CONTENTS

S.no      CHAPTER              PAGENO

1.           CHAPTER: 1 Introduction 3

1.1 Description of IR Music Transmitter & Receiver 41.2 Specifications 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 8-9 2.2.2 PCB Layout of IR Music Transmitter & Receiver 10-11 2.2.3 Block Diagram of IR Music Transmitter & Receiver 12-13 2.3 List of Components 14-15 2.4 Datasheet 15 2.4.1 npn general purpose amplifier 15-17 2.4.2 pnp General purpose transistor 17 2.4.3 IC 741 Operational amplifier 18-19 2.4.4 IC LM386 20-22 2.5 PCB Manufacturing process 23 2.6 PCB Designing 24-29

3. CHAPTER :3 30

3.1 Result 31 3.2 Conclusion 32 3.3 Future Enhancement 33 3.4 Applications 34 3.5 Advantages & Disadvantages 35 3.6 References 36

1

LIST OF FIGURES :

FIGURES Page No

Circuit Diagram 8

Transmitter 8

Receiver 9

PCB layout 10

Transmitter 10

Receiver 11

Block Diagram 12

Transmitter 12

Receiver 13

2

CHAPTER – 1

INTRODUCTION

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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.

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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 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

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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

8

[b] Receiver:

Fig: 2

9

2.2.2. PCB Layout:

[a] Transmitter:

Fig: 3

10

[b] Receiver:

Fig: 4

11

2.2.3. Block Diagram:

[a] Transmitter:

Fig: 5

+9v

12

3.3 v regulatorMelody

GeneratorTransistor

Driver

Stage - 1

Transistor Driver

Stage - 2

IR LED

LED Music Flicker

Indicator

[b] Receiver:

Fig: 6

+9V

13

Photo

Transistor

Audio Amplifier

stage-1

Audio Amplifier

stage-2

Loud Speaker

Gain Control

Gain Control

2.3 LIST OF COMPONENTS

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

14

22.

23.

24.

Speaker (8 ohm, 1W)

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

9V battery

1

2

2

2.4 DATASHEET

2.4.1 NPN General Purpose Amplifier

Absolute Maximum Ratings TA=25°C :-

Symbol Paramet

er

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 :-

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Symbol Characteristic Max

Units

BC548 / A / B / C

PD 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 :-

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

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5.0

nA

A

ON CHARACTERISTICS

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Symbol Parameter Test Conditions Min Max Units

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

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.

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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).

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.

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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.

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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 resistanceof 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

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are only chosen where the circuit complexities and density of components

does not leave any other choice.

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

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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:

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.

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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,

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

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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.

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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.

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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.

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

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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.

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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.

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3.5 [a] ADVANTAGES

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

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3.6 REFERENCES

Electronics for you (jan 2007)

www.fairchild.com

www.national.com

www.scridb.com

www.wineyardtechnologies.com

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