Room Noise Detector

ROOM NOISE DETECTORProject – 2 Third Year of Engineering By Mujumdar Amit Anant Nair Ajesh Rajan Nambiar Rohit Chandran Under the guidance of 300832 300833 300834 Mr. Ashish Harsola DEPARTMENT OF ELECTRONICS AND TELECOMMUNICATION ENGINEERING Fr. C. Rodrigues Institute of Technology Sector-9A, Vashi, Navi Mumbai – 400 703 UNIVERSITY OF MUMBAI 2010 E.CERTIFICATE OF APPROVAL Project entitled: Room Noise Detector Submitted by: Mujumdar Amit Anant Nair Ajesh Rajan Nambiar Rohit Chandran 300832 300833 300834 In the subject Electronic Hardware Workshop of the degree of T. in "Electronics and Telecommunication Engineering" is approved. Subject Teacher . 1 5. Software Simulation and PCB Designing 4. Aim of the Project Organization of the Project Report Literature Survey 2.3 2. Conclusion 7.2 5.4 5.TABLE OF CONTENTS List of Figures List of Tables 1.2 3.1 4.1 2.Theoretical Observation Table . Implementation of Room Noise Detector 3.2 6.2 2.1 6.5 5. Software Simulation using PROTEUS PCB Designing using ARES Circuit Diagram Transfer to PCB Etching of PCB Continuity Testing Drilling Soldering Observation Table .1 3.2 5.2 2.4 Basics of detectors Types of detectors Parameters (a) Sensitivity (b) Resolution Applications Circuit Diagram Pin out of IC LM358 Pin out of BC327 Specifications of Microphone Working 3.3 5.4 3.3 3.6 6.1 1.Simulation Conclusion Procedure 5. Observations 7.5 4. Introduction 1.1 References . 4 4. 3.1 6.1 6. No.2 6.2 Caption Table showing dB level for different sound sources Table showing software simulation for different dB settings Page No. 8 8 8 9 10 11 14 15 16 16 LIST OF TABLES Sr. 13 14 .3 3.LIST OF FIGURES Sr.2 3.4 Caption Circuit Diagram Internal Configuration of LM358 Pin out of BC327 Electret Microphone Proteus – ISIS Schematic File PCB layout Proteus Simulated waveforms to describe working Output waveforms for 85 dB Output waveforms for 70 dB Output waveforms for 50 dB Page No.3 6. No 6.1 4.2 6.1 3. Chapter 5: Step-by-step procedure to prepare a working PCB. Organization of the Project Report: The information in the subsequent chapters is set in the following fashion: 1. heavy mechanical pressure. etc. Chapter 2: Discusses the basics plus types of noise detectors. A detector is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument. 1. this project aims at providing a rugged and cost effective detector circuit assembled using low-cost components with the intention of substituting the current commercially existing versions. Chapter 6: Enlists the observations and tabulates the practical results. Chapter 3: Reveals about the practical implementation of the project. light detector (LDR). There are various kinds of detectors like – temperature detector (Thermocouple). .2. Scrutinizing Room Noise Detector: This circuit keeps a tab on the noise levels in a room using detectors like microphone. 5. etc. Chapter 4: Discloses the software simulation of the project. It can detect three threshold levels – 50. 1. 85 dB.1 Aim of the Project Usually. 2. sound detector (microphone). small-scale and large-scale factories do not have systems to inspect noise levels. Also they have some physical constraints such as – cannot bear heat. Keeping a view of these shortcomings. This project aims at giving a highly accurate output thus providing a good calibration of the level of noise in the room. 4.Chapter 1 INTRODUCTION A sensor is a device capable of registering a specific substance or physical phenomenon. 6. Chapter 7: Summarizes as well as concludes the project based on above observations. A three array LED just makes the output look magnificent. The high expenditure to acquire such devices from the current competitive market makes them shy off from installing such systems. and displays output in the form of blinking LED’s. 70. 3. Temperature detectors like thermocouple. Light detectors like LDRs. Here. 3. phototransistors. Some of them are: 1. etc.1 Sensitivity The sensitivity is then defined as the ratio between output signal and measured property. Barometer. free fall sensor. Pressure Detector like Bourdon gauge. 