CONTENTS

S.no      CHAPTER              PAGENO

1.           CHAPTER: 1 Introduction 3

1.1 Description of IR Music Transmitter & Receiver 41.2 Specifications 4-5

2. CHAPTER: 2 Fundamentals 6

2.1 How IR Music Transmitter & Receiver Works 7 2.2 List of Figures 8 2.2.1 Circuit Diagram of IR Music Transmitter & Receiver 8 2.2.2 PCB Layout of IR Music Transmitter & Receiver 9 2.2.3 Block Diagram of IR Music Transmitter & Receiver 10-11 2.2.4 Description of the Project 12-13 2.3 List of Components 14 2.4 Datasheet 15 2.4.1 npn general purpose amplifier 15-16 2.4.2 pnp General purpose transistor 17 2.4.3 IC 741 Operational amplifier 17-18 2.4.4 IC LM386 19-21 2.5 PCB Manufacturing process 22 2.6 PCB Designing 23-27

3. CHAPTER :3 28

3.1 Result 29 3.2 Conclusion 30 3.3 Future Enhancement 31 3.4 Applications 32 3.5 Advantages & Disadvantages 33 3.6 References 34

1

LIST OF FIGURES :

FIGURES Page No

Circuit Diagram

Transmitter 8

Receiver 8

PCB layout

Transmitter 9

Receiver 9

Block Diagram

Transmitter 10

Receiver 10

2

CHAPTER – 1

INTRODUCTION

3

INTRODUCTION

1.1 DESCRIPTION OF IR MUSIC TRANSMITTER & RECEIVER

The main idea behind the project is to generate musical notes by infrared radiations. The infrared radiations are transmitted and received by IR LED and Phototransistor respectively.

This project emphasizes the way by which music is generated and driven by IR rays. This circuit uses a popular melody generator IC UM66 that can continuously generate musical notes. The melody produced is heard through the receiver’s loudspeaker.

For maximum sound transmission the IR LEDs should be oriented towards IR phototransistor.

It can be used in wireless music systems, mobile gadgets and cc cameras.

1.2 Specifications :

1.2(a) Infrared (IR) LED - As normal PN junction diode provide current as the output when subjected to forward bias, in the same way an IR led gives IR radiation at its output in forward bias. Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.7 micrometers, and extending conventionally to 300 micrometers. These wavelengths correspond to a frequency range of approximately 430Hz to 1THz, and include most of the thermal radiation emitted by objects near room temperature. Microscopically, IR light is typically emitted or absorbed by molecules when they change their rotational or irrational movements.

1.2(b) Photo Diode – A photodiode is a type of photo detector, capable of converting light into either current or voltage, depending upon the

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mode of operation. Photodiode works on the principle of photoconductivity. When light is absorbed by a semiconductor material, the number of free electrons and electron’s holes changes and raises its electrical conductivity, this phenomenon is called photoconductivity. To cause excitation, the light that strikes the semiconductor must have enough energy to raise electrons across the band gap Photoconductivity may also be defined as an electrical property of Light Emitting Diode (LED) which is the fact that a LED produces a voltage difference across its leads when it is subjected to light, as if it was in photo-cell, but with much lower output current. In other words, the voltage generated by the LED cannot be, in any way, used to generate electrical power from the output voltage, it can barely be detected. This is why we used an Op-Amp (operational Amplifier) to accurately detect very small voltage changes. Photoconductivity is a phenomenon in which a material becomes more electrically conductive due to the absorption of electromagnetic radiation such as visible light, ultraviolet light, infrared light, or gamma radiation. Photodiodes are similar to regular semiconductor diodes except that they may be either exposed to (detect UV or X-rays) or an optical fiber connection to allow light to reach the sensitive part of the device.

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CHAPTER – 2FUNDAMENTALS

6

2.1 HOW IR MUSIC TRANSMITTER & RECEIVER WORKS

TRANSMITTER

The IR music transmitter works off a 9V battery. Figure (1) shows the circuit of the IR music Transmitter. It uses popular melody generator IC U M-66 (IC1) that can continuously generate musical tones. The output of IC1 is fed to the IR driver stage (Built across the transistors T1 and T2) to get the maximum range. Here the red LED (LED1) flickers according to t he musical tones generated by UM66 IC, indicating modulation. IR LED2 and LED3 are infrared transmitting LEDs. For maximum sound transmission these should be oriented towards IR phototransistor L14F1 (T3).

