Laser Based Communication Link

LASER BASED COMMUNICATION LINK A MAJOR PROJECT REPORT SUBMITTED TO RAJIV GANDHI PROUDYOGIKI VISHWAVIDYALAYA, BHOPAL (M.P.) SUBMITTED BY

SAURABH KOLHE

0206EC071095

VATSAL TRIPATHI TRIPATH I

0206EC071113

VIPIN PATEL PATE L

0206EC071115

VIRENDRA PATEL PATE L

006EC071117

VIVEK BHARDWAJ

0206EC071118

VIVEK NANDANWAR 0206EC071120 In partial fulfillment for the award of the degree Of BACHELOR OF ENGINEERING IN ELECTRONICS & COMMUNICATION ENGINEERING

GYAN GANGA INSTITUTE OF TECHNOLOGY & SCIENCES

UNIVERSITY

RAJIV GANDHI PROUDYOGIKI VISHWAVIDYALAYA MAY 2011

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LASER BASED COMMUNICATION LINK A MAJOR PROJECT REPORT SUBMITTED BY

SAURABH KOLHE

0206EC071095

VATSAL TRIPATHI TRIPATH I

0206EC071113

VIPIN PATEL PATE L

0206EC071115

VIRENDRA PATEL PATE L

006EC071117

VIVEK BHARDWAJ

0206EC071118

VIVEK NANDANWAR 0206EC071120 Under the Guidance of MS. BRAJLATA CHOURASIYA MS. NAMRATA RAPARTIWAR

In partial fulfillment for the award of the degree Of BACHELOR OF ENGINEERING IN ELECTRONICS & COMMUNICATION ENGINEERING

GYAN GANGA GAN GA INSTITUTE OF TECHNOLOGY & SCIENCES


























BONAFIDE CERTIFICATE

This

is

to

certify

that

the

major

project

report

LASER

BASED

COMMUNICATION LINK Submitted by Saurabh Kolhe, Vatsal Tripathi,

Vipin Patel, Virendra Patel, Vivek Bharadwaj and Vivek Nandanwar has been carried out under my guidance & supervision. The project report is approved for submission towards partial fulfillment of the requirement for the award of degree

of BACHELOR

&COMMUNICATION

OF

ENGINEERING

ENGINEERING

from

in

ELECTRONICS

RAJIV

GANDHI

PROUDYOGIKI VISHWAVIDYALAYA, BHOPAL (M.P.)

Signature Signature of Guide Ms Brajlata Chourasiya Ms Namrata Rapartiwar

Signature Signature of HOD (EC) Prof Vinod Kapse


























CERTIFICATE

This

is

to

certify

that

the

major

project

report

LASER

BASED

COMMUNICATION LINK Submitted by Saurabh Kolhe, Vatsal Tripathi,

Vipin Patel, Virendra Patel, Vivek Bharadwaj and Vivek Nandanwar has been carried out under my guidance & supervision. The project report is approved for submission towards partial fulfillment of the requirement for the award of degree

of BACHELOR

&COMMUNICATION

OF

ENGINEERING

ENGINEERING

from

in

ELECTRONICS

RAJIV

GANDHI

PROUDYOGIKI VISHWAVIDYALAYA, BHOPAL (M.P.)

Internal Examiner

External Examiner

























DECLARATION

We hereby declare that the project entitled LASER BASED COMMUNICATION LINK  Which is being submitted in partial fulfillment of the requirement for award

of

the

Degree

of

bachelor

of

engineering

in

ELECTRONICS

&COMMUNICATION and end Engineering to  RAJIV GANDHI PROUDYOGIKI VISHWAVIDYALAYA, BHOPAL (M.P.) is an authentic record of our own work done under the guidance of Ms Brajlata Chourasiya & Ms Namrata Rapartiwar, Rapartiwar , department of electronics & communication &Engineering , GYAN GANGA INSTITUTE OF TECHNOLOGY &SCIENCES , JABALPUR.

The matter reported in this project has not been submitted earlier for the award of any other degree.

Dated

SAUR SAUR AB Place

ATSAL TR TR ATHI VIPIN PATEL VIR VIR ENDR ENDR A PATEL VIVEK B VIVEK BHAR HAR DWAJ DWAJ VIVEK NANDANWAR NANDANWAR

























ACKNOWLEDGEMENT

We sincerely express indebtedness to esteemed and revered guide  Ms Brajlata Chourasiya & Ms Namrata Rapartiwar , Lecturer in Department name for his invaluable guidance. We take this opportunity to express deep sense of gratitude to our HOD (EC) Kapse, Electronics and communication for his encouragement Prof Vinod Kapse, and kind approval. We are also thankful to our project Co-ordinator  Mr. S.N. Jarholiya , for his sincere supervision and encouragement. We are also thank him in providing the computer lab facility .we would like to express our sincere regards to him for advice and counseling from time to time. We owe sincere thanks to all the faculties faculties in  Electronics and communi cation  for their advice and counseling time to time. ti me.