5.3 Parameters 2. Sound detectors like microphone. Flow detector like air flow meter.1 Basics of Detectors A detector is a device which receives and responds to a signal or stimulus. anemometer. For example. this sensor is linear because the ratio is constant at all points of measurement. A good detector obeys the following rules:  Is sensitive to the measured property. detector can be defined as a device which receives a signal and converts it into electrical form which can be further used for electronic devices. A sound detector has its measurement calibrated in decibels (dBs). etc. 6. 7.  Is insensitive to any other property likely to be encountered in its application.3. etc. 4. etc. the term "stimulus" means a property or a quantity that needs to be converted into electrical form. the sensitivity is a constant with the unit [V/K]. 8. etc. Radiation detector like particle detector. 2. Position Detector like accelerometer. 2. lace sensor. 2. A detector differs from a transducer in the way that a transducer converts one form of energy into other form whereas a detector converts the received signal into electrical form only. Hence. if a sensor measures temperature and has a voltage output.  Does not influence the measured property. etc. RTD.Chapter 2 LITERATURE SURVEY 2. . etc. etc. hydrophone. Infrared detector like IR sensor.2 Types of Detectors Detectors can be classified on the basis of quantity it measures. Scientific analysis of noise. indicating that changes of that magnitude are only just resolved. Study effect of noise on human body. Checking decibel level in industries. a scanning tunneling probe (a fine tip near a surface collects an electron tunneling current) can resolve atoms and molecules. 4. Often in a digital display. 2. . etc.3. the least significant digit will fluctuate. For example. The resolution is related to the precision with which the measurement is made.2. 3. near hospitals.4 Applications of Noise Detectors 1. 2.2 Resolution The resolution of a sensor is the smallest change it can detect in the quantity that it is measuring. Traffic Noise level studies. 1 Circuit Diagram Fig 3. It provides a high gain for weak signals. Fig 3. Fig 3.3 Terminals of transistor BC327 This 45V.4 Specifications of Microphone .Chapter 3 IMPLEMENTATION OF ROOM NOISE DETECTOR 3. 500mA PNP transistor has a TO-92 package.2 Internal configuration of LM358 3.3 Pin out for BC327 3.1 Circuit Diagram 3.2 Pin out of IC LM358 This has two inbuilt operational amplifiers having two inputs and one output each. Hence a descriptive working for positive half cycle of the signal is in this manner: 1.6. 3. The R4 – C1 combination is responsible for AC coupling with the high gain OPAMPs.4 Electret microphone : : : -45 ± 3 dB 100 Hz to 10 kHz ≥ 58 dB 3. The R3 – C2 parallel arrangement makes sure that only DC signal flows through R3 and remains shorted for sound signal. 2. It is clear that noise or sound signals have a positive amplitude w. The R11 – C3 combination is an LPF – allowing only low frequency signals to pass through and attenuating high frequency signals. Thus the LEDs show the output – depending upon user selection of dBs.7 4.7.Sensitivity Frequency Range Signal to Noise Ratio Fig 3. IC1A configuration is employed in non-inverting amplifier mode with variable gain controlled by resistors – R5. the R8 resistor takes along a signal synchronized with input signal with its negative cycles clipped.r. . 7. The output of IC1B is only negative pulses in every positive cycles of input. IC1A is coupled with IC1B and the second OPAMP is in difference amplifier mode.e. capacitor is for input coupling and the transistor being PNP – it gets ON when base voltage is negative when compared to the emitter i. These resistors provide selection for 50 dB.5 Working of Room Noise Detector The complete working of Room Noise Detector has been described under the consideration that sound signal is sinusoidal in nature. Formula for Gain: AV = 1 + where i = 5. 