GOVERNMENT ENGINEERING COLLEGE IDUKKI

PAINAVU 685 603

NOISE DETECTORMINI PROJECT REPORT

Submitted by

ANJANENDU C (Reg.no:12004732) ARYA S (Reg. no:12004784) ATHIRA PRADEEP (Reg. no:12004742) NEETHU C K (Reg. no:12004765)

In partial fulfillment for the award of the degree

of

BACHELOR OF TECHNOLOGY

IN

ELECTRONICS AND COMMUNICATION ENGINEERING

MAHATMA GANDHI UNIVERSITY

MAY, 2015

GOVERNMENT ENGINEERING COLLEGE IDUKKI

PAINAVU 685 603

DEPARTMENT OF

ELECTRONICS AND COMMUNICATION ENGINEERING

BONAFIDE CERTIFICATE

This is to certify that the project report entitled “NOISE DETECTOR” is a

bonafide record of the paper presented by ANJANENDU C(12004732), ARYA

S(12004784), ATHIRA PRADEEP(12004742), NEETHU C K(12004765) during

their sixth semester in partial fulfillment of the requirement for the award of B-

Tech Degree in Electronics & Communication Engineering of Mahatma Gandhi

University, Kottayam, Kerala.

PROJECT GUIDES HEAD OF THE DEPARTMENT

Ms. NELSA ABRAHAM Asst.Prof.ECE

Mr. SUNIL RAJAsst.Prof.ECE

INTERNAL EXAMINER EXTERNAL EXAMINER

…………………………. …………………………...

DECLARATION

I hereby declare that the project titled SOUND DETECTOR being submitted in partial

fulfillment for the award of B.Tech degree is the original work carried out by me. It has not

formed the part of any other thesis submitted for award of any degree or diploma, either in this or

anyother University.

(Signature of the Candidate)

NAME

Register No: NU

ACKNOWLEDGEMNT

We give all honor and praise to the LORD who gave us wisdom and enabled us to complete this project successfully.

We express our heartfelt thanks to Dr. J. David, Principal, Government Engineering College, Idukki for granting us permission to do the project.

We express our sincere thanks to our head of the department Prof.K R Ramesh Babu and project guide Ms Nelsa Abraham and Mr Sunil Raj for their valuable advice and guidance.

We also express our gratitude and thanks to all our teachers and other faculty members of the department of Electronics and Communication, Government Engineering College, Idukki for their sincere and friendly cooperation in completing this project.

We are extremely grateful to our parents for their silent prayer.

ABSTRACT

Project is all about a circuit that can detect sound , such as talking, clapping, or shouting. Based on this sound that the circuit detects, we can let anything happen in the circuit, such as have an LED light. This sound detector circuit mainly consists of - an op-amp, LED, microphone.The sound detector monitors the sound level and indicates through the LED when the level is above the preset value. For this the sound is captured by the microphone.The preset value can be set according to the requirements.

This circuits can be used for various applications by making some changes

in the circuit.The product can be used as security system by providing the

microphone at the door.

TABLE OF CONTENTS

ACKNOWLEDGEMENTS

ABSTRACT

LIST OF FIGURES

CHAPTER 1. INTRODUCTION …………………………………01

CHAPTER 2. SYSTEM DESIGN

2.1 BLOCK DIAGRAM ………………………………02

2.2 BLOCK DESCRIPTION …………………………..03

2.3 CIRCUIT DIAGRAM …………………………..…08

2.4 WORKING …………………………………..….…09

CHAPTER 3. PCB DESIGNING ………………………………….10

3.1 COMPONENT LAYOUT …………………………12

3.2 PCB LAYOUT …………………………….….…..12.CHAPTER 4. CONCLUSION ……………………………….…….13

4.1 FUTURE ASPECTS ………………………………...13

REFERENCE ……………………………………………………….14APPENDIX ……………………………………………….15

CHAPTER 1

INTRODUCTION

Noise is a major issue in the present world. Living beings are sensitive to various sound levels. Noise disturbances may harm the activity or balance of human and animal life. Due to noise pollution, stress or excitation may create increased chance of heart attack in old people, and hearing loss may occur to any aged ones. So reduction of noise is a must for our life safety. A murmuring or music in low volume will not be considered a noise. So noise is something above a particular threshold value. This value which we selected for our project is 70dB, corresponding to a loud conversation or noisy street or TV set at high volume. This circuit is intended to signal, through a flashing LED, at the exceeding of the fixed threshold in room noise. For capturing sound we use an electret microphone. It can detect sound levels from 50dB onwards.

