embedded system report

CHAPTER-1
Introduction to Robotics
In practical usage, a Robot is a mechanical device which performs automated physical
tasks, either according to direct human supervision, a pre-defined program, or a set of
general guidelines using artificial intelligence techniques. Robots are typically used to
do the tasks that are too dirty, dangerous, difficult, repetitive or dull for humans. This
usually takes the form of industrial robots used in manufacturing lines. Other
applications include toxic waste cleanup, underwater and space exploration, mining,
search and rescue, and mine finding. Recently however, robots are finding their way
into the consumer market with uses in entertainment, vacuum cleaning, and lawn
mowing. A robot may include a feedback-driven connection between sense and
action, not under direct human control, although it may have a human override
function. The action may take the form of electro-magnetic motors or actuators (also
called effectors) that move an arm, open and close grips, or propel the robot. The step
by step control and feedback is provided by a computer program run on either an
external or embedded computer or a microcontroller. By this definition, a robot may
include nearly all automated devices.
Ask a number of people to describe a robot and most of them will answer they look
like a human. Interestingly a robot that looks like a human is probably the most
difficult robot to make. It is usually a waste of time and not the most sensible thing to
model a robot after a human being. A robot needs to be above all functional and
designed with qualities that suit its primary tasks. It depends on the task at hand
whether the robot is big, small, is able to move or nailed to the ground. Each and
every task means different qualities, form and function; a robot needs to be designed
with the task in mind.
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1.1 Types of robots
Figure 1.1 mobile robots
Mobile robots are able to move, usually they perform task such as search areas. A
prime example is the Mars Explorer, specifically designed to roam the mars surface.
Mobile robots are a great help to such collapsed building for survivors Mobile robots
are used for task where people cannot go. Either because it is too dangerous of
because people cannot reach the area that needs to be searched.
Mobile robots can be divided in two categories:
Figure 1.2 rolling robots
1. Rolling Robots: Rolling robots have wheels to move around. These are the type
of robots that can quickly and easily search move around. However they are only
useful in flat areas, rocky terrains give them a hard time. Flat terrains are their
territory.
2

Figure 1.3 walking robots
2. Walking Robots: Robots on legs are usually brought in when the terrain is rocky
and difficult to enter with wheels. Robots have a hard time shifting balance and keep
them from tumbling. That’s why most robots with have at least 4 of them, usually
they have 6 legs or more. Even when they lift one or more legs they still keep their
balance. Development of legged robots is often modeled after insects or crawfish.
3

CHAPTER 2
INTRODUCTION TO LINE PATH 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.
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.
In our minor project we had built a collision avoidance system in which we made a
robot which could detect objects in its front and rear and could avoid a collision using
infrared radiations.
We have extended the same project as major making it a line path follower and a
collision avoidance system altogether. In this our robot will be able to detect white
line only leaving all other colors undetected and also it will be able to detect obstacles
in its front making the robot turn 360 degrees and follow the white line again.
For this we had to make certain changes in our circuit. Earlier 20 pin microcontroller
was used in our project which is now changed to a 40 pin one.
We also included LED-LDR sensors for color detection and we have attached a
comparator IC for control of sensors. Two 9 volts motors have been used for which
we added a motor driving IC also.
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Figure 2.1: Basic Block Diagram of Line Path Follower
The robot uses IR sensors to sense the line, an array of 8 IR LEDs (Tx) and sensors
(Rx), facing the ground has been used in this setup. The output of the sensors is an
analog signal which depends on the amount of light reflected back, this analog signal
is given to the comparator to produce 0s and 1s which are then fed to the
microcontroller.
L4 L3 L2 L1 R1 R2 R3 R4
Left Center Right
Sensor Array
Starting from the center, the sensors on the left are named L1, L2, L3, L4 and those
on the right are named R1, R2, R3, and R4.
Let us assume that when a sensor is on the line it reads 0 and when it is off the line it
reads 1. The microcontroller decides the next move according to the algorithm given
below which tries to position the robot such that L1 and R1 reads 0 rest reads 1.
L4 L3 L2 L1 R1 R2 R3 R4
5

1 1 1 0 0 1 1 1
Left Center Right
Desired State L1=R1=0, and Rest=1
Figure 2.2: circuit Diagram of Line Path Follower
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CHAPTER 3
COMPONENT LIST
Component Specifications Quantity
Microcontroller AT89S51 1
Sensors LED-LDR 3
TSOP 1
Actuators DC motor 2
Motor driving IC IC L293D 1
Comparator IC IC LM324 1
Motor 100 rpm, 12 V 2
Crystal oscillator 11.054 MHz 1
Battery 6V 1
Regulator IC IC7805, IC7812 1
Resistors 10 Kohm 5
20 Kohm 6
1 Kohm 10
Capacitors 33pF 7
1uF 8
7

