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LINE FOLLOWING PICK AND PLACE
A Project submitted in partial fulfillment of the requirements for
the award of the degree of
ELECTRONICS AND INSTRUMENTATION
YASH KUMAR YADAV (1009032059)
VINOD KUMAR (1009032058)
PRADEEP KUMAR (1009032037)
ELECTRONICS AND INSTRUMENTATION
IEC COLLEGE OF ENGINEERING & TECHNOLOGY
We, hereby declare that this submission is our own work and that, to the best of our
knowledge and belief, it contains no material previously published or written by
another person nor material which to a substantial extent has been accepted for the
award of any other degree or diploma of the university or other institute of higher
learning, except where due acknowledgement has been made in the text.
Name YASH KUMAR YADAV
Roll No 1009032059
Name VINOD KUMAR
Roll No 1009032058
Name PRADEEP KUMAR
Roll No. 1009032037
MR.SATISH JAISWAL MR. R.P. SINGH
Guide Head of the Department
Project Viva-voce held on _____________________________
Internal Examiner External Examiner
Mankind has always strived to give life like qualities to its artifacts in an attempt to
find substitutes for himself to carry out his orders and also to work in a hostile
environment. The popular concept of a robot is of a machine that looks and works like
a human being.
The industry is moving from current state of automation to Robotization, to increase
productivity and to deliver uniform quality. The industrial robots of today may not
look the least bit like a human being although all the research is directed to provide
more and more anthropomorphic and humanlike features and super-human
capabilities in these.
One type of robot commonly used in industry is a robotic manipulator or simply a
robotic arm. It is an open or closed kinematic chain of rigid links interconnected by
movable joints. In some configurations, links can be considered to correspond to
human anatomy as waist, upper arm and forearm with joint at shoulder and elbow. At
end of arm a wrist joint connects end effectors which may be a tool and its fixture or a
gripper or any other device to work.
Here how a pick and place Line following robot can be designed for a workstation
where loading and packing of lead batteries is been presented. All the various
problems and obstructions for the loading process has been deeply analyzed and been
taken into consideration while designing the pick and place line following robot.
It gives us a great sense of pleasure to present the report of the B. Tech Project
undertaken during. Tech. Final Year. We owe special debt of gratitude to Project In
charge Mr. Satish Jaiswal, Department of Electronics & Instrumentation
Engineering, IEC College of engineering & technology, Greater Noida for his
constant support and guidance throughout the course of our work. His sincerity,
thoroughness and perseverance have been a constant source of inspiration for us. It is
only his cognizant efforts that our endeavours have seen light of the day.
We also take the opportunity to acknowledge the contribution of Professor R.P.
Singh Head, Department of Electronics & Instrumentation Engineering, IEC College
of Engineering, Greater Noida for his full support and assistance during the
development of the project.
We also do not like to miss the opportunity to acknowledge the contribution of all
faculty members of the department for their kind assistance and cooperation during
the development of our project. Last but not the least, we acknowledge our friends for
their contribution in the completion of the project.
TABLE OF CONTENTS
TITLE PAGE NO.
