universal mobile charger.doc

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UNIVERSAL MOBILE CHARGER

CHAPTER 1

INTRODUCTION

Today, our country INDIA is progressing in every field of technology & science.

Also it has a great advancement in all electronics & electrical field. Today, the world is

becoming smaller & smaller day by day. Because of this highly advanced world, the

human comes across a very limitation of time. At this fast movement of time & adding an

effort with science & technology. Also, by keeping the view to conventional energies &

fuels. We have concluded an instrument which is now very helpful to common man.

Today the common mans need is not only food, clothing, shelters but also to live

in comfort, to have all facilities & also a very important inventionCELLPHONE.

Mobile phones have a great application in a day to day life for metropolitan cities. Butmobile phone doesnt last for long time. Mobile phone needs some source to charge itself

i.e. we must have charger with us. But electrical source is not available everywhere.

So, by focusing the aim as a charger problem we have to come to conclusion that,

we must have such device that must charge mobile at time of need. Our project is to make

charger which charge the mobile by two ways first solar energy and second radio

frequency.

For solar energy with the help of solar panel a portable device can be made. This

charger is designed to help the people when they are unable to charge because of no

electricity. This circuit describes a solar cell phone charger that uses solar panels. DC

voltage is transformed to a mobile phone battery and then charge the battery.

For radio frequency we use the concept of energy harvesting. Energy

harvesting is the idea of gathering transmitted energy and either using it

to power a circuit or storing it for later use. The concept needs an efficient

antenna along with a circuit capable of converting alternating-current (AC)

voltage to direct-current (DC) voltage. The efficiency of an antenna, asbeing discussed here, is related to the shape and impedance of the

antenna and the impedance of the circuit. If the two impedances arent

matched then there is reflection of the power back into the antenna

meaning that the circuit was unable to receive all the available power.

Dept. of Instrumentation & Control, KBTCOE, Nashik-422013

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After the both stage done we then combine the both circuits so that both way of

charging is available.This is a hand carry device which can be taking or travel easily. If

can be kept in hand to charge our cell phones or must keep at one place & can charge the

phones.

Universal charger is kind of charger that can charge any mobile battery by radio

waves & solar energy. This project gives us a resultant to save electricity & time for

waiting to charge it.

This is an instrument which is highly applicable for the travelling purpose. For

this energy source is available at any time.


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CHAPTER 2

BASICS OF SOLAR ENERGYSolar Energy is the energy received from the sun that sustains life on earth. For

many decades solar energy has been considered as a huge source of energy and also an

economical source of energy because it is freely available. However, it is only now after

years of research that technology has made it possible to harness solar energy.

Solar technologies are broadly characterized as either passive solar or active solar

depending on the way they capture, convert and distribute solar energy. Active solar

techniques include the use of photovoltaic panels and solar thermal collectors to harnessthe energy. Passive solar techniques include orienting a building to the Sun, selecting

materials with favorable thermal mass or light dispersing properties, and designing spaces

that naturally circulate air.

2.1 SOLAR PANEL

A solar cell (also called a photovoltaic cell) is an electrical device that converts

the energy of light directly into electricity by the photovoltaic effect. It is a form of

photoelectric cell (in that its electrical characteristics-- e.g. current, voltage, or

resistance-- vary when light is incident upon it) which, when exposed to light, can

generate and support an electric current without being attached to any external voltage

source.


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Fig.1:- Solar panel 12 volt.

The structural (load carrying) member of a module can either be the top layer

(superstrate) or the back layer (substrate). The majority of modules use wafer-

based crystalline silicon cells or a thin-film cell based on cadmium telluride or

silicon. Crystalline silicon, which is commonly used in the wafer form in photovoltaic

(PV) modules, is derived from silicon, a commonly used semi-conductor.

2.2 PHOTOVOLTAIC EFFECT

The photovoltaic effect is the creation of voltage or electric current in a material

upon exposure to light. Though the photovoltaic effect is directly related to the

photoelectric effect, they are different processes.

The photovoltaic effect is the basic physical process through which a PV cell

converts sunlight into electricity Sunlight is composed of photons--packets of solar

energy. These photons contain different amounts of energy that correspond to the

different wavelengths of the solar spectrum. When photons strike a PV cell, they may be

reflected or absorbed, or they may pass right through. The absorbed photons generate

electricity.


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Fig.2:-PHOTOVOLTAIC EFFECT

The energy of a photon is transferred to an electron in an atom of the semiconductor

device. With its newfound energy, the electron is able to escape from its normal position

associated with a single atom in the semiconductor to become part of the current in an

electrical circuit. Special electrical properties of the PV cell a built-in electric field

provide the voltage needed to drive the current through an external load.


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CHAPTER 3

RADIO WAVEES

Radio waves are a type of electromagnetic radiation with wavelengths in the

electromagnetic spectrum longer than infrared light. Radio waves have frequencies from

300 GHz to as low as 3 kHz, and corresponding wavelengths from 1 millimeter to 100

kilometers. Like all other electromagnetic waves, they travel at the speed of light.