CHAPTER 4
SENSORS
A sensor is a type of transducer. A sensor is a device that converts a physical
phenomenon into an electrical signal. As such, sensors represent part of the interface
between the physical world and the world of electrical devices, such as computers.
The other part of this interface is represented by actuators, which convert electrical
signals into physical phenomena. Sensors are used in everyday life. Applications
include automobiles, machines, aerospace, medicine, industry and robotics.
4.1 Key Characteristics of Sensors
There are a vast number of different sensors being used in robotics, applying different
measurement techniques, and using different interfaces to a controller.
What is important is to find the right sensor for a particular application. This involves
the right measurement technique, the right size and weight, the right operating
temperature range and power consumption, and of course the right price range.
The key characteristics of sensors are as:
S. No. KEY POINT CONSIDERATION
1. Range How far the object to be detected?
2. Environment How dirty or dark is the environment?
3. Accessibility What accessibility is there to both sides of
the object to be detected?
4. Wiring Is wiring possible to one or both sides of
the object?
5. Size What size is the object?
6. Consistency Is the object consists in size, shape, and
reflectivity?
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7. Requirements What are mechanical and electrical
requirements?
8. Output signal What kind of output is needed?
9. Logic functions Are logic function needed at the sensing
point?
10. Integration Is the system required to be integrated?
Table 4.1 key characteristics of sensors
4.2 Types of sensors
Sensors are classified broadly in two types:
1. Energy detected.
2 Signal detection.
4.2.1 Energy detected
Since there is a significant exchange of energy involved, on the basis of energy
sensors are classified as:
S.No. Energy Example
1. Thermal Thermometer, bolometer
2. Electromagnetic Multimeter, RADAR
3. Mechanical Pressure gauge, strain
gauge
4. Chemical Oxygen sensors, pH glass
5. Optical radiation Photo detector,
Fiber optics
6. Ionizing radiation Neutron detection
7. Acoustic Microphones,
Ultrasonic
Table 4.2 on the basis of energy sensors
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There are much more examples & types of sensor e.g. Motion sensor, orientation
sensor etc.
4.2.2 Signal detection
Different sensors require different sensing strategies. There are three modes of signal
detection used by sensors:
1. Through-beam detection
2. Reflex detection.
3. Proximity detection.
Through beam detection method
The through-beam method requires that the source and detector are positioned
opposite each other and the light beam is sent directly from source to detector. When
an object passes between the source and detectors, the beam is broken; signal shows
the detection of an object.
Through-beam detection generally provides the longest range of the three operating
modes and provides high power at shorter range to penetrate steam, dirt, or other
contaminants between the source and detector. Alignment of the source and detector
must be accurate.
Reflex detection method
The reflex method requires that the source and detector are installed at the same side
of the object to be detected. The light beam is transmitted from the source to a retro
reflector that returns the light to the detector. When an object breaks a reflected beam,
the object is detected.
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The reflex method is widely used because it is flexible and easy to install and
provides the best cost-performance ratio of the three methods. The object to be
detected must be less reflective than retro reflector.
Proximity detection method
The proximity requires that the source and detector are installed on the same side of
the object to be detected and aimed at a point in front of the sensor. When an object
passes in front of source and detector, light from the source is reflected from the
object’s surface back to the detector, and the object is detected.
The only difference between reflex detection & proximity method is reflection of
signal from retro reflector and from object to be detected. Each sensor type has a
specific operating range. In general through-beam sensor offer the greatest range,
followed by reflex sensors, then by proximity sensors.
4.2.3 Infrared Emitter Detector
Figure 4.1 Infrared Emitter Detector
Description: The infrared emitter detector pair act as an eye with a flashlight in the
infrared spectrum. The detector (a transistor) detects all ambient infrared light. The
emitter (a LED) emits infrared light into an otherwise dark (in the infrared spectrum)
room.
Availability: It is easily available anywhere, very cheap.
Power: Low, Typical LED power requirements.
4.2.4 LED & LDR Sensor:-
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Figure 4.2 LED & LDR Sensor
We have used this sensor in our project as this is one of the cheapest sensors available
in the market.
FEATURES
• Input common-mode voltage range
• Includes ground
• Large voltage gain: 100dB
• very low supply current/amplitude : 375mA
• Low input bias current: 20nA
• Low input offset voltage: 5mV max.
• Low input offset current: 2nA
DESCRIPTION
We have used this sensor in our project as LED & LDR sensor is one of the cheapest
sensor used in mobile robotics. The major parts of this sensor are as:
Light-dependent resistances (LDR): are cheap light sensors. The light dependent
resistor (LDR) is a sensor whose resistance decreases when light impinges on it. The
schematic symbol of LDR is as:-
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Figure 4.3 symbol of LDR
This kind of sensor is commonly used in light sensor circuits in open areas. LDR’s are
made of semiconductors as light sensitive materials, on an isolating base. The most
common semiconductors used in this system are cadmium sulphide, lead sulphide,
germanium, silicon and gallium arsenide.
The light falling on the brown zigzag lines on the sensor causes the resistance of the
device to fall. This is known as a negative co-efficient. There are some LDRs that
work in the opposite way i.e. their resistance increases with light called positive co-
efficient. The resistance of the cell varies depending on the intensity of the light
striking it. When no light strikes the cell, the device exhibits very high resistance,
typically in the high 100 kilo ohms, or even mega ohms. Light reduces the resistance,
usually significantly. An LDR may be connected either way round and no special
precautions are required when soldering.
Light-emitting diode (LED): is a semiconductor device that emits incoherent
narrow-spectrum light when electrically biased in the forward direction of the p-n
junction. The color of the emitted light depends on the composition and condition of
the semiconducting material used, and can be infrared, visible, or near ultraviolet.
Figure 4.4 symbol of LED
Precautions:
• Don’t bother using this circuit outside, the sun will flood your IR detector and
make it useless.
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• Certain indoor lighting can also emit IR interference.
• Only if you modulate the IR emitter and set the detector to only detect
modulated IR can you use this outside. This is commonly done with Sharp IR
rangefinders.
• Tweaking is necessary to determine sensitivity of your circuit. Sensitivity will
help increase range but also increase ambient interference.
By using certain resistor values, your IR emitter detector can also detect color, such as
for line tracking.
Maximum Rating
Table 4.3 Maximum Rating
Like a normal diode, an LED consists of a chip of semi-conducting material
impregnated, or doped, with impurities to create a p-n junction. As in other diodes,
current flows easily from the p-side, or anode, to the n-side, or cathode, but not in the
reverse direction. Charge-carriers electrons and holes flow into the junction from
electrodes with different voltages. When an electron meets a hole, it falls into a lower
energy level, and releases energy in the form of a photon. The wavelength of the light
emitted, and therefore its color, depends on the band gap energy of the materials
forming the p-n junction.
This is photo of 5mm. white/white LED which is used.
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LEDs are made from a variety of inorganic semiconductor materials. The most
common color of led & materials used are as follows:
S No Material Used Color
1. Aluminum gallium
arsenide (AlGaAs)
red and
infrared
2. Aluminum gallium
phosphide (AlGaP)
green
3. Gallium phosphide (GaP) red, yellow
and green
4. InGaN-GaN White
Table 4.4 LED color material
The accurate use of led depends on the polarity selected, the way to determine the
polarity of an LED is to examine its datasheet, these methods are usually reliable:
Sign + -
Polarity Positive Negative
Terminal Anode (A) Cathode (K)
Leads Long Short
Exterior Round Flat
Interior Small Larger
Table 4.5 Polarity datasheet
4.2.5 IR LED & PHOTO DIODE Sensor
The major parts of this sensor are as follows:
1. IR LEDs are not any other special kind of led. These are just like any other simple led
they are differ in only the material used for emitting the light. The emitted light is in
the Infrared range which is not visible by nicked eyes. The symbol of IR LED is:
15