6. R6 and R7. For positive half cycles. 70 dB and 85 dB threshold respectively. The PNP transistor produces positive collector current spikes when a negative pulse is provided to base of the transistor. VBE ≥ -0.t ground. Also input to non-inverting terminal is the original amplified signal. The 5. the entire circuit was redrawn using Proteus basic tools.1 Software Simulation using PROTEUS – ISIS 7 Professional Initially. the circuit was put into simulation mode and for different resistors – R5.1 Proteus – ISIS schematic file .4 sp3 pro’. Oscilloscope was attached in order to check the output. R6 and R7 – the waveforms were noted. Fig 4.Chapter 4 SOFTWARE SIMULATION AND PCB DESIGNING Before practical implementation of Room Noise Detector we carried out a software imitation using ‘Proteus 7. 4. Then. & to make the circuit more compact as well as efficient.2 PCB Layout . its PCB was designed using ‘ARES’ software. Auto-Routing command helped in giving a rough PCB layout which we later modified in order to reduce the number of jumpers. Fig 4.2 PCB designing using ARES 7 Professional After the successful verification of the circuit.4. avoid interconnections & faults. The ground and the Vcc terminals are the thickest and the other lines need to be a bit less thick.3 Etching Process: Take the PCB and dip in a solution of FeCl3. 5.5 mm for Vcc supply. Also scratch the marker ink off the connecting spots so as to ensure continuity.6 Soldering: Solder the components of the circuit. 2. Break the extra long legs of the components and perform the final working of the project . To make the Cu dissolve faster keep on stirring the PCB. Keep the PCB in the solution till the layer of Cu on the PCB gets dissolved in the solution. Then draw the exact circuit on a butter paper with the help of a pencil. 5. Thickness of the lines is needed to be taken care of. 5mm for Grounding.1 Circuit Diagram: Draw the circuit diagram on a graph sheet considering the width of the lines—1mm for connecting wires. The impression would be a mirror image to the actual circuit. 5.4 Continuity: Check the continuity of the system with the help of multimeter.As soon as the Cu gets dissolved remove the PCB from the solution. If at all there is discontinuity then make that part of the circuit continuous with the help of soldering. 5.2 Transfers to the PCB: Take the butter paper and draw the impression of the circuit on the PCB.5 Drilling: Drill holes on the PCB as per the circuit to mount the components on the PCB.Chapter 5 PROCEDURE The following processes are involved in procedure for making the PCB:- 5. Draw the circuit on the PCB with the help of a marker. 5. crowded restaurants 69 Dish-washers. circular saw 100 Motorcycle without silencer 6. fridges. wrinkling paper @ 1 m. 90 Passing train. shuffling @ 1 m.Theoretical 6. whisper @ 1 m.1 Table 6. radio & TV sets at normal volume 64 Washing machines.2 Observation Table – Software Simulation The waveforms concerning the above discussion are as shown below: . floor-polishers 70 Loud conversation. 95 Mega "disco". quiet streets. car hooter @ 1 m. quiet typewriters 67 Hair-dryers. drizzling rain 30 Blast of wind. conversation @ 1 m. pneumatic hammer. noisy street.Chapter 6 OBSERVATIONS Observation Table . noisy hall or plant.1 Table showing decibel level of different sound sources. 50 Residential areas. radio & TV sets at high volume 72 Vacuum cleaners 78 Telephone ring. electric-clock ticking. 40 Countryside areas. air-conditioners 60 Alarm-clocks. mechanical workshop 80 Passing trucks. dB Example of sound sources 20 Quiet garden. 55 Offices. quiet apartment. 1 Proteus Simulated waveforms to describe working of Room Noise Detector The waveforms below detail the output at the three LEDs Table 6.2 Table showing software simulation Condition Observation .Fig 6. 6k .2 Output waveforms for 85dB Fig 6.Switch connected to OHM 56k Fig 6.3 Output Waveforms for 70 dB Switch connected to OHM 5. 1 .Switch to OHM is 560 connected Fig 6.4 Output waveforms for 50 dB Chapter 7 CONCLUSION Conclusion 7. REFERENCES .