Naturally occurring radio waves are made by lightning, or by astronomical objects.

Artificially generated radio waves are used for fixed and mobile radio communication,

broadcasting, radar and other navigation systems, communications satellites, computer

networks and innumerable other applications. Different frequencies of radio waves have

different propagation characteristics in the Earth's atmosphere; long waves may cover a

part of the Earth very consistently, shorter waves can reflect off the ionosphere and travel

around the world, and much shorter wavelengths bend or reflect very little and travel on a

line of sight.

3.1 RADIO SPECTRUM


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Radio spectrum refers to the part of the electromagnetic spectrum corresponding

to radio frequencies that is, frequencies lower than around 300 GHz (or, equivalently,

wavelengths longer than about 1 mm).

Different parts of the radio spectrum are used for different radio transmission

technologies and applications. Radio spectrum is typically government regulated in

developed countries and, in some cases, is sold or licensed to operators of private radio

transmission systems (for example, cellular telephone operators or broadcast television

stations). Ranges of allocated frequencies are often referred to by their provisioned use

(for example, cellular spectrum or television spectrum).

The National Frequency Allocation Plan (NFAP) forms the basis for development

and manufacturing of wireless equipment and spectrum utilization in the country.

Frequency bands allocated to various types of radio services in India are as follows.

i) 0-87.5 MHz is used for marine and aeronautical navigation, short and medium wave

radio, amateur (ham) radio and cordless phones.

ii) 87.5-108 MHz is used for FM radio broadcasts

iii) 109- 173 Used for Satellite communication, aeronautical navigation and outdoor

broadcast vans

iv) 174-230 MHz not allocated.

v) 230450 Used for Satellite communication, aeronautical navigation and outdoor

broadcast vans

vi) 450- 585. Not allocated.

vii) 585-698 Used for TV broadcast

viii) 698-806 not allocated.

ix) 806-960 Used by GSM and CDMA mobile services

x) 960-1710 Aeronautical and space communication

xi) 1710- 1930 Used for GSM mobile services

xii) 1930-2010 Used by defence forces

xiii) 2010-2025 Not allocated

xiv) 2025-2110 Satellite and space communications

xv) 2110-2170 Not allocated

xvi) 2170-2300 Satellite and space communications


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xvii) 2300-2400 not allocated.

xviii) 2400- 2483.5 Used for Wi-Fi and Bluetooth short range services

xix) 2483.5-3300 Space communications

xx) 3300-3600 not allocated.

xxi) 3600-10000 Space research, radio navigation

xxii) 10000 used for satellite downlink for broadcast and DTH services

CHAPER 4

CIRCUITT DIAGRAM

4.1 SOLAR PANEL

Fig 3-CIRCUIT DIAGRAM FOR SOLAR PANEL


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4.2 Working

Here is solar charger circuit that is used to charge Lead Acid or Ni-Cd batteries

using solar energy power. The circuit harvests solar energy to charge a 6 volt 4.5Ah

rechargeable battery for various applications. The charger has voltage & currentregulation & over voltage cut off facilities.

The circuit uses a 12V solar panel & variable voltage regulator IC LM317. The

solar panel consists of solar rated 1.2V. 12V DC is available from the solar panel to

charge the battery. Charging current passes through D1 to the voltage regulator IC

LM317. By adjusting its adjust pin, output voltage & current can be regulated.

Voltage regulator is placed between the adjust pin & ground to provide tan output

voltage of 9V to the battery. Resistor R3 restricts charging current & diode D2 o prevent

discharge of current from the battery. Transistor T1 & zener diode ZD acts as a cut-off

switch when battery is full. Normally T1 is off & battery gets charging current.

When terminal voltage of battery rises above 6.8V, zener diode conducts &

provides base current to T1. It is then turn on grounding the output of LM317 to stop

charging.

IC LM317

Fig 4- IC LM 317


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LM 317 is the three-terminal positive voltage regulator. The different grades of regulator

in the series are available with output voltage of 1.2V to 57V & output current from

0.10A to 1.5A.The LM317 series regulators are available in standard transistor packages

that are easily mounted & handle.

This IC LM317 having three terminals , the terminals are Vin, Vout, &

adjustment. LM 317requires only 2 external resistors to set output voltage.LM 317

develop nominal 1.25V referred to as the reference voltage Vref, between the output &

adjustment terminal. This referred voltage is appears across R1 resistor & since the

voltage is constant, the current I1 is also constant for a given value of R1 Because of

resistor R1 sets current I1. It is called current set or programmed resistor. In addition to

current I1, the current Iadj also flow from the adjustment terminal also flows through the

The output of LM 317 is

Vo=R1.I1+R2(I1+ Iadj) -----(1)

Where,

I1= Vref/R1

R1= Current (I1) set resistor

R2=output (Vo) set resistor

Iadj= adjustment pin current

Substituting the value of\\\i1 in equation 1 & rearranging, we get substituting the

value of I1 in equation 1 & rearranging, we get

Vo=vref(1=R2/R1)+Iadj*R2

Where

Vref= 1.25 (Referance voltage between output & input terminal)

Iadj= 100 micro ampere (It is very small & can be neglected)

Vo=1.25(1+R!/R2)


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4.3 RADIO FREQUENCY

THE CHARGE PUMP

A charge pump is a circuit that when given an input in AC is able to output a DC

voltage typically larger than a simple rectifier would generate. It can be thought of as a

AC to DC converter that both rectifies the AC signal and elevates the DC level.