TABLE OF CONTENT
LIST OF TABLE
LIST OF FIGURE
1.1INTRODUCTION TO LINE FOLLOWING ROBOT
1.2 TYPES OF ROBOT
1.6 INTRODUCTION TO EMBEDDED SYSTEM
2.1 AT89C51 MICROCONTRILLE
2.2 HARDWARE COMPONENT EXPLANATION
2.3 BLOCK DIAGRAM
CONCLUSION AND FUTURE SCOPE
LIST OF TABLE
TABLE 2.1 PORT 3 ALTERNATE FUCTION
TABLE 2.2 H BRIDGE SWITCH OPERATIONS
LIST OF FIGURE
FIG 1.1 INDUSTRIAL ROBOT
FIG1.2 AGRICULTURE ROBOT
FIG1.3 TELE ROBOT
FIG1.4 HUMAN ROBOT
FIG1.5 BLOCK DIAGRAM OF EMBEDED SYSTEM
FIG2.1 PIN DIAGRAM OF AT89C51
FIG2.2 AT89C51 IC
FIG2.3 TYPICAL CRSTAL OSCILLATOR
FIG2.4 PULLUP RESISTER
FIG2.5 ELECTROLYTIC CAPACITOR
FIG2.6 BASE IC OF 8PIN AND 40 PIN
FIG2.8 VOLTAGE REGULATOR
FIG2.9 IR SENSOR
FIG2.10 IR SENSOR CIRCUIT
FIG2.11 PIN CONFIGURATION OF LM324 TOP VIEW
FIG2.12 PIN DIAGRAM OF L293D
FIG2.13 CIRCUIT DIAGRAM OF H BRIDGE
FIG 2.14 BLOCKS DIAGRAM OF L293D
FIG 2.15 DC MOTOR
FIG2.17 LIFTER ASSEMBLY
1.1 INTRODUCTION TO LINE FOLLING ROBOT
A line follower robot is basically a robot designed to follow a ‘line’ or path already
predetermined by the user. This line or path may be as simple as a physical white line
on the floor or as complex path marking schemes e.g. embedded lines, magnetic
markers and laser guide markers. In order to detect these specific markers or ‘lines’,
various sensing schemes can be employed. These schemes may vary from simple low
cost line sensing circuit to expansive vision systems. The choice of these schemes
would be dependent upon the sensing accuracy and flexibility required. From the
industrial point of view, line following robot has been implemented in semi to fully
autonomous plants. In this environment, these robots functions as materials carrier to
deliver products from one manufacturing point to another where rail, conveyor and
gantry solutions are not possible. Apart from line following capabilities, these robots
should also have the capability to navigate junctions and decide on which junction to
turn and which junction ignore. This would require the robot to have 90 degree turn
and also junction counting capabilities. To add on to the complexity of the problem,
sensor positioning also plays a role in optimizing the robots performance for the tasks
Line-following robots with pick- and- placement capabilities are commonly used in
manufacturing plants. These move on a specified path to pick the components from
specified locations and place them on desired locations. Basically, a line-following
robot is a self-operating robot that detects and follows a line drawn on the floor. The
path to be taken is indicated by a white line on a black surface. The control system
used must sense the line and man oeuvre the robot to stay on course while constantly
correcting the wrong moves using feedback mechanism, thus forming a simple yet
effective closed- loop system.
Industrial robots are found in a variety of locations including the automobile and
manufacturing industries. Robots cut and shape fabricated parts, assemble machinery
and inspect manufactured parts. Some types of jobs robots do: load bricks, die cast,
drill, fasten, forge, make glass, grind, heat treat, load/unload machines, machine parts,
handle parts, measure, monitor radiation, run nuts, sort parts, clean parts, profile
objects, perform quality control, rivet, sand blast, change tools and weld.
Outside the manufacturing world robots perform other important jobs. They can be
found in hazardous duty service, CAD/CAM design and prototyping, maintenance
jobs, fighting fires, medical applications, military warfare and on the farm.
1.2 TYPES OF ROBOTS AS PER APPLICATIONS
Nowadays, robots do a lot of different tasks in many fields.
And this number of jobs entrusted to robots is growing steadily.
That's why one of the best ways how to divide robots into types is
a division by their application.
1.2.1 INDUSTRIAL ROBOTS: Robots today are being utilized
in a wide variety of industrial applications. Any job that involves
repetitiveness, accuracy, endurance, speed, and reliability can be
done much better by robots, which is why many industrial jobs
that used to be done by humans are increasingly being done by
1.2.2 MOBILE ROBOTS: Also known as Automated Guided
Vehicles, or AGVs, these are used for transporting material over
large sized places like hospitals, container ports, and warehouses,
using wires or markers placed in the floor, or lasers, or vision, to
sense the environment they operate in. An advanced form of the
AGV is the SGV, or the Self Guided Vehicle, like PatrolBot
Gofer, Tug, and Specie-Minder, which can be taught to
autonomously navigate within a space.
1.2.3 AGRICULTURE ROBOTS: Although the idea of robots
planting seeds, ploughing fields, and gathering the harvest may
FIG 1.1 INDUSTRIAL
FIG 1.2 AGRICULTURAL
FIG 1.3 TELE ROBOT
seem straight out of a futuristic science fiction book, nevertheless there are several
robots in the experimental stages of being used for agricultural purposes, such as
robots that can pick apples.