DATED: Place:



























ABST ACT

Laser as a communi commun icati cation on medi medium can provi provide a good substit subs titu ute for t e present present day communi communicati cation on syst systems as t e probl problem of interference faced in case of el elect ectromagneti romagneticc waves is not not t ere and hi high deal dea l of secrecy is avail availab ablle. Laser communi commun icati cations ons offers a vi viabl able alterna lternati tive ve to R communi communicati cations ons for inter sat satellite llite links links and ot other appli applica cati tions ons where hi high performance links links are a necessit necess ity. y. High dat data rat rate, small sma ll ant antenna siz size, e, narrow beam divergence, and a narrow f ield of vi view are charact charac ter istics tics of l of laser communi communicati cations ons that hat offer a number of pot potenti entiaal advant advantages for syst sys tem desi design. The purpose of the pro jec jectt is to det determi ermine the feasi feas i bilit bility y of repl replaci acing microwave communi communicati cations ons wit with h laser communi communicati cations ons to remot remot e locati ocations. ons. Thi This link link is unreli unreliab ablle and can be di disrupt srupted in fog or rai ra in. The current curren t syst system has a sl s low dat data rat rate of 1.54 M bps, equi equival valent ent to usi us ing a di dial up modem on any indi ndividual dual comput comput er. When this link link goes down, tionare lost tion unabl its all communi communicati cations ons to and from the st stationare ost, leavi eaving the st station unable to carry out out its missi ssions. The syst sys t em proposed to sol so lve this probl problem utiliz u tilizes es a long cavit cavity y laser operati operating ng at at 1550 nm. The syst sys t em will will also use redundanci redundanc ies as well well as spati spa tiaal diversit versity y of seven lasers t o achi achieve reli reliab abilit ility y and hi high dat data rat rates averagi averaging 2.4 Gbps. The transmitt ransmitter er and recei receiver will will be set set up on gi gimbal mbals connect connected to a cont control rol syst system that hat ensures ali a lignmen gnmentt based off a pul pu lse trai rain on the recei receiver pl plate. Thi This pul pulse trai rain a lso ensures that hat the signal gnal is penet penetrati rating ng the atmosphere over the 8 mil milee distance. A compar ison bet between the microwave and laser communi communicati cations ons was compl completed and fut future work incl ncludes impl mplementi ementing ng a proposed three phase test est plan. A basi basic communi communicati cation on syst system is made up of three mai ma in par ts bei being the

























medi medium is some type of cabl cable or wi wire. The si s ignal gnal is then coll collec ectt ed by the recei receiver, whi which is comparabl comparable to the person on the recei receiving end hear ing the sound of the person¶s voi vo ice. Someti Sometimes mes the si signal gnal can be immedi mmediately underst understood, but but other ti her times mes the si signal gnal must must f irst rst be decoded in order t order to underst understand the message.

























L ST OF TABLE

1

PIN SPEC SPECIFIC IFICATION OF 555 TIM TIMER

17

2

PIN SPEC SPECIFIC IFICATION OF LM 3869 IC IC

20

3

PIN SPEC SPECIFIC IFICATION OF CD4033 IC IC

22

4

PIN SPEC SPECIFIC IFICATION OF NE567 IC IC

25

5

COLOUR OLOUR C CODING TEC TECHNIQUES FOR FOR R R ESISTOR ESISTOR S

36

6

COMPONENT LIST

63

























L ST OF SYMB SYMBOLS

1

LDR LDR

19

2

LOW VOLTAGE AMPLIFIER PLIFIER

AUDIO

20

3

SCHEM HEMATIC ATIC SYMB SYMBOL OL FOR FOR PNP AND NPN TYPE BJTs

45

4

THE

SYMB SYMBOL OL

OF

AN

NPN

49

NPN

50

BIPOLAR IPOLAR JUNC JUNCTIONTR TIONTR ANSISTOR ANSISTOR

5

THE

SYMB SYMBOL OL

OF

A

BIPOLAR IPOLAR TR ANSISTOR ANSISTOR

6

A ZENER ZENER DIODE DIODE

52

























TABLE OF CONTENTS

BONAFIDE CERTIFICATE

i

CANDIDATES DECLARATION

ii

ACKNOWLEDGEMENT

iii

ABSTRACT

iv

LIST OF TABLE

v

LIST OF SYMBOLS

vi

1.

