COIN BASED MOBILE CHARGER

COIN BASED MOBILE CHARGER

With mobile phones becoming the major source of business/personal

communication, the mobile phone business is currently worth billion of

dollars, and supports millions of phones. The need to provide a public

charging service is essential. Many critics argued that a public mobile

phone charging service is not a lucrative business because most users

can charge their phones at home, in their office or in their cars.

STAYTALKING Coin Operated Mobile Phone Charger is a new business

milestone because many are attending business conventions and

forgetting their charger at home or in hotel rooms. Students and many

that use the public transportation that don't know that their level of

their battery is low are prospective customers for coin operated mobile

phone charger service. Recommended locations include: Hotels,

conference centers, exhibition halls, serviced offices, exchange halls,

motels, leisure centers, health clubs, training centers, golf clubs, retail

outlets, shopping malls, Internet cafes, universities, colleges, hall of

residence, airports, train terminals, etc., so that the mobile phone users

can reactivate a low or dead battery by simply plugging in and charging

for as low as one dollar. Coin Operated Mobile Phone Charger benefits

to the users include: -To reactivate a low or dead battery -To retrieve

vital text or voice mail -No need to carry around a charger -Fast micro

pulse charge in 10 minutes -Make and receive calls while charging -

Never be without a charged phone again The key features of the

STAYTALKING Charger includes: -Simple to operate, plug and charge -

Supports 95% of all mobile phones -Stylish design and eye catching

signage -Select the charging lead for your make of phone -Allows up to

10 users to recharge their mobile phones simultaneously -Unique

service to customers -Generate revenue from day one. Public Coin

Operated Mobile Phone Chargers are now available. To become a

provider in your area or for more information.

ABSTRACT

Introduction:

The objective of this project is inserting the coin using charge

for your mobile phone in public places.

Scope:

This project is very useful to people who are all using mobile

phone without charging condition in pubic places.

Explanation:

In this project, who are all using mobile phones in outside of

home are office without charging condition. The coin based mobile

phone charger is very useful to that person for using coin to charge for

that mobile. The IR (infrared) transmitter is used to transmit IR signal in

the transmitter side. The IR receiver is used to receive the IR signal in

the receiver side. Between the IR transmitter and receiver, insert a coin

to change the polarity of pulse in SCU input.

The SCU is used to converting low pulse to high pulse and that

pulse is inverted in inverter. The 555 IC is act as a timer to produces

high pulse for particular time period. Again the SCU is used to

converting low pulse to high pulse and this output is give to input of

driver circuit. Driver circuit is used for provide the sufficient input

voltage of relay. The relay will on to activate the 230v charger, we will

use charger to charge for our mobile phone.

Advantages:

The main merits of this is

i. Simple and hand efficient.

ii. Less expensive.

iii. Reduced man power.

iv. Low power consumption.

Application:

The coin based mobile phone charger is very useful to public for using coin to charge for the mobile phone in any places.

BLOCK DIAGRAM

:

BLOCK DIAGRAM DESCRIPTION

1.IR SENSOR

A InfraRed sensor (IR sensor) is an electronic device that measures

infrared (IR) light radiating from objects in its field of view.Apparent

motion is detected when an infrared source with one temperature, such

as a human, passes in front of an infrared source with another

temperature, such as a wall.

All objects emit what is known as black body radiation. It is usually

infrared radiation that is invisible to the human eye but can be detected

by electronic devices designed for such a purpose.

“Infra” meaning below our ability to detect it visually, and “Red”

because this color represents the lowest energy level that our eyes can

sense before it becomes invisible. Thus, infrared means below the

energy level of the color red, and applies to many sources of invisible

energy.

Infrared transmitter is one type of LED which emits infrared rays

generally called as IR Transmitter. Similarly IR Receiver is used to

receive the IR rays transmitted by the IR transmitter. One important

point is both IR transmitter and receiver should be placed straight line

to each other.

The transmitted signal is given to IR transmitter whenever the signal is

high, the IR transmitter LED is conducting it passes the IR rays to the

receiver.

When receiver receives the signal from the transmitter it resistance value

is low.it resistance value become high when the signal was cut. By this

sensor sense the value.

