INTELLIGENT LINE INTELLIGENT LINE FOLLOWING ROBOTFOLLOWING ROBOT

INTRODUCTIONINTRODUCTION

Robotics is an interesting subject to discuss about and in this advanced world, Robots Robotics is an interesting subject to discuss about and in this advanced world, Robots are becoming a part of our life.are becoming a part of our life.

As strange as it might seem, there is no standard definition for a robot. However, As strange as it might seem, there is no standard definition for a robot. However, there are some essential characteristics that a robot must have and this might help there are some essential characteristics that a robot must have and this might help one to decide what is and what not a robot is. It will also help us to decide what one to decide what is and what not a robot is. It will also help us to decide what features are required to build into a machine before it can behave like a robot.features are required to build into a machine before it can behave like a robot.

A robot has the essential characteristics:A robot has the essential characteristics:1.1. Sensing : The robot should be able to sense its surroundings. Providing the robot with Sensing : The robot should be able to sense its surroundings. Providing the robot with

the sensors such as light sensors (eyes), touch and pressure sensors (hands), chemical the sensors such as light sensors (eyes), touch and pressure sensors (hands), chemical sensors (nose), hearing and sonar sensors (ears), and taste sensors (tongue) will give sensors (nose), hearing and sonar sensors (ears), and taste sensors (tongue) will give the robot awareness of its environment. the robot awareness of its environment.

2.2. Movement : The robot needs to be able to move around its environment. Whether Movement : The robot needs to be able to move around its environment. Whether rolling on wheels, walking on legs or propelling by thrusters a robot should be able to rolling on wheels, walking on legs or propelling by thrusters a robot should be able to move. move.

3.3. Energy : The robot needs to be able to power itself. A robot might be solar powered, Energy : The robot needs to be able to power itself. A robot might be solar powered, electrically powered, battery powered. electrically powered, battery powered.

4.4. Intelligence : A robot needs some kind of "smarts." A programmer is the person who Intelligence : A robot needs some kind of "smarts." A programmer is the person who gives the robot its 'smarts.' The robot will have to have some way to receive the gives the robot its 'smarts.' The robot will have to have some way to receive the program so that it knows what it is to do. program so that it knows what it is to do.

So what is a robot? So what is a robot? It is a system that contains sensors, control systems, manipulators, power supplies and It is a system that contains sensors, control systems, manipulators, power supplies and

software all working together to perform a task. software all working together to perform a task.

Designing, building, programming and testing a robots is a combination of physics, Designing, building, programming and testing a robots is a combination of physics, mechanical engineering, electrical engineering, structural engineering, mathematics and mechanical engineering, electrical engineering, structural engineering, mathematics and computing. In some cases biology, medicine, chemistry might also be involved.computing. In some cases biology, medicine, chemistry might also be involved.

A study of robotics means that it is an active involvement in all of these disciplines in a A study of robotics means that it is an active involvement in all of these disciplines in a deeply problem-posing problem-solving environment. deeply problem-posing problem-solving environment.

What is a line follower?What is a line follower?

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

What is the need to build a line follower?What is the need to build a line follower?

Sensing a line and maneuvering the robot to stay on course, while constantly correcting 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. wrong moves using feedback mechanism forms a simple yet effective closed loop system. The programmer gets the opportunity to ‘teach’ the robot how to follow the line thus The programmer gets the opportunity to ‘teach’ the robot how to follow the line thus giving it a human-like property of responding to stimuli.giving it a human-like property of responding to stimuli.

MICROCONTROLLER(AT89S52)

It has 40 pins and it is in It has 40 pins and it is in dual in packagedual in package

It has 4 ports, 6 interrupts It has 4 ports, 6 interrupts and 2 timersand 2 timers

It has RAM of 128bytes and It has RAM of 128bytes and ROM of 4KBROM of 4KB

It is used for interfacing of It is used for interfacing of the input and output the input and output modulesmodules