INTR INTR ODUC ODUCTION

1

1.1

BLOC LOCK DIAGR DIAGR AM

2

EXPLANATION 1.1.1

CONDENSOR ONDENSOR M MICR OPHONE OPHONE

2

1.1.2

TR T R ANSM ANSMITTING SEC SECTION

2

1.1.3

LASER LASER TO TORC RCH H

2

1.1.4

R ECEIVING SEC SECTION

3

1.1.5

LOUDSPEAKER LOUDSPEAKER

3

LITER LITER ATUR ATUR E R IVIEW IVIEW

4

2



























UNM UNMANNED AER AER IAL IAL VEHIC VEHICLES 2.4

FR FR EE EE

SPAC SPACE

OPTIC OPTICAL

7

COMMUNI MMUNIC CATION LINK METHODOLOGY

8

3.1

SYSTEM SYSTEM DESCR DESCR IPTION IPTION

8

3.2

THE TR ANSM ANSMITTER ITTER C CIRCUIT RC UIT

9

3.3

THE R ECIEVER IEVER C CIRCUIT RCUIT

11

DEVIC DEVICES & TOOLS

14

4.1

LASER LASER

14

4.2

555 TIM TIMER

16

4.3

MICR OPHONE OPHONE

17

4.4

LIGHT DEPENDENT R ESISTOR ESISTOR

18

4.5

LOW VOLTAGE AUDIO

19

3

4

AMPLIFIER PLIFIER IIC LM386 4.6

DEC DECADE COUNTER OUNTER IIC CD4033

20

4.7

SEVEN SEGM SEGMENT DISPLAY

22

4.8

PHASE LOC LOCKED LOOP NE567

24

























5.3.1.2.1

ETC ET CHING PR PR OCESS

55

5.3.1.2.2

COMPONENT ASSEMB ASSEMBLY LY

56

5.3.1.2.3

SOLDER SOLDER ING ING

57

6

R ESULT ESULT

58

7

CONC ONCLUSION & FUTUR FUTUR E SC SCOPE

59

7.1

CONC ONCLUSION

59

7.2

FUTUR FUTUR E SC SCOPES

59

8

R EFER EFER ENC ENCES

60

9

APPENDIX

61

9.1

PCB PCB LAYOUT

61

9.2

COMPONENT LAYOUT

62

9.3

COMPONENT LIST

63

9.4

DATASHEETS

65

9.4.1

CD4033BM D4033BMS S

65

9.4.2

LM LM 7806

68

9.4.3

LM LM386

70

9.4.4

NE 567

74

























CHAP TE 1 INT INT ODUCTION Laser as a communi commun icati cation on medi medium can provi provide a good substit subs titu ute for the present present day communi communicati cation on syst systems as the probl problem of interference faced in case of el elect ectromagneti romagneticc waves is not not there and hi high deal dea l of secrecy is avail ava ilab ablle. Laser communi commun icati cations ons offers a vi v iabl able alterna lternati tive ve to R F communi communicati cations ons for inter sat satellite llite links links and ot other appli applica cati tions ons where hi highgh performance links links are a necessit necess ity. y. High dat data rat rate, small sma ll ant antenna siz size, e, narrow beam divergence, and a narrow f ield of vi view are charact charac ter istics tics of l of laser communi communicati cations ons that hat offer a number of pot po tenti entiaal advant advantages for syst sys tem desi design. The present present paper i paper invol nvolves the st study of wirel reless, open channel channe l communi communicati cation on syst syst em usi using laser a carr ier for voi voice signal gnals. Usi Using this circuit rcuit we can communi communicat cate with ith your own nei neighbors wi wirel relessl essly. Inst Instead of R F si s ignal gnals, ligh lightt from a laser t aser torch is used as the carr ier i er in the ci c ircuit rcuit.. The laser t aser torch can transmit ransmit ligh lightt up to a distance of about abou t 500 met meters. The phot phototransi ransistor of the recei receiver must must be accurat accuratel y or ient ented towards the laser beam from the torch. If t If there is any obst obs tructi ruction on in the pat path of l of laser beam, no sounds will will be heard from the recei receiver.

























1.1BL 1.1BLO OCK DIAGRAM EXPLANATION 1.1.1CONDE ONDENSE NSER MICR OPHONE ONE

It is also call ca lled ed a capacit capacitor or or el elect ectrost rostatic tic microphone. Condenser means capacit capac itor, or, whi which stores energy in the form of an el elect ectr ic f ield. Condenser mi microphones requi requ ire power from a batt battery ery or ext external erna l source. Condenser al a lso tends to be more sensiti sens itive ve and responsi respons ive than dynami dynamic, mak ing them well well suit suited ed to capt captur ing subtl subtlee nuances in a sound. The di d iaphragm vi brat brates when st struck by sound waves, changi chang ing the distance bet between the two plates and therefore changi changing the capacit capacitance. ance. Speci Specif icall cally y when the plates are cl closer toget ogether capacit capacitance ance increases and a charge current curren t occurs and this current current will be used to tr igger the transmitti ransmitting ng secti section. on.

1.1.2 TRANSMITT NSMITTIN ING SECTION The transmitt ransmitter er secti section on compr ises condenser mi microphone. In transmitt ransmitter er the frequency is generat generated whi which is used to mat match the frequency in the phase locked loop used in the recei receiver secti section. on. A swit switch ch S generate a tone whi which is transmitt ransmitted ed by the transmitt ransmitter er to the recei receiver secti section on so that hat is used to generat

























1.1.4 R ECEIVING SECTION

The recei receiver ci circuit rcuit uses an NPN phot phototransi rans istor as the ligh lightt sensor t sensor that hat is foll fo llowed owed by a t wo stage transi rans istor preampli preamplif f ier and LM L M386-based audi audio power ampli amplif f ier. The recei receiver doesn't doesn' t need any compli complica catt ed a lignmen lignmentt. Just Just keep the phot phototransi rans istor or ient ented towards the remot remot e transmitt ransmitter's er's laser poi point and ad jus justt the vol volume cont control rol for a cl clear sound.

1.1.5 LOUD SPEAK ER

A loudspeaker (or "speaker") is an el elect ectro acousti acousticc transducer that hat conver ts an elect ectr ical cal signal gnal into sound. The speaker moves in accordance wit with h the var iations tions of an el elect ectr ical cal signal gnal and causes sound waves to propagat propaga te through a medi med ium such as ai a ir or wat water.



























