Submitted by:-

Ankur khurana

(07EI407)Acknowledgement

It is our privilege to express our sincerest regards to ourproject coordinator, Mr Jitender Singh Saggu for their valuable inputs, able guidance, encouragement, whole-hearted cooperation and constructive criticism throughout the duration of our project. We deeply express our sincere thanks to our teacher Dr Vishnu for encouraging and allowing us to present the project on the topic “Line Follower Robot “at our department premises for the partial fulfillment of the requirements leading to the award of B-Tech degree.We take this opportunity to thank all our lecturers who have directly or indirectly helped our project. We pay our respects and love to our parents and all other family members and friends for their love and encouragement through out our career. Last but not the least we express our thanks to ourfriends for their cooperation and support.

FOREWORD:

The word robot was coined by the Czech writer Kapek in his play ‘Rossum's Universal Robots’. Since then countless devices have been created and have been associated with the word ‘Robot’. The works of Isaac Asimov have laid the foundation of sociology pertaining to the use of robots instead of humans and the word ‘Robotics’ was also coined by him. In today’s world, work on robots, that resemble and look almost human, and others which don’t resemble humans in any way, progresses in leaps and bounds. The world has forerunners in this technology like MIT, CMU, Sony, Honda etc. In this world of ASIMO, AIBO, Packbot etc., we have made an attempt to create machines which we dare call ‘Robots’. In this era where organizations like ABU – Asia Pacific Broadcasting Union are organizing robot contests like Robocon we have made an attempt to make robotic systems which could send and receive communication signal amongst them and complete the task assigned to them with coordinated efforts. Today when technology is developing faster then a blink of an eye and the competition is tough to win at any stage may it be national or international, we have put in tireless efforts to implement the technology in simpler and effective form to compete against some of the best in field of robotics in the country.

Table of contents:-

1: Introduction

2: Microcontroller

2.1: definition

2.2 ATMEL 89S52

2.3 FEATURES

2.4 DESCRIPTION

2.5 89S52 PROCESSOR ARCHITECTURE

2.6 PIN DESCRIPTION

2.7 PIN DIAGRAM OF AT89S52

2.8 DESIGN OF INFRARED SENSOR CIRCUIT

2.9 POSITIONING OF SENSORS

2.10 SENSOR ARRAY

2.11 MOTOR DRIVER:-L293D

2.12 COMPARATOR

2.13 DC MOTORS

2.14 BIPOLAR MOTOR DRIVER:-

2.15 PIN CONNECTIONS

2.16 Multipurpose Schematics and PCB Designs

2.17 Line Following and Turning

2.18 WHAT IS ISP?

2.19 BLOCK DIAGRAM OF LINE FOLLOWER ROBOT

2.20 ONBOARD PIN CONNECTIONS

2.21 SOFTWARE

2.22 SOURCE CODE

2.23 HEX CODE GENERATED FOR THECODE

2.24 PROBLEMS ENCOUNTERED

2.25 REFERENCES AND RESOURCES

INTRODUCTION

What is a line follower?Line follower is a machine that can follow a path. The path can be visible like a black line on a white surface (or vice-versa) or it can be invisible like a magnetic field.

Why build a line follower?Sensing a line and maneuvering the robot to stay on course, while constantly correcting wrong moves using feedback mechanism forms a simple yet effective closed loop system. As a programmer you get an opportunity to ‘teach’ the robot how to follow the line thus giving it a human-like property of responding to stimuli. Practical applications of a line follower: Automated cars running on roads with embedded magnets; guidance system for industrial robots moving on shop floor etc.Prerequisites:

Knowledge of basic digital and analog electronics.Assembly Programming Sheer interest, an innovative brain and perseverance!

MICROCONTROLLER:-

2.1:-Defination

A Microcontroller is a single-chip microcomputer that contains all the componentssuch as the CPU, RAM, some form of ROM, I/O ports, and timers.

