LASER GUIDED VEHICLE
In this project we show
that how we design a laser follower robot to move on any track. In
this project we use two slow speed motor for running the platform of
the small robot. In this project we use 89c2051 microcontroller as a
main processor. We use this processor to run the vehicle. This
controller is basically a 20 pin ic. In this project we use two
sensor also. These sensor are connected to the port p3.4 and port
Pin no 20 is connected
to the positive supply. In this project we provide a 5 volt dc power
supply. This power supply is truly regulated power supply. Pin no 10
is connected to the negative supply. Here we supply a negative
voltage on this pin. Crystal is connected to the pin no 4 and 5 of
the microcontroller. Crystal provide a clock signal to run the
vehicle and process all the internal requirement of the circuit. We
use two sensor and these two sensor are connected to the p3.4 and
p3.5 of the microcontroller.For the regulated power supply we use ic
7805 as a regulator to provide a fix 5 volt power supply.
When we move the robot
on surface then infra red light is not reflected from the surface.
When Laser light is not fallingfrom the surface then sensor is not
getting a signal. We program the robot like this when sense the
light then it means position of sensor is on the surface. If the
sensor1 gets signal from laser then one motor change its direction
and due to that robot change its path and when sensor2 gets signal
then only vehicle move backwatd. We use three sensor for two
motorís. if the one sensor gets signal from laser then vehicle move
backward , if one sensor1 and sensor3 gets signal then vehicle
change its direction. Microcontroller provide a signal to the motor
circuit. Motor is not directly connected with the microcontroller.
For the safety of the main processor we interface the motor with
optocoupler circuit. Here we use pc 817 ( 4 pin opto coupler) to
interface the micro controller with the motor circuit. We use H
bridge circuit with the motor. H bridge basically control the
movement of the motor. With the help of this H bridge we change the
direction of the motor. We use four transistor circuit with each
motor. We are using four transistor circuit. Out of these four
transistor two transistor is NPN and two transistor and PNP
transistor. One NPN and One PNP provide a one direction voltage and
motor moves on one direction. Second NPN and second PNP transistor
again change the direction of the motor automatically. In this
project we will also make it autopath. We will connect Two infrared
sensors with ir transmitter on left and right for moving right and
left. Others will work for antifalling function.
word "laser" stands for "light amplification by stimulated emission
of radiation." Lasers are possible because of the way light
interacts with electrons. Electrons exist at specific energy levels
or states characteristic of that particular atom or molecule. The
energy levels can be imagined as rings or orbits around a nucleus.
Electrons in outer rings are at higher energy levels than those in
inner rings. Electrons can be bumped up to higher energy levels by
the injection of energy-for example, by a flash of light. When an
electron drops from an outer to an inner level, "excess" energy is
given off as light. The wavelength or color of the emitted light is
precisely related to the amount of energy released. Depending on the
particular lasing material being used, specific wavelengths of light
are absorbed (to energize or excite the electrons) and specific
wavelengths are emitted (when the electrons fall back to their
ruby laser was the first laser invented in 1960. Ruby is an aluminum
oxide crystal in which some of the aluminum atoms have been replaced
with chromium atoms. Chromium gives ruby its characteristic red
color and is responsible for the lasing behavior of the crystal.
Chromium atoms absorb green and blue light and emit or reflect only
a ruby laser, a crystal of ruby is formed into a cylinder. A fully
reflecting mirror is placed on one end and a partially reflecting
mirror on the other. A high-intensity lamp is spiraled around the
ruby cylinder to provide a flash of white light that triggers the
laser action. The green and blue wavelengths in the flash excite
electrons in the chromium atoms to a higher energy level. Upon
returning to their normal state, the electrons emit their
characteristic ruby-red light. The mirrors reflect some of this
light back and forth inside the ruby crystal, stimulating other
excited chromium atoms to produce more red light, until the light
pulse builds up to high power and drains the energy stored in the
laser flash that escapes through the partially reflecting mirror
lasts for only about 300 millionths of a second-but very intense.
Early lasers could produce peak powers of some ten thousand watts.
Modern lasers can produce pulses that are billions of times more
Another characteristic of laser light is that it is coherent. That
is, the emitted light waves are in phase with one another and are so
nearly parallel that they can travel for long distances without
spreading. (In contrast, incoherent light from a light bulb diffuses
in all directions.) Coherence means that laser light can be focused
with great precision.
different materials can be used as lasers. Some, like the ruby
laser, emit short pulses of laser light. Others, like helium-neon
gas lasers or liquid dye lasers emit a continuous beam of light. Our
ICF lasers, like the ruby laser, are solid-state, pulsed lasers.
the First Ruby Laser Works
contrast to an ordinary light source, a laser produces a narrow beam
of very bright light. Laser light is "coherent," which means that
all of a laser's light rays have the same wavelength and are in
1. High-voltage electricity causes the quartz flash tube to
emit an intense burst of light, exciting some of the atoms in
the ruby crystal to higher energy levels.