Figure 4.5 IR LED
2. Photodiode is a semiconductor diode that functions as a photo detector. Photodiodes
are packaged with either a window or optical fiber connection, in order to let in the
light to the sensitive part of the device. Most Photodiodes will look like similar to a
Light Emitting Diode. A photodiode is a p-n junction or p-i-n structure. When a
photon of sufficient energy strikes the diode, it excites an electron thereby creating a
mobile electron and a positively charged electron hole. If the absorption occurs in the
junction's depletion region, or one diffusion length away from it, these carriers are
swept from the junction by the built-in field of the depletion region, producing a
photocurrent.
Figure 4.6 photodiode
Photodiodes can be used under either zero bias or reverse bias. In zero bias, light
falling on the diode causes a current across the device, leading to forward bias which
in turn induces "dark current" in the opposite direction to the photo current, this is
called the photovoltaic effect. Reverse bias induces only little current known as
saturation or back current along its direction. But a more important effect of reverse
bias is widening of the depletion layer therefore expanding the reaction volume and
strengthening the photocurrent, this is called the photoconductive effect. Circuits
based on this effect are more sensitive to light than ones based on the photovoltaic
effect.
4.2.6 Ultrasonic sensor
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Ultrasonic sensing is an example of reflective sensing. The sensor usually consists of
a transmitter and receiver pair and responds to variation in the amount of reflected
energy detected by the receiver. The transmitter emits a high frequency sound wave,
which reflects off the object and is detected by the receiver, where the Time-of-Flight
(TOF) information can be calculated. The range of the object can be determined from
the TOF data if the speed of the sound wave is a known constant. These sensors are
accurate over distances of several meters, with their accuracy dependent on the span
of the transmitted signal.
Figure 4.7 ultrasonic sensor
If the transmitted signal covers a large area, the likelihood of an obstacle being
detected is higher than if a narrow span were used. The advantage of the narrow span
is that the position of the obstacle relative to the device is known with more accuracy.
Ultrasonic proximity sensor circuit has two parts: a transmitter and a receiver. The
transmitter circuit works as follows: a stream of 40 kHz pulses are produced by a 555
timer wired up as an astable multi vibrator. The receiving transducer is positioned two
or more inches away from the transmitter transducer. The use of foam piece between
the two transducers eliminates direct interference. The signal from the receiving
transducer needs to be amplified; an op-amp LM741 is used for amplification. The
amplified output of the receiver transducer is directly connected to another 741 op-
amp wired as a comparator. The ultrasonic receiver is sensitive only to sounds in
about the 40 kHz range. The closer the ultrasonic sensor is to an object, the stronger
the reflected sound will be. The output of the comparator will change between LOW
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and HIGH as the sensor is moved closer to or farther away from an object. Depending
on the quality of the transducers the range of this sensor is varies.
Figure 4.8:
Ultrasonic
Proximity Sensor
Transmitter
Figure 4.9: Ultrasonic Proximity Sensor Receiver
CHAPTER 5
Comparator IC LM324
18

The LM324 consist of four independent, high gain, internally frequency compensated
operational amplifiers which were designed specifically to operate from a single
power supply over a wide voltage range. The operational amplifier is used in open
loop configuration.
Figure 5.1 LM324
Figure 5.2 Op-Amp loop configuration
Operational amplifier has two terminals positive terminal known as non-inverting
terminal & negative terminal as inverting terminal. The input to non-inverting &
inverting terminals are Vin1 & Vin2 respectively. The output voltage is:
V0 = A (Vin1 – Vin2)
Where,
A is gain of amplifier.
When input to inverting terminal is greater than non-inverting terminal output is low
& when input to non-inverting terminal is greater than the inverting terminal output is
high.
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5.1 Features
• Wide gain bandwidth: 1.3MHz
• Input common-mode voltage range
• Includes ground
• Large voltage gain: 100dB
• very low supply current/amplitude : 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
5.2 Description
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
voltage.
20

Figure 5.3 Pin Diagram for LM324
Figure 5.4: Schematic Diagram
21

CHAPTER 6
TSOP1738 & TIMER 555 Sensor
6.1 TSOP1738
The TSOP17XX – series are miniaturized receivers for infrared control systems. PIN
diode and preamplifier are assembled on lead frame, the epoxy package is designed as
IR filter. The demodulated output signal can directly be decoded by a microprocessor
or microcontroller.
Figure 6.1 TSOP1738
TSOP17XX consists a photo detector and preamplifier in a single package with
internal filter for PCM frequency. It is an output active low device & TTL and CMOS
compatible. It consumes very little power. The circuit of the TSOP17XX is designed
in that way that unexpected output pulses due to noise or disturbance signals are
avoided. The signal carrier frequency should be close to center frequency of the band-
pass filter e.g. 38 kHz for TSOP1738.
FEATURES
• 600ma output current capability per channel.
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• 1.2a peak output current (non repetitive) per channel.
• Enable facility.
• Over temperature protection
• Logical”0” input voltage up to 1.5 V (high noise imm.) internal clamp diode.
6.2 TIMER555:-
The 555 is a monolithic timing circuit that can produce accurate and highly stable
time delays and oscillation. Timer 555 is reliable, easy to use, and economical with
TTL compatibility. Timer 555 has many applications as: mono stable and astable
multivibrator, voltage regulator & infrared transmitter etc.
Figure 6.2 timer 555
DESCRIPTION:
Figure 6.3 functional diagram of timer
23

As in timer 555 functional diagram there are two internal comparators with reference
voltage 2/3 Vcc & 1/3 Vcc at C1 and C2 respectively. The frequency and duty cycle
both are controlled by two external resistors and one capacitor. To use with
TSOP1738 sensor timer 555 is used in astable multivibrator mode.
Figure 6.4 Description of timer with TSOP
Timer 555 as astable multivibrator to generate 38 kHz frequency at output.
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The external resistors R1, R2 & capacitor C determine the output frequency f0
CHAPTER 7
25

