WK130
WIRELESS MUSIC TRANSMISSION AND RECEPTION BY IR COMMUNICATION
INDEX
1. ABSTRACT
2. BLOCK DIAGRAM
3. HARDWARE EXPLNATION
4. MELODY GENERATOR
5. IR
6. TRANSISTOR DRIVER CIRCUIT
7. SIREN
8. APPLICATIONS
9. ADVANTAGES
10. CONCLUSION
11. REFERENCES
ABSTRACT
ABSTRACT:
By using this project audio musical notes can be generated and heard up to a distance of 10 meters. The circuit can be divided into two parts: IR music transmitter and receiver. The IR music transmitter works off a 9V battery, while the IR music receiver works off regulated 9V to 12V. The transmitter uses popular melody generator IC UM66 that can continuously generate musical tones. The output of this music melody generator is fed to the IR driver stage to get the maximum range.
An LED is connected in the Transmitter section. This LED flickers according to the musical tones generated by UM66 IC, indicating modulation. Two IR LEDs are connected in series. For maximum sound transmission these should be oriented towards IR phototransistor L14F1. The IR music receiver uses popular op-amp IC μA741 and audio-frequency amplifier IC LM386 along with phototransistor L14F1 and some discrete components. The melody generated by IC UM66 is transmitted through IR LEDs, received by phototransistor and fed to pin 2 of IC μA741. Its gain can be varied using potentiometer VR1. The output
of IC μA741 is fed to IC LM386 via capacitor C5 and potentiometer. The melody produced is heard through the receiver’s loudspeaker. Potentiometer VR2 is used to control the volume of loudspeaker (8-ohm, 1W). Switching off the power supply stops melody generation.
This project uses regulated 9V, 750mA power supply. 7805 three terminal voltage regulator is used for voltage regulation. Bridge type full wave rectifier is used to rectify the ac out put of secondary of 230/18V step down transformer.
HARDWARE EXPLANATION
Hardware Explanation:
RESISTOR:
Resistors "Resist" the flow of electrical current. The higher the value of resistance (measured inohms) the lower the current will be.Resistance is the property of a component whichrestricts the flow of electric current. Energy is used up as the voltage across the component drives the current through it and this energy appears as heat in the component.
Colour Code:
CAPACITOR:
Capacitors store electric charge. They are used with resistors intimingcircuitsbecause it takes time for a capacitor to fill with charge. They are used tosmoothvarying DC supplies by acting as a reservoir of charge. They are also used in filter circuits because capacitors easily pass AC (changing) signals but they block DC (constant) signals.
Circuit symbol:
Electrolytic capacitors are polarized andthey must be connected the correct way round, at least one of their leads will be marked + or -.
Examples:
DIODES:
Diodes allow electricity to flow in only one direction. The arrow of the circuit symbol shows the direction in which the current can flow. Diodes are the electrical version of a valve and early diodes were actually called valves.
Circuit symbol:
Diodes must be connected the correct way round, the diagram may be labeledaor+for anode andkor-for cathode (yes, it really is k, not c, for cathode!). The cathode is marked by a line painted on the body. Diodes are labeled with their code in small print; you may need a magnifying glass to read this on small signal diodes.
Example:
LIGHT-EMITTING DIODE (LED):
The longer lead is the anode (+) and the shorter lead is the cathode (&minus). In the schematic symbol for an LED (bottom), the anode is on the left and the cathode is on the right. Lighemitting diodes are elements for light signalization in electronics.
They are manufactured in different shapes, colors and sizes. For their low price, low consumption and simple use, they have almost completely pushed aside other light sources- bulbs at first place.
It is important to know that each diode will be immediately destroyed unless its current is limited. This means that a conductor must be connected in parallel to a diode. In order to correctly determine value of this conductor, it is necessary to know diode’s voltage drop in forward direction, which depends on what material a diode is made of and what colors it is. Values typical for the most frequently used diodes are shown in table below: As seen, there are three main types of LEDs. Standard ones get full brightness at current of 20mA. Low Current diodes get full brightness at ten time’s lower current while Super Bright diodes produce more intensive light than Standard ones.
Since the 8052 microcontrollers can provide only low input current and since their pins are configured as outputs when voltage level on them is equal to 0, direct confectioning to LEDs is carried out as it is shown on figure (Low current LED, cathode is connected to output pin).
Switches and Pushbuttons:
A push button switch is used to either close or open an electrical circuit depending on the application. Push button switches are used in various applications such as industrialequipmentcontrol handles, outdoor controls, mobile communication terminals, and medical equipment, and etc. Push button switches generally include a push button disposed within a housing. The push button may be depressed to cause movement of the push button relative to the housing for directly or indirectly changing the state of an electrical contact to open or close the contact. Also included in a pushbutton switch may be an actuator, driver, or plunger of some type that is situated within a switch housing having at least two contacts in communication with an electrical circuit within which the switch is incorporated.
Typical actuators used for contact switches include spring loaded force cap actuators that reciprocate within a sleeve disposed within the canister. The actuator is typically coupled to the movement of the cap assembly, such that the actuator translates in a direction that is parallel with the cap. A push button switch for a data input unit for a mobile communication device such as a cellular phone, a key board for apersonal computeror the like is generally constructed by mounting a cover member directly on a circuit board. Printed circuit board (PCB) mounted pushbutton switches are an inexpensive means of providing an operator interface on industrial control products. In such push button switches, a substrate which includes a plurality of movable sections is formed of arubberelastomeric. The key top is formed on a top surface thereof with a figure, a character or the like by printing, to thereby provide a cover member. Push button switches incorporating lighted displays have been used in a variety of applications. Such switches are typically comprised of a pushbutton, an opaque legend plate, and a back light to illuminate the legend plate.