2. At a specific energy level, some atoms emit particles of
light called photons. At first the photons are emitted in all
directions. Photons from one atom stimulate emission of photons
from other atoms and the light intensity is rapidly amplified.
3. Mirrors at each end reflect the photons back and forth,
continuing this process of stimulated emission and
4. The photons leave through the partially silvered mirror at
one end. This is laser light.
There are many types of lasers, including solid-state, gas,
semiconductor, or liquid. The ruby laser is a solid-state laser.
Solid-state lasers provide the highest output power of all laser
types. The National Ignition Facility laser will also be a
solid-state laser, but will use a special glass (rather than
crystals of ruby) to amplify the initial laser pulses to very high
energy levels. The NIF laser will be the most powerful laser in the
a Laser Works:
The Basics of an Atom
Everything we see within the universe is made up of an
infinitesimally large number of combinations of the 100 different
kinds of atoms. The arrangement and bonding of these atoms
determines what material/object they constitute.
Atoms are constantly in motion. They continuously vibrate and move.
Although all atoms are vibrating to a degree, atoms can be in a
different state of excitation (i.e. they can have different levels
of energy). If a large degree of energy is applied to an atom then
it can leave what is referred to as ground-state energy level and go
to an excited level. The level of excitation is proportional to the
amount of energy applied.
simple atom as shown in Figure 1 consists of a nucleus, which
consists of protons and neutrons and what is often referred to as an
electron cloud. For a simplistic interpretation of the atom model it
is easy to think of the electrons within the electron cloud
following discrete paths or orbits within the cloud. This analogy
suits our purpose as we can then consider these orbits to be the
different energy levels that make up the atom. If we add some form
of energy to the atom we can assume that electrons from the
lower-energy orbitals will transfer to the higher-energy orbitals at
a greater distance from the nucleus, resulting in a higher level of
atoms reach a higher-energy orbital the eventually seek to return to
the ground-state energy level. Upon returning to ground-state energy
level the excess energy is released in the form of a photon - a
particle of light.
The Connection Between Atoms and Lasers
Laser is an abbreviation for Light Amplification by
Stimulated Emission of Radiation.
laser is a device that controls the way in which energised atoms
release protons. There are many different types of laser available;
all the different types of laser rely on the same basic elements. In
all types of laser there is a lasing medium, which is pumped to get
the electrons within the atoms to a higher-energy orbital i.e. to
get the atoms excited. Typically, very intense flashes of light or
an electrical discharge pump the lasing medium and create a large
number of excited-state atoms. This creates a high degree of
population inversion (the number of excited state atoms versus the
number of atoms at ground-state energy level). At any stage the
excited state atoms can release some of the energy and return to a
lower-energy orbital. The energy released, which comes in the form
of photons, has a very specific wavelength that is dependant on the
level of energy or excitation of the electron when the photon is
released. Two identical atoms with electrons in identical states
will release photons with identical wavelengths. This forms the
basis for laser light.
Laser light has the following properties:
Laser light is monochromatic. It contains one specific wavelength of
light, which as described earlier is determined by the amount of
energy released when the electron drops to a lower-energy orbital.
∑ Laser light is coherent. Each proton moves in step with the other
(i.e. all protons have wave fronts that move in unison).
∑ Laser light is highly directional (i.e. a laser beam is very tight
ensure the aforementioned properties are apparent within the laser
light the process briefly mentioned earlier, 'stimulated emission'
photon that has been released by an atom, (which therefore has a
wavelength, phase and energy level dependant on the difference
between the excited atom state and the ground-state energy level)
should encounter another atom that has another electron in the same
excited state, stimulated emission can occur. The first photon can
stimulate or induce atomic emission so that the emitted photon
vibrates with the same frequency and direction.
produce laser light it is necessary to have a pair of mirrors at
either end of the lasing medium. These mirrors are often known as an
optical oscillator due to the process of oscillating photons between
the two mirrored surfaces. The mirror positioned at one end of the
optical oscillator is half-silvered, therefore it reflects some
light and lets some light through. The light that is allowed to pass
through is the light that is emitted from the laser. During this
process photons are constantly stimulating other electrons to make
the downward energy jump, hence causing the emission of more and
more photons and an avalanche effect, leading to a large number of
photons being emitted of the same wavelength and phase.
Below is a graphical illustration of what has been detailed above.
The graphics illustrate how laser light is created using a ruby
laser, the first fully functioning laser. Theodore Maiman invented
the ruby laser on May 16th 1960 at the Hughes Research Laboratories
(for more information on dates relating to laser invention see a
Brief History of Lasers).
Figure 6 - Schematic Showing Column of Laser Light Leaving Optical
CRO 20 Mhz
ORCAD for PCB design
simulation 7.4 version
Transformer 0-12v 500mA