RECEIVER

The IR music receiver uses popular op-amp IC µA741 and audio-frequency amplifier IC LM386 along with phototransistor L14F1 and some discrete components(Fig. 2).The melody generated by IC UM66 is transmitted through IR LEDs, received by phototransistor T3 and fed to pin 2 of IC µA741 (IC2). Its gain can be varied using pot meter VR1. The output of IC µA741 is fed to IC LM386 (IC3) via capacitor C5 and pot meter V- R 2 .The melody produced is heard through the receiver’s loudspeaker. Pot meter VR2 is used to control the volume of Loudspeaker LS1 (8-ohm, 1W).

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2.2 LIST OF FIGURES :

2.2.1. Circuit Diagram:

[a] Transmitter:

Fig: 1

[b] Receiver:

Fig: 2

8

2.2.2. PCB Layout:

[a] Transmitter:

Fig: 3

[b] Receiver:

Fig: 4

9

2.2.3. Block Diagram:

[a] Transmitter:

Fig: 5

+9v

[b] Receiver:

10

3.3 v regulatorMelody

GeneratorTransistor

Driver

Stage - 1

Transistor Driver

Stage - 2

IR LED

LED Music Flicker

Indicator

Fig: 6

+9V

2.2.4 Description of the Prjoect

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Photo

Transistor

Audio Amplifier

stage-1

Audio Amplifier

stage-2

Loud Speaker

Gain Control

Gain Control

Using this circuit, audio musical notes can be generated and can be heard up to a distance of 10 meters. The receiver can be placed at a maximum distance of 1 meter from the transmitter with our any considerable noise interference. The circuits of transmitter and receiver are quite simple and can be placed and carried any where easily. The small apparatus provided with the infrared communication function is in many cases operated by a battery incorporated inside so that it is convenient when a user carries it during movement, and it is preferable that power consumption be minimized also to lengthen the continuous operation possible time of IR emission is optimized. Here there is no use of any modulation technique when working with the IT rays. Hence there is no use of necessity of carrier generation. This makes the transmitter and receiver designs much simpler. However the communication distance can be improved by using Far IR LEDs. The range of communication can be increased to about 250 meters by using far IR LEDs. In the apparatus provided with a conventional communication function, however, the infrared light with a constant intensity is constantly radiated regardless of the communication distance. This project emphasizes the way by which music is generated and driven by IR rays and gives an explanation to the one of the methods of receiving IR rays without considerable noise interference.

The circuit can be divided into two parts: IR music transmitter and receiver. The IR music transmitter works off a 9V battery, while the IR music receiver works off regulated 9V to 12V. Fig. 1.1 shows the circuit of the IR music transmitter. It uses popular melody generator IC UM66 (IC1) that can continuously generate musical tones. The output of IC1 is fed to the IR driver stage (built across the transistors T1 and T2) to get the maximum range. Here the red LED (LED1) flickers according to the musical tones generated by UM66 IC, indicating modulation. IR LED2 and LED3 are infrared transmitting LEDs. For maximum sound transmission these should be oriented towards IR phototransistor L14F1 (T3). The IR music receiver uses popular op-amp IC μA741 and audio-frequency amplifier IC LM386 along with phototransistor L14F1 and some discrete components. The melody generated by IC UM66 is transmitted through IR LEDs, received by phototransistor T3 and fed to pin2 of IC μA741 (IC2). Its gain can be varied using potential meter VR1. The output of IC μA741 is fed to IC LM386 (IC3) via capacitor C5 and potential meter VR2.The melody produced is heard through the receiver’s loudspeaker. Potential meter VR2 is used to

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control the volume of loudspeaker LS1 (8-ohm, 1W). Switching off the power supply stops melody generation.

The electrical signal from your music player is converted into an invisible infrared light signal by the infrared light emitting diode (IR LED) in the transmitter circuit. To transmit this over a longer distance, a brighter IR LED is needed or an invisible light is to be focused using lens. The invisible infrared light signal must hit the photo transistor in the receiver. The photo transistor in the receiver converts this invisible infrared light signal into an electrical signal. Then, the amplifier in the receiver circuit takes this electrical signal and makes it larger using energy from the battery. Finally, this larger electrical signal drives the speaker which turns electrical energy into sound energy.