Unlike a generalpurpose computer, which also includes all of these

components, a microcontroller is designed for a very specific task -- to

control a particular system. Microcontrollers are sometimes called embedded microcontrollers, which just means that they are part ofan embedded system. A microprocessor is a general-purpose digital computer with central processing unit (CPU), which contains arithmetic and logic unit (ALU), a program counter (PC), a stack pointer (SP), some working registers, a clock timing circuit, and interrupts circuits. The main disadvantage of microprocessor is that it has no on-chip memory. So we are going for micro controller since it has on-board programmable ROM and I/O that can be programmed for various control functions

2.2:- ATMEL 89S52

AT89S52 MICROCONTROLLERThe microcontroller development effort resulted in the 8051 architecture, whichwas first introduced in 1980 and has gone on to be arguably the most popularmicro controller architecture available. The 8051 is a very complete microcontroller with a large amount of built in control store (ROM & EPROM) andRAM, enhanced I/O ports, and the ability to access external memory. Themaximum clock frequency with an 8051 micro controller can execute instructionsis 20MHZ.Microcontroller is a true computer on chip. The design incorporates all of thefeatures found in a microprocessor: CPU, ALU, PC, SP and registers. It also hasthe other features needed to, make complete computer: ROM, RAM, parallel I/O,serial I/O, counters and a clock circuit.The 89C51/89C52/89C54/89C58 contains a non-volatile FLASH program memorythat is parallel programmable. For devices that are serial programmable (In-SystemProgrammable (ISP) and In-Application Programmable (IAP) with a boot loader)Allthree families are Single-Chip 8-bit Microcontrollers manufactured in advancedCMOS process and are Derivatives of the 80C51 microcontroller family. All thedevices have the same instruction set as the 80C51.

2.3 FEATURES• 8K Bytes of In-System Reprogrammable Flash Memory• Endurance: 1,000 Write/Erase Cycles• Fully Static Operation: 0 Hz to 33 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

2.4 DESCRIPTION:The AT89s52 is a low power, high performance CMOS 8-bit micro computer with 8Kbytes of flash programmable and erasable read only memory(PEROM).The device ismanufactured using Atmel’s high density nonvolatile memory technology and iscompatible 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 aconventional nonvolatile memory programmer. By combining a versatile 8-bit CPUwith flash on a monolithic chip, the Atmel AT89s52 Is a powerful microcomputerwhich provides a highly flexible and cost effective solution to many embeddedcontrol applications. The main advantages of 89s52 over 8051 are Software Compatibility Program Compatibility RewritabilityThe 89s52 microcontroller has an excellent software compatability, i.e.

the software used can be applicable to any other microcontroller. The program writtenon this microcontroller can be carried to any base.Program compatibility is the major advantage in 89s52. The program can beused in any other advanced microcontroler. The program can be reloaded andchanged for nearly 1000 times.

2.5:- 89S52 PROCESSOR ARCHITECTURE:

The AT89s52 provides the following standard features: 8K bytes of Flash,256 bytes of RAM, 32 I/O lines, three 16-bit timer/counters, a six-vector two-levelinterrupt architecture, a full-duplex serial port, on-chip oscillator, and clock circuitry.

In addition, the AT89s52 is designed with static logic for operation down to zerofrequency and supports two software selectable power saving modes. The Idle Modestops the CPU while allowing the RAM, timer/counters, serial port, and interruptsystem to continue functioning. The Power-down mode saves the RAM contents butfreezes the oscillator, disabling all other chip functions until the next hardware reset.

2.6:- PIN DESCRIPTION:

VCCSupply voltage.

GNDGround.

Port 0Port 0 is an 8-bit open drain bi-directional I/O port. As an output port, each pincan sink eight TTL inputs. When 1s are written to port 0 pins, the pins can be used ashigh impedance inputs. Port 0 can also be configured to be the multiplexed lowerorder address/data bus during accesses to external program and data memory. In thismode, P0 has internalpullups.Port 0 also receives the code bytes during Flashprogramming and outputs the code bytes during program verification. External pullupsare required during program verification.

Port 1

Port 1 is an 8-bit bi-directional I/O port with internal pull-ups. The Port 1 outputbuffers can sink/source four TTL inputs. When 1s are written to Port 1 pins, they arepulled high by the internal pull-ups and can be used as inputs. As inputs, Port 1 pinsthat are externally being pulled low will source current (IIL) because of the internalpull-ups. In addition, P1.0 and P1.1 can be configured to be the timer/counter 2 externalcount input (P1.0/T2) and the timer/counter 2

2.7:- PIN DIAGRAM OF 89S52

2.8:- DESIGN OF INFRARED SENSOR CIRCUIT:

Pr inciple of operation of the I.R L.E.D . andPhototransistor: -A Photodiode is a p-n junction or p-i-n structure. When an infrared photon ofsufficient energy strikes the diode, it excites an electron thereby creating a mobileelectron and a positively charged electron hole. If the absorption occurs in thejunction's depletion region, or one diffusion length away from it, these carriersare swept from the junction by the built-in field of the depletion region,producing a photocurrent. Photodiodes can be used under either zero bias(photovoltaic mode) or reverse bias (photoconductive mode). Reverse biasinduces only little current (known as saturation or back current) along itsdirection. But a more important effect of reverse bias is widening of the depletionlayer (therefore expanding the reaction volume) and strengthening thephotocurrent when infrared falls on it. There is a limit on the distance betweenI.R. L.E.D. and infrared sensor for the pair to operate in the desired manner. Inour case distance is about 5mm.Infra-Red emitter sends out IR pulses.Position calculation is done throughintensity of reflected light received bythe detector.Ambient interference is negligible