CHAP TER 2 LITERATUR E R EVIE VIE 2.1 Optical and microwave communications system conceptual design for a realistic interstellar explorer

B.G. Boone, R.S. Bokuli Bokuli , G.B. Andrews Andre ws , R.L. McNutt McNu tt , Jr and N. Dagal Dagal ak ak isb isb 

ABSTRACT

The concept concept of a reali rea lisstic tic int erst erstellar llar expl explorer has been addressed by the Johns Hopk ins Uni Universit versity y Appli Applied ed Physi Physics Laborat Laboratory (JHU/APL) wit with h suppor t from the NASA Instit Ins titu ute for

























ABSTRACT

In this thesi hesis, the opti optica call communi communicati cation on syst systems for milli millime metter-scal er-scale sensi sensing and communi communicati cation on devi devises known as ³Smar t Dust Dust´ are descr i bed and anal analyzed. A smar t dust dust element ement is a sel selfcont contained sensi sensing and communi communicati cation on syst system that hat can be combi comb ined into roughl roughly a cubi cub icmillime illimetter mot mote to perform integrat egrated, massi massivel vely distr but i buted sensor net networks. The suit suitab ablle passi passive opti optica call and f i ber-opti ber-opticc communi communicati cation on syst systems will will be sel select ected for the fur ther performance design and anal ana lysi ysis based on the requi requirement rements for impl mplementi ementing ng these syst systems. Based on the communi communicati cation on link link desi designs of the free-space passi pass ive opti optica call and f ber-opti i ber-opticc communi communicati cation on syst systems, the si simul mulations tions for li for link nk performance will will be performed.

























2.3 Toward a Wireless Optical Communication Link between Two Small Unmanned Aerial Vehicles M. La st , B.S. Leib Leibo owitz , B. Cagda ser, ser, A. Jog, L. Zhou, B. Bo ser, ser, K.S.J. P ist ist er er ABSTRACT

A communi communicati cation on syst system bet between two aut autonomous mi micro ai a ir vehi vehicles is proposed. Laser communi communicati cation on offers advant advan tages in range, power, and bandwi bandw idth when line line of si sight ght is avail availab ablle. Beam st steer ing is accompli accomplished shed usi us ing gyro-st gyro-stabiliz abilized ed MEMS micro mi mirrors. A cust custom CMOS CMOS smar t-pi -pixel xel imager i mager impl mplement ements a 1M bps recei receiver, incl ncludi uding anal ana log front front-end and var iabl able-gai e-gain ampli amplif f ier at each pi pixel xel. Algor ithms ithms are present presen ted for initia itial link link est establi ablishmen shmentt and mai ma intenance.

























2.4 Free Space Optical Laser Communication Link

Andrew Andrew W. Reb Rebeiro and Rodney Tan ABSTRACT

A Free Space Opti Optica call (FSO) LASER LASER Communi ommunicati cation on Link is present present ed. Thi This pro jec jectt deal deals with ith the devel development opment of a full full-dup -dupllex FSO anal ana logue / di digita ital transcei ransceiver. In this informati nforma tion on age, the demand for hi h igh speed, hi h igh bandwi bandwidth communi communicati cations ons channel channel, is ever i ever increasi ncreas ing. FSO is present present ed as a sol solution tion to these demands in that hat it is free to impl mplement ement, easy to inst nstall and of very hi h igh bandwi bandwidth. The reader is introduced to the FSO syst system of communi communicati cation on and the devel development opment of a small sma ll scal scale communi communicat cator usi us ing laser as the carr ier signal gnal for informati nformation on transfer. Exper iment mental result resultss expl explain the performance of the compl completed syst sys tem

























CHAPTER 3 METHODOL ODOLOGY

3.1 SYSTE SYSTEM M DE DESCR IPTION



























R CIRCUIT 3.2 THE TRANSMITTE NSMI TTER C UIT

























The out out put puts of IC IC2 and IC I C3 and voi voice signal gnals are mi mixed by transi ransistor T1 to dr ive the laser poi pointer LED. The mi mixer out out put put modul modulates the intensit ensity y of li of ligh ghtt signal gnals emitt emitted ed by the laser diode modul module in accordance wit with h the level evel of t of the code oscill osc illaator and tone and audi audio si s ignal gnals avail availab ablle at at the bade of t of the mi mixer t xer transi ransistor.

