2.3 LIST OF COMPONENTS

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S.No. Name Of The Component Quantity

1. IC UM-66(IC1) 1

2. IC LM741 (IC2) 1

3. IC LM386 (IC3) 1

4. RED LED(1) 1

5. IR LED(2 & 3) 2

6. Resistance R1 & R11 (1 K) 2

7. Resistance R2(4.7 K) 1

8. Resistance R3(22 K) 1

9. Resistance R4(82 ohm) 1

10. Resistance R5 & R12(10 ohm) 2

11. Resistance R6 & R7(10 K) 2

12. Resistance R8 & R13(15 K) 2

13. Resistance R9(100K) 1

14. Resistance R10(680 ohm) 1

15. Capacitor C1(1uF,16V) 1

16. Capacitor C2,C4,C8 & C10(220 uF, 25V) 4

17. Capacitor C3,C5,C7 & C9(0.1 uF) 4

18. Capacitor C6(10 uF,16V) 1

19. Transistor BC547(T1) & SK140/BD140(T2) 2

20. IR Phototransistor L14F1(T3) 1

21. Zener diode 3.3V 1/4W 2

22.

23.

24.

Speaker (8 ohm, 1W)

Preset VR1 (1M) & VR2 (10K)

9V battery

1

2

2

2.4 DATASHEET

14

2.4.1 NPN General Purpose Amplifier

Absolute Maximum Ratings TA=25°C :-

Symbol

Paramet

Value Units

VCEO Collector-Emitter Voltage 30

V

VCES Collector-Base Voltage 30

V

VEBO Emitter-Base Voltage 5.0

V

IC Collector Current - Continuous 500

mA

TJ,

Tstg

Operating and Storage Junction Temperature Range

-55 to +150 C

NOTES:

1) These ratings are based on a maximum junction temperature of 150 degrees C.

2) These are steady state limits. The factory should be consulted on applications involving pulsed or low duty cycle operations.

Thermal Characteristics TA=25°C :-

Symbol Characteristic Max

Units

BC548 / A / B / CPD Total Device Dissipation

Derate above 25 C

625

mW

R JC Thermal Resistance, Junction to Case

83.3

C/W

R JA Thermal Resistance, Junction to Ambient

200

C/W

Electrical Characteristics TA = 25°C :-

15

OFF CHARACTERISTICS

V(BR)CEO

Collector-Emitter Breakdown Voltage

IC = 10 mA, IB = 0 30 V

V(BR)CBO

Collector-Base Breakdown Voltage

IC = 10 A, IE = 0 30 V

V(BR)CES

Collector-Base Breakdown Voltage

IC = 10 A, IE = 0 30 V

V(BR)EBO

Emitter-Base Breakdown Voltage

IE = 10 A, IC = 0 5.0 V

ICBO Collector Cutoff Current VCB = 30 V, IE = 0

VCB = 30 V, IE = 0, TA = +150 C

15

5.0

nA

A

ON CHARACTERISTICS

hFE DC Current Gain VCE = 5.0 V, IC = 2.0 mA 548

548A

548B

548C

110

110

200

420

800

220

450

800

VCE(sat) Collector-Emitter Saturation Voltage

IC = 10 mA, IB = 0.5 mA IC = 100 mA, IB = 5.0 mA

0.25

0.60

V

V

VBE(on) Base-Emitter On Voltage VCE = 5.0 V, IC = 2.0 mA VCE = 5.0 V, IC = 10 mA

0.58 0.70

0.77

V

V

2.4.2 PNP General Purpose Transistor

16

Symbol Parameter Test Conditions Min Max Units

General Description:-

FEATURES :-

1. Low current (max. 100 mA).

2. Low voltage (max. 65 V).

DESCRIPTION :-

PNP transistor in a TO-92; SOT54 plastic package.

NPN complements: BC546 and BC547.

2.4.3 LM741 Operational Amplifier

General Description

The LM741 series are general purpose operational amplifiers which feature improved performance over industry standards like the LM709.

They are direct, plug-in replacements for the 709C, LM201, MC1439 and 748 in most applications. The amplifiers offer many features which make their application nearly foolproof: overload protection on the input and output, no latch-up when the common mode range is exceeded, as well as freedom from oscillations. The LM741C is identical to the LM741/LM741A except that the LM741C has their performance guaranteed over a 0˚C to+70˚C temperature range, instead of −55˚C to +125˚C.

Electrical Characteristics

Note 1: “Absolute Maximum Ratings” indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is functional, but do not guarantee specific performance limits.