1.2.4 TELEROBOTS: These robots are used in places that are hazardous to humans,
or are inaccessible or far away. A human operator located at a distance from a Tele
robot controls its action, which was accomplished with the arm of the space shuttle.
Telerobots are also useful in nuclear power plants where they, instead of humans, can
handle hazardous material or undertake operations potentially harmful for humans.
1.2.5 SERVICE ROBOTS: The Japanese are in the forefront in these types of robots.
Essentially, this category comprises of any robot that is used outside an industrial
facility, although they can be sub-divided into two main types of robots: one, robots
used for professional jobs, and the second, robots used for personal use. Amongst the
former type are the above mentioned robots used for military use, and then there are
robots that are used for underwater jobs, or robots used for cleaning hazardous waste,
HUMANOID ROBOT : A humanoid robot is a robot with its body shape built to
resemble that of the human body. A humanoid design might be for resemble humans
functional purposes, such as interacting with human tools and environments, for
experimental purposes, such as the study of bipedal locomotion, or for other purposes.
In general, humanoid robots have a torso, a head, two arms, and two legs, though
some forms of humanoid robots may model only part of the body, for example, from
the waist up. Some humanoid robots may also have heads designed to replicate human
facial features such as eyes and mouths. Androids are humanoid robots built to
1.3 PROJECT AIM AND OBJECTIVE:
The aim of this project is design an autonomous robot with complete system allow
the robot wander about its environment and to interact with certain object that its
encounter. In order to achieve the aim of this project, several objectives are needed to
1.4 IMPORTANCE OF WORK:
In this scenario, the industry having a problem by human life in some hazardous duty
service. Robot can work in environments so hazardous that an unprotected human
would quickly die
1.5 SCOPE OF PROJECT:
Industrial automation, equipment and goods carrier, tour guide in museum, deliver the
mail in office building, delivers medication in the hospital, can be used in place of
crane in various lifting and carriage application.
1.6 INTRODUCTION TO EMBEDDED SYSTEMS
An embedded system is a system which is going to do a predefined specified task is
the embedded system and is even defined as combination of both software and
hardware. A general-purpose definition of embedded systems is that they are devices
used to control, monitor or assist the operation of equipment, machinery or plant.
"Embedded" reflects the fact that they are an integral part of the system. At the other
extreme a general-purpose computer may be used to control the operation of a large
complex processing plant, and its presence will be obvious.
All embedded systems are including computers or microprocessors. Some of these
computers are however very simple systems as compared with a personal computer.
The simplest devices consist of a single microprocessor (often called a "chip”), which
may itself be packaged with other chips in a hybrid system or Application Specific
Integrated Circuit (ASIC). Its input comes from a detector or sensor and its output
goes to a switch or activator which (for example) may start or stop the operation of a
Figure: 1.4 Block diagram of Embedded System
Embedded consist of both software and hardware:
Memory: It is used to store data or address.
Peripherals: These are the external devices connected
Processor: It is an IC which is used to perform some task
Applications of embedded systems
Manufacturing and process control
Buildings and premises
Office systems and mobile equipment
Banking, finance and commercial
Medical diagnostics, monitoring and life support
Testing, monitoring and diagnostic systems
CHAPTER – 2
2.1 AT89S52 MICROCONTROLLERS:
The AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller with
4K bytes of programmable Flash memory and erasable read only memory (PEROM).
The device is manufactured using Atmel’s high-density nonvolatile memory
technology and is compatible with the industry- standard MCS-51 instruction set and
pin out. The on-chip Flash allows the program memory to be reprogrammed in-system
or by a conventional nonvolatile memory programmer. By combining a
versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89S52 is a
powerful microcontroller which provides a highly-flexible and cost-effective solution
to many embedded control applications.