PIN DIAGRAMPIN DIAGRAM

1234567891011121314151617181920

4039383736353433323130292827262524232221

P1.0P1.1P1.2P1.3P1.4P1.5P1.6P1.7RST

(RXD)P3.0(TXD)P3.1

(T0)P3.4(T1)P3.5

XTAL2XTAL1

GND

(INT0)P3.2(INT1)P3.3

(RD)P3.7(WR)P3.6

VccP0.0(AD0)P0.1(AD1)P0.2(AD2)P0.3(AD3)P0.4(AD4)P0.5(AD5)P0.6(AD6)P0.7(AD7)EA/VPPALE/PROGPSENP2.7(A15)P2.6(A14)P2.5(A13)P2.4(A12)P2.3(A11)P2.2(A10)P2.1(A9)P2.0(A8)

AT89S52

Compatible with MCS-51® ProductsCompatible with MCS-51® Products 8K Bytes of In-System Programmable (ISP) Flash Memory8K Bytes of In-System Programmable (ISP) Flash Memory – – Endurance: 1000 Write/Erase CyclesEndurance: 1000 Write/Erase Cycles 4.0V to 5.5V Operating Range4.0V to 5.5V Operating Range Fully Static Operation: 0 Hz to 33 MHzFully Static Operation: 0 Hz to 33 MHz Three-level Program Memory LockThree-level Program Memory Lock 256 x 8-bit Internal RAM256 x 8-bit Internal RAM 32 Programmable I/O Lines32 Programmable I/O Lines Three 16-bit Timer/CountersThree 16-bit Timer/Counters Eight Interrupt SourcesEight Interrupt Sources Full Duplex UART Serial ChannelFull Duplex UART Serial Channel Low-power Idle and Power-down ModesLow-power Idle and Power-down Modes Interrupt Recovery from Power-down ModeInterrupt Recovery from Power-down Mode

FEATURESFEATURES

WORKING PRINCIPLEWORKING PRINCIPLE The Embedded Line following robot uses two motors to control rear wheels and the single front The Embedded Line following robot uses two motors to control rear wheels and the single front

wheel is free. It has 3-infrared sensors on the bottom for detection of black tracking tape. When the wheel is free. It has 3-infrared sensors on the bottom for detection of black tracking tape. When the middle sensor detects the black color, this sensor output is given to the comparator LM324. The middle sensor detects the black color, this sensor output is given to the comparator LM324. The output of comparator compares this sensor output with a reference voltage and gives an output. The output of comparator compares this sensor output with a reference voltage and gives an output. The output of comparator will be low when it receives an input from the sensor.output of comparator will be low when it receives an input from the sensor.

A simple logic has been used to implement this project. As it is known that black colour is capable of A simple logic has been used to implement this project. As it is known that black colour is capable of absorbing the radiation and white colour or a bright colour reflects the radiation back. Here, 3 pairs absorbing the radiation and white colour or a bright colour reflects the radiation back. Here, 3 pairs of IR TX and Rx are used. The robot uses these IR sensors to sense the line and the arrangement is of IR TX and Rx are used. The robot uses these IR sensors to sense the line and the arrangement is made such that sensors face the ground. The output from the sensors is an analog signal which made such that sensors face the ground. The output from the sensors is an analog signal which depends on the amount of light reflected back and this analog signal is given to the comparator to depends on the amount of light reflected back and this analog signal is given to the comparator to produce 0s and 1s.produce 0s and 1s.

Internally we have an OTP (one time programmable) processor which is used to control Internally we have an OTP (one time programmable) processor which is used to control the rotation of the wheels. The rotation of these wheels depends up on the response from the rotation of the wheels. The rotation of these wheels depends up on the response from the comparator. Let us assume that when a sensor is on the black line it reads 0 and the comparator. Let us assume that when a sensor is on the black line it reads 0 and when it is on the bright surface it reads 1.when it is on the bright surface it reads 1.

Here we can get three different cases, they are:Here we can get three different cases, they are:

1. Straight direction1. Straight direction

2. Right curve2. Right curve

3. Left curve3. Left curve

Straight direction:Straight direction:

It can be assumed that the robot moves in straight direction when the middle sensors It can be assumed that the robot moves in straight direction when the middle sensors response is low and the remaining two sensors response is high. i.e., according to our response is low and the remaining two sensors response is high. i.e., according to our arrangement the middle sensor will always be on the line and as the line is black in arrangement the middle sensor will always be on the line and as the line is black in colour it will not reflect the emitted radiation back and the response of the sensor will be colour it will not reflect the emitted radiation back and the response of the sensor will be low and the response of the remaining two sensors will be high as they will be on the low and the response of the remaining two sensors will be high as they will be on the bright surface.bright surface.