NOTE 2: For operation at elevated temperatures, these devices must be derated based on thermal resistance, and Tj max. (Listed under “Absolute MaximumRatings”). Tj = TA + (θjA PD).

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Thermal Resistance

Cerdip (J) DIP (N) HO8 (H) SO-8 (M)

jA (Junction to Ambient)

100˚C/W 100˚C/W 170˚C/W 195˚C/W

jC (Junction to Case)

N/A N/A 25˚C/W N/A

Note3: For supply voltages less than ± 15V, the absolute maximum input Voltage is equal to the supply voltage.

Note 4: Unless otherwise specified, these specifications apply for VS = ± 15V, −55˚C ≤TA ≤+125˚C (LM741/LM741A). For the LM741C/LM741E, these specifications are limited to 0˚C ≤TA ≤+70˚C.

Note 5: Calculated value from: BW (MHz) = 0.35/Rise Time(µs).

Connection Diagrams

Metal Can Package Dual-In-Line or S.O. Package

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2.4.4 LM386 Low Voltage Audio Power Amplifier

General Description

The LM386 is a power amplifier designed for use in low voltage consumer applications. The gain is internally set to 20 to keep external part count low, but the addition of an external resistor and capacitor between pins 1 and 8 will increase the gain to any value from20 to 200. The inputs are ground referenced while the output automatically biases to one-half the supply voltage. The quiescent power drain is only 24 mill watts when operating from a 6 volt supply, making the LM386 ideal for battery operation.

Features

Battery operation Minimum external parts Wide supply voltage range: 4V–12V or 5V–18V Low quiescent current drain: 4mA Voltage gains from 20 to 200 Ground referenced input Self-centering output quiescent voltage Low distortion: 0.2% (AV = 20, VS = 6V, RL = 8W, PO =

125mW, f = 1kHz) Available in 8 pin MSOP package

Applications

AM-FM radio amplifiers Portable tape player amplifiers Intercoms TV sound systems Line drivers Ultrasonic drivers Small servo drivers Power converters

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Parameter Conditions Min Typ Max UnitsOperatingSupply Voltage (VS)LM386N1,3,LM386M1, LM386MM1LM386N-4

45

1218

VV

Quiescent Current (IQ) VS = 6V, VIN = 0 4 8 mAOutput Power (POUT)LM386N-1, LM386M-1, LM386MM-1LM386N-3LM386N-4

VS = 6V, RL=8THD=10%

VS = 9V, RL = 8, THD =10%,VS = 16V, RL = 32,

THD = 10%

250500700

3257001000

mWmWmW

Voltage Gain (AV) VS = 6V, f = 1 kHz 10 μF from Pin1to8

26 dB

Bandwidth (BW) VS = 6V, Pins 1 and 8 Open

300 khz

Total HarmonicDistortion(THD)

VS = 6V, RL = 8W,POUT=125mW f = 1 kHz, Pins1and 8 Open

0.2 %

Power Supply Rejection Ratio (PSRR)

Input Resistance (RIN) Input Bias Current (IBIAS) VS = 6V, Pins 2 and 3 Open

VS = 6V, f = 1 kHz,CBYPASS=10 μF Pins 1 and 8 Open, Referred to Output

50

50 250

dB

kWnA

Absolute Maximum Ratings Note 1: All voltages are measured with respect to the ground pin, unless otherwise specified.

Note 2: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. OperatingRatingsindicateconditions,for which the device is functional, but do not guarantee specific performance limits. Electrical Characteristics state DC and AC electrical specifications under particular test conditions which guarantee specific performance limits. This assumes that the device is within the Operating Ratings. Specifications are not guaranteed for parameters where no limit is given, however, the typical value is a good indication of device performance.

Note 3: For operation in ambient temperatures above 25°C, the device must be derated based on a 150°C maximum junction temperature and 1) a thermal resistance

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of 107°C/W junction to ambient for the dual-in-line package and 2) a thermal resistance of 170°C/W for the small outline package

Top View

LM 386 PIN OUT

LM 386 Audio Amplifier

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2.5 PCB manufacturing process:

2.5(a) Design Specification

It is an important process in the fabrication of electronic equipment. The design of

PCBs (Printed circuit board) depends on circuit requirements like noise immunity,

working frequency and voltage levels etc. High power PCBs requires a special design

strategy. The fortification process to the printed circuit board will determine to a large

extent the price and reliability of the equipment. A common target aimed is the

fabrication of small series of small series of highly reliable professional quality PCBs

with low investment.

