in load. Commercial voltage regulators normally operate on a range of voltages, for example 150–240 V or 90–280 V. Servo stabilizers are also manufactured and used widely in spite of the fact that they are obsolete and use out- dated technology.

Voltage regulators are used in devices like air conditioners, refrigerators, televisions etc. in order to protect them from fluctuating input voltage. The major problem faced is the use of relays in voltage regulators. Relays create sparks which result in faults in the product.

41 3.7 P.C.B. LAYOUT AND DESIGNING:

The entire circuit can be easily assembled on a general purpose P.C.B. board respectively.

Layout of desired diagram and preparation is first and most important operation in any printed circuit board manufacturing process. First of all layout of component side is to be made in accordance with available components dimensions.

The following points are to be observed while forming the layout of P.C.B.

1. Between two components, sufficient space should be maintained. 2. High voltage/max dissipated components should be mounted at sufficient distance from semiconductor and electrolytic capacitors. 3. The most important points are that the components layout is making proper compromise with copper side circuit layout. Printed circuit board (P.C.B.s) is used to avoid most of all the disadvantages of conventional breadboard. These also avoid the use of thin wires for connecting the components; they are small in size and efficient in performance.

3.7.1 Preparing Circuit Layout :

First of all the actual size circuit layout is to be drawn on the copper side of the copper clad board. Then enamel paint is applied on the tracks of connection with the help of a shade brush. We have to apply the paints surrounding the point at which the connection is to be made. It avoids the disconnection between the leg of the component and circuit track. After completion of painting work, it is allowed to dry.

42 3.7.2 Etching :

The removal of excess of copper on the plate apart from the printed circuit is known as etching. From this process the copper clad board with printed circuit is placed in the solution of FeCl with 3-4 drops of HCL in it and is kept so for about 10 to 15 minutes and is taken out when all the excess copper is removed from the P.C.B.

After etching, the P.C.B. is kept in clean water for about half an hour in order to get P.C.B. away from acidic, field, which may cause poor performance of the circuit. After the P.C.B. has been thoroughly washed, paint is removed by soft piece of cloth dipped I thinner or turbine. Then P.C.B. is checked as per the layout, now the P.C.B. is ready for use.

3.7.3 Drilling :

After completion of painting work, holes 1/23inch (1mm) diameter are drilled at desired points where we have to fix the components.

3.7.4 Soldering :

Soldering is the process of joining two metallic conductor the joint where two metal conductors are to be join or fused is heated with a device called soldering iron and then as allow of tin and lead called solder is applied which melts and converse the joint. The solder cools and solidifies quickly to ensure is good and durable connection between the jointed metal converting the joint solder also present oxidation.

3.7.5 Soldering Techniques :

These are basically two soldering techniques.

1. Manual soldering with iron. 2. Mass soldering.

43 3.7.6 Soldering with iron :

The surface to be soldered must be cleaned & fluxed. The soldering iron switched on and bellowed to attain soldering temperature. The solder in form of wire is allied hear the component to be soldered and heated with iron. The surface to be soldered is filled, iron is removed and joint is cold without disturbing.

3.7.7 Solder Joint are supposed to :

1. Provide permanent low resistance path. 2. Make a robust mechanical link between P.C.B. and leads of components. 3. Allow heat flow between component, joining elements and P.C.B. 4. Retain adequate strength with temperature variation.

The following precaution should be taken while soldering:

1. Use always an iron plated copper core tip for soldering iron. 2. Slightly for the tip with a cut file when it is cold. 3. Use a wet sponge to wipe out dirt from the tip before soldering instead of asking the iron. 4. Tighten the tip screw if necessary before iron is connected to power supply. 5. Clean component lead and copper pad before soldering. 6. Apply solder between component leads, P.C.B. pattern and tip of soldering iron. 7. Iron should be kept in contact with the joint for 2-3 seconds only instead of keeping for very long or very small time. 8. Use optimum quantity of solder

44 3.8 WORKING:

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 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 algeabric 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 1336hz and 770hz to the other end of the mobile. In order to control the robot, you need to make a call to the cell phone attached to the robot (through head phone) from any phone, which sends DTMF tunes on pressing the numeric buttons. The cell phone in the robot is kept in ‘auto answer’ mode. (If the mobile does not have the auto answering facility, receive the call by ‘OK’ key on the rover-connected mobile and then made it in hands-free mode.) So after a ring, the cellphone accepts the call. Now you may press any button on your mobile to perform actions as listed in Table III. The DTMF tones thus produced are received by the cellphone in the robot. These tones are fed to the circuit by the headset of the cellphone. The MT8870 decodes the received tone and sends the equivalent binary number to the microcontrollerThe cell phone in the

45 robot is kept in 'auto answer' mode.( if the mobile does not have the auto answering facility ,receive the call by 'OK' key on the rover connected mobile and then made it in hands-free mode.) so after a ring, the cellphone accepts the call. Now you may press any button on your mobile to perform actions as listed in the table . The DTMF tones thus produced are received by the cellphone in the robot. These tones are fed to the circuit by headset of the cellphone. The MT8870 decodes the received tone and sends the equivalent binary number to the microcontroller. According to the program in the microcontroller, the robot starts moving. When you press key '2' (binary equivalent 00000010) on your mobile phone, the microcontroller outputs '10001001'binary equivalent. port pins PD0, PD3 and PD7 are high. The high output at PD7 of the microcontroller drives the motor driver (L293D). port pins PD0 and PD3 drive motors M1 and M2 in forward direction( as per table ).Similarly, motors M1 and M2 move for left turn, right turn, backward motion and stop condition as per table is provided below:

Fig3.8.1 DTMF Action

46 4.