2.9:- POSITIONING OF SENSORS:-

The resistance of the sensor decreases when IR (infrared) light falls on it. A goodsensor will have near zero resistance in presence of light and a very largeresistance in absence of light. Whether the sensors are Light Dependent Resistors,laser diode, Infrared Sensors, Ultrasonic Sensors or anything else,the outputs ofthe sensor modules are fed to the Non-inverting input of a comparator . Thereference voltage of the comparator is fed to the inverting input of thecomparator by a trim pot or a tuning device connected between the supply lines.LM339 is a comparator IC that digitizes the analog signal from the sensor array.Since the output of LM339 is TTL compatible it can be directly fed to the master

microcontroller. The generalized connection diagram of Sensor Interfacing with microcontroller isshown below:-

CONNECTING INFRARED MODULE WITH MICROCONTROLLER MCS-51

When the sensor/emitter pair is on shining surface sensor is on i.e. inlow impedance mode which one can easily view as L.E.D. correspondingto that sensor doesn’t glow. The output of the opamp is HIGH

SIGN AL and this HIGH SIGNAL is given to the microcontroller andwhen the sensor is on normal non-reflecting surface it’s off i.e. inHIGH IMPEDANCE state which one can easily view as L.E.D.corresponding to that sensor glows up and LOW SIG NAL is given tothe microcontroller.

2.10:- Infra-Red Sensor Array

2.11:- MOTOR DRIVER:-L293D

The L298 Motor Driver has 4 inputs to control the motion of the motors and two enable inputs which are used for switching the motors on and off. To control the speed of the motors a PWM waveform with variable duty cycle is applied to the enable pins. Rapidly switching the voltagebetween Vs and GND gives an effective voltage between Vs and GND whose value depends on the duty cycle of PWM. 100% duty cycle corresponds to voltage equal to Vs, 50 % corresponds to 0.5Vs and so on. The 1N4004 diodes are used to prevent back EMF of the motors from disturbing the remaining circuit. Many circuits use L293D for motor control, I chose L298 as it has current capacity of 2A per channel @ 45V compared to 0.6 A @ 36 V of a L293D. L293D’s package is not suitable for attaching a good heat sink, practically you can’t use it above 16V

2.12:-COMPARATOR

2.13:- DC MOTORS

These are very commonly used in robotics. DC motors can rotate in bothdirections depending upon the polarity of current through the motor. Thesemotors have free running torque and current ideally zero. These motors havehigh speed which can be reduced with the help of gears and traded off for torque.Speed Control of DC motors is done through Pulse Width Modulation techniques,i.e. sending the current in intermittent bursts. PWM can be generated by 555timer IC with adjusted duty cycle. Varying current through the motor varies thetorque.

PICTURE OF DC MOTOR USED

2.14:- BIPOLAR MOTOR DRIVER:-L293D is a bipolar motor driver IC. This is a high voltage, high current pushpullfour channel driver compatible to TTL logic levels and drive inductive loads. Ithas 600 mA output current capability per channel and internal clamp diodes.The L293 is designed to provide bidirectional drive currents of upto 1 A at

voltages from 4.5 V to 36 V. The L293D is designed to provide bidirectional drivecurrents of up to 600-mA at voltages from 4.5 V to 36 V. Both devices aredesigned to drive inductive loads such as relays, solenoids, dc and bipolar steppingmotors, as well as other high-current/high-voltage loads in positive supplyapplications. All inputs are TTL compatible. Each output is a complete totem-poledrive circuit, with a Darlington transistor sink and a pseudo-Darlington source.Drivers are enabled in pairs, with drivers 1 and 2 enabled by 1,2EN and drivers 3and 4 enabled by 3,4EN. When an enable input is high, the associated drivers areenabled, and their outputs are active and in phase with their inputs. When theenable input is low, those drivers are disabled, and their outputs are off and in thehigh-impedance state. With the proper data inputs, each pair of drivers forms afull-H (or bridge) reversible drive suitable for solenoid or motor applications

2.15:-PIN CONNECTIONS

2.16:- Multipurpose Schematics and PCB Designs

The Schematics and PCB Designs of the Electronic Circuits have been done such that the PCBs are multipurpose and just with the minute change in the number of components mounted on the PCB and some change in the interconnections between the PCBs, they could be used for all the robots. In fact the PCBs are made such that in most of the general robotic applications these PCBs could be used.