2.SCU

Signal conditioning unit

The signal conditioning unit accepts input signals from the analog

sensors and gives a conditioned output of 0-5V DC corresponding to the

entire range of each parameter. This unit also accepts the digital

sensor inputs and gives outputs in 10 bit binary with a positive logic

level of +5V. The calibration voltages* (0, 2.5 and 5V) and the health

bits are also generated in this unit.

Microcontrollers are widely used for control in power electronics. They

provide real time control by processing analog signals obtained from

the system. A suitable isolation interface needs to be designed for

interaction between the control circuit and high voltage hardware. A

signal conditioning unit which provides necessary interface between a

high power grid inverter and a low voltage controller unit.

3.TIMER 555

The 555 Timer IC is an integrated circuit (chip) implementing a variety

of timer and multivibrator applications. The IC was designed by Hans R.

Camenzind in 1970 and brought to market in 1971 by Signetics (later

acquired by Philips). The original name was the SE555 (metal

can)/NE555 (plastic DIP) and the part was described as "The IC Time

Machine".[1] It has been claimed that the 555 gets its name from the

three 5 kΩ resistors used in typical early implementations,[2] but Hans

Camenzind has stated that the number was arbitrary.[3] The part is still

in wide use, thanks to its ease of use, low price and good stability. As of

2003, it is estimated that 1 billion units are manufactured every year.[3]

Depending on the manufacturer, the standard 555 package includes over

20 transistors, 2 diodes and 15 resistors on a silicon chip installed in an

8-pin mini dual-in-line package (DIP-8).[4] Variants available include the

556 (a 14-pin DIP combining two 555s on one chip), and the 558 (a 16-

pin DIP combining four slightly modified 555s with DIS & THR

connected internally, and TR falling edge sensitive instead of level

sensitive).

Ultra-low power versions of the 555 are also available, such as the 7555

and TLC555.[5] The 7555 requires slightly different wiring using fewer

external components and less power.

The 555 has three operating modes:

Monostable mode: in this mode, the 555 functions as a "one-

shot". Applications include timers, missing pulse detection,

bouncefree switches, touch switches, frequency divider,

capacitance measurement, pulse-width modulation (PWM) etc

Astable - free running mode: the 555 can operate as an oscillator.

Uses include LED and lamp flashers, pulse generation, logic clocks,

tone generation, security alarms, pulse position modulation, etc.

Bistable mode or Schmitt trigger: the 555 can operate as a flip-

flop, if the DIS pin is not connected and no capacitor is used. Uses

include bouncefree latched switches, etc.

4.RELAY

A RELAY IS AN ELECTRICALLY OPERATED SWITCH.

Many relays use an electromagnet to operate a switching mechanism,

but other operating principles are also used. Relays find applications

where it is necessary to control a circuit by a low-power signal, or

where several circuits must be controlled by one signal.

The first relays were used in long distance telegraph circuits, repeating

the signal coming in from one circuit and re-transmitting it to another.

Relays found extensive use in telephone exchanges and early

computers to perform logical operations. A type of relay that can

handle the high power required to directly drive an electric motor is

called a contactor.

Solid-state relays control power circuits with no moving parts, instead

using a semiconductor device to perform switching. Relays with

calibrated operating characteristics and sometimes multiple operating

coils are used to protect electrical circuits from overload or faults; in

modern electric power systems these functions are performed by

digital instruments still called "protection relays".

5MOBILE CHARGER

A battery charger is a device used to put energy into a secondary cell

or (rechargeable) battery by forcing an electric current through it.

The charge current depends upon the technology and capacity of the

battery being charged. For example, the current that should be applied to

recharge a 12 V car battery will be very different from the current for a

mobile phone battery.

OVER ALL CIRCUIT DIAGRAM

CIRCUIT DIAGRAM DESCRIPTION

1. POWER SUPPLY

Block diagram

The ac voltage, typically 220V rms, is connected to a transformer,

which steps that ac voltage down to the level of the desired dc output.

A diode rectifier then provides a full-wave rectified voltage that is

initially filtered by a simple capacitor filter to produce a dc voltage. This

resulting dc voltage usually has some ripple or ac voltage variation.