3.3 THE R ECIEVER CIRCUIT UIT

























A snubber net ne twork compr ising capacit capacitors ors and resi res istors is used for out ou t put put stabilit ability.I y.IC C LM386 is a low volt voltage age audi audio ampli amplif f ier. It Its gai gain is int ernall erna lly y set set to 20 to keep ext external ernal par t count count low. The preampli preamplif f ier out out put put, as st stated ear lier, lier, is a lso connect connected to phase locked loopIC oopIC5 and

























generat genera tes a mel melodi odious tune whenever the ligh lightt beam is interrupt errupted. The out out put put of IC10 is ampli amplif f ied by transi rans istor T5 to dr ive loudspeaker oudspeaker LS2. For initia itiating ting a call ca ll,, the person at a t the transmitt ransmitter er end depresses swit sw itch ch S1 to a ler t t he remot remote end person of an impendi mpending voi voice communi communicati cation. on. Thus the modul modulated ligh lightt out out put put















































































































































































































































































































































































































































































































































































































































































































































NPN is one of the two types of bi b i pol polar transi ransistors, consi cons isting ting of a layer of P-doped semi semiconduct conduc tor (t (the "base") bet between two N-doped layers. A small sma ll current current ent ent er ing the base is ampli amplif f ied to produce a large coll collec ecttor and emitt emitter er current current. That That is, an NPN transi ransistor i or is "on" when its its base is pull pulled ed hi high rel relative tive to the emitt emitter. er. Most ost of t of the NPN current current is carr ied by el elect ectrons, movi moving from emitt emitter er tto coll collec ecttor as mi minor ity it y carr iers in the P-t P-type base regi region. Most ost bi pol polar transi ransistors used today are NPN, because elect ectron mobilit mobility y is higher than Hol Hole mobilit mobility y in semi semiconduct conductors, all allow owiing great greater current currents and fast faster operati operation. on.

The symbol of a PNP Bipolar Junction Transistor

The ot other t her type of BJT is the PNP, consi consisting ting of a layer of N-doped semi semiconduct conduc tor bet between two layers of P-doped mat ma ter ial. A small sma ll current current leavi eaving the base is ampli amplif f ied in the coll collec ecttor out out put put. That That is, a PNP transi ransistor is "on" when its its base is pull pulled ed low rel relative tive to the emitt emitter. er. The arrows in the NPN and PNP transi ransistor symbol symbols are on the emitt emitter er legs and poi point in the directi rection on of the conventi conventiona onall current current f low when the devi device is in forward acti active ve mode. A mnemoni mnemonic devi device for the NPN / PNP di distinc tincti tion, on, based on the arrows in thei heir symbol symbols and the letters tters in thei heir names, is not not poi pointing ting in for NPN and poi po inting ting in for PNP. The BC548 is a general purpose silicon N PN BJT transistor found commonly in European electronic equipment.

If t If the TO-92 package is hel held in front front of one's face wit with h the f lat side faci facing toward you and the leads downward, (see pi picture) the order of t of the leads, from lef t to r ight ght is coll collec ecttor, base, emitt emitter. er. Specifications: The exact exact specs of a gi given devi device depend on the manufact manufacturer. It It is impor tant ant

to check the dat datasheet asheet for the exact exact devi device and brand you are dea ling ling with. ith. Phili Phili ps and Tel Telefunken are two manufact manufacturers of t of the BC548. BC548.

























Pt otal = 50 mW f t = 300 MHz The BC548 BC548 is a member of a larger group of si s imilar ilar ly numbered transi rans istors. Ot Other par t numbers have di d ifferent fferent charact charact er istics tics and rati ra tings. ngs. It Its compl complement ement is the BC558. BC558. A famil family y of ol older "BC "BC"" transi ransistors predat predates the TO-92 BC54x BC54x ser ies, the BC107, BC107, BC108 BC108 and BC109, BC109, (wit (with h compl complement ements BC177, BC177, BC178 BC178 and BC179). BC179). These are genera generall lly y housed in the TO-18 met metal package, the same as what wha t the Nor th Amer ican 2N2222 uses. These ol o lder transi ransistors have si s imilar ilar charact charact er istics tics as the TO-92 BC5xx BC5xx devi devices and are el elect ectr icall cally y interchangeabl erchangeable. There are many ot o ther devi devices based on the BC54x BC54x famil family, y, such as the surface-mount surface-mount versi versions of t of the BC547, BC547, 548 and 549; the BC847, BC847, BC848 BC848 and BC849. BC849.

4.15 ZE ZENER DIODE DIODE A Zener diode is a type of di diode that hat permit permitss current current not not onl only in the forward di directi rection on like like a normal normal diode, but but also in the reverse di d irecti rection on if the volt voltage age is larger than the breakdown volt voltage age known as "Zener knee volt vo ltage" age" or "Zener volt vo ltage". age". The devi device was named af t er Clarence Clarence Zener, who di d iscovered this el elect ectr ical cal proper ty. A conventi conventiona onall soli solid-s d-sttate di diode will will not not allow llow signi gnif icant cant current current if it is reverse-bi reverse-biased bel below its its reverse breakdown volt vo ltage. age. When the reverse bi bias breakdown volt voltage age is exceeded, a conven c onventi tiona onall diode is sub jec jectt to hi high current current due to aval ava lanche breakdown. Unl Unless this current current is lim limited ited by ci circuit rcuitry, ry, the di diode will will be permanentl permanently y damaged due to overheati overhea ting. ng. In case of large forward bi bias (current (current in the directi rection on of the arrow), the di d iode exhi exhi bit bitss a volt voltage age drop due to its its junc juncti tion on built built--in volt voltage age and internal erna l resi resistance. The amount amount of the volt voltage age drop depends on the semi semiconduct conduc tor mat mater ial

and

the

dopi doping

concent concentrati rations. ons.

