The Motor Driving IC L293D
7.1 Features
• 600ma output current capability per channel.
• 1.2a peak output current (non repetitive) per channel.
• Enable facility.
• Over temperature protection
• Logical”0” input voltage up to 1.5 V (high noise imm.) internal clamp diode.
7.2 Description
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 (such
as relays solenoids, DC and stepping motors) 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
L293DD is assembled in a 20 lead surface mount which has 8 center pins connected
together and used for heat sinking.
26

Figure 7.1. Block Diagram of L293D
Fig.7.2 Pin Description of L293D
27

CHAPTER 8
Microcontroller – AT89S51
The AT89S51 is a low-power, high-performance CMOS 8-bit microcontroller with
8K bytes 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 80C52 instruction set and pin out. The on-chip Flash allows the
program memory to be reprogrammed in-system or by a conventional nonvolatile
memory programmer. By combining a versatile 8-bit CPU with in-system
programmable Flash on a monolithic chip, the Atmel AT89S51 is a powerful
microcontroller which provides a highly-flexible and cost-effective solution to many
embedded control applications. The AT89S51 provides the following standard
features: 8K bytes of Flash, 256 bytes of 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
AT89S51 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 con-tents but freezes the
oscillator, disabling all other chip functions until the next interrupt or hardware reset.
8.1 Pin Configuration
28

Figure 8.1 pin diagram of microcontroller
8.2 Pin Description:
VCC +5V
GND -5V
Port 0 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
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. In addition, P1.0 and P1.1 can be configured to be the timer/counter 2
29

external count input (P1.0/T2) and the timer/counter 2 trigger input (P1.1/T2EX),
respectively, as shown in the following table. Port 1 also receives the low-order
address bytes during Flash programming and verification.
Table 8.1 port 1
Port 2
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.
Port 3
that are externally being pulled low will source current (IIL) because of the pull ups.
Port 3 receives some control signals for Flash programming and verification. Port 3
also serves the functions of various special features of the AT89S52, as shown in the
following table:
30

Table 8.2 port 3
RST
Reset input. A high on this pin for two machine cycles while the oscillator is running
resets the device. This pin drives high for 98 oscillator periods after the Watchdog
times out. The DISRTO bit in SFR AUXR (address 8EH) can be used to disable this
feature. In the default state of bit DISRTO, the RESET HIGH out feature is enabled.
ALE/PROG
Address Latch Enable (ALE) is an output pulse for latching the low byte of the
address during accesses to external memory. This pin is also the program pulse input
(PROG) during Flash programming. 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. Setting the ALE-disable bit has
no effect if the microcontroller is in external execution mode.
PSEN
Program Store Enable (PSEN) is the read strobe to external program memory. When
the AT89S51 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.
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EA/VPP
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. This pin also
receives the 12-volt programming enable voltage (VPP) during Flash programming.
XTAL1
Input to the inverting oscillator amplifier and input to the internal clock operating
circuit
.
XTAL2
Output from the inverting oscillator amplifier.
8.3 Block Diagram
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8.4 Special Function Registers
A map of the on-chip memory area called the Special Function Register (SFR) space.
Timer 2 Registers: Control and status bits are contained in registers T2CON (shown
in Table 5- 2) and T2MOD (shown in Table 10-2) for Timer 2. The register pair
(RCAP2H, RCAP2L) are the Capture/Reload registers for Timer 2 in 16-bit capture
mode or 16-bit auto-reload mode.
8.4.1 Interrupt Registers: The individual interrupt enable bits are in the IE register.
Two priorities can be set for each of the six interrupt sources in the IP register.
Table 8.3 Interrupt Registers 1
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Table 8.4 Interrupt Registers 2
8.4.2 Dual Data Pointer Registers: To facilitate accessing both internal and external
data memory, two banks of 16-bit Data Pointer Registers are provided: DP0 at SFR
address locations 82H-83H and DP1 at 84H-85H. Bit DPS = 0 in SFR AUXR1 selects
DP0 and DPS = 1 selects DP1. The user should always initialize the DPS bit to the
appropriate value before accessing the respective Data Pointer Register.
Power off Flag: The Power off Flag (POF) is located at bit 4 (PCON.4) in the PCON
SFR. POF is set to “1” during power up. It can be set and rest under software control
and is not affected by reset.
35

Table 8.5 Dual data pointer register
8.5 Absolute Maximum Ratings
Table 8.6 Absolute Maximum Ratings
36

8.6 DC Characteristics
Table 8.7 DC Characteristics
37

CHAPTER 9
REGULATOR IC LM7812
9.1 General Description
The LM78LXX series of three terminal positive regulators is available with several
fixed output voltages making them useful in a wide range of applications. When used
as a zener diode/resistor combination replacement, the LM78LXX usually results in
an effective output impedance improvement of two
orders of magnitude, and lower quiescent current. These
regulators can provide local on card regulation,
eliminating the distribution problems associated with
single point regulation. The voltages available allow the
LM78LXX to be used in logic systems, instrumentation,
HiFi, and other solid state electronic equipment.
Voltage regulator ICs are available with fixed (typically
5, 12 and 15V) or variable output voltages. They are also
rated by the maximum current they can pass. Negative
voltage regulators are available, mainly for use in dual
supplies. Most regulators include some automatic
protection from excessive current ('overload protection') and overheating ('thermal
protection').
Figure 9.1 LM7812 regulator IC
Many of the fixed voltage regulator ICs has 3 leads and look like power transistors,
such as the 7805 +5V 1A regulator shown on the right.
38

9.2 Features
• Output voltage tolerances of g5% (LM78LXXAC) over the temperature
range
• Output current of 100 mA Y Internal thermal overload protection
• Output transistor safe area protection
• Internal short circuit current limit
• Available in plastic TO-92 and metal TO-39 and plastic SO-8 low profile
• Output voltages of 5.0V, 6.2V, 8.2V, 9.0V, 12V, 15V
Figure 11.2 features
39