2.17:-Line Following and Turning

The autonomous robots are required to perform their respective tasks without any manual guidance. Thus the technique used to make the robots reach the desired locations in order to perform their tasks is the white line following, cross detection and turning technique using the optoelectronic sensors. These optoelectronic sensors are actually developed during the project using light to voltage converter IC – OPT101 and LED. These sensors work on the principle ofreflective light amplification. The IC – OPT101 comprised of a photodiode and amplifier. The light of LED reflects from the surface and falls on to the OPT101 which is amplified by the amplifier inbuilt the IC. The intensity of the light falling onto the photodiode of ICdepends upon the color of the surface. Thus while the sensor is on the white line it gives the saturated output voltage where as while not on the white line it gives a low voltage. This voltage is converted into a digital signal using an analog comparator IC TLC324 where the second input to the IC is a fixed voltage. Thus when the output voltage of the sensor is below certain level i.e. when the sensor is not on white line it gives ‘0’

as the output whereas if the output voltage of the sensor is above certain level i.e. when the sensor is on the white line it gives ‘1’ as the output.Using six such sensors divided into two rows on in front and one at the rear side the white line following is achieved. To make the robot follow the white line various sequences of the possible states of the sensors are considered and depending upon the same, position of the robot and correction required in the proper direction is analyzed. Finally on the basis of the required correction, PWM signal is applied to the H-Bridge drive circuit which uses LMD18200T IC, and the straight line is followed by the robot. For the motion of the robot high torque Maxon Motors are used with the gearbox having 1:18 ratio of gear reduction. While the robot follows the white line it is also required for the robot to take 90 degree turn in certain direction. For the same the cross detection is used in which the robot counts the number of crosses in the grid it passes and when this number matches with the number of cross where it has to turn or stop, the robot stops the straight line motion and the by rotating both the motors in the opposite directions it takes the turn in the desired direction till the desired sensor in the front line of the sensors come onto the white line.

2.18:- WHAT IS ISP?

In-Syste m Programming (abbreviated ISP) is the ability of someprogrammable logic devices, microcontrollers, and other programmableelectronic chips to be programmed while installed in a complete system, ratherthan requiring the chip to be programmed prior to installing it into the system.The primary advantage of this feature is that it allows manufacturers of electronicdevices to integrate programming and testing into a single production phase,rather than requiring a separate programming stage prior to assembling thesystem. This may allow manufacturers to program the chips in their own system'sproduction line instead of buying preprogrammed chips from a manufacturer ordistributor, making it feasible to apply code or design changes in the middle of aproduction run. Typically, chips supporting ISP have internal circuitry togenerate any necessary programming voltage from the system's normal supplyvoltage, and communicate with the programmer via a serial protocol. Mostprogrammable logic devices use proprietary protocols or protocols defined byolder standards. In systems complex enough to require moderately large gluelogic.

2.19:- BLOCK DIAGRAM OF LINE FOLLOWER ROBOT

2.20:- CIRCUIT DIAGRAM OF LINE FOLLOWER ROBOT:-

2.22:- ONBOARD PIN CONNECTIONS

2.23:- SOFTWARE

The software programs for the microcontroller have been developedusing Assembly Level Programming language. Microcontroller used in the project is 89S52 manufactured by atmel which is 8052 based microcontroller. Thus for microcontroller software programming Evaluation Version of Assembler – 8051IDE developed by AceBus has been used to assemble, compile and simulate the software programs. The benefit of using AT89S52 microcontroller is that the AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller with 8Kbytes of in-system programmable Flash memory. The device is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry- standard 80C51 instruction set and pinout. The on-chip Flash allows the programmemory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with in-system programmable Flash on a monolithic chip, the Atmel AT89S52 is a powerful microcontroller which provides a highly-flexible and cost-effective solution to many embedded control applications. The AT89S52 provides the following standard features: 8K bytes of Flash, 256 bytesof RAM, 32 I/O lines, Watchdog timer, two data pointers, three 16-bit timer/counters, a six-vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator, and clock circuitry. In addition, the AT89S52 is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port, and interrupt system to continue functioning. The Power-down mode saves the RAM contents but freezes the oscillator, disabling all other chip functions until the next interrupt or hardware reset.

