04-10-2012, 07:35 PM
document for clap based digital volume control
04-10-2012, 07:35 PM
document for clap based digital volume control
16-05-2013, 12:40 PM
Clap Based Digital Volume Control
Clap Based Digital.docx (Size: 537.96 KB / Downloads: 26) ABSTRACT Entertainment is a prime concern in our day-today life. Everyone wants to be comfortable and enjoy as much as possible. So this project is one of the best product which is useful for those person who like entertainment. The clap based digital volume control is an access control system that allows only authorized clap detected by a microphone. The system is fully controlled by the counter IC CD4040 and quad bilateral switch IC CD4066. This clap-based digital volume control offers four levels of volume control. With each clap, the volume of the audio system increases. After the fourth clap, the level of volume returns to the first or minimum level. The circuit consists of a microphone, a level detector, a 4-stage counter and four analogue switches connected to a resistive ladder network. INTRODUCTION:- “Clap Based Digital Volume Control” is used in the places where we need more entertainment. It can also used in MP3 players and PCs. The circuit consists of a microphone, a level detector, a 4-stage counter and four analogue switches connected to a resistive ladder network. The IC CD4040 and IC CD4066 are one of the popular microcontroller. Each has 16 and 14 number of pins respectively. The microcontroller has a program memory of 2 Kilobytes. The clapping signal captured by the electret microphone (MIC1) is amplified by transistor T1. MIC1 gets its bias voltage through resistor R1. Counter IC CD4040 (IC1) gets a clock pulse at its pin 10 when a certain noise level (threshold) is received through T1. The counter output determines the configuration of the four electronic switches inside IC2. The volume control operates as a digital controlled attenuator between the audio input pin and the power amplifier. In the maximum volume control setting the attenuation is 0 dB and in the minimum volume control setting the typical attenuation is 80 dB. The attenuation can be set in 64 steps by the UP/DOWN pin. Transistor BC547:- BC547 is an NPN bi-polar junction transistor. A transistor, stands for transfer of resistance, is commonly used to amplify current. A small current at its base controls a larger current at collector & emitter terminals. BC547 is mainly used for amplification and switching purposes. It has a maximum current gain of 800. Its equivalent transistors are BC548 and BC549. The transistor terminals require a fixed DC voltage to operate in the desired region of its characteristic curves. This is known as the biasing. For amplification applications, the transistor is biased such that it is partly on for all input conditions. The input signal at base is amplified and taken at the emitter. BC547 is used in common emitter configuration for amplifiers. The voltage divider is the commonly used biasing mode. For switching applications, transistor is biased so that it remains fully on if there is a signal at its base. In the absence of base signal, it gets completely off. The common-emitter amplifier is designed so that a small change in voltage (Vin) changes the small current through the base of the transistor; the transistor's current amplification combined with the properties of the circuit mean that small swings in Vin produce large changes in Vout. COMPONENTS DETAILS:- Resistor Resistor is a component that resists the flow of direct or alternating electric circuit. Resistors can limit or divide the current, reduce the voltage, protect an electric circuit, or provide large amounts of heat or light. An electric current is the movement of charged particles called electrons from one region to another. Resistors are usually placed in electric circuits. Physicists explain the flow of current through a material, such as a resistor, by comparing it to water flowing through a pipe. Resistors are designed to have a specific value of resistance. Resistors used in electric circuits are cylindrical. They are often colour coded by three or four colour bands that indicate the specific value of resistance. Resistors obey ohm’s law, which states that the current density is directly proportional to the electric field when the temperature is constant. Capacitor Capacitor or electric condenser is a device for storing an electric charge. The simplest form of capacitor consists of two metal plates separated by a non touching layer called the dielectric. When one plate is charged with electricity from a direct current or electrostatic source, the other plate have induced in it a charge of the opposite sign; that is, positive if the original charge is negative and negative if the original charge is positive. The electrical size of the capacitor is its capacitance. Capacitors are limited in the amount of electric charge they can absorb; they can conduct direct current for only instances but function well as conductors in alternating current circuits. Fixed capacity and variable capacity capacitors are used in conjunction with coils as resonant circuits in radios and other electronic equipment. Capacitors are produced in a wide variety of forms. Condenser Microphone:- Condenser means capacitor, an electronic component which stores energy in the form of an electrostatic field. The term condenser is actually obsolete but has stuck as the name for this type of microphone, which uses a capacitor to convert acoustical energy into electrical energy. Condenser microphones require power from a battery or external source. The resulting audio signal is stronger signal than that from a dynamic. Condensers also tend to be more sensitive and responsive than dynamics, making them well-suited to capturing subtle nuances in a sound. They are not ideal for high-volume work, as their sensitivity makes them prone to distort. Light Emitting Diode: The LEDs involved may be conventional semiconductor light-emitting diodes, organic LEDs (OLED), or polymer light-emitting diodes (PLED) devices. However, PLED technologies are not commercially available. Diode technology improves steadily. Efficiency of LED devices continues to improve, with some chips able to emit more than 100 lumens per watt. LEDs do not emit light in all directions, and their directional characteristics affect the design of lamps. The efficiency of conversion from electric power to light is generally higher than with incandescent lamps. Since the light output of many types of light-emitting diodes is small compared to incandescent and compact fluorescent lamps, in most applications multiple diodes are assembled. Step-Down Transformer Considerations It is possible to operate either of these transformer types backwards (powering the secondary winding with an AC source and letting the primary winding power a load) to perform the opposite function: a step-up can function as a step-down and vise-versa. One convention used in the electric power industry is the use of “H” designations for the higher-voltage winding (the primary winding in a step-down unit; the secondary winding in a step-up) and “X” designations for the lower-voltage winding. One of the most important considerations to increase transformer efficiency and reduce heat is choosing the metal type of the windings. Copper windings are much more efficient than aluminum and many other winding metal choices, but it also costs more. Transformers with copper windings cost more to purchase initially, but save on electrical cost over time as the efficiency more than makes up for the initial cost. Step-down transformers are commonly used to convert the 220 volt electricity found in most parts of the world to the 110 volts required by North American equipment. |
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