RESULT

AND

DISCUSSION

47 4.1 RESULT:

The project we have undertaken has helped us gain a better perspective on various aspects related to our course of study as well as practical knowledge of electronic equipment’s and communication. We became familiar with software analysis, designing, implementation, testing and maintenance concerned with our project. The extensive capabilities of this system are what make it so interesting. From the convenience of a simple cell phone, a user is able to control and monitor virtually any electrical devices. This makes it possible for users to rest assured that their belongings are secure and that the television and other electrical appliances was not left running when they left the house to just list a few of the many uses of this system. The end product will have a simplistic design making it easy for users to interact with. This will be essential because of the wide range of technical knowledge that homeowners have. GSM Based Control System.

When constructing any robot, one major mechanical constraint is the number An actual-size, single-side PCB layout for cellphone operated land rover Fig. 5: Component layout of motors being used. You can have either a two-wheel drive or a four- wheel drive. Though four-wheel drive is more complex than two-wheel drive, it provides more torque and good control. Two-wheel drive, on the other hand, is very easy to construct. Top view of a four-wheel-driven land rover is shown in Fig. 3. The chassis used in this model is a 10×18cm2 sheet made up of parax. Motors are fixed to the bottom of this sheet and the circuit is affixed firmly on top of the sheet. A cellphone is also mounted on the sheet as shown in the picture. In the four-wheel drive system, the two motors on a side are controlled in parallel. So a single L293D driver IC can drive the rover. For this robot, beads affixed with glue act as support wheels. In the process of realizing this project, the construction was initially carried out on a breadboard to allow for checking and to ascertain that it is functioning effectively. All irregularities were checked then tested and found to have a satisfactory output. The component were then removed and transferred to a Vero board strip and soldered into place and all discontinuous point were cut out to avoid short-circuiting.

48 4.2 DISCUSSION

When constructing any robot, one major mechanical constraint is the number an actual-size, single-side PCB layout for cellphone-operated land rover. Component layout of motors being used. You can have either a two-wheel drive or a four-wheel drive. Though four-wheel drive is more complex than two-wheel drive, it provides more torque and good control. Two-wheel drive, on the other hand, is very easy to construct. Top view of a four-wheel-driven land rover

4.2.1 Testing of Project :

With the knowledge of operation of the system was tested step by step to the transistor output and the load was connected across the collector terminal of the transistor.

4.2.2 Precautions :

4.2.2.1 Soldering Precautions :

The construction was carried out with care. The precautions taken during the soldering were:

1. The tip of soldering iron was kept clean with the help of a file from time to time. 2. The solder wire was of smaller thickness. 3. Extra solder was not used in order to avoid a cause of short circuit in the conductive path. 4. The overheating of components was avoided to prevent component damage as a result of excessive heat on the components due to the heat from the soldering iron. 5. The leads of the components were kept clean before soldering, with the use of sand paper.

49 4.2.2.2 Components Precaution :

IR sensor used should be sensitive. Before using in the circuit it should be tested with a multi-meter.

1. I.C should not be heated much while soldering; too much heat can destroy the I.C. For safety and ease of replacement, the use of I.C socket is suggested. 2. While placing the I.C pin no 1 should be made sure at right hole. 3. Opposite polarity of battery can destroy I.C so please check the polarity before switching ON the circuit. One should use diode in series with switch for safety since diode allows flowing current in one direction only. 4. Each component was soldered neatly and clean. 5. We should use insulated wires.

50 4.2.3. ADVANTAGES:

1. Cellphone-operated-robotic landrover includes.

2. Wireless controlling provisioning and surveillance system.

3. 3G-technology-based vehicle navigation.

4. Limitless operational range based on the network of the cellphone.

51 4.2.4 DISADVANTAGES:

1. The cost as the cellphone billing is high.

2. Mobile batteries discharge : the discharging problem associated with the batteries as the batteries loss charge due to quick discharge because the load is high.

3. Adaptability: the system is not adaptable to all cellphones, but the ones with the headset attached can only be used.

52 4.2.5 APPLICATIONS:

1. Remote control 2. Home appliance control 3. Stepper motor control 4. DC motor control 5. This Cellphone-operated robot project is very useful in military applications to control military vehicles by using a mobile phone.

5. CONCLUSION

53 AND FUTURE SCOPE

5.1 CONCLUSION:

54 5.2 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 dialler' 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.

