Communication With Laser Beam

8/3/2019 Communication With Laser Beam

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Communication with laser beam

Communicating with laser is

not new. Here the laser beam is used as a

carrier, which is modulated by the

signal to be transmitted. On the

receiver end, the desired signal is

separated from the carrier. A wireless

laser link (through a laser diode) is used

to transmit information from one end to

another in its line of sight.


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References

1.Application Of Electronics

R. D. Supekar.

1.Practical Electronics

P. K. Patil.

M. M. Chitnis.

1. Electronics For U. ( Magazine )

2.Source- Internet.

- Guided by

S. S. Patil Sir.

R. S. Rajput Sir.


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Costing

Sr

NO.

Name of

Component

Qty. Price Amount.

1. IC 555 1 5 5

2. IC LM356 3 25 75

3. Diode 2 1 2

4. Resistor 9 1 9

5. Capacitor (0.1

)

9 0.25 2.25

6. Transistor

2N2222

L14F1

2

1

15

125

30

125

7. IC holder 4 3 12

8. PCB Layout 2 500 1000

9. PCB 2 200 400

10. Laser Diode 1 30 30

11. Battery 9 V 4 25 100

12. Speaker 8 0.5w

1 25 25

13. Pot ( 10 k) 3 10 30

TOTAL 44 1845.25


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ACKNOLEDGEMENTWe extend our sincere thanks to Prof. S. S. Patil Sir

and Prof. R. S. Rajput Sir for guiding us with very

valuable information, and for making our project a

great success. Our thanks also extend to the following

list of books application of electronics-Prof. R. D.

Supekar, Practical electronics-Prof. P. K. Patil, M.M.Chitnis.

Our friends also had a prime part in making this

project of success by sharing their ideas about how to

go on with it. Thus last but not least, our special thanks

goes to the person who is reading this

project..


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Introduction

Todays world is considered as the great worldof electronics where each and every moment of life is

concerned with the works of electronics. One such

great event that is considered as important in this

above world is the military communication through

laser beam.


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Resistor

A resistor is a passive two-terminal electrical component thatimplements electrical resistance as a circuit element. The currentthrough a resistor is in direct proportion to the voltage across theresistor's terminals. Thus, the ratio of the voltage applied across aresistor's terminals to the intensity of current through the circuit iscalled resistance. This relation is represented by Ohm's law:

Resistors are common elements ofelectrical networks and electroniccircuits and are ubiquitous in most electronic equipment. Practicalresistors can be made of various compounds and films, as well as

resistance wire (wire made of a high-resistivity alloy, such as nickel-chrome). Resistors are also implemented within integrated circuits,

particularly analog devices, and can also be integrated into hybrid andprinted circuits.
http://en.wikipedia.org/wiki/Electronic_componenthttp://en.wikipedia.org/wiki/Electrical_resistancehttp://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Direct_proportionhttp://en.wikipedia.org/wiki/Ohm's_lawhttp://en.wikipedia.org/wiki/Electrical_networkhttp://en.wikipedia.org/wiki/Electronic_circuithttp://en.wikipedia.org/wiki/Electronic_circuithttp://en.wikipedia.org/wiki/Resistance_wirehttp://en.wikipedia.org/wiki/Integrated_circuitshttp://en.wikipedia.org/wiki/Electrical_resistancehttp://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Direct_proportionhttp://en.wikipedia.org/wiki/Ohm's_lawhttp://en.wikipedia.org/wiki/Electrical_networkhttp://en.wikipedia.org/wiki/Electronic_circuithttp://en.wikipedia.org/wiki/Electronic_circuithttp://en.wikipedia.org/wiki/Resistance_wirehttp://en.wikipedia.org/wiki/Integrated_circuitshttp://en.wikipedia.org/wiki/Electronic_component


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Capacitor

A capacitor (formerly known as condenser) is a passive two-

terminal electrical component used to store energy in an electric field.The forms of practical capacitors vary widely, but all contain at leasttwo electrical conductors separated by a dielectric (insulator); forexample, one common construction consists of metal foils separated

by a thin layer of insulating film. Capacitors are widely used as partsof electrical circuits in many common electrical devices.

When there is a potential difference (voltage) across the conductors, astatic electric field develops across the dielectric, causing positive

charge to collect on one plate and negative charge on the other plate.Energy is stored in the electrostatic field. An ideal capacitor ischaracterized by a single constant value, capacitance, measured infarads. This is the ratio of the electric charge on each conductor to the

potential difference between them.

Diode


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In electronics, a diode is a type of two-terminalelectronic component with nonlinear resistance andconductance (i.e., a nonlinear currentvoltagecharacteristic), distinguishing it from components suchas two-terminal linear resistors which obey Ohm's law.A semiconductor diode, the most common type today,is a crystalline piece of semiconductor materialconnected to two electrical terminals. A vacuum tubediode (now rarely used except in some high-powertechnologies) is a vacuum tube with two electrodes: aplate and a cathode.

The most common function of a diode is to allow anelectric current to pass in one direction (called thediode's forwarddirection), while blocking current in theopposite direction (the reverse direction). Thus, thediode can be thought of as an electronic version of acheck valve. This unidirectional behavior is calledrectification, and is used to convert alternating currentto direct current, and to extract modulation from radio

signals in radio receiversthese diodes are forms ofrectifiers.