2.2 PIN CONFIGURATIONS:
FIGURE 2.1 PIN DIAGRAM AT89S52
2.2.1 Standard Features:
4K bytes of Flash,
128* 8 bits of internal RAM,
32 programmable I/O lines,
Full static operation: 0Hz to 24 MHz
Three level program memory Lock
two 16-bit timer/counters,
a six-vector two-level interrupt architecture,
2.2.2 PIN DESCRIPTION
Port 0 is an 8-bit open drain bidirectional I/O port. As an output port, each pin can
sink eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as
high impedance inputs. Port 0 can also be configured to be the multiplexed low order
address/data bus during accesses to external program and data memory. In this mode,
P0 has internal pull ups. Port 0 also receives the code bytes during Flash
programming and outputs the code bytes during program verification. External pull
ups are required during program verification.
Port 1 is an 8-bit bidirectional I/O port with internal pull ups. The Port 1 output
buffers can sink/source four TTL inputs. When 1s are written to Port 1 pins, they are
pulled high by the internal pull ups and can be used as inputs. As inputs, Port 1 pins
that are externally being pulled low will source current (IIL) because of the internal
pull ups. Port 1 also receives the low-order address bytes during Flash programming.
Port 2 is an 8-bit bidirectional I/O port with internal pull ups. The Port 2 output
buffers can sink/source four TTL inputs. When 1s are written to Port 2 pins, they are
pulled high by the internal pull ups and can be used as inputs. As inputs, Port 2 pins
that are externally being pulled low will source current (IIL) because of the internal
pull ups. Port 2 emits the high-order address byte during fetches from external
program memory and during accesses to external data memory that use 16-bit
addresses (MOVX @ DPTR). In this application, Port 2 uses strong internal pull-ups
when emitting 1s. During accesses to external data memory that use 8-bit addresses
(MOVX @ RI), Port 2 emits the contents of the P2 Special Function Register. Port 2
also receives the high-order address bits and some control signals during Flash
programming and verification.
Port 3 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 3 output
buffers can sink/source four TTL inputs. When 1s are written to Port 3 pins, they are
pulled high by the internal pull-ups and can be used as inputs. As inputs, Port 3 pins
that are externally being pulled low will source current (IIL) because of the pull-ups.
Port 3 also serves the functions of various special features of the AT89S52, as shown
in the following table. Port 3 receives some control signals for Flash Programming.
Table: 2.1 port 3 alternate functions
Reset input. A high on this pin for two machine cycles while the oscillator is running
resets the device.
Address Latch Enable (ALE) is an output pulse for latching the low byte of the
address during accesses to external memory. In normal operation, ALE is emitted at a
constant rate of 1/6 the oscillator frequency and may be used for external timing or
clocking purposes. Note, however, that one ALE pulse is skipped during each access
to external data memory. If desired, ALE operation can be disabled by setting bit 0 of
SFR location 8EH. With the bit set, ALE is active only during a MOVX or MOVC
instruction. Otherwise, the pin is weakly pulled high.
Program Store Enable (PSEN) is the read strobe to external program memory. When
the AT89S52 is executing code from external program memory, PSEN is activated
twice each machine cycle, except that two PSEN activations are skipped during each
access to external data memory.
External Access Enable. EA must be strapped to GND in order to enable the device to
fetch code from external program memory locations starting at 0000H up to FFFFH.
Note, however, that if lock bit 1 is programmed, EA will be internally latched on
reset. EA should be strapped to VCC for internal program executions.
Input to the inverting oscillator amplifier and input to the internal clock operating
Output from the inverting oscillator amplifier.
2.2.3 CRYSTAL OSILLATOR
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 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.
A crystal is a solid in which the constituent atoms, molecules, or ions are packed in a
regularly ordered, repeating pattern extending in all three spatial dimensions.
Almost any object made of an elastic material could be used like a crystal, with
appropriate transducers, since all objects have natural resonant frequencies
of vibration. For example, steel is very elastic and has a high speed of sound. It was
often used in mechanical filters before quartz. The resonant frequency depends on
size, shape, elasticity, and the speed of sound in the material. High-frequency crystals
are typically cut in the shape of a simple, rectangular plate. Low-frequency crystals,
such as those used in digital watches, are typically cut in the shape of a tuning fork.
For applications not needing very precise timing, a low-cost ceramic resonator is often
used in place of a quartz crystal.
When a crystal of quartz is properly cut and mounted, it can be made to distort in
an electric field by applying a voltage to an electrode near or on the crystal. This
property is known as electrostriction or inverse piezoelectricity. When the field is
removed, the quartz will generate an electric field as it returns to its previous shape,
and this can generate a voltage. The result is that a quartz crystal behaves like a circuit
composed of an inductor, capacitor and resistor, with a precise resonant frequency.
