DESIGN & IMPLEMENTATION OF A MOBILE
PHONECHARGING SYSTEM BASED ON SOLAR ENERGY
HARVESTING
ABSTRACT
The ability to harvest energy from the environment represents an important
technology area that promises to eliminate wires and battery maintenance for many important
applications and permits deploying self powered devices. This paper suggests the use of a solar
and wind energy harvester to charge mobile phone devices. In the beginning, a comprehensive
overview to the energy harvesting concept and technologies is presented. Then the design
procedure of our energy harvester was detailed. Our prototype solar energy harvester proves its
efficiency to charge the aimed batteries under sunlight or an indoor artificial light. Solar energy
harvesting devices use photovoltaic (PV) cells to convert incident light into electricity. As such,
they leverage the extensive investments made and progress achieved in increasing the efficiency
and reducing the cost of PV for building- and utility-scale power. wind energy that is converted
into electrical energy by a wind turbine. wind turbine converts kinetic energy from the wind into
electrical energy.
INTRODUCTION
Energy harvesting devices can harvest different kinds of energy, including radio
frequency, solar, thermal, and vibration. In addition, a single device can harvest energy from
multiple ambient energy sources. Radio frequency (RF) devices harvest electromagnetic
radiation emitted by radio devices, such as wireless radio networks. As the most commonly used
frequencies are well known, the devices have an antenna and circuitry tuned to maximize energy
harvesting at these frequencies. Unfortunately, typical electric field strengths are weak (unless
located close to sources), which severely limits the quantity of energy that can be harvested, e.g.,
to approximately two orders of magnitude less than indoor solar and thermoelectric devices.
Active systems attempt to overcome this limit by broadcasting RF energy, as is done currently
for RFID tags used in commerce. Thermoelectric [TE] devices harvest energy developed from
temperature differences via the Seebeck effect, i.e., a temperature difference at the junction of
two metals or semiconductors causes current to flow across the junction. The power density of
TE increases with the temperature difference increasing their attractiveness in applications such
as sun/shade installations, compressors, and hot/cold/air/water/refrigerant flows. Vibration
harvesters extract energy from ambient vibrations. As power usually scales with the cube of
vibration frequency and the square of vibration amplitude, these devices have the most value in
applications with high frequency, high-amplitude vibrations[3] Thus, potentially promising
vibration sources could include compressors, motors, pumps, blowers, and, perhaps to a lesser
extent, fans and ducts. All vibration-harvesting systems contain mechanical elements that
vibrate, typically a spring-mass assembly with its natural frequency close to those of the
vibration source to maximize energetic coupling between the vibration source and the harvesting
system. Several different ways exist to translate the vibrating elements into electric energy,
including piezoelectric, capacitive, and inductive systems. Solar energy harvesting devices use
photovoltaic (PV) cells to convert incident light into electricity. As such, they leverage the
extensive investments made and progress achieved in increasing the efficiency and reducing the
cost of PV for building- and utility-scale power. Solar devices can produce energy from both
outdoor and indoor light sources, although outdoor insulation levels yield approximately two to
three orders of magnitude more electricity per unit area than indoor electric light sources.
Relative to other sources, solar devices can achieve high energy densities when used in direct
sun, but will not function in areas without light (e.g., highly shaded areas, ducts). Applications to
date include contact and motion sensors for building applications, as well as calculators, PDAs,
and wristwatches. Table 1 shows the power generation potential of several energy harvesting
modalities. While a wide variety of harvesting modalities are now feasible, solar energy
harvesting through photo-voltaic conversion provides the highest power density, which makes it
the modality of choice to power an embedded system that consumes several mW using a
reasonably small harvesting module.
TABLE 1 .POWER DENSITIES OF HARVESTING TECHNOLOGIES
HARVESTING TECHNOLOGIES
Solar cells (outdoor at noon)
Piezoelectric (shoe inserts)
Vibration (Small microwave oven )
Thermoelectric (10 0 gradient)
Acoustic noise (100 db)
POWER DENSITY
15mW/cm2
330µW/ cm3
116 µW/ cm3
40 µW/ cm3
900n W/ cm3
EXISTING SYSTEM
The previous work focus on using solar cell energy harvesting in providing an alternative
power source to charge mobile phone devices. The paper focus on using solar cell energy
harvesting in providing an alternative power source to charge mobile phone devices. Previous
works in this field. A solar harvesting augmented high-end embedded system was switch matrix
was used to power individual system components from either the solar panel or the battery.
Harvesting aware protocols have also been proposed for data routing and distributed
performance scaling. Solar energy harvesting devices use photovoltaic (PV) cells to convert
incident light into electricity. As such, they leverage the extensive investments made and
progress achieved in increasing the efficiency and reducing the cost of PV for building- and
utility-scale power.
DISADVANTAGES

Under direct sunlight, it possible to charge an empty battery using the necessary
number of parallel solar cells.

