Design and Construction of Sound Detector With Alarm System
CHAPTER ONE
OBJECTIVE DESIGN
The main objective design of the project is to design and construct an electronically operated system capable of picking sound of a visitor at the door processing the alarm put natural sound wave to an out put electrical sound signal to alarm signal to alert the people inside the house that some body is at the door outside, also it help increasing the standard exposure in the practical aspect of engineering training.
CHAPTER TWO
LITERATURE REVIEW
HISTORICAL BACKGROUND OF THE PROJECT
This kind of project was first designed at university of Lagos using discreet components throughout and moving coil microphone as an input transducer and the latest module to be designed using carbon microphone as an input transducer and few transistor with three integrated circuits IC’s which calls for high degree of reliability. The integrated circuit like NC 555 their which is a very versatile building block for almost every electronic circuits is use to build the alarm circuit of the project design work in my own project design work I have chosen to add some newly inverted circuit like RV delay in discreet logic gate used to firm invertors whose out put drives a 12V delay finally is been interfaces by an alarm circuit. The discreet logic circuit (transistor switching circuit) was designed from the first principle using some of the transistor parameters that come from to that particular design.
The out put was connected to an inductive load, but I had wanted to used a static switching system which is far fetching
THEORIES AND MODELS RELEVANT TO THE DESIGN.
The theories and models relevant to this design are that of electromagnetic waves introduced by James Clerk Maxwell and Heinich Hertz in the mid 1800s, switching action of transistor switching transistor and oscillation. In electromagnetic waves as show below in accordance with their wave lengths and frequencies.
Wave length
Radio Micro Hy-ra-red visible ultra X-ray crymomu rays
Wave, wave light violet
Frequency
The first four are used in communication the first two are used for telecommunication while the second two are used in digital communication in this project microwave is used which serve as input transducer
Concerning the switching action transistor switching circuit the output was connected to inductive load. It is used as a switch. Another thing relevant to this design is IC signal timer (NC555) is specifically used to a-stable model for the alarm circuit.
LIST AND DESCRIPTION OF SYSTEM COMPONENTS USED.
For proper comprehension of this project it is important to have a brief look at some of the component used in the project.
RESISTOR
RESISTOR
Resistor are component that oppose the flow of current through it.
They are constructed in tow categories linear and non-linear. The linear are of two types, variable and fixed. The fixed consist of carbon film carbon composition and wire wound. The one I have chosen in the project is carbon film because of its durability. Under variable resistor we have pre sat, potentiometer and Rlveostat. But I have chosen pre set here for sensitivity control.
And they be connected in series, parallel or the combination of both and it can be measured in ohms (W).
CHPATER THREE
SYSTEM DESIGN
DESCRIPTION OF THE SYSTEM BUILDING BLOCKS.
The sound detector with alarm contains five (5) different blocks namely, the pick-up amplifier, comparator with hystersis transistor switching circuit see delay, Relay circuit and the alarm circuit. The capacitor microphone is a transducer that convert physical sound into electrical sine wave, whose out put is fed into a pick up amplifier, which is a class. A amplifier with feedback that amplifier the sine wave from the transducer the comparator with hystersis is a Schmitt trigger that filters noise and also function as an analog to digital converter (A/D) it is built using single Op AMP LM 741 with a single positive feedback resistor. Then the out put of a comparator with hystersis feds a three stage transistor switching circuit that in comparators a 3 second delay has it’s out put driven by a 12v 10A relay meant to be energized whenever the microphone at the input picks sound. Once the relay is energized the normally open contact. (No) will switch on the alarm circuit, which serves as an interface to the relay circuit. The loud speaker serves as a transducer those coverts the square wave from the pin 3 of the 555 timer (alarm circuit) into alarm tone. The power supply unit is a high regulated one with +9v output.
SYSTEM DESIGN SPECIFICATION
- The alarm tone frequency should be 1kHz maximum
- The relay sound be 12v, 10A and 100 ohms
- Capacitor microphone with high resistance Rs 205 must be emaproy as input transducer amber sound from the sounding.
- The power supply of entire system sound be 9v regulated voltage.
CHAPTER FOUR
IMPLEMENTATION, TESTING AND RESULTS
The assembling of the project complement and its functionality is the primary aim of this section.
Since this project is divided into 4 (four) modules in the components, assembling I adopted step by step approach to ensure that the work will be reliable at the end of the design integrated circuit were used in conjunction with discreet components to ensure reliability, efficiency, high sensitivity and availability of the components in the market repair and changing the faulty components.
CHAPTER FIVE
COST ANALYSIS, CONCLUSION AND RECOMMENDATION
COST ANALYSIS
The design and construction of this project involves some expenses. The materials used are locally sourced and their cost are given below.
CONCLUSION
This project design and construction of a sound detector with alarm system has made it possible for me to apply my knowledge in various aspects of electronic. However, the system has met my design specification and has proved to be efficient. The system should be properly positioned (for instance close to the door entrance) so that it will easily detect sound. Thus, with the aid of this circuit which can be detected noise are any prompt in time were by the person round veracity can be alert. And also it should be properly positioned in industrial.
RECOMMENDATION
For further improvement that I recommend that an indicator using 100 watts in cendescent bulb for illumination of the face of the visitor. Once he falls into the microphone.
Secondly, I recommend that polytechnic in engineering discipline should increase their practice orientation to help sustain their graduates interims of self-employment.
Thirdly, I recommend that project design work should be genuine to graduating students in and second semesters to enable them do wonderful research and elaborate design and implementation with a preliminary deforms schedule from the supervisor.
Lastly I recommend that our curriculum in assent should be changed from British to America standard.
REFERENCES
- W.O Cooper and A.O Helfrick, Electronic instrumentation and measurement Techniques 3rd Edition Prentice Hill India Private ltd 1989 pages used 30 – 60 and 300 – 380
- B. L. Theraja and A. K. Theraja Electrical Technology. Thoroughly Revised Twenty-Third Edition 2002 Reprint 2003 pages 1862 – 1885
- Paul Horowes and Winfield Hall the art of Electronics 2ndEdition Cambridge University Press International UK. 1985 Pages used 40, 49 and 150 – 200
- Chiaguiyi Ralph, Electronic circuit Design technique Hingotez Publication 1st Edition 1999
- Henry Jacob Wiez, Electronics made simple, W.H. Allen London 1998 pages used 167 – 179
- Huffman, Introduction to Electronics for Technologist Hongton, Multlin Company 1998 pages used 151 – 153