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Transistor

A transistor is a semiconductor device used to amplify and

switch electronic signals and power. It is composed of asemiconductor material with at least three terminals for connection toan external circuit. A voltage or current applied to one pair of thetransistor's terminals changes the current flowing through another pairof terminals. Because the controlled (output) power can be muchmore than the controlling (input) power, a transistor can amplify asignal. Today, some transistors are packaged individually, but manymore are found embedded in integrated circuits.

The transistor is the fundamental building block of modern electronicdevices, and is ubiquitous in modern electronic systems. Followingits release in the early 1950s the transistor revolutionized the field ofelectronics, and paved the way for smaller and cheaper radios,calculators, and computers, among other things.


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Speaker

A loudspeaker (or "speaker") is an electro acoustic

transducer that produces sound in response to an

electrical audio signal input. Non-electrical

loudspeakers were developed as accessories to

telephone systems, but electronic amplification by

vacuum tube made loudspeakers more generally

useful. The most common form of loudspeaker uses apaper cone supporting a voice coil electromagnet

acting on a permanent magnet, but many other types

exist. Where accurate reproduction of sound is

required, multiple loudspeakers may be used, each

reproducing a part of the audible frequency range.

Miniature loudspeakers are found in devices such as

radio and TV receivers, and many forms of musicplayers. Larger loudspeaker systems are used for

music, sound reinforcement in theatres and concerts,

and in public address systems.


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Battery

An electrical battery is one or more electrochemical cells thatconvert stored chemical energy into electrical energy. Since theinvention of the first battery (or "voltaic pile") in 1800 by AlessandroVolta and especially since the technically improved Daniell cell in1836, batteries have become a common power source for manyhousehold and industrial applications. According to a 2005 estimate,the worldwide battery industry generates US$48 billion in sales eachyear, with 6% annual growth.

There are two types of batteries: primary batteries (disposablebatteries), which are designed to be used once and discarded, andsecondary batteries (rechargeable batteries), which are designed to berecharged and used multiple times. Batteries come in many sizes,from miniature cells used to power hearing aids and wristwatches to

battery banks the size of rooms that provide standby power fortelephone exchanges and computer data centers.

Pot


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A preset is a three legged electronic component which

can be made to offer varying resistance in a circuit. The

resistance is varied by adjusting the rotary control over it.

The adjustment can be done by using a small screw driver

or a similar tool. The resistance does not vary linearly but

rather varies in exponential or logarithmic manner. Such

variable resistors are commonly used for adjusting

sensitivity along with a sensor.

The variable resistance is obtained across the single

terminal at front and one of the two other terminals. The

two legs at back offer fixed resistance which is divided by

the front leg. So whenever only the back terminals are

used, a preset acts as a fixed resistor. Presets are specified

by their fixed value resistance.

pcb


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A printed circuit board, or PCB, is used tomechanically support and electrically connectelectronic components using conductive pathways,tracks or signal traces etched from copper sheetslaminated onto a non-conductive substrate. It is alsoreferred to as printed wiring board (PWB) or etchedwiring board. A PCB populated with electroniccomponents is a printed circuit assembly (PCA), alsoknown as a printed circuit board assembly or PCBAssembly (PCBA). Printed circuit boards are used invirtually all but the simplest commercially producedelectronic devices.

PCBs are inexpensive, and can be highly reliable. Theyrequire much more layout effort and higher initial costthan either wire wrap or point-to-point construction,but are much cheaper and faster for high-volumeproduction; the production and soldering of PCBs can

be done by automated equipment. Much of theelectronics industry's PCB design, assembly, andquality control needs are set by standards that arepublished by the IPC organization.


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a heat sink. Instead we use an IC holder, strictly calleda DIL socket (DIL = Dual In-Line), which can be safelysoldered onto the circuit board. The IC is pushed intothe holder when all soldering is complete.

IC holders are only needed when soldering so they arenot used on breadboards.

workingIn this circuit, an electric signal is transmitted from

one place to another riding over the laser beam. If youvary some parameters of the transmitted signal (such

as amplitude and frequency) the received signal

changes accordingly.

The entire circuit can be divided into two parts

transmitter and receiver.

Fig.1 shows the transmitter circuit built aroundtimer 555 (IC1) .IC1 is wired as an astable multivibrator

generating a pulse train at its pin 3 that serves as the

modulation input for the laser diode. Set the frequency

of this pulse train to around 1 kHz using presets VR1 &

VR2.

The potential divider arrangement of resistors R2,

R3 and preset VR3 is used to reduce the peak


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amplitude of the pulse train. The driver circuit for the

laser diode is built around ICLM356 (IC2), transistor T1

and a few discrete components.

The transmitter circuit is powered by two 9V

batteries that provides +9V, -9V and ground supplies.

These voltages are provided to the transmitter circuit

through DPST switch S1.

The receiver circuit is built around IC3, IC4 and a

few discrete components. The gain stage is built

around ICLM356 (IC3) with gain value of (R6+R7)/R6.The output of IC3 drives a speaker through the emitter-

follower arrangement configured around transistor T3.

The unity-gain buffer stage built around IC4 facilitates

viewing of the received signal on an oscilloscope if so

desired.

The receiver circuit too is powered by two 9V

batteries that provide +9V,-9V and ground supplies.

These voltages are provided to the receiver circuit

through DPST switch S2.

Working of the circuit is simple. Align the

transmitter and the receiver so that the laser light

directly falls on the phototransistor. The speaker

connected between emitter of T3 and ground beeps toindicate that laser communication is taking place. You

can change the pitch of the audio beep by changing

the frequency of the transmitted signal through presets

VR1 in the transmitter.


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Documents

Communication With Laser Beam