The further information about the project is given in the following chapters.Chapter 2 explains the block level description of the system, It includes high pass filter, amplifier, comparator, and peak detector blocks. Chapter 3 includes the PCB design general steps, and the specification of op-amp lm324. The 4th chapter deals with the entire working of the system.The last chapter includes the application and future aspects of our project.

01

CHAPTER 2

SYSTEM DESIGN

2.1 BLOCK DIAGRAM

Figure 2.1 includes the major block diagram of sound detector.the system includes microphone,high pass filter,amplifier,peak detector,comparator and LED,power supply.The power supply is provided by a 6V battery source for the entire system.The amplification is provided by LM324 IC.

2.2 BLOCK DESCRIPTION

The system includes the following blocks:-

TRANSDUCER Transducer is a device which converts one form of energy in to another form.Here the transducer we are using is microphone. It converts sound signals in to electrical signals. Microphone – converts sound into an electrical signal (air pressure → motion of conductor/coil → magnetic field → electrical signal)

Figure 2.2 example, the first transducer could be a microphone, and the second transducer could be a speaker.

HIGH PASS FILTER

A high-pass filter is an electronic filter that passes signals with a frequency higher than a certain cutoff frequency and attenuates signals with frequencies lower than the cutoff frequency. The amount of attenuation for each frequency depends on the filter design. A high-pass filter is usually modeled as a linear time-invariant system .

FIGURE 2.3

03

TRANSDUCER HIGH PASS FILTER AMPLIFIER

OUTPUT STAGE

COMPARATOR PEAK DETECTOR

The product of the resistance and capacitance (R×C) is the time constant (τ); it is inversely proportional to the cutoff frequency fc, that is,

where fc is in hertz, τ is in seconds, R is in ohms, and C is in farads.

High-pass filters are also used for AC coupling at the inputs of many audio power amplifiers, for preventing the amplification of DC currents which may harm the amplifier, rob the amplifier of headroom

In this sound detector circuit the out put of the microphone is given as the input to high pass filter.

AMPLIFIERS

An electronic amplifier,is an electronic device that increases the power of a signal. The amplifier is often described as the heart or the nervous system of a microphone or loudspeaker. It does this by taking energy from a power supply and controlling the output to match the input signal shape but with a larger amplitude. In this sense, an amplifier modulates the output make the output signal stronger than the input signal. An amplifier is effectively the opposite of an attenuator: while an amplifier provides gain, an attenuator provides loss. The four basic types of electronic amplifiers are voltage amplifiers, current amplifiers, transconductance amplifiers, and transresistance amplifiers. A further distinction is whether the output is a linear or nonlinear representation of the input

Figures of merit

Amplifier quality is characterized by a list of specifications that includes:

Gain, the ratio between the magnitude of output and input signals Bandwidth, the width of the useful frequency range Efficiency, the ratio between the power of the output and total power consumption Linearity, the degree of proportionality between input and output Noise, a measure of undesired noise mixed into the output Output dynamic range, the ratio of the largest and the smallest useful output levels Slew rate, the maximum rate of change of the output Rise time, settling time, ringing and overshoot that characterize the step response Stability, the ability to avoid self-oscillatio.

Hera we use an Operational amplifiers (op-amps) LM324.

An operational amplifier is an amplifier circuit with very high open loop gain and differential

04

inputs that employs external feedback to control its transfer function, or gain. Though the term today commonly applies to integrated circuits, the original operational amplifier design used valves, and later designs used discrete transistor circuits.

PEAK DETECTOR

A Peak detector is a series connection of a diode and a capacitor outputting a DC voltage equal to the peak value of the applied AC signal. The circuit is shown in Figure below with the corresponding SPICE net list. An AC voltage source applied to the peak detector, charges the capacitor to the peak of the input. The diode conducts positive “half cycles,” charging the capacitor to the waveform peak. When the input waveform falls below the DC “peak” stored on the capacitor, the diode is reverse biased, blocking current flow from capacitor back to the source. Thus, the capacitor retains the peak value even as the waveform drops to zero. Another view of the peak detector is that it is the same as a half-wave rectifier with a filter capacitor added to the output.