A regulator circuit removes the ripples and also remains the same

dc value even if the input dc voltage varies, or the load connected to

the output dc voltage changes. This voltage regulation is usually

obtained using one of the popular voltage regulator IC units.

Block diagram (Power supply)

Working principle

Transformer

The potential transformer will step down the power supply

voltage (0-230V) to (0-6V) level. Then the secondary of the potential

transformer will be connected to the precision rectifier, which is

constructed with the help of op–amp. The advantages of using

LOADIC REGULATOR

FILTERRECTIFIERTRANSFORMER

precision rectifier are it will give peak voltage output as DC, rest of the

circuits will give only RMS output.

Bridge rectifier

When four diodes are connected as shown in figure, the circuit is

called as bridge rectifier. The input to the circuit is applied to the

diagonally opposite corners of the network, and the output is taken

from the remaining two corners.

Let us assume that the transformer is working properly and there

is a positive potential, at point A and a negative potential at point B. the

positive potential at point A will forward bias D3 and reverse bias D4.

The negative potential at point B will forward bias D1 and reverse

D2. At this time D3 and D1 are forward biased and will allow current

flow to pass through them; D4 and D2 are reverse biased and will block

current flow.

The path for current flow is from point B through D1, up through

RL, through D3, through the secondary of the transformer back to point

B. this path is indicated by the solid arrows. Waveforms (1) and (2) can

be observed across D1 and D3.

One-half cycle later the polarity across the secondary of the

transformer reverse, forward biasing D2 and D4 and reverse biasing D1

and D3. Current flow will now be from point A through D4, up through

RL, through D2, through the secondary of T1, and back to point A. This

path is indicated by the broken arrows. Waveforms (3) and (4) can be

observed across D2 and D4. The current flow through RL is always in

the same direction. In flowing through RL this current develops a

voltage corresponding to that shown waveform (5). Since current flows

through the load (RL) during both half cycles of the applied voltage, this

bridge rectifier is a full-wave rectifier.

One advantage of a bridge rectifier over a conventional full-wave

rectifier is that with a given transformer the bridge rectifier produces a

voltage output that is nearly twice that of the conventional full-wave

circuit.

This may be shown by assigning values to some of the components

shown in views A and B. assume that the same transformer is used in

both circuits. The peak voltage developed between points X and y is

1000 volts in both circuits. In the conventional full-wave circuit shown

—in view A, the peak voltage from the center tap to either X or Y is 500

volts. Since only one diode can conduct at any instant, the maximum

voltage that can be rectified at any instant is 500 volts.

The maximum voltage that appears across the load resistor is

nearly-but never exceeds-500 v0lts, as result of the small voltage drop

across the diode. In the bridge rectifier shown in view B, the maximum

voltage that can be rectified is the full secondary voltage, which is 1000

volts. Therefore, the peak output voltage across the load resistor is

nearly 1000 volts. With both circuits using the same transformer, the

bridge rectifier circuit produces a higher output voltage than the

conventional full-wave rectifier circuit.

IC voltage regulators

Voltage regulators comprise a class of widely used ICs.

Regulator IC units contain the circuitry for reference source,

comparator amplifier, control device, and overload protection all in a

single IC. IC units provide regulation of either a fixed positive voltage, a

fixed negative voltage, or an adjustably set voltage. The regulators can

be selected for operation with load currents from hundreds of milli

amperes to tens of amperes, corresponding to power ratings from milli

watts to tens of watts.

Circuit diagram (Power supply)

A fixed three-terminal voltage regulator has an unregulated dc

input voltage, Vi, applied to one input terminal, a regulated dc output

voltage, Vo, from a second terminal, with the third terminal connected

to ground.

The series 78 regulators provide fixed positive regulated voltages

from 5 to 24 volts. Similarly, the series 79 regulators provide fixed

negative regulated voltages from 5 to 24 volts.

For ICs, microcontroller, LCD --------- 5 volts

For alarm circuit, op-amp, relay circuits ---------- 12 volts

2.IR SENSING CIRCUIT

Infrared transmitter is one type of LED which emits infrared rays

generally called as IR Transmitter. Similarly IR Receiver is used to

receive the IR rays transmitted by the IR transmitter. One important

point is both IR transmitter and receiver should be placed straight line

to each other.