9.3 Electrical Characteristics
*
Table 9.1 Electrical characteristics LM78L05ac
40

Table 9.2 Electrical characteristics LM78l05AC
41

CHAPTER 10
LINE PATH FOLLOWER
I started with building a parallel port based robot which could be controlled manually
by a keyboard. On the robot side was an arrangement of relays connected to parallel
port pins via opto-couplers.
The next version was a true computer controlled line follower. It had sensors
connected to the status pins of the parallel port. A program running on the computer
polled the status register of the parallel port hundreds of times every second and sent
control signals accordingly through the data pins.
The drawbacks of using a personal computer were soon clear –
It’s difficult to control speed of motors.
As cable length increases signal strength decreases and latency increases. A long
multi core cable for parallel data transfer is expensive. The robot is not portable if you
use a desktop PC. The obvious next step was to build an onboard control circuit; the
options a hardwired logic circuit or a microcontroller. Since I had no knowledge of
microcontroller at that time, I implemented a hardwired logic circuit using
multiplexers. It basically mapped input from four sensors to four outputs for the motor
driver according to a truth table. Though it worked fine, it could show no intelligence
like coming back on line after losing it, or doing something special when say the line
ended. To get around this problem and add some cool features, using a
microcontroller was the best option.
10.1 Algorithm
1.L= leftmost sensor which reads 0; R= rightmost sensor which reads 0.
If no sensor on Left (or Right) is 0 then L (or R) equals 0;
42

Ex:
Left Center Right
Here L=3 R=0
Left Center Right
Here L=2 R=4
2. If all sensors read 1 go to step 3,
else,
If L>R Move Left
If L<R Move Right
If L=R Move Forward
Goto step 4
3. Move clockwise if line was last seen on Right
Counter Clockwise if line was last seen on Left
Repeat step 3 till line is found.
4. Goto step 1.
L4 L3 L2 L1 R1 R2 R3 R4
1 0 0 1 1 1 1 1
L4 L3 L2 L1 R1 R2 R3 R4
1 1 0 0 0 0 0 0
10.2 Sensor Circuit
To get a good voltage swing, the value of R1 must be carefully chosen. If Rsensor =
a when no light falls on it and Rsensor = b when light falls on it. The difference in
the two potentials is:
Vcc * {a/ (a+R1) - b/ (b+R1)}
Relative voltage swing = Actual Voltage Swing / Vcc
= Vcc * {a/ (a+R1) - b/ (b+R1)} / Vcc
= a/ (a+R1) - b/ (b+R1)
The resistance of the sensor decreases when IR light falls on it. A good sensor will
have near zero resistance in presence of light and a very large resistance in absence of
light.
43

We have used this property of the sensor to form a potential divider. The potential at
point ‘2’ is Rsensor / (Rsensor + R1). Again, a good sensor circuit should give
maximum change in potential at point ‘2’ for no-light and bright-light conditions.
This is especially important if you plan to use an ADC in place of the comparator.
Figure 10.1 sensor circuit
10.3 Diagrammatical representation of our robot
For our final project, we decided to make a line-follower robot. This simple robot is
designed to be able to follow a black line on the ground without getting off the line
too much. The robot has two sensors installed underneath the front part of the body,
and two DC motors drive wheels moving forward. A circuit inside takes an input
signal from two sensors and controls the speed of wheels’ rotation. The control is
done in such a way that when a sensor senses a black line, the motor slows down or
even stops. Then the difference of rotation speed makes it possible to make turns. For
instance, in the figure on the right, if the sensor somehow senses a black line, the
wheel on that side slows down and the robot will make a right turn.
44

Figure 10.2 Diagrammatical representation of our robot
45

i) How to sense a black line
The sensors used for the project are Reflective Object Sensors, 0PB710F that are
already ready in the Electronic Lab. The single sensor consists of an infrared emitting
diode and a NPN Darlington phototransistor. When a light emitted from the diode is
reflected off an object and back into the phototransistor, output current is produced,
depending on the amount of infrared light, which triggers the base current of the
phototransistor. In my case, the amount of light reflected off a black line is much less
than that of a white background, so we can detect the black line somehow by
measuring the current. (This current is converted to voltage.)
ii) How to control a DC motor
Instead of applying a constant voltage across a DC motor, we repeat switching on and
off the motor with a fixed voltage (Vcc) applied to the motor. This is done by sending
a train of PWM (Pulse Width Modulation) pulses to a power MOSFET in order to
turn it on and off. Then, the motor sees the average voltage while it depends on duty
cycle of PWM pulses. The speed of rotation is proportion to this average voltage.
By PWM method, it’s easier to control the DC motor than by directly controlling the
voltage across it. All we have to do is to modulate pulse width, in order words, a duty
cycle. Also, a power MOSFET consumes only negligible power in switching.
iii) Circuit diagram
My circuit consists of two parts: PWM (Pulse Width Modulation) part and a sensor
part. First, we take a look at the sensor part. The photodiode turns on the
phototransistor and then the output current is converted to output voltage through the
first op-amp circuit. The R6 is a variable resistor, so that we can tune the scale of
output voltage. The second op-amp circuit is added to change the polarity of voltage.
(Positive CV is necessary later.) One thing we should know is that –Vcc to Vcc of
voltage rail is needed, not from 0 to Vcc.
In the circuit built-up, LM747 Dual Operational Amplifiers were used. Second, in the
PWM section, two 555 timers (LM555) are used to produce a pulse-width modulated
train of pulses. The timer on the left works in astable mode to generate regular square-
46

wave pulses. The frequency is fixed by the values of R1, R2 and C1 here. Then, this
output Q1 is connected to the trigger pin of the second timer that works in monostable
mode this time. As you can see in the diagram, at a falling edge of Q1, a pulse is
triggered and stays high during some time. The time (width of a pulse) is purely
determined by the value of R3 and C3 if CV (Control Voltage) pin is not connected at
all. (Look at the pulse diagrams of Q1 and Q2 at the bottom of the circuit diagram.)
CV plays a role of changing the threshold level of a timer. (Without CV, threshold =
2/3 * Vcc) CV just becomes triggering voltage level. Therefore, the higher the CV is,
the longer it takes time until discharge. In this way, the duty cycle of output pulses Q2
can be controlled. Back to my circuit, the output voltage of the sensor part provides
CV.
47