Quartz has the further advantage that its elastic constants and its size change in such a
way that the frequency dependence on temperature can be very low. The specific
characteristics will depend on the mode of vibration and the angle at which the quartz
is cut (relative to its crystallographic axes). Therefore, the resonant frequency of the
plate, which depends on its size, will not change much, either. This means that a
quartz clock, filter or oscillator will remain accurate. For critical applications the
quartz oscillator is mounted in a temperature-controlled container, called a crystal
oven, and can also be mounted on shock absorbers to prevent perturbation by external
Figure 2.3diagram of typical crystal oscillator generating a frequency of 11.0592
2.2.4 CERAMIC CAPACITOR:
A ceramic capacitor is a fixed value capacitor in which ceramic material acts as the
dielectric. It is constructed of two or more alternating layers of ceramic and a
metal layer acting as the electrode The composition of the ceramic material defines
the electrical behavior and therefore applications. Ceramic capacitors are divided into
two application classes:
Class 1 ceramic capacitors offer high stability and low losses for resonant
Class 2 ceramic capacitors offer high volume efficiency for buffer, by-pass and
Ceramic capacitors, especially the multilayer style (MLCC), are the most produced
and used capacitors in electronic equipment that incorporate approximately one
trillion pieces (1000 billion pieces) per year.
Ceramic capacitors of special shapes and styles are used as capacitors for RFI/ MFI
suppression, as feed-through capacitors and in larger dimensions as power capacitors
2.2.5 Pull-up resister:
Pull up resister are used in electronic logic circuits to ensure that inputs to logic
systems settle at expected logic levels if external devices are disconnected or high
impedance is introduced. They may also be used at the interface between two different
types of logic devices, possibly operating at different power supply voltages
When the switch is open the voltage of the gate input is pulled up to the level of Vin.
When the switch is closed, the input voltage at the gate goes to ground.
A pull-up resistor weakly "pulls" the voltage of the wire it is connected to towards its
voltage source level when the other components on the line are inactive. When all
other connections on the line are inactive, they are high-impedance and act like they
are disconnected. Since the other components act as though they are disconnected, the
circuit acts as though it is disconnected, and the pull-up resistor brings the wire up to
the high logic circuits When another component on the line goes active, it will
override the high logic level set by the pull-up resistor. The pull-up resistor ensures
that the wire is at a defined logic level even if no active devices are connected to it.
A pull-down resistor works in the same way but is connected to ground. It holds the
logic signal near zero volts when no other active device is connected.
Figure 2.4 pull up resister
ELECTROLYTIC CAPACITOR: electrolytic capacitor is a capacitor that uses
an electrolytic (an ionic conducting liquid) as one of its plates to achieve a larger
capacitance per unit volume than other types. The large capacitance of electrolytic
capacitors makes them particularly suitable for passing or bypassing low-frequency
signals and storing large amounts of energy. They are widely used in power supply
and interconnecting stages of amplifiers at audio frequencies. An electrolytic capacitor
will generally have higher leakage current than a comparable (dry) capacitor, and may
have significant limitations in its operating temperature range, parasitic resistance and
inductance, and the stability and accuracy of its capacitance value.
FIGURE 2…. A Electrolytic capacitor
2.2.7 BASES OF IC : IC sockets are generally for preventing damage to IC's from
soldering and while testing multiple circuits. These are made from Black
Thermoplastic and tin-plated alloy contacts. One end is notched to aid in
identification. They can be mounted end to end to suit longer IC's
Figure 2.5base of 8 pin
2.2.8 RESISTOR: These do exactly what they say, they resist the flow of electron.
These are necessary for several reasons. They control how much current goes down to
each wire. They control the power uses. They can control voltages (since current,
The last point is important as it is the basis of Ohm's law, V=IR. Voltage = Current x
Resistance. For example, suppose you take a resistor and connect the two ends of a
battery with it. You know that your battery is 9V (or whatever) and you know the
resistor is 3Kohm (determined by the color stripes on the resistor), so 9V divided by
3Kohm is .003amps (3 milliamps). So why is this information useful? Well now that
you know the current, you can determine other useful things such as power. P=IV.