Figure 2.3

In our sound detector circuit the output of amplifier is given as the input to peak detector. it enables to hold the output for few seconds. time for which the out put being hold depends on the value of resistor and capacitor.

COMPARATOR

In electronics , a comparator is a device that compares two voltages or currents and outputs a

digital signal indicating which is larger. It has two analog input terminals and and one binary digital output . The output is ideally

A comparator consists of a specialized high-gain differential amplifier. They are commonly used in devices that measure and digitize analog signals, such as analog-to-digital converters (ADCs), as well as relaxation oscillators.

05

An operational amplifier (op-amp) has a well balanced difference input and a very high gain. This parallels the characteristics of comparators and can be substituted in applications with low-performance requirements.[4]

In theory, a standard op-amp operating in open-loop configuration (without negative feedback) may be used as a low-performance comparator. When the non-inverting input (V+) is at a higher voltage than the inverting input (V-), the high gain of the op-amp causes the output to saturate at the highest positive voltage it can output. When the non-inverting input (V+) drops below the inverting input (V-), the output saturates at the most negative voltage it can output. The op-amp's output voltage is limited by the supply voltage. An op-amp operating in a linear mode with negative feedback, using a balanced, split-voltage power supply, (powered by ± VS) has its

transfer function typically written as: . However, this equation may not be applicable to a comparator circuit which is non-linear and operates open-loop (no negative feedback)

Figure 2.4

OUTPUT STAGE

In the output stage we can you an indicator to show that the input is above the threshold value.The indicator can be a buzzer or a LED .here we use a LED.

A light-emitting diode (LED) is a two-lead semiconductor light source. It is a pn-junction diode, which emits light when activated.[4] When a suitable voltage is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence, and the color of the light (corresponding to the energy of the photon) is determined by the energy band gap of the semiconductor.An LED is often small in area (less than 1 mm2) and integrated optical components may be used to shape its radiation pattern

Color Wavelength range (nm) Typical efficacy (lm/W) Typical efficiency (W/W)Red 620 < λ < 645 72 0.39

Red-orange 610 < λ < 620 98 0.29Green 520 < λ < 550 93 0.15Cyan 490 < λ < 520 75 0.26Blue 460 < λ < 490 37 0.35

06

Advantages

Efficiency: LEDs emit more lumens per watt than incandescent light bulbs.[127] The efficiency of LED lighting fixtures is not affected by shape and size, unlike fluorescent light bulbs or tubes.

Color: LEDs can emit light of an intended color without using any color filters as traditional lighting methods need. This is more efficient and can lower initial costs.

Size: LEDs can be very small (smaller than 2 mm2[128]) and are easily attached to printed circuit boards.

On/Off time: LEDs light up very quickly. A typical red indicator LED will achieve full brightness in under a microsecond.[129] LEDs used in communications devices can have even faster response times.

Figure 2.5

07

2.3 CIRCUIT DIAGRAM

2.4 WORKING

The input audio signal is fed in to a microphone which is powered with 5V.Microphone convert audio signals in to electrical signals.These are ac signals having varying frequencies.In the next stage a high pass filter is used.It consists of a capacitor and resistor.Only those audio signals that are converted in to electrical signals go through the high pass filter.This signal passes on to the op-amp which LM-324.In this case it has been configured as an amplifier.Since the input from microphone is very low like 0.02V,it is amplified by the op-amp by putting two resistors overhead .This provides a gain of 100 and it’s out become 2V.This output is being fed to a peak detector circuit,which consists of a diode ,capacitor and resistor.This circuit enables to hold the output for few seconds and the time for which the output is being hold at its peak depends on the value of capacitor and resistor.This is fed to an op amp working as comparator.This stage contains a potential divider to fix a voltage. Here it is 0.45V,which is at the negative input of op amp.The positive input is fed with the output of peak detector.When the comparator exceeds 0.45V,the output goes to the posive which is +5V in this case and LED glows.If 0.45V is greater than the audio signal voltage ,the output goes to negative ,which is at ground and the LED does not glows.A 100Ω resistor is used before LED to limit the current through it.So this circuit will work as aperfect sound detector

ADVANTAGES

Easily implementable.

We use low cost LM324.

Availability of components.