The transmitted signal is given to IR transmitter whenever the

signal is high, the IR transmitter LED is conducting it passes the IR rays

to the receiver. The IR receiver is connected with comparator. The

comparator is constructed with LM 358 operational amplifier. In the

comparator circuit the reference voltage is given to inverting input

terminal. The non inverting input terminal is connected IR receiver.

When interrupt the IR rays between the IR transmitter and receiver, the

IR receiver is not conducting. So the comparator non inverting input

terminal voltage is higher then inverting input. Now the comparator

output is in the range of +5V. This voltage is given to microcontroller or

PC and led so led will glow.

When IR transmitter passes the rays to receiver, the IR receiver is

conducting due to that non inverting input voltage is lower than

inverting input. Now the comparator output is GND so the output is

given to microcontroller or PC. This circuit is mainly used to for

counting application, intruder detector etc.

3.TIMER 555

      Monostable means that once the circuit is switched on it will time

once and then stop. In order to start it again it must be switched on

manually a second time.      

In the circuit drawn opposite, the 555 timer is set to turn on the buzzer

when the push switch is pressed; the buzzer sounds for approximately 8

seconds. This is a monostable circuit as it works only once. The switch

must be pressed again for the buzzer to sound again.

 

On the diagram above if the components 'boxed in' by the dotted line are

removed and the alternative components (shown on the right) are added

- the 555 timer circuit can be used to energise a relay.

The timer can now be used to trigger a relay which then allows another

circuit to work. In this case the timer holds the relay closed for a preset

amount of time allowing the second circuit to work and then switches

the relay open, which stops the secondary circuit.

 Monostable multivibrator often called a one shot multivibrator is a

pulse generating circuit in which the duration of this pulse is

determined by the RC network connected externally to the 555 timer.

In a stable or standby state, the output of the circuit is approximately

zero or a logic-low level. When external trigger pulse is applied output

is forced to go high ( VCC). The time for which output remains high is

determined by the external RC network connected to the timer. At the

end of the timing interval, the output automatically reverts back to its

logic-low stable state. The output stays low until trigger pulse is again

applied. Then the cycle repeats. The monostable circuit has only one

stable state (output low) hence the name monostable.

The 555 Timer IC is an integrated circuit (chip) implementing a variety

of timer and multivibrator applications. The IC was designed by Hans R.

Camenzind in 1970 and brought to market in 1971 by Signetics (later

acquired by Philips). The original name was the SE555 (metal

can)/NE555 (plastic DIP) and the part was described as "The IC Time

Machine".[1] It has been claimed that the 555 gets its name from the three

5 kΩ resistors used in typical early implementations,[2] but Hans

Camenzind has stated that the number was arbitrary.[3] The part is still in

wide use, thanks to its ease of use, low price and good stability. As of

2003, it is estimated that 1 billion units are manufactured every year.[3]

Depending on the manufacturer, the standard 555 package includes over

20 transistors, 2 diodes and 15 resistors on a silicon chip installed in an

8-pin mini dual-in-line package (DIP-8).[4] Variants available include the

556 (a 14-pin DIP combining two 555s on one chip), and the 558 (a 16-

pin DIP combining four slightly modified 555s with DIS & THR

connected internally, and TR falling edge sensitive instead of level

sensitive).

Ultra-low power versions of the 555 are also available, such as the 7555

and TLC555.[5] The 7555 requires slightly different wiring using fewer

external components and less power.

The 555 has three operating modes:

4.RELAY

A relay is an electrically operated switch. Many relays use an

electromagnet to operate a switching mechanism, but other operating

principles are also used. Relays find applications where it is necessary

to control a circuit by a low-power signal, or where several circuits must

be controlled by one signal. The first relays were used in long distance

telegraph circuits, repeating the signal coming in from one circuit and

re-transmitting it to another. Relays found extensive use in telephone

exchanges and early computers to perform logical operations. A type of

relay that can handle the high power required to directly drive an

electric motor is called a contactor. Solid-state relays control power

circuits with no moving parts, instead using a semiconductor device

triggered by light to perform switching. Relays with calibrated operating

characteristics and sometimes multiple operating coils are used to

protect electrical circuits from overload or faults; in modern electric

power systems these functions are performed by digital instruments

still called "protection relays".