Right curve:Right curve: When a right curve is found on the line the responses will change i.e. the response of the When a right curve is found on the line the responses will change i.e. the response of the

first sensor which is to the right will become low as that sensor will be facing the black first sensor which is to the right will become low as that sensor will be facing the black line and the remaining sensors response will be high. When this data is achieved, the line and the remaining sensors response will be high. When this data is achieved, the control of the wheels is changed i.e. the right wheel is held constant and the left wheel is control of the wheels is changed i.e. the right wheel is held constant and the left wheel is made to move freely until the response from the middle sensor becomes low. Then the made to move freely until the response from the middle sensor becomes low. Then the same process repeats again.same process repeats again.

Left curve: Left curve:

When a left curve is found on the line the response of the left most sensor will be changed When a left curve is found on the line the response of the left most sensor will be changed from high to low as the sensor will now face the black or the dark surface. Then the from high to low as the sensor will now face the black or the dark surface. Then the control of the wheel changes i.e. by holding the left wheel constant and allowing the control of the wheel changes i.e. by holding the left wheel constant and allowing the right wheel to move freely until the middle sensor changes its response from high to low.right wheel to move freely until the middle sensor changes its response from high to low.The same process continues for all the turns and the robot moves continuously until the The same process continues for all the turns and the robot moves continuously until the supply is removed.supply is removed.

Steps to follow the line (using single sensor):Steps to follow the line (using single sensor):-Start.-Start.-Check for line.-Check for line.-Line detected go right.-Line detected go right.-Check for line.-Check for line.

-If no line turn left till line detected.-If no line turn left till line detected.

The arrangement of the sensors is shown in the figure. The arrangement of the sensors is shown in the figure.

LM 324LM 324

Wide gain bandwidth . : 1.3MHZ input common-mode voltage range

Includes ground .largevoltage gain : 100DB .very lowsupply current/ampli : 375MA .low input bias current : 20NA low input offset voltage : 5mv max.

Low input offset current : 2NA wide power supply range :

Single supply : +3v to +30v Dual supplies : ±1.5v to ±15v

PIN CONFIGURATION PIN CONFIGURATION

WHAT IS INFRARED?WHAT IS INFRARED?

Infrared is a energy radiation with a frequency Infrared is a energy radiation with a frequency below our eyes sensitivity, so we cannot see itbelow our eyes sensitivity, so we cannot see itEven that we can not "see" sound frequencies, Even that we can not "see" sound frequencies, we know that it exist, we can listen them.we know that it exist, we can listen them.

Even that we can not see or hear infrared, we Even that we can not see or hear infrared, we can feel it at our skin temperature sensors. can feel it at our skin temperature sensors. When you approach your hand to fire or warm When you approach your hand to fire or warm element, you will "feel" the heat, but you can't element, you will "feel" the heat, but you can't see it. You can see the fire because it emits see it. You can see the fire because it emits other types of radiation, visible to your eyes, but other types of radiation, visible to your eyes, but it also emits lots of infrared that you can only it also emits lots of infrared that you can only feel in your skinfeel in your skin

IR sectionIR section

IR TRANSMITTERIR TRANSMITTER The IR LED emitting infrared light is put on in The IR LED emitting infrared light is put on in

the transmitting unit. To generate IR signal, the transmitting unit. To generate IR signal, 555 IC based astable multivibrator is used. 555 IC based astable multivibrator is used. Infrared LED is driven through transistor BC Infrared LED is driven through transistor BC 548.548.