2.24:- SOURCE CODE

PROGRAM FOR LINE FOLLOWER=======SYSTEM REGISTERS==============P0 EQU 080HP1 EQU 090HP2 EQU 0A0HP3 EQU 0B0HTH1 EQU 08DHTL1 EQU 08BHTCON EQU 088HTMOD EQU 089HIE EQU 0A8HSP EQU 081HFLAG1 EQU 0D0H;======= PORT PIN DEFINITIONS ========SENSOR1 EQU P1.0SENSOR2 EQU P1.1LED_RED EQU P0.6LED_GREEN EQU P0.7L_EN EQU P0.2R_EN EQU P0.4L_MO1 EQU P0.1L_MO2 EQU P0.0R_MO1 EQU P0.3R_MO2 EQU P0.5; X X X X M X L R; X X X X 1 X 0 0 - FWD -- 03; 0 1 - TR 01; 1 0 - TL 02; 00 - STOP 00

;========== HERE THE MAIN PROGRAM STARTS ==========ORG 0000HAJMP STARTORG 0050HSTART: MOV R1,#0FFHMOV R2,#004HMOV P2,#000HLOOP: MOV C,SENSOR1MOV LED_RED,CMOV C,SENSOR2MOV LED_GREEN,CMOV A,P1ANL A,#003HCJNE A,#000H,CHECK_LEFT ;////// GO FORWARD /////////SETB R_MO1CLR R_MO2SETB L_MO1CLR L_MO2MOV R1,#0FFHMOV R2,#004HAJMP LOOPCHECK_LEFT:CJNE A,#001H,CHECK_RIGHT ;////// TURN LEFT ///////////SETB R_MO1CLR R_MO2CLR L_MO1SETB L_MO2MOV R1,#0FFHMOV R2,#004HHERE_LEFT:MOV A,P1ANL A,#003HCJNE A,#003H,LEFT_CONT

DJNZ R1,LEFT_CONTDJNZ R2,LEFT_CONTAJMP STOPLEFT_CONT:JB P1.0,HERE_LEFTAJMP LOOPCHECK_RIGHT:CJNE A,#002H,CHECK_STOP ;/////// TURN RIGHT ///////CLR R_MO1SETB R_MO2SETB L_MO1CLR L_MO2MOV R1,#0FFHMOV R2,#004HHERE_RIGHT:MOV A,P1ANL A,#003HCJNE A,#003H,RIGHT_CONTDJNZ R1,LEFT_CONTDJNZ R2,LEFT_CONTAJMP STOPRIGHT_CONT:JB P1.1,HERE_RIGHTAJMP LOOPCHECK_STOP:DJNZ R1,LOOPSTOP: SETB R_MO1SETB R_MO2SETB L_MO1SETB L_MO2HERE_STOP:AJMP HERE_STOPEND

2.25:- HEX CODE GENERATED FOR THE CODE

: 020000000150AD: 1000500079FF7A0475A000A2909286A2919287E51A: 10006000905403B4000ED283C285D281C28079FF3E: 100070007A040157B4011ED283C285C281D280792D: 10008000FF7A04E5905403B40306D904DA0201B8F8: 100090002090F00157B4021EC283D285D281C28063

: 1000A00079FF7A04E5905403B40306D9E3DAE10159: 1000B000B82091F00157D99FD283D285D281D280C6: 0200C00001C07D: 00000001FF

2.26:- PROBLEMS ENCOUNTERED

The ISP programmer requires dedicated supply of 9V from the USB of your P.C.Extern supply of other than 9V generates error while writing the HEX code to theMicrocontroller. The programmer was soldered 3 times before it couldsuccessfully program the chip.

• The program was difficult to implement as it was our first encounter withmicrocontroller programming in assembly.• The large number of interconnections in the circuit made it too difficult tosolder.• The IR sensors burnt up on soldering so we have to use temperature controlledsoldering iron.• In the model designed to show line follower robot, electric motors ought to bebidirectional and of low wattage i.e. should draw lesser current otherwise themotor can draw current to such a level to burn up the entire circuit.

2.27:- REFERENCES AND RESOURCES

Books :1) The 8051 Microcontroller and Embedded Systems UsingAssembly and C By Muhammad Ali Mazidi, Janice GillispieMazidi & Ro lin D. McKinlay

Webs ite s r ef er re d:1) Atmel Corp. Makers of the AVR microcontrollerwww.atmel.com2) One of the best sites AVR site www.avrfreaks.net3) One of the best site for Microcontroller projectswww.kmitl.ac.th4) Keil™, the developer of Keilμvision www.keil.com5) Information from www.wikipedia.com