Block Diagram For Regulated Power Supply (RPS):
Figure: Power Supply
Description :
Transformer
A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer's coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core, and thus a varying magnetic field through the secondary winding. This varying magnetic field induces a varying electromotive force (EMF) or "voltage" in the secondary winding. This effect is called mutual induction.
Figure: Transformer Symbol
(or)
Transformer is a device that converts the one form energy to another form of energy like a transducer.
Figure: Transformer
Basic Principle
A transformer makes use of Faraday's law and the ferromagnetic properties of an iron core to efficiently raise or lower AC voltages. It of course cannot increase power so that if the voltage is raised, the current is proportionally lowered and vice versa.
Figure: Basic Principle
Transformer Working
A transformer consists of two coils (often called 'windings') linked by an iron core, as shown in figure below. There is no electrical connection between the coils; instead they are linked by a magnetic field created in the core.
Figure: Basic Transformer
Transformers are used to convert electricity from one voltage to another with minimal loss of power. They only work with AC (alternating current) because they require a changing magnetic field to be created in their core. Transformers can increase voltage (step-up) as well as reduce voltage (step-down).
Alternating current flowing in the primary (input) coil creates a continually changing magnetic field in the iron core. This field also passes through the secondary (output) coil and the changing strength of the magnetic field induces an alternating voltage in the secondary coil. If the secondary coil is connected to a load the induced voltage will make an induced current flow. The correct term for the induced voltage is 'induced electromotive force' which is usually abbreviated to induced e.m.f.
The iron core is laminated to prevent 'eddy currents' flowing in the core. These are currents produced by the alternating magnetic field inducing a small voltage in the core, just like that induced in the secondary coil. Eddy currents waste power by needlessly heating up the core but they are reduced to a negligible amount by laminating the iron because this increases the electrical resistance of the core without affecting its magnetic properties.
Transformers have two great advantages over other methods of changing voltage:
- They provide total electrical isolation between the input and output, so they can be safely used to reduce the high voltage of the mains supply.
- Almost no power is wasted in a transformer. They have a high efficiency (power out / power in) of 95% or more.
Classification of Transformer
Ø Step-Up Transformer
Ø Step-Down Transformer
Step-Down Transformer
Step down transformers are designed to reduce electrical voltage. Their primary voltage is greater than their secondary voltage. This kind of transformer "steps down" the voltage applied to it. For instance, a step down transformer is needed to use a 110v product in a country with a 220v supply.
Step down transformers convert electrical voltage from one level or phase configuration usually down to a lower level. They can include features for electrical isolation, power distribution, and control and instrumentation applications. Step down transformers typically rely on the principle of magnetic induction between coils to convert voltage and/or current levels.
Step down transformers are made from two or more coils of insulated wire wound around a core made of iron. When voltage is applied to one coil (frequently called the primary or input) it magnetizes the iron core, which induces a voltage in the other coil, (frequently called the secondary or output). The turn’s ratio of the two sets of windings determines the amount of voltage transformation.
Figure: Step-Down Transformer
An example of this would be: 100 turns on the primary and 50 turns on the secondary, a ratio of 2 to 1.
Step down transformers can be considered nothing more than a voltage ratio device.
With step down transformers the voltage ratio between primary and secondary will mirror the "turn’s ratio" (except for single phase smaller than 1 kva which have compensated secondary). A practical application of this 2 to 1 turn’s ratio would be a 480 to 240 voltage step down. Note that if the input were 440 volts then the output would be 220 volts. The ratio between input and output voltage will stay constant. Transformers should not be operated at voltages higher than the nameplate rating, but may be operated at lower voltages than rated. Because of this it is possible to do some non-standard applications using standard transformers.
Single phase step down transformers 1 kva and larger may also be reverse connected to step-down or step-up voltages. (Note: single phase step up or step down transformers sized less than 1 KVA should not be reverse connected because the secondary windings have additional turns to overcome a voltage drop when the load is applied. If reverse connected, the output voltage will be less than desired.)
Step-Up Transformer
A step up transformer has more turns of wire on the secondary coil, which makes a larger induced voltage in the secondary coil. It is called a step up transformer because the voltage output is larger than the voltage input.
Step-up transformer 110v 220v design is one whose secondary voltage is greater than its primary voltage. This kind of transformer "steps up" the voltage applied to it. For instance, a step up transformer is needed to use a 220v product in a country with a 110v supply.
A step up transformer 110v 220v converts alternating current (AC) from one voltage to another voltage. It has no moving parts and works on a magnetic induction principle; it can be designed to "step-up" or "step-down" voltage. So a step up transformer increases the voltage and a step down transformer decreases the voltage.
The primary components for voltage transformation are the step up transformer core and coil. The insulation is placed between the turns of wire to prevent shorting to one another or to ground. This is typically comprised of Mylar, nomex, Kraft paper, varnish, or other materials. As a transformer has no moving parts, it will typically have a life expectancy between 20 and 25 years.
Figure: Step-Up Transformer
Applications :
Generally these Step-Up Transformers are used in industries applications only.
Types of Transformer
Mains Transformers
Mains transformers are the most common type. They are designed to reduce the AC mains supply voltage (230-240V in the UK or 115-120V in some countries) to a safer low voltage. The standard mains supply voltages are officially 115V and 230V, but 120V and 240V are the values usually quoted and the difference is of no significance in most cases.
Figure: Main Transformer
To allow for the two supply voltages mains transformers usually have two separate primary coils (windings) labeled 0-120V and 0-120V. The two coils are connected in series for 240V (figure 2a) and in parallel for 120V (figure 2b). They must be wired the correct way round as shown in the diagrams because the coils must be connected in the correct sense (direction):