A ZENER ZENER DIODE DIODE

CHAR HAR ACTER TER ISTIC ISTIC GR APH APH

CHAPTER 5

DESIGN & IMPLE LEM MENTATION

5.1 PCB MANUFACTUR IN ING PR OCESS

It is an impor tant ant process in the fabr icati cation on of el e lect ectroni ronic equi equi pment pment. The desi des ign of PCB PCBss (Pr inted Circu Circuit it Boards) depends on c ircuit rcuit requi requirement rements like like noi noise immunit mmunity, y, work ing frequency and volt vo ltage age level evels et etc. Hi High power PCB P CB s requi requires a speci spec ial desi design st strat rategy. The fabr icati cation on process to the pr inted ci c ircuit rcuit board will will det determi ermine to a large ext extent ent the pr ice

























The layout ayout of a PCB PCB has to incorporat ncorporate all all the informati nformation on of t of the board before one can go on the ar twork preparati preparation. on. Thi This means that hat a concept concept whi which cl clear ly def ines all all the det details ils of t of the circuit rcuit and par tly tly def ines the f inal nal equi equi pment pment, is prerequi prerequisite ite before the act actual ual lay out out can star t. The det detailed iled ci circuit rcuit diagram is very impor tant ant for t for the layout ayout desi designer but but he must must also be famili familiar ar wit with h the desi des ign concept concept and wit with h the phil philosophy osophy behi behind the equi equi pment pment.

5.2 BOAR D TYPES:

The two most most popul popular PCB PCB types are: 1. Single Sided Boards

The si singl ngle sided PCB PCBss are mostl mostly y used in ent ent er tainment nment elect ectroni ronics where manufact manufac tur ing cost costs have to be kept kept at a minimum. However in indust ndustr ial elect ectroni ronics cost cost fact factors cannot cannot be negl neglect ect ed and si s ingl ngle sided boards shoul shou ld be used wherever a par ticu ticullar circuit rcuit can be accommodat accommodat ed on such boards. 2. Double Sided Boards

Doubl Double-si e-sided PCB PCBss can be made wit with h or wit withou houtt plated through hol holes. The producti produc tion on of boards wit with h pl plated through hol holes is fai fair ly expensi expensive. Therefore pl plated through hol hole boards are onl only chosen where the circuit rcuit compl complexiti exities es and densit dens ity y of component components does not not leave any other choi choice.

























5.3 DESI GN SPECIFI CATION: 5.3.1 STEPS TAK EN WHILE PR EPAR IN ING CIRCUIT UIT 5.3.1.1 PCB DESIGNING

The mai ma in purpose of pr inted circuit rcuit is in the routi routing ng of el elect ectr ic current currents and si signal gnal through a thin copper layer that hat is bounded f irml rmly to an insul nsulating ting base mat mater ial someti sometimes mes call ca lled ed the subst substrat rate. Thi This base is manufact manufactured wit with h integrall egrally y bounded layers of t of thin copper foil fo il whi which has to be par tly tly etched or removed to arr ive at a pre-desi pre-des igned patt pattern ern to suit suit the ci circuit rcuit connecti connections ons or ot other appli applica cati tions ons as requi required. The term pr inted ci circuit rcuit board is der ived from the or iginal nal met method where a pr inted patt pattern ern is used as the mask over want wan ted areas of copper. The PCB P CB provi provides an ideal deal baseboard upon whi which to assembl assemble and hol hold f irml rmly most most of t of the small sma ll component componen ts. From the const construct ructor¶s poi point of view, the mai ma in att a ttrac racti tion on of usi us ing PCB P CB is its its rol role as t he mechani mechanical cal suppor t for small sma ll component componen ts. There is less need for compli comp lica catted and time ti me consumi consuming met metal work of chassi chass is cont contracepti raception on except except perhaps in provi providing the f inal nal encl enclosure. Most ost strai raight ght forward ci circuit rcuit desi designs can be easil eas ily y conver ted in to pr inted wir ing layer the thought hought requi required to carry out out the inversi nvers ion cab foot foo ted high ligh lightt an possi possi bl ble error that hat woul would otherwi herwise be mi missed in conventi conventiona onall poi point to poi point wir ing .The f inished pro jec jectt is usuall usua lly y neat neater and trul ruly a work of ar t. Act Actual ual size ize PCB PCB layout ayout for t for the ci c ircuit rcuit shown is drawn on the copper board. The board is then immersed in FeCl FeCl3 sol solution tion for 12 hours. In this process onl on ly the exposed copper por tion tion is et etched out out by the sol solution. tion. Now the pet petrol rol washes out out the pai pa int and the copper layout ayout on PCB is rubbed wit w ith h a smoot smooth sand paper sl s lowl owly and ligh lightl tly y such that hat onl only the oxi oxide layers over the Cu are removed. Now the hol holes are dr illed illed at the respecti respective ve places accordi according to component component layout ayout as shown in f igure. 5.3.1.2 LAYOUT YOUT DESIGN:

When desi designi gning the layout ayout one shoul should observe the minimum siz sizee (component (component body lengt ting to desi ength and wei weight ght). Before st star ting design the layout ayout we need all a ll the requi required re d component componen ts in hand so that hat an accurat accurate assessment assessment of space can be made. Ot O ther space iderati derati

ight ght lso be i

luded from case to case of mount mounted component component

t he



























by positi position oniing the component components on the squared paper. If any connec tion tion crosses, then one can rerout reroute to avoi avoid such conditi cond ition. on. All common or ear th lines lines shoul should ideall deally y be connect connected to a common line line rout rout ed around the per imet met er of t of the layout ayout. Thi This will act act as the ground pl plane. If possi poss i bl ble try to rout route the out outer suppl suppl y line line to the ground pl p lane. If possi poss i bl ble try to rout rout e the ot other suppl supply lines lines around the opposit oppos itee edge of the layout ayout through the cent cent er. The f irst rst set set is tear ing the circuit rcuit to elim liminat nate the crossover wit withou houtt alter lter ing the ci circuit rcuit det detail in any way. Plan the layout ayout look ing at the topsi opside to this board. Fi F irst rst this shoul should be transl ranslated inversel nversely; later for the etchi ching patt pattern ern large areas are recommended to mai maintain good copper adhesi adhes ion. It It is impor tant ant to bear in mind a lways that hat copper track wi width must must be accordi according to the recommended mi minimum di dimensi mens ions and all a llowance owance must must be made for increased wi width where termi erminati nation on hol holes are needed. From this aspect aspect, it can become little little tr icky to negoti negotiaate the rout rout e to connect connect small small transi ransistors. There are basi bas icall cally y two ways of copper interconnecti erconnection on patt patterns erns under si s ide the board. The f irst rst is the removal remova l of onl only the amount amount of copper necessary to isol solate the j he junc uncti tions ons of t of the component componen ts to one anot another. The second is to make the int erconnecti erconnec tion on patt pattern ern look ing more like like conventi conventiona onall poi point wir ing by routi rou ting ng uni uniform wi width of copper from componen t to component component. 5.3.1.2.1

ETCHING PR OCESS:

Etchi ching process requi requ ires the use of chemi chem ical cals. Aci Acid resi res istant ant dishes and runni runn ing wat water suppl supply. Ferr ic chl chlor ide is mostl mos tly y used sol solution tion but but other et etchi ching mat mater i als such as ammoni ammonium per sul sul phat phate can be used. Nit N itr r ic aci ac id can be used but bu t in general genera l it is not not used due to poi poisonous fumes. The patt pattern ern prepared is glued to the copper surface of the board usi us ing a latex type of

























To prevent prevent par tic ticles of copper hi h inder ing fur ther et etchi ching, agit agitaate the sol solutions tions carefull carefully y by gentl gently y twisting ting or rock ing the tray. The board shoul shou ld not not be lef t in the bat bath a moment moment longer than is needed to remove jus justt the r ight ght amount amount of copper. Inspit Insp itee of t of there bei being a resi res istive tive coati coating ng there is no prot prot ecti ection on agai against nst etchi ching away through exposed copper edges. Th is leads to over et etchi ching. Have runni running wat water ready so that hat etched board can be removed proper l proper ly and r insed. Thi This will halt halt etchi ching immedi mmediately. Dr illing illing is one of those operati opera tions ons that hat call call for great grea t care. For most most purposes a 0.5mm dr ill ill is used. Dr ill ill all hol holes with ith this size ize f irst rst those that hat need to be larger can be easil eas ily y dr illed illed agai again wit with h the appropr iate larger siz size. e. 5.3.1.2.2

COMPONE ONENT ASSE SSEMBL BLY Y

From the great great est est var iety of el elect ectroni ronic component components avail ava ilab ablle, whi which runs into thousands it, is of ten a perpl of di different fferent types it, perplexi exing task t ask to know whi which is r ight ght for a gi given j ven job. ob. There coul could be damage such as ha ir line line crack on PCB P CB.. If there are, then they can be repai repaired by sol solder ing a shor t link link of bare copper wi w ire over the affect affect ed par t. The most most popul popular met method of hol holding all all the items items is to br ing the wi wires far apar t af ter t er they have been inser ted in the appropr iat e hol holes. Thi This will hol hold the component component in positi pos ition on ready for sol solder ing. Some component components will w ill be consi considerabl derably larger .So it is best best to st star t mounti mounting ng the small sma lles estt f irst rst and progressi progress ing through to the largest argest. Before st star ting, ting, be cer tain that hat no fur ther dr illing illing is like likelly to be necessary because access may be impossi mposs i bl ble later. Next Next will probabl probably be the resi resistor, small sma ll signal gnal diodes or ot other si similar ilar size ize component components. Some capacit capacitors ors are al a lso very small sma ll but but it woul would be best bes t to f it it these af terwards. When f itting itting each group of component componen ts mark off each one on the ci c ircuit rcuit as it is f itted itted so that hat if

























5.3.1.2.3

SOL SO LDER IN ING

Thi This is the operati operation on of j of jo oining the component components with ith PCB P CB af ter t er this operati operation on the ci c ircuit rcuit will be ready to use to avoi avoid any damage or fault fau lt dur ing this operati operation on foll follow owiing care must must be taken. 1. A longer durati dura tion on cont contact act bet between sol solder ing iron bit bit & component components lead can exceed the temperat emperature rati rating ng of devi device & cause par tia tial or t or total damage of t of the devi device. Hence before sol solder ing we must mus t carefull carefully y read the maxi maximum sol solder ing temperat emperature & sol solder ing time ti me for devi device. 2. The watt wattage age of sol solder ing iron shoul should be sel select ected as mi minimum as permi permissi ssi bl ble for that hat sol solder ing pl place. 3. To prot protect ect the devi devices by leakage current current of i of iron its its bit bit shoul should be ear thed proper ly. 4. We shoul should sel se lect ect the sol solder ing wi wire with ith proper rati ra tio o of Pb & Tn to provi provide the suit suitab ablle melti melting ng temperat emperature. Proper amount amoun t of good qualit qua lity y f lux must mus t be appli applied ed on the sol solder ing poi point to avoi avoid dry sol solder ing.

