You will notice that if you increase resistance, you decrease current. If you decrease
current, you decrease power use. Put a 1ohm resistor between the battery and it will
get so hot it could burn because of the power use. Use a 100Kohm resistor and almost
no power at all will be used.
Figure 2.6 Resistor
2.2.9 VOLTAGE REGULATOR
Figure 2.7 voltage regulator ic 7805
A voltage regulator is an electrical regulator designed to automatically maintain a
constant voltage level. It may use an electromechanical mechanism, or passive or
active electronic components. Depending on the design, it may be used to regulate one
or more AC or DC voltages. There are two types of regulator are they.
Positive Voltage Series (78xx) and
Negative Voltage Series (79xx)
78xx: ’78’ indicate the positive series and ‘xx’indicates the voltage rating. Suppose
7805 produces the maximum 5V.’05’indicates the regulator output is 5V.
79xx: ’78’ indicate the negative series and ‘xx’indicates the voltage rating.
Suppose 7905 produces the maximum -5V.’05’indicates the regulator output is -5V.
These regulators consists the three pins there are
Pin1: It is used for input pin.
Pin2: This is ground pin for regulator
Pin3: It is used for output pin. Through this pin we get the output.
2.2.10 IR SENSORS
An Infra-Red sensor detects Infra-Red light/white light from a particular object/line
and then converts light energy to electrical energy. An IR sensor pair consists of an
emitter and a detector. The emitter is blue in color and the detector can be grey, black
or white in color.
figure 2.8 IR sensor
2.2.11 IR EMITTER
An infra-red emitter is a Light Emitting Diode (LED) made from Gallium Arsenide. It
detects IR energy at a wavelength of 880nm and emits the same. 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 variable current source. Greater amount
of IR light cause greater currents to flow through the collector-emitter leads.
The variable current traveling through the resistor causes a voltage drop in the pull-up
resistor. This voltage is measured as the output of the device.
2.2.12 IR DTECTOR
An infra-red detector is a photo detector. It detects IR energy emitted by the emitter
and converts it into electrical energy.
The main principle involved in the conversion of light energy to electrical energy is
IR sensor circuit to detect a black line on white background:
Fig: 2.9. IR sensor circuit
The output is taken at negative terminal of IR detector.
The output can be taken to a microcontroller either to its ADC (Analog to Digital
Converter) or LM 339 can be used as a comparator.
2.2.13 LM 324
Wide gain bandwidth : 1.3MHZ input common-mode voltage range
Includes ground .large voltage gain: 100DB .very low supply current/amplify :
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
It is a comparator ic
These circuits consist of four independent, high gain, internally frequency
compensated operational amplifiers .They operate from a single power supply over a
wide range of voltages. Operation from split power supplies is also possible and the
low power supply current drain is independent of the magnitude of the power supply
Fig:2.10. pin configuration top view
L2 9 3D INPUT
4 5 12 13
2.2.14 L293D( H-BRIDGE):
LM+ OUTPUT FOR
Figure 2.11 PIN DIAGRAM OF L293D IC
VCC1 - LOGIC
Motor are arrange in a fashion called H bridge. H bridge is an electronics circuits
which enables a voltage to be applied across the load in either direction. It allow a
circuit full control, that is an H bridge, a microcontroller logic chip, or remote control
can electronically command the motor to go forward ,reverse and brake
An H-bridge is an electronic circuit which enables DC electric motors to be run
forwards or backwards. These circuits are often used in robotics. H-bridges are
available as integrated circuits, or can be built from discrete components.
Figure 2.12 circuit diagram of H bridge
The two basic states of a H-bridge. The term "H-bridge" is derived from the typical
graphical representation of such a circuit. An H-bridge is built with four switches
(solid-state or mechanical). When the switches S1 and S4 (according to the first
figure) are closed (and S2 and S3 are open) a positive voltage will be applied across
the motor. By opening S1 and S4 switches and closing S2 and S3 switches, this
voltage is reversed, allowing reverse operation of the motor.
Using the nomenclature above, the switches S1 and S2 should never be closed at the
same time, as this would cause a short circuit on the input voltage source. The same
applies to the switches S3 and S4. This condition is known as shoot-through.