Figure 10.3 line follower path circuit diagram
48

Third, the PWM pulses are supplied to the gate of a power MOSFET (IRF520) to
switch the DC motor on and off. Then, the DC motor only sees the average voltage
proportional to the duty cycle of the pulses. When CV is high, so is the duty cycle and
the motor turns fast.
In my robot, the distance between sensors and the ground is fixed. So, when a sensor
is off the black line (The sensor sees white paper.), CV keeps its maximum value and
both motors keep turning in a constant speed. As soon as the sensor enters the black
line part, CV drops down and thus duty cycle decreases, which means the slowdown
of a wheel.
* Component Values:
R1=6K, R2=1K, R3=20K, R4=10, R5=82, R6=5K (variable), R7=1K
C1=1μF, C2=0.1μF, C3=0.1μF,
49

Figure 10.4 line path follower robot
Flow Chart:
Figure 10.5 Figure Flow Diagram
As per the flow diagram, the microcontroller receives signals from the sensors placed
in front (SFront) and at the rear end (SRear) of the vehicle. Based on the signals the
vehicle is moved forward and backward.
50
SENSORS
CONTROL
UNIT
(µC)
ACTUATORS
(DC MOTOR)
FORWARD
REVERSE
STOP
IF
SFRONT
=1
IF
SREAR
=1
IF
SFRONT
=1
IF
SREAR
=1
REVERSE
REVERSEFORWARD
FORWARD
STOP
NO
YES
NO NO
NO
YES YES
YES

If the signal from SFront is high (i.e. this sensor detects the object) then the
microcontroller turns the direction of the motor to make the vehicle move in reverse
direction, else the vehicle will continue moving in the forward direction.
When signal from SFront is high and the vehicle starts moving back then, the signal
from SRear is checked by the microcontroller. Now if SRear is high then the vehicle stops,
otherwise the vehicle continues moving in reverse direction. This process takes place
when initially the vehicle was moving in the forward direction.
If initially the vehicle was moving in reverse direction then SRear is checked first and
then SFront is analyzed for similar conditions as explained above.
51

CHAPTER- 11
INTRODUCTION OF COLLISION AVOIDANCE
SYSTEM
11.1 What is a Collision Avoidance System?
A Collision Avoidance System can be defined as a device that detects possible
obstructions in the way of a host vehicle (i.e. the vehicle that has the system installed
in it), and helps in evading a collision.
11.2 Why use a Collision avoidance System?
Many systems and technologies are now being implemented to alert the driver of a
vehicle of a potential hazard and assist him or her in taking action to avoid that
hazard.
Although object detection and collision avoidance systems may still be regarded as
being in their infancy, their perceived value in enhancing safety and reducing
accidents is high. Such systems provide special benefits for older systems: as drivers
grow in age, they expect to continue to be able to drive safely, even though their
reaction times are increasing and senses like sight and hearing are diminishing.
Two categories of systems are currently available or under development: Passive
collision warning systems and Active collision avoidance systems. A passive system
detects a hazard and alerts the driver to risks, whereas an active system detects the
hazard and then takes preventive action to avoid a collision, if possible. Both types of
systems require object detection. The only difference in them is how a collision
diverting event is actuated following object detection, by the driver or automatically.
52

Like other automotive safety systems, to be truly effective and influence safety
statistics, these systems need to be widely adopted, and that in turn would require a
low production cost. The technology impact is significant, as an improvement in
sensing capability on the vehicle is necessary, and increased computing throughput is
required. The challenge now faced by the suppliers of such systems is to find a
balance between the perceiving value by the customers and the cost of producing such
a system. The University of Michigan Transportation Research Institute has predicted
that by 2007 passive systems will be implemented on 1% of North American vehicles
and active systems will be implemented on further 10% vehicles.
Development engineers are proceeding cautiously with active collision avoidance
work. Any systems that control the brakes from the driver are potential sources of
litigation. Standards and federal regulations will emerge during the next few years
which will cover such systems. For example, today there are no universally accepted
standards for false-alarm rates and the certainty of detecting a target for automotive
object detection systems. In Europe and the United States (by the Federal
Communications Commission), a frequency standard of 76 to 77 GHz has already
been approved for vehicle frontal radar systems.
In the United States, the National Highway Traffic Safety Administration (NHTSA) is
establishing functional requirements for collision avoidance systems. These will cover
parameters such as sensor range and sensitivity, system reliability, drive warning
information and data architecture standards. Similarly, in Japan the Ministry of
Transport is conducting an advanced safety program (ASV).
The total cost of such systems may largely within existing vehicle costs, as there will
be much reuse of existing electronic controllers. It is now commonplace for to have
engine controllers, anti-lock braking systems, electronic steering control and audio
systems. The collision warning and avoidance systems will use these existing systems
control units for additional functions.
53

11.3 Different Types of Systems
There are different types of Collision Avoidance systems. Categories are based on
different aspects viz. the functionality of the system, the location of the sensors in the
vehicle, and the technology used to implement such a system.
Based on functionality the systems are differentiated as Passive or Active systems. In
a passive system when a situation arises, an alarm is generated for the driver to take
further action. Whereas an active system itself takes control and performs the
necessary action to prevent the accident.
In case of system based on location of sensors the systems are of three types; Frontal
system, Rear system and Side system. In a Frontal system the sensors are placed only
in front of the vehicle to detect the object coming in the way when vehicle is moving
in forward direction. Similarly in Rear and Side systems the sensors are located at the
back and sides of the vehicle respectively.
Third criterion is of the technologies or the type of sensors used. Based on this there
are again two types one is the radar based systems and second is the Camera based
systems. A radar based system may use Laser or Ultrasonic radars. While a camera
based system uses a digital camera which gives images of the object in front of the
vehicle and then it is decided by the microcontroller whether the object is static or
moving and whether it is a threat to the host vehicle or not.
The details of all the above mentioned systems along with the appropriate diagrams is
given in the subsequent chapters
54