Basic design and operation

Small relay as used in electronics

A simple electromagnetic relay, such as the one taken from a car in the

first picture, is an adaptation of an electromagnet. It consists of a coil of

wire surrounding a soft iron core, an iron yoke, which provides a low

reluctance path for magnetic flux, a movable iron armature, and a set,

or sets, of contacts; two in the relay pictured. The armature is hinged to

the yoke and mechanically linked to a moving contact or contacts. It is

held in place by a spring so that when the relay is de-energized there is

an air gap in the magnetic circuit. In this condition, one of the two sets

of contacts in the relay pictured is closed, and the other set is open.

Other relays may have more or fewer sets of contacts depending on

their function. The relay in the picture also has a wire connecting the

armature to the yoke. This ensures continuity of the circuit between

the moving contacts on the armature, and the circuit track on the

printed circuit board (PCB) via the yoke, which is soldered to the PCB.

When an electric current is passed through the coil, the resulting

magnetic field attracts the armature, and the consequent movement of

the movable contact or contacts either makes or breaks a connection

with a fixed contact. If the set of contacts was closed when the relay

was De-energized, then the movement opens the contacts and breaks

the connection, and vice versa if the contacts were open. When the

current to the coil is switched off, the armature is returned by a force,

approximately half as strong as the magnetic force, to its relaxed

position. Usually this force is provided by a spring, but gravity is also

used commonly in industrial motor starters. Most relays are

manufactured to operate quickly. In a low voltage application, this is to

reduce noise. In a high voltage or high current application, this is to

reduce arcing.

If the coil is energized with DC, a diode is frequently installed across the

coil, to dissipate the energy from the collapsing magnetic field at

deactivation, which would otherwise generate a voltage spike

dangerous to circuit components. Some automotive relays already

include a diode inside the relay case. Alternatively a contact protection

network, consisting of a capacitor and resistor in series, may absorb the

surge. If the coil is designed to be energized with AC, a small copper

ring can be crimped to the end of the solenoid. This "shading ring"

creates a small out-of-phase current, which increases the minimum pull

on the armature during the AC cycle.[1]

By analogy with the functions of the original electromagnetic device, a

solid-state relay is made with a thyristor or other solid-state switching

device. To achieve electrical isolation an optocoupler can be used which

is a light-emitting diode (LED) coupled with a photo transistor.

A latching relay has two relaxed states (bistable). These are also called

"impulse", "keep", or "stay" relays. When the current is switched off,

the relay remains in its last state. This is achieved with a solenoid

operating a ratchet and cam mechanism, or by having two opposing

coils with an over-center spring or permanent magnet to hold the

armature and contacts in position while the coil is relaxed, or with a

remanent core. In the ratchet and cam example, the first pulse to the

coil turns the relay on and the second pulse turns it off. In the two coil

example, a pulse to one coil turns the relay on and a pulse to the

opposite coil turns the relay off. This type of relay has the advantage

that it consumes power only for an instant, while it is being switched,

and it retains its last setting across a power outage. A remanent core

latching relay requires a current pulse of opposite polarity to make it

change state.

Circuit description:

This circuit is designed to control the load. The load may be motor

or any other load. The load is turned ON and OFF through relay. The

relay ON and OFF is controlled by the pair of switching transistors (BC

547). The DPDT relay is connected in the Q2 transistor collector

terminal. A Relay is nothing but electromagnetic switching device which

consists of six pins. They are two set of Common, Normally close (NC)

and Normally open (NO) pins.

The relay common pin is connected to supply voltage. The

normally open (NO) pin connected to load. When high pulse signal is

given to base of the Q1 transistors, the transistor is conducting and

shorts the collector and emitter terminal and zero signals is given to

base of the Q2 transistor. So the relay is turned OFF state.

When low pulse is given to base of transistor Q1 transistor,

the transistor is turned OFF. Now 12v is given to base of T2 transistor so

the transistor is conducting and relay is energized. Hence the common

terminal and NO terminal of relay are shorted. Now load gets the

supply voltage through relay.

Voltage Signal from Transistor Q1 Transistor Q2Relay

Microcontroller or PC

1 on off

off

0 off on

on