2.2. 13.1 OPERATION
The H-Bridge arrangement is generally used to reverse the polarity of the motor, but
can also be used to 'brake' the motor, where the motor comes to a sudden stop, as the
motors terminals are shorted, or to let the motor 'free run' to a stop, as the motor is
effectively disconnected from the circuit. The following table summarizes operation.
S1 S2 S3 S4 Result
1 0 0 1 Motor moves right
0 1 1 0 Motor moves left
0 0 0 0 Motor free runs
0 1 0 1 Motor brakes
Table: 2.2 H-bridge switch operation
2. 2.13.2 H-BRIDGE DRIVER
The switching property of this H-Bridge can be replaced by a Transistor or a Relay or
A Mosfet or even by an IC. Here we are replacing this with an IC named L293D as
the driver whose description is as given below. The Device is a monolithic integrated
high voltage, high current four channel driver designed to accept standard DTL or
TTL logic levels and drive inductive loads as and switching power transistors. To
simplify use as two bridges each pair of channels is equipped with an enable input. A
separate supply input is provided for the logic, allowing operation at a lower voltage
and internal clamp diodes are included. This device is suitable for use in switching
applications at frequencies up to 5 kHz. The L293D is assembled in a 16 lead plastic
package which has 4 center pins connected together and used for heat sinking The
L293D is assembled in a 20 lead surface mount which has 8 center pins connected
together and used for heat sinking.
2. 13.3 FEATURES
600mA OUTPUT CURRENT CAPABILITY
1.2A PEAK OUTPUT CURRENT (non repetitive)
LOGICAL "0" INPUT VOLTAGE UP TO 1.5 V
(HIGH NOISE IMMUNITY)
INTERNAL CLAMP DIODES
184.108.40.206 BLOCK DIAGRAM:
Figure 2.13block diagram of LM293D
2.2. 14 DC MOTORS:
These are very commonly used in robotics. DC motors can rotate in both directions
depending upon the polarity of current through the motor. These motors have free
running torque and current ideally zero. These motors have high 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 555 timer IC with adjusted duty cycle.
Varying current through the motor varies the torque.
FIGURE 2.14(DC MOTOR
GRIPPER ARM: The gripper module is state of the art robotic arm which can be
used in various 'pick and place' kind of robots. It works on DC Motor (9 to 12V
Change in rotation direction of the DC Motor, generates Jaw Open & Close
The DC motor can be easily be controlled with the help of DPDT Switch (manual
mode) or with the help of any micro controller along with L293D Motor Driver
FIGURE3…Gripper orthogonal view, main view
LIFTER ASSEMBLY: It is made from laser cut Metal and acrylic. There is
a worm gear and spur gear assembly which is attached with a DC motor (9 to
10 volt) to provide torque so that gripper can pick and lift the load.
Figure 3…..Lifter assembly
• Gripper assembly Plates.
• Fiber Grippers-2nos.
• 45 RPM Motor-1nos.
• Worm Gear-1nos.
• Spur Gear-2nos.
• Different Screws and nuts.
Worm drive: Worm drive is a gear arrangement in which a worm (which is a gear in
the form of a screw) meshes with a worm gear (which is similar in appearance to
a spur gear, and is also called a worm wheel). The terminology is often confused by
imprecise use of the term worm gear to refer to the worm, the as a worm gear, or the
worm drive unit.
Like other gear arrangements, a worm drive can reduce rotational speed or allow
higher torque to be transmitted. The image shows a section of a gear box with a worm
gear being driven by a worm. A worm is an example of a screw, one of the six simple
Figure: 3.12 worm drive arrangement
Figure 3.125 (a) Spur gear (b) Worm gear, (Made by acrylic fiber)
TRACK WHEEL: Track wheel is a circular wheel with rubber grip fastened on DC
motor shaft by screw. Track wheel provide help in movement of robot in any
Figure 3.125 Track wheel
CHASSIS: A chassis consists of an internal framework that supports a man-made
object in its construction and use. It is analogous to an animal's skeleton. An example
of a chassis is the under part of a motor vehicle, consisting of the frame (on which the
body is mounted). Here metallic chassis is used.