11.4 Types of Systems based on Functionality
11.4.1 Active and Passive Safety Systems
A passive collision warning safety system seeks to reduce the risk of a collision by
warning the driver of an impending risk so that he or she can take action to avoid the
hazard. For example – Parking assist type of systems that provide an audible alarm
when parallel parking and approaching a stationary object such as another vehicle or
wall. A passive collision warning system is shown in Figure 14.1
Figure 11.1 Passive Safety System
Active safety systems take the Collision avoidance philosophy a stage further by
interacting with the power train, braking, and even the steering systems. Advanced
active collision avoidance systems use many clever techniques, over and above object
event is facilitated safely and efficiently.
55
Driver Vehicle
Passive
System
Audio Warning
Visual Warning
Driver Vehicle
Passive
System
Audio Warning
Visual Warning

Figure 11.2 Active Safety System
11.5 Types of systems based on their position in Vehicles
There are types of systems categories of such safety systems for collision avoidance
viz. Frontal Vehicle Systems Rear Vehicle systems Side Vehicle Systems. These
categories are explained below.
11.5.1 Frontal Vehicle Systems
For Frontal systems, long range and large azimuth resolution radars are required
because of the high forward speed of the car and the need to determine objects in
adjacent lanes. The forward range of these systems is usually about 100 to 200m,
which gives about 3 to 6 seconds warning of a stationary hazard when the host car is
traveling at 100Kmph. It is important that frontal systems distinguish when there is
more than one car ahead, positioned very closely but in different lanes. Therefore
frontal radars must operate at high frequency than rear systems, as better azimuth
resolution is obtained at higher frequencies.
A key difference between the object detection systems used in active and passive
systems is that the active systems require more accurate object recognition, so as to
56
Driver Vehicle
Active
System
Audio Warning
Visual Warning
+
+/-

prevent collision avoidance maneuvers against objects like road signs. So in such
systems road recognition is prime importance. The most challenging task here is to
find whether which object is hazardous when there are many objects present. It may
be possible to detect all obstacles but if a warning is generated for each of such
circumstances then there will be a lot of false alarms which may irritate the driver.
11.5.2 Rear Vehicle Systems
Rear warning systems can use short range, often non scanning sensors to provide
close range sensing for parking assist capability. These systems are nowadays
provided in many cars by different manufacturers.
A rear system uses lower frequency radar system than a frontal system, as the azimuth
resolution required is not as large. The operating range is also shorter.
11.5.3 Side vehicle Systems
Side warning systems use radar sensors to detect objects in the traditional blind spots
that are often responsible for causing accidents. These sensors would be mounted in
the rear quarter area of the cars (usually rear doors) and detect objects in adjacent
lanes. These systems enhance the car safety by complementing the use of the wing
mirrors. The radars mounted on the sides of car are not just useful for blind spot
warnings, but also aid in lane tracking, in order to determine corridor trajectory.
11.6 Technologies already in use or under consideration
The key element in a collision warning and collision avoidance system is a sensor that
sends information to the electronic control unit on distance between the host vehicle
and a potentially hazardous object. The object could be another vehicle or even an
inanimate object such as a road sign or tree. If the object is scanned as a horizontal
line and its distance is known, it can be tracked as the movement of the target vehicle
negotiates the curves in the road. A smart algorithm may also analyze the placing of
57

roadside identifiers such as reflectors. For these reasons, scanning radars are a popular
solution in the industry.
11.6.1 Scanning Pulse Laser Radar
The principal operation of the scanning radar is very straight forward. The time of
flight of a pulse, which is proportional to range, is measured. The scanning device
transmits a pulse of light in a horizontal line, back and forth. Distance is calculated
easily, as the microcontroller timer can determine the time interval from the
transmitting pulse and received pulse. The receiver looks for an echo pulse, hence the
transmission is non-continuous.
As transmission frequency is phase coherent from pulse to pulse, it is also possible to
measure the Doppler Shift of the target. This information can in turn yield target
motion, speed and direction. Doppler shift occurs when the frequency of the reflected
waves becomes higher or lower, relative to the receiver, as the target moves closer or
farther away.
A simplified control circuit for this system is shown in the Figure 14.3. The circuit
consists of a microcontroller which executes the control algorithm and generates
output signals to control the laser diode. The laser diode signal is reflected via a
system of mirrors and lenses, controlled by stepper motor. The motor is used to step
through different positions and allows the deflected horizontally in a scanning motion.
There are several different mechanisms that can scan the laser beam, the most popular
being the galvanometer and a polygon mirror. Both have good accuracy and anti-
vibration capabilities.
58

Figure 11.3 Block Diagram for Scanning Pulse Laser Radar System
In each position, the laser beam echo will be reflected back to a complementarily
located mirror, through a laser diode, and then back to the microcontroller. The
microcontroller will then calculate distance to target or object using the formula
D= c (t)/2, where D is distance, t is time and c is speed of light. The time value is
measured using a counter which is enabled when the pulse is transmitted and read
when the input is received from the signal amplifier. As the speed of light is 3 x
108
m/s, the microcontroller clock speed must be reasonably high in order to measure
distance with acceptable resolution.
A disadvantage of the pulse radar is the requirement of a narrow pulse. In order to
achieve an acceptable resolution on range, a very high receiver bandwidth is required.
This in turn means that a lot of noise is received with the echo pulse, so the
transmitter must have a relatively high peak power. The radar will provide several
hundred distance measurements and calculations per scan, and the algorithm executed
by the microcontroller will average these data to obtain a higher degree of reliability
in the result.
59

A photo diode is also used in the system to determine whether the optical port is clean
and free from debris. If the port glass is dirty, the laser beam pulse may be scattered,
and performance can be affected. Bad weather can also affect performance, although
this may be overcome by increasing the output power of laser pulse. The addition of
the photodiode to determine clarity of the optical port is necessary, as this type of
frontal scanning pulse radar system is likely to be mounted at the front of car, where
debris and dirt from the road are common place. One solution is a wiper system for
optical port.
An alternative for laser radar can be Ultrasonic radar. The same principle of sending a
pulsed wave and measuring the time for an echo to return applies, except with
ultrasonic sensors a sound wave is used instead of a pulse of light. Knowing the speed
of sound the distance can be calculated. As speed of sound is relatively slow,
ultrasonic sensors are only considered effective for use in low-speed type applications
such as parking assistance.
11.7 WORKING OF COLLISION AVOIDANCE SYSTEM
11.7.1 Introduction
The system here in consideration consists of five vehicles with two sensors each, one
at the front end and the other at the rear end. The vehicles are initially kept at different
coordinates and then turned on. Each vehicle moves in forward and reverse directions
and the sensors check for obstructions in the front and rear of the vehicle. Based on
the obstruction detected by any of the two sensors, the collision is avoided by moving
the vehicle in appropriate direction.
11.7.2 Bock Diagram of the system
The system mainly consists of three blocks viz. Sensors block, Control unit and
Actuators, as shown in the figure below.
60