IR RECEIVERIR RECEIVER   The TSOP17.. – Series are miniaturized The TSOP17.. – Series are miniaturized

receivers for infrared remote control systems. receivers for infrared remote control systems. PIN diode and preamplifier are assembled on PIN diode and preamplifier are assembled on lead frame, the epoxy package is designed as lead frame, the epoxy package is designed as IR filterIR filter

IR Transmitter, Receiver

   An infrared emitter is an LED made from gallium arsenide, which emits An infrared emitter is an LED made from gallium arsenide, which emits

near-infrared energy at about 880nm.near-infrared energy at about 880nm. The infrared phototransistor acts as a transistor with the base voltage The infrared phototransistor acts as a transistor with the base voltage

determined by the amount of light hitting the transistor. Hence it acts as a determined by the amount of light hitting the transistor. Hence it acts as a variable current source. variable current source.

Greater amount of IR light cause greater currents to flow through the Greater amount of IR light cause greater currents to flow through the collector-emitter leads. collector-emitter leads.

IR Emitter and IR phototransistor:IR Emitter and IR phototransistor:

IR SensorIR Sensor

Features:Features:

• • Extra high radiant power and radiant Extra high radiant power and radiant intensityintensity• • High reliabilityHigh reliability• • Low forward voltageLow forward voltage• • Suitable for high pulse current Suitable for high pulse current operationoperation• • Standard T-1¾ ( 5 mm) package∅Standard T-1¾ ( 5 mm) package∅• • Angle of half intensity ϕ = ± 17°Angle of half intensity ϕ = ± 17°• • Peak wavelength λp = 940 nmPeak wavelength λp = 940 nm• • Good spectral matching to Si Good spectral matching to Si photodetectorsphotodetectors

Lead Acid BatteryLead Acid BatterySpecifications12V 1.3Ah sealed lead acid battery 1. CE and RoHs 2. high quality and relaibility 3. miantenance free 4. long life cycle12V 1.3Ah sealed lead acid battery General Features:Sealed and maintenance free operation.Non-Spillable construction design.ABS containers and covers(UL94HB, UL94-0)optional.Safety valve installation for explosion proof.High quality and high reliability.Exceptional deep discharge recovery performance.Low self discharge characteristic.Flexibility design for multiple install positions. 

H-BridgeH-Bridge

Features:Features:

600 mA Output Current Capability 600 mA Output Current Capability Per DriverPer Driver

Pulsed Current 1.2 A / DriverPulsed Current 1.2 A / Driver Wide Supply Voltage Range: 4.5 V Wide Supply Voltage Range: 4.5 V

to 36 Vto 36 V Separate Input-Logic SupplySeparate Input-Logic Supply NE Package Designed for Heat NE Package Designed for Heat

SinkingSinking Thermal Shutdown & Internal ESD Thermal Shutdown & Internal ESD

ProtectionProtection High-Noise-Immunity InputsHigh-Noise-Immunity Inputs

DC Geared MotorDC Geared MotorTechnical Specifications:Technical Specifications:•60RPM 12V DC motors with Metal Gearbox60RPM 12V DC motors with Metal Gearbox•6mm shaft diameter6mm shaft diameter•Gearbox diameter 37 mm.Gearbox diameter 37 mm.•Motor Diameter 28.5 mmMotor Diameter 28.5 mm•Length 63 mm without shaftLength 63 mm without shaft•Shaft length 15mmShaft length 15mm•300gm weight300gm weight•38kgcm torque38kgcm torque•No-load current = 800 mA(Max), Load current = upto 9.5 No-load current = 800 mA(Max), Load current = upto 9.5 A(Max)A(Max)

ADVANTAGESADVANTAGES

Robot movement is automatic. Fit and Forget system. Used for long distance applications. Defense applications. Used in home, industrial automation. Cost effective.

APPLICATIONSAPPLICATIONS

Automated cars running on roads with embedded magnets.Automated cars running on roads with embedded magnets.

Guidance system for industrial robots moving on shop floor etc.Guidance system for industrial robots moving on shop floor etc.

Guidance system for industrial robots moving on shop floor etc.

Industrial applications

Home applications

In this project we have studied and implemented a Line Following Robot using a Microcontroller for blind people. The programming and interfacing of microcontroller has been mastered during the implementation. This device is designed to provide with a greater advantage.  

CONCLUSION