FIGURE 3.212 A metallic chassis
POWER SUPPLY: To provide energy to DC motors for movement of robot A
Battery of DC (6 volt to 12 V, 4.5A) is being used.
Figure 3.225 Battery
3. WORKING PROCEDURE
Robotics is an interesting subject to discuss about and in this advanced world Robots
are becoming a part of our life. In this project we are going to discuss about a robot
which is capable of following a line without the help of any external source.
The Embedded Line following robot uses four motors to control rear wheels and the
single front wheel is free. It has 2-infrared sensors on the bottom for detection of
white tracking tape. When 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 will be
low when it receives an input from the sensor
When a sensor is on the black line it reads 0 and when it is on the bright
surface read 1. and sensor module gives the value to controller to generate
control signal according to programmer
When both right and left sensors are on bright surface (read 1) then both
couple of motor move.
When left sensor comes in black (for white line tracer) region then left motor
stops while right motor continue to move so that left turn takes place and robot
returns on black line.
When right sensor comes in black region then right motor stops while left
motor continue to move so that right turn takes place and robot returns on
By correcting the path robot move to destination.
When both sensors comes on black surface simultaneously (read 0) than both
When both sensor read 0 simultaneously and both wheel motor stops than
immediately motor for right and left movement of lifter arm start moving for
some definite time duration using Timer of controller.
After movement of left- right motor of lifter the motor for lifting and gripping move
one by one for some definite time duration defined in program using timer of
The lifter and gripper arm have various gear arrangement, so that after
movement of each motor of arm one by one the arm pick an object or work
After movement of gripper motor, all the motor of arm starts moving in
reverse direction of previous movement, one by one.
After picking an object by gripper and lifter arm, either left or right wheel
motor starts moving until the robot reverts his path and both sensor comes on
bright surface after crossing a black surface between.
After reversing the path robot move by correcting path and reach to destination
At destination both sensors read 0 simultaneously, so that previous process is
repeated and the object is now placed by same movement of motor.
The robot revert its path and repeats the pick and place process again and again
Robot movement is automatic.
Fit and Forget system.
Used for long distance applications.
Used in home, industrial automation.
Simplicity of building
LFR follows a black line about 1 or 2 inches in width on a white surface.
LFR are simple robots with an additional sensors placed on them.
Needs a path to run either white or black since the IR rays should reflectfrom
the particular path.
Slow speed and instability on different line thickness or hard angles.
Guidance system for industrial robots moving on shop floor etc.
4. SOFTWARE TOOLS
4.1 KEIL SOFTWARE:
Keil compiler is software used where the machine language code is written and
compiled. After compilation, the machine source code is converted into hex code
which is to be dumped into the microcontroller for further processing. Keil compiler
also supports C language code.
The objective of the line following robot is to follow a line on its given path which is
obtained for which it uses IR sensors which detects the line and sends the information
to LM324 comparator and then to H bridge which controls the working of the wheel’s.
Microcontroller controls the other operations.
4.2 SAFETY REQUIREMENTS
The various safety requirements which were considered while designing the
robot are decided as follows:
1. The Robot should not be programmed such that it should damage the Battery
while holding it in its gripper.
2. Correct holding position should be set as if it not set then while movement of
the Robot it may drop the Lead Batteries which can arise a Hazardous situation
in the industry.
3. The Robot should be interfaced properly with the sensors been placed near the
Belt conveyor so as to know when the belt conveyor is to be stopped or to be
started to move the batteries ahead.
4. Load carrying capacity should be maintained as it should be always more than
the default load which is to be shifted.
CONCLUSION AND FUTURE SCOPE
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.
Smarter versions of line followers are used to deliver mails within office
building and deliver medications in a hospital.
This technology has been suggested for running buses and other mass transit
systems and may end up as a part of autonomous cars navigating the freeway.
Used in heavy machinery industry
Used where high load and risky operation going on
Use in place of the crane
The 8051 Microcontroller and Embedded Systems Using Assembly and C
By Muhammad Ali Mazidi, Janice Gillispie Mazidi & Ro linD. McKinley
Atmel Corp. Makers of the AVR
EMBEDDED SYSTEM BY RAJ KAMAL