Figure 14.4 Block Diagram of the System
11.7.2.1 Sensors Block
This part of the system contains the sensors which perceive the signals reflected by
the objects falling in the path of host vehicle. This is an important part of the system
as based on the signals received the sensors the system is made to perform some
scheduled tasks.
There are different types of sensors that can be used for the purpose viz., IR sensors,
Radars and even digital cameras.
The system here, being just a prototype uses two IR sensors with a range of 1-3m.
One sensor is placed in front of the vehicle and one at the rear end. Based on the
signals from these sensors the vehicle will move.
11.7.2.2 Control Unit
The control unit consists of a microcontroller which receives signals from sensors,
and decides what operation to be performed by the system. The microcontroller used
here is 8051 core.
61
CONTROL UNIT (µC)
ACTUATORS
(DC MOTOR)
SENSORS

The microcontroller here is interfaced with a DC motor whose motion is controlled on
the basis of the signals received from the sensors at the front and rear of the vehicle.
11.7.2.3 Actuators
The actuator used in this system is a DC Motor. The motor is interfaced with the
microcontroller using the motor driving IC L293D. This IC has an H-bridge built into
it, which allows the motor to be run in both clockwise and anti-clockwise by changing
the polarity. This motor is responsible for the movement of the vehicle.
62

CHAPTER-12
CONCLUSION
Robotics systems is the collbaration of software & hardware through which most of
the complicity reduces, even systems size & coast also reduced. Such human creation
put us spell bound that why a topic of invention is taken Robotics design.
The line path follower and collision avoidance system that we have created has been
in practical use in various companies like in constuction companies and reasearch
areas.
This system can avoid collisions in traffic systems when used and will also be able to
detect only a single colour light for usage in definite purpose areas.
Limitations of the system
The system carries only two sensors in front, hence the collision with any object lying
in the sides (i.e. the left and the right sides) of the vehicle cannot be evaded.
1. IR Sensors have a short range so they cannot be widely used in real time
applications.
2. The performance of IR Sensors is affected by day light and bad weather.
Industrial Implementation of the System
This type of system can be used in robotic vehicle that travel within a store or a
factory compound. The work of such vehicles may be to carry certain things around
the area from one point to the other. If such a system is installed in these vehicles then
they can be left to travel without anyone bothering to be hit by them, because in this
case the vehicles’ system will take care of any such collision.
This basic idea can also be used in automotive systems with certain up gradations and
enhancements. For instance if case of a car if the IR sensors and the LED LDR
sensors are replaced by radars or cameras then it can be used to detect distant objects
with a better resolution and hence can help in evading collisions and saving lives of
the peo
63

FUTURE ASPECTS
We humans are fortunate & we always inspired from the nature because it is only
which is our beast friend in the universe. Robotics dreation is also inspired by the
human body itself. The human body is, all things considered, a nearly perfect
machine: it is (usually) intelligent, it can lift heavy loads, it can move itself around,
and it has built-in protective mechanisms to feed itself when hungry or to run away
when threatened.
Robots are often modeled after humans, if not in form then at least in function. For
decades, scientists and experimenters have tried to duplicate the human body, to
create machines with intelligence, strength, mobility, and auto-sensory mechanisms.
That goal has not yet been realized, but perhaps some day it will.
Nature provides a striking model for robot experimenters to mimic, and it is up to us
to take the challenge. Some, but by no means all, of nature’s mechanisms—human or
otherwise— can be duplicated to some extent in the robot shop. Robots can be built
with eyes to see, ears to hear, a mouth to speak, and appendages and locomotion
systems of one kind or another to manipulate the environment and explore
surroundings.
Many futurists believe that robots will eventually and inevitably become more
capable than humans, but some experts in artificial intelligence assert that machines
will never be able to develop the consciousness and emotions needed for reasoning
and creativity.
Nonetheless, there are already commercially available robots that can live in our
houses and do basic chores for us. Robots are very good at processing certain kinds of
information, and they are ideally suited to answering the telephone and being
controlled over the Internet.
64

REFERENCES
[1] Ronald K Jurgen “Automotive Electronic Handbook”: New York: McGraw-Hill,
2nd ed., 1999, Part 7 Chapter 29.
[2] Peter Seiler, Bong sob Song, J. Karl Hedrick “Development of a Collision
Avoidance System”: 1998 Society of Automotive Engineers.
[3] Toyota debuts Line Path Follower in Lexus [online], available:
http://www.abrn.com
[4] Mercedes Autonomous Braking Can Reduce Crash Severity [online], available:
http://www.abrn.com/abrn/article/articleDetail.jsp?id=359127
[5] General Motors: “The Ultimate Crash Safety is Avoiding Crashes” [online],
available:
http://www.gm.com/company/careers/career_paths/rnd/nws_071800.html
[6] Daimler-Chrysler: “Safety on the Interstate” [online], available:
http://www.daimlerchrysler.com/dccom/0-5-7180-1-465281-1-0-0-0-0-0-8-7165-0-0-
0-0-0-0-0.html
[7] Ford Motors: “Active Safety system turns vehicles into co-drivers” [online],
available:
http://media.ford.com/newsroom/feature_display.cfm?release=22037
[8] Volvo Cars: “City Safety: System for avoiding collisions at low speeds and line
path follower” [online], available:
http://media.ford.com/newsroom/feature_display.cfm?release=24310
[9] Douglas H. Williams “Line Follower”: New York: McGraw-Hill, 2003, Chapter 6,
pg 107-pg114.
[10] Datasheet of NE555
[11] Datasheet of TSOP1738
[12] Datasheet of TIP122 and TIP127
[13] www.alldatasheets.com
65

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