CHAPTE R 6 R ESULT SULT

The result result we got got is the successful successful work ing of t of the pro jec jectt and a communi communicati cation on is est establi ablished shed bet between the two transcei ransceivers.

























CHAPTE R 7 CONCLUSION & FUT FUTUR E SCOP E

7.1CONCLUSION ter Af ter

the successf ul ul working o f the project, it can be concluded that this project is

suitable f or or communication. There can be f u urther rther up gradations in the project which could lead to a much better system f o orr communication. Some of the possible ways are as f ollows: ollows: o

Instead of the short range laser, high range lasers can be used which range a ew f ew

hundred kilometers.

7.2 FUT FUTUR E SCOPE y

In f uture uture it can be commissioned in satellites f or or communication.

y

Lasers can also transmit through glass, however the physical properties o f the glass have to be considered and hence can be used f o orr a verylonge distance communication.

y

It can be used in inaccessible areas.



























CHAPTE R 8 R EFER ENCES

1. [Online] // wikipedia. - www.wikipedia.com. 2. [Online] // circuitstoday. - www.circuitstoday.com. 3. [Online] // electronics schematics. schematics. - www.electroschematic.com. www.electroschematic.co m. 4. [Online] // electronics f or or you. - www.ef y.com. y.com. 5. D.ROY CHOUDHARY SHALIN B. JAIN LINE AR INTEGR ATED CIRCUITS [Book]. - DELHI : NEW AGE INTERN ATIONL PUBLISHERS, UBLISHERS, THIRD EDITION E DITION 2009. 6. ELECTRONICS FOR YOU M AG AZINE [Book]. 7. GUPTA J.B. ELECTRONICS DEVICE & CIRCUITS [Book]. - INDI A: S.K. K AT ARI A & SONS, FIRST EDITION DEC 2000. - Vol. 1. 8. KUMAR N. SURESH ELECTRONICS DEVICE & CIRCUITS [Book]. - 2008. 9. MEHTA V.K. PRINCIPLES OF ELECTRONICS [Book]. 10. NAVAS K.A. ELECTRONICS L AB M ANU AL [Book]. - [s.l.] : Rajath publishers, 2008. - Vol. 1&2. 11. RAI A. VALLAVE ELECTRONICS DEVICE & CIRCUITS [Book]. - 2007. 12.EFY Magzine -june 2004 edition

























CHAPTER 9 APPENDI

9.1 PCB LAYOUT

























9.2 COMPONENT LAYOUT

























9.3 COMPONE ONENT LIST IST IC1 IC2, IC3, IC7, IC8 IC4 IC5,IC6 IC9 IC10 BR1 D1 ZD1 LED1-LED3 D1S1

7805 5 V regulator 555 Timer LM386 low power audio amplifier NE567 phase locked loop decade counter 7-segment decoder UM66 melody generator Bridge rectifier 1N4001 rectifier diode 3.3zener diode 5mm red LED LTS543 common cathode display

Resistors R1, R19, R20, R27, R32 R2, R5 R6, R8, R18, R21, R28 R7, R12 R9 R10 R11 R13, R17, R26 R14

1 kilo ohm 5.6 kilo ohm 8.2 kilo ohm 15 kilo ohm 22ohm 2kilo ohm 68ohm 2.2 kilo ohm 2.7kilo ohm

























C1 C2, C12, C13, C40 C3, C5, C6, C9, C19, C22, C32, C35 C4 C7, C10, C11, C14, C15, C17, C20, C26, C29 C8,C16,C38 C16 C18, C27, C33, C39 C21, C24 C25 C23, C28 C30 C31 C34 C37

2200µF, 5 V electrolytic 100µF, 16 V electrolytic 0.01µF ceramic disk 3.3nF ceramic 0.1µF ceramic disk 470µF,16 V electrolytic 56µF ceramic disk 10µF, 16 V electrolytic 2.2µF,16 V electrolytic 1nF ceramic disk 0.22µF ceramic disk 47µF, 16 V electrolytic 1µF, 16 V electrolytic 6.8µF,16 V electrolytic 3.3µF, 16 V electrolytic

Miscellaneous S1,S2 LS1,LS2 Mic PZ1 X1

Push to on tactile switch 8 ohm,1W loudspeaker Condenser microphone Piezobuzzer 230V AC primary 0-9V,



























9.4 DATASHEET EETS S 9.4.1 CD4033B D4033BMS





























































































































































































































































































































Laser Based Communication Link

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