09

CHAPTER 3

3.1 PCB DESIGNING

PRINTED CIRCUIT BOARD is popularly known as PCB. A PCB ensures that various circuit components are interconnected as per the circuit diagram after they are placed on the PCB in their proper fabrication. Terms & AcronymsPCB–Printed Circuit BoardTracks–Form the connections between components.Pads–Used to make connections between your component and the track with solder.Layers-Everything is drawn on a layer, layers canhavedifferentphysicalproperties.Examplelayersare:Toplayer,bottomlayer,Topoverlay,bottom overlay, Mechanical1,KeepOut.Plated Through Holes (PTH)–Drilled holes that are plated with conductive material(usually copper). Footprints–collectionofpadsandoutlineswhichdescribeanindividualcomponent’sphysicallayoutonaPCB.DesignRules–RulesspecifiedbythedesignertoensurePCBintegrity(moreonthislater).Vias–UsedtomakeconnectionsbetweendifferentlayersofthePCB.Silkscreen–Aprotectivelayeroverthetopoftheboard,makessolderingeasier.

Different steps involved in the fabrication of a PCB are as follows:

1. Components layout designing.2. PCB layout designing. 3. Transferring the PCB layout design onto the PC board laminate.4. Developing the PCB.5. Other operations like drilling, cutting, tinning etc.

1.COMPONENTS LAYOUT DESIGNING

Component layout designing is the placement of different components with their interconnections as per the circuit diagram on PCB board. This exercise usually begins with an estimate of size of PCB needed to accommodate various circuit components. Interconnections can be made by drawing lines known as tracks.

2.PCB LAYOUT DESIGN

PCB layout designing is the mirror image of components layout. The components layout is drawn looking from the components side whereas the PCB layout is drawn looking from the copper side. It is obtained by taking a carbon copy of the computer layout by placing a reverse carbon underneath the paper. 10

3.PCB LAYOUT ONTO PCB LAMINATE

First the PCB laminate is chosen. The copper side of the laminate is thoroughly cleaned with petrol to make it completely free from contaminants. The PCB layout is drawn on the copper side. Care should be taken to position of the holes. The same is redrawn giving proper width to different tracks and leaving proper space using permanent marker.

4.DEVELOPING THE PCB

In this process, all excess copper is removed leaving behind only the drawn pattern. To do etching, an aqueous solution of ferric chloride is poured into a tray with the quantity depending upon the size of the PCB to be etched. The mark is then removed using an alcohol.5.DRILLING AND TINNING

After etching, drilling is done. The diameter of holes varies from components to components. It is1mm for IC pins, 1.25 for resistors and capacitors, 1.5mm for diodes and even larger for mounting presence. Tinning can prevent the oxidation of copper portions which can be done by using a soldering.3.1 SOLDERING

Solder is an alloy of lead and tin used to fuse metals at relatively low temperature, about 260-315k. The joint where two metal conductors are to be fused is heated and then solder is applied so that it can melt and cover the connection. The reason for soldering is that it makes good bond between the joint metals, covering the joints completely to prevent oxidation. The coating of solder provides protection for practically long period of time. The trick in soldering is to heat the joints and not the solder. Either a soldering iron or soldering gun can be used, rated at 25-100W.

In addition to the solder, flux is used to remove any oxide film on the metal being joined. The flux enables the molten solder to wet the met. 11

3.2 COMPONENT LAYOUT

3.3PCB LAYOUT

12

CHAPTER 4

CONCLUSION

The “Noise detector” circuit is cost effective, practical, eco-friendly way to detect noise.It can detect the noise pollution any where , so that it alerts us to reduce noise.

It can be easily implemented in a public place or a concert hall. The circuit can be implemented in may ways , even by using basic components.

4.1 FUTURE ASPECTS

SECURITY SYSTEMReplace the LED with a buzzer, and place the mic on your door. Any robber trying to trespass our room making a sound can be detected.

SPY CIRCUITReplace the LED with a speaker and place the mic on your dress collar unable to distinguish. Voice from a secret meeting can be captured and given to the speaker placed somewhere else.

HOME APPLIANCESReplacing LED with FET connected to light or fan, then you can switch it ON/OFF even with your clap.

ENTERTAINMENTLED is made to flash according to the music beats that the mike sense.

13

REFERENCE

Electronicsforu

www,Wikipedia.com

www.alldatasheets.com

www.Electronicscircuits.com

14

APPENDIX

15

CHAPTER 3

COMPONENT STUDY

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

35

.

36