4.4 VOLTAGE DOUBLER

The charge pump circuit is made of stages of voltage doublers. This circuit is

called a voltage doubler because in theory, the voltage that is received on the output is

twice that at the input.

Fig 4:- Voltage Double Schematic

The schematic in Figure 3.5 represents one stage of the circuit. The RF wave is rectified

by D2 and C2 in the positive half of the cycle, and then by D1 and C1 in the negative

cycle. But, during the positive half-cycle, the voltage stored on C1 from the negative

half-cycle is transferred to C2. Thus, the voltage on C2 is roughly two times the peak

voltage of the RF source minus the turn-on voltage of the diode, hence the name voltage

doubler.

4.5 OUTPUT OF VOLTAGE DOUBLER

The output is not exactly DC. Ii is AC signal with a DC offset. This is

equivalent to saying the DC signal contains noise. This can be seen in

Figure 3.6. This is where the other stages come in. If a second stage is


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added on top of the first, the only wave that the second stage sees is

the noise of the first stage. This noise is then doubled and added to the

DC of the first stage. Therefore, the more stages that are added,

theoretically, more voltage will come from the system irregardless of

the input.

Fig 5:- Voltage Doubler Waveform

Each independent stage, with its dedicated voltage doubler circuit, can be seen as a

battery with open circuit output voltage VO and internal resistance RO. When n of these

circuits are put in series and connected to a load of RL, the output voltage will be given by

Equation


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4.6 NUMBER OF STAGES

FIG 6:-VOLTAGE DOUBLER WITH OUTPUT CAPACITANCE

The number of stages is essentially directly proportional to the amount of voltage

obtained at the output of the system. Generally, the voltage of the output increases as the

number of stages increases.

4.6.1 STAGE CAPACITANCE

Minimal changing of the capacitance will have a drastic effect on the output

voltage. There are a couple of different values that can be used for the capacitance. The

first, is to keep all the values in all the stages the same. A second way is to gradually

decrease the value of the stage capacitors as the number of stages increases. Each stage

uses two capacitors, and those are kept the same, but the change is made from one stage

to the next. If the first stage uses 100pF capacitors, then the next stage would use 50Pf.

4.6.2 OUTPUT CAPACITANCE


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The value of this capacitor only affects the speed of the transient response. The

bigger the value for the output capacitance, the slower the voltage rise time. Without a

capacitor there, the output is not a good DC signal, but more of an offset AC signal,

meaning that it will be DC with ripple.

4.6.3 ALTERNATIVE CHARGE PUMP

A popular charge pump, due to Dickson has the configuration shown in

Figure 7. This circuit uses two complementary phase clocks to multiply the input

Voltage.

FIG 7:-DICKSON CHARGE PUMP


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FIG 8:-DICKSON CHARGE PUMP INPUT & OUTPUT

CHAPTER 5

FUTURE WORK

Material purchasing.

Implementation of circuits.

Combining both circuits.

Interfacing with cellphone.


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CHAPTER 6

APPROXIMATE COSTING

Main parts

Solar panel-1400/-

RF receiver-800/-

Tools and hardware-1000/-

Total estimate cost-3200/-


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CHAPTER 7

ADVANTAGES AND DISADVANTAGES

ADVANTAGES

Utilization of non conventional energy (solar energy). Low maintenance.

Portable.

As radio waves available at everywhere charging can be done at any time.

DISADVANTAGES

Cost is high (solar panel).

Charger may not work properly in rainy days.

For radio waves efficiency may get decrease in village areas.

Impedance matching affects the circuit.

APPLICATIONS


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Use for most cell phone models.

Also for small digital electronics (PDA, MP3, Digital Camera,).

Charging of rechargeable batteries.

CHAPTER 8

CONCLUSION

In world in which millions of people have mobile phones but lack access to the

electricity, it is even more important to develop charging solution.

This device can be used widely where peoples are suffering from the problem of

electricity, load shedding & power cut off. This device uses non conventional energy

therefore it is beneficial for the environment.


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CHAPPTER 9

REFRENCES

1. Electroschematics.com

2. WIRELESS BATTERY CHARGING SYSTEM USING RADIO FREQUENCY

ENERGY HARVESTING by Daniel W. Harrist BS, University of Pittsburgh.

3. RF TO DC POWER GENERATION, Juventino Delfino Rosas Espejel, Master

of Science, 2003by: Professor Robert Wayne Newcomb Department of Electrical

& Computer Engineering.


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