55 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.This land rover can be further improved to serve specific purposes.It requires four controls to roam around. The remaining eight controls can be configured to serve other purposes,with some modifications in the source program.

REFERENCES

1. “The 8051 Microcontroller and Embedded Systems” By Muhammad Ali Mazidi and Janice Gillispie Mazidi. Pearson Education.

2. S. Chemishkian, “Building smart services for smart home”, Proceedings of IEEE 4thInternational Workshop on Networked Appliances, 2011 pp: 2 15 -224.s

3. R. Sharma, K. Kumar, and S. Viq, “DTMF Based Remote Control System,” IEEE International Conference ICIT 2006, pp. 2380-2383, December 2006.

4. R.C. Luo, T.M. Chen, and C.C. Yih, “Intelligent autonomous mobile robot control through the Internet,”IEEE International Symposium ISIE 2000, vol. 1, pp. 6-11, December 2000

5. G. Arangurenss, L. Nozal, A. Blazquez, and J. Arias, "Remote control of sensors and actuators by GSM", IEEE 2002 28th Annual Conference of the Industrial Electronics Society IECON 02, vol. , 5-8 Nov. 2002,pp.2306 – 2310

6. Robotics and automation proceedings,1997 IEEE international conference on robotics & control systems .

56 7. Intelligent control 1989 proceedings IEEE international symposium on robotics & control systems.

8. Emerging trends in robotics and communication technologies, 2010 International conference on Robotics & control systems.

APPENDICES

The programming codes for this model are done in the programming language C and are given below. void main(void) { unsigned int k, h; DDRC=0x00; DDRD=0XFF; while (1) { k =~PINC; h=k & 0x0F; switch (h) { case 0x02: //if I/P is 0x02 { //O/P 0x89 ie Forward PORTD2_bit = 1; PORTD3_bit = 0; PORTD7_bit = 1; break; } case 0x08: //if I/P is 0x08 { //O/P 0x86 ie Backward PORTD2_bit = 0; PORTD3_bit = 1; PORTD7_bit = 1;

57 break; } case 0x04: { // Left turn PORTD0_bit = 1; PORTD1_bit = 0; PORTD7_bit = 1; break; } case 0x06: { // Right turn PORTD0_bit = 0; PORTD1_bit = 1; PORTD7_bit = 1; break; } case 0x05: { PORTD=0x00; // Stop break; } } } }

ATMEGA 16 MICROCONTROLLER DATA SHEET: • High-performance, Low-power Atmel® AVR® 8-bit Microcontroller • Advanced RISC Architecture – 131 Powerful Instructions – Most Single-clock Cycle Execution – 32 x 8 General Purpose Working Registers – Fully Static Operation – Up to 16 MIPS Throughput at 16 MHz – On-chip 2-cycle Multiplier • High Endurance Non-volatile Memory segments – 16 Kbytes of In-System Self- programmable Flash program memory – 512 Bytes EEPROM – 1 Kbyte Internal SRAM – Write/Erase Cycles: 10,000 Flash/100,000 EEPROM – Data retention: 20 years at 85°C/100 years at 25°C(1) – Optional Boot Code Section with Independent Lock Bits In-System Programming by On-chip Boot Program True Read-While-Write Operation – Programming Lock for Software Security • JTAG (IEEE std. 1149.1 Compliant) Interface – Boundary-scan Capabilities According to the JTAG Standard – Extensive On-chip Debug Support – Programming of Flash, EEPROM, Fuses, and Lock Bits through the JTAG Interface

58 • Peripheral Features – Two 8-bit Timer/Counters with Separate Prescalers and Compare Modes – One 16-bit Timer/Counter with Separate Prescaler, Compare Mode, and Capture Mode – Real Time Counter with Separate Oscillator – Four PWM Channels – 8-channel, 10-bit ADC 8 Single-ended Channels 7 Differential Channels in TQFP Package Only 2 Differential Channels with Programmable Gain at 1x, 10x, or 200x – Byte-oriented Two- wire Serial Interface – Programmable Serial USART – Master/Slave SPI Serial Interface – Programmable Watchdog Timer with Separate On-chip Oscillator – On-chip Analog Comparator • Special Microcontroller Features – Power-on Reset and Programmable Brown-out Detection – Internal Calibrated RC Oscillator – External and Internal Interrupt Sources – Six Sleep Modes: Idle, ADC Noise Reduction, Power-save, Power-down, Standby and Extended Standby • I/O and Packages – 32 Programmable I/O Lines – 40-pin PDIP, 44-lead TQFP, and 44-pad QFN/MLF • Operating Voltages – 2.7V - 5.5V for ATmega16L – 4.5V - 5.5V for ATmega16 • Speed Grades – 0 - 8 MHz for ATmega16L – 0 - 16 MHz for ATmega16 • Power Consumption @ 1 MHz, 3V, and 25°C for ATmega16L – Active: 1.1 mA – Idle Mode: 0.35 mA – Power-down Mode: < 1 µA