The layout of a PCB has to incorporate all the information of the board before one can

go on the artwork preparation. This means that a concept which clearly defines all the

details of the circuit and partly defines the final equipment is prerequisite before the

actual layout can start.

2.5(b) Board types –

The two most popular PCB types are:

1.] Single Sided Boards ~

The single sided PCBs are mostly used in entertainment electronics where

manufacturing costs have to be kept at a minimum. However in industrial electronics

cost factors cannot be neglected and single sided boards should be used wherever a

particular circuit can be accommodated on such boards.

2.] Double Sided Boards ~

Double sided PCBs can be made with or without plated through holes. The production

of boards with plated through holes is fairly expensive. Therefore plated through hole

boards are only chosen where the circuit complexities and density of components does

not leave any other choice.

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2.6 PCB Designing :

After the accomplishment of circuit designing, next step that follows is PCB making.

Among the various discoveries and development to bring electronics to the level it has

reached until now, PCB has definitely contributed in a significant manner as a means

to inter-connect electronic components. The design of PCB can be considered as the

last step in the electronic circuit design as well as the first major step in the production

of PCB’s. Intimate knowledge of all implication is required. The designing of PCB

consist of designing of layout followed by generation or preparation of artwork. The

layout therefore includes all the relevant aspects and details of the PCB design. The

various steps involved in PCB making are as follows:

a) Layout Planning

b) Component Hole

c) Graphic Layout

d) Etching

e) Drilling

f) Component Mounting

g) Soldering

2.6(a) Layout Planning –

The layout of PCB must incorporate all the information that clearly defines all details

of the circuit and partly of the final equipment. A detail circuit diagram is an

important prerequisite. Layout planning takes care of component layout as well as

their interconnection. The layout should be developed in the direction of signal flow

as far as possible, so that one achieves shortest possible interconnections. Among the

components, the larger ones are placed first and the space between is filled with

smaller ones. Components requiring input/output connections come near the

connectors. In designing the interconnection, which are usually done with pencil,

actual space requirement in the artwork must be considered. The end of the layout

designing is the pencil sketched component and conductor drawing, which is called

layout sketch. Beside the component outline, component holes and interconnecting

pattern, the layout sketch should also include information on:

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2.6(b) Component holes –

Usually in a given PCB cost of the holes required is of one particular diameter and

this diameter is mentioned once in the layout sketch. Holes of different diameter are

shown with a code in the actual layout sketch. The code must explain outside the

layout area. For e.g. we have used two kinds of holes are of 0.8mm and 1.1mm.0.8

mm for all the components except jumpers and IC base. For jumpers and IC based we

drilled 1mm holes. Changing of our track from large to small and then back to large

again is known as “necking”. This is often required when we have to go between IC

or component pads. This allows having nice big low impedance tracks, but still has

the flexibility of route between tight spots.

In practice, the current flowing through it and the maximum temperature rise of the

track that can be tolerated will dictate track width. Every track will have a certain

amount of resistance, so the track will dissipate heat just like a resistor. The wider the

track, the lower is the resistance.

2.6(c) Graphic Layout –

The Graphic layout or the Artwork is the basic circuit design that is required on the

PCB. The circuit connections and the components are together setup in a particular

design which is printed on the Circuit Board.

2.6(d) Etching (Patterning) –

Copper over the entire substrate, sometimes on both sides, (creating a “blank PCB”)

then removing unwanted copper after applying a temporary mask (e.g. by chemical

etching), leaving only the desired copper traces. A few PCB’s are made by adding

traces to the bare substrate (or a substrate with a very thin layer of copper) usually by

a complex process of multiple electroplating steps.

1.] Chemical etching –

Inexpensive ingredients, and with proper use and maintenance, literally never wears

out. The real beauty of this mixture of hydrogen peroxide, sulphuric acid, copper

sulphate and organic stabilizers is that excess copper can be removed by simple

precipitation, after which, the bath is ready to consume more copper. In addition,

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during operation, the etch ant is “self agitating”. The bubbles and heat evolve during

etching, so thoroughly stir up the bath the etch ant works almost as well in a simple

dip (immersion) tank as it does in a far more expensive spray etcher. Screen printing

ink is used according to the type of etch ant used. For acid etching, an acid resistive

ink is used, which is soluble in alkaline solution

2.6(e) Drilling –

Drilling can be done using a CNC machine or manually.

1.] Manual Drilling ~

With the laminate stack formatted as detailed above, manual drilling is a

straightforward, if somewhat mind-numbing process. Items to consider include: When

using a conventional drill press, hole placement accuracy can be improved and drill

breakage minimized through the use of a “sensitive drilling” or “finger” chuck. Small

format, precision high-speed drill presses, ideal for PCB fabrication, is also available

from a number of sources.

If available, position a work lamp on a flexible mount as close to the work surface as

possible. Minimize burr formation, and outlast HSS bits almost 10 to 1. The carbide

drills are easier to break and must be handled carefully. Always use drill bits that have

been fitted with depth setting rings. This will allow you to set the plunge depth stop

on your drill press to a single value that will work for all bit diameters.

2.] Through-holes ~

Load the largest diameter bit to be used into the drill chuck, making sure that the

depth ring is pressed firmly against the ends of the chuck jaws when they are fully

tightened. Using a piece of scrap backing materials as a gauge, adjust the spindle

travel stop on your drill press to a depth that insures that the entire tip of the drill bit

penetrates at least half of the material’s thickness. Under no circumstances allow a

PCB drill bit to drill into the table of your drill press. PCB bits are specially designed

to drill copper clad and will shatter if plunged into cast iron, steel, or aluminum.

25

Starting with largest diameter drill bit, drill all the through holes, stopping

periodically to insure that the drill bit has not snapped off and that the spindle travel

stop has not slipped.

As you drill each hole size check off that diameter on the drilling chart. This is a good

bookkeeping technique that will help you keep track of your progress and insure that

no holes size is missed.

Hold the stack up to the light for visual inspection. Ascertain that all of the holes have

been drilled through and that none are blocked by drill debris. If some debris is seen,

remove by carefully pushing a smaller diameter bit through the hole.

2.6(f) Component Mounting –

From the greatest variety of electronic components available, which runs into

thousands of different types 1, is often a perplexing task to know which is right for a

given job. There could be damage such as hairline crack on PCB. If there are, then

they can be repaired by soldering a short link of bare copper wire over the affected

part. This holds the component in position ready for soldering. Some components will

be considerably larger. So it is best to start mounting the smallest first and progressing

through the largest. Next will be probably the resistor, small signal diodes or other

similar size components. Some capacitors are also very small but it would be best to

fit it afterwards. Although transistors and integrated circuit are small items there are

good reasons for leaving the soldering of these until the last step. All the components

before mounting are rubbed with sand paper so that oxide layer is removed from the

tips. Now they are mounted according to the component layout.

2.6(g) Soldering –

This is the operation of joining the components with PCB after this operation the

circuit will be ready to use to avoid any damage or fault during this operation

following care must be taken. A longer duration contact between soldering iron bit

and components lead can exceed the temperature rating of the device and cause partial

or total damage of the device. Hence, before soldering we must read the maximum

soldering temperature and soldering time for device.

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The wattage of soldering iron should be selected as maximum as permissible for that

soldering place. To protect the device by leakage current of iron its bit should be

earthed properly.

We should select soldering wire with proper ratio of Pb and Tn to provide the suitable

melting temperature. Proper amount of good quality flux must be applied on the

soldering point to avoid dry soldering.

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CHAPTER – 3

28

3.1 RESULT

The IR Musical Transmitter & Receiver we designed is working properly. By doing the project we got a lot of experience with the electronics components & more over we learn the PCB designing.

29

3.2 CONCLUSION

IR ray communication is very easy to understand and simple to implement. It finds various applications in short distance field of communications. It is one of the best ways of building wireless gadgets.

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3.3 FUTURE ENHANCEMENT

In future there is scope of building virtual environment using the principles of IR ray transmission and reception. Virtual gaming which also employs IR reception techniques is still in research process which is soon going to rule the world of gaming.

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3.4 APPLICATIONS

1. Wireless Music Systems.

2. Mobile gadgets.

3. CC cameras.

4. Remote controls.

5. Infrared lasers are used in communications.

3.5 [a] ADVANTAGES

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1. Highly sensitive

2. Two stage Gain control

3. Very low noise

4. Low cost and reliable circuit

5. Can transmit up to 10 meter

3.5 [b] DISADVANTAGES

1. Not for long distance

2. Work in fixed range

3. Noise if object between transmitter and receiver

3.6 REFERENCES

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1. www.google.com

2. www.wikipedia.org

3. www.pdfmachine.com

4. www.efymag.com

5. www.electronicsforu.com

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