Cost is high.
PROPOSED SYSTEM
In the present work we are using solar panel and wind energy to charge the mobile phone.
The power generation using renewable energy sources gained more attraction. The most
commonly available and used energy resources are solar and wind. Solar energy harvesting
devices use photovoltaic (PV) cells to convert incident light into electricity. As such, they
leverage the extensive investments made and progress achieved in increasing the efficiency and
reducing the cost of PV for building- and utility-scale power. wind energy that is converted into
electrical energy by a wind turbine. wind turbine converts kinetic energy from the wind into
electrical energy.
ADVANTAGES

It’s a clean fuel source

Cost effective

Sustainable

It doesn’t pollute the air

It doesn’t produce atmospheric emissions that cause acid rain or greenhouse gases.
CHAPTER 1
LITERATURE SURVEY
Overview of Energy Harvesting Systems
In Authors
G.
Park ”Overview of Energy Harvesting Systems (for Low-Power
Electronics).” Presentation at the First Los Alamos National Laboratory Engineering Institute
Workshop: Energy Harvesting, 2005 . This chapter presents a literature review about the various
ambient energy sources that can be harvested and the description of some related systems. As
such, this chapter will provide a brief overview about each source and describe some systems that
use that same energy source. This will be extended on to the domain of the wireless sensor
networks and the aspects related to it, being presented some examples of energy harvesting
powered WSN in different environments. A brief description of what is expected from each
network and how it succeeds in harvesting the energy that enables it to work will receive a
particular focus. Since light is the energy source being harvested, in order to power the system
described in this book, some more attention will be dedicated to the analysis of this source.
Proceeding with this purpose, a more detailed overview about PV technologies. In addition, a
more focused insight covering DC–DC converters, energy storing devices, and MPPT techniques.
Solar power for Wireless Sensor Networks in
Environment Monitoring
Application
In Authors T. Voigt, H. Ritter, and J. Schiller, “Utilizing solar power in wireless sensor
networks”, Proc. IEEE Conference on Local Computer Networks, 2003. Routing in Wireless
Sensor Networks has to take into account the limited battery resources of the nodes. Sensor
nodes can also be powered by other energy sources like solar energy. This paper provides a
review of Environment monitoring using Wireless Sensor Networks. The issues
environment sensor networks is highlighted. The real time applications
related to
in environment
monitoring is presented with emphasis on energy conservation. Furthermore in this paper we
address the problem of scavenging energy using solar powered devices.
Power Utility Maximization for Multiple-Supply Systems by a Load-Matching
Switch
In Authors C. Park and P. Chou , “Power utility maximization for multiple-supply
systems by a load-matching switch”, Proc. ACM/IEEE International Symposium on Low Power
Electronics and Design, pp. 168–173, 2004. For embedded systems that rely on multiple power
sources (MPS) power management must distribute the power by matching the supply and
demand in conjunction with the traditional power management tasks. Proper load matching is
especially critical for renewable power sources such as solar panels and wind generators, because
it directly affects the utility of the available power. This paper proposes a power distribution
switch and a source-consumption matching algorithm that maximizes the total utility of the
available power from these ambient power sources. Our method yields over 30% more usable
power than conventional MPS designs.
Energy Scavenging for Wireless Sensor Nodes with a Focus on Vibration to
Electricity Conversion
In Authors S. Roundy “Energy scavenging for wireless sensor nodes with a focus on
vibration-to-electricity conversion.” Presentation at University of California, Berkeley.
http://tinyurl.com/2s8khk, 2003. The vast reduction in size and power consumption of CMOS
circuitry has led to a large research effort based around the vision of ubiquitous networks of
wireless communication nodes. As the networks, which are usually designed to run on batteries,
increase in number and the devices decrease in size, the replacement of depleted batteries is not
practical. Methods of scavenging ambient power for use by low power wireless electronic
devices have been explored in an effort to make the wireless nodes and resulting wireless sensor
networks indefinitely self-contained. After a broad survey of potential energy scavenging
methods, the conversion of ambient vibrations to electricity was chosen as a method for further
research. Converters based on both piezoelectric and electrostatic (capacitive) coupling were
pursued. Both types of converters were carefully modeled. Designs were optimized based on the
models developed within total size constraint of1 cm3. Test results from the piezoelectric
converters demonstrate power densities of about 200 µW/cm3 from input vibrations of 2.25 m/s2
at 120 Hz. Furthermore, test results matched simulated outputs very closely thus verifying the
validity of the model as a basis for design. One of the piezoelectric converters was used to
completely power a small wireless sensor device from vibrations similar to those found in
common environments.
Electrostatic converters were designed for a category of MEMS
processes in which a structural MEMS device is patterned in the top layer of a Silicon on
Insulator (SOI) wafer. Simulation results show a maximum power density of 110µW/cm3 from
the same vibration source. Initial electrostatic converter prototypes were fabricated in a SOI
MEMS process. Prototypes have been tested and when manually actuated have demonstrated a
net electrical power increase due to mechanical work done on the converter. However, a fully
functional power generator driven by vibrations has yet to be demonstrated. Both theory and test
results demonstrate that piezoelectric converters are capable of higher power output densities
than electrostatic converters. However, because electrostatic converters are more easily
implemented in silicon micromachining processes they hold the future potential for complete
monolithic integration with silicon based sensors and microelectronics.
Perpetual Environmentally Powered Sensor Networks
In
Authors En Ocean. Perpetual International Edition4(6). http://tinyurl.com/2lxbo5
orwww.enocean.com/fileadmin/redaktion/pdf/perpetuum/perpetuum_06_en.pdf),2007.Environm
ental energy is an attractive power source for low power wireless sensor networks. We present
Prometheus, a system that intelligently manages energy transfer for perpetual operation without
human intervention or servicing. Combining positive attributes of different energy storage
elements and leveraging the intelligence of the microprocessor, we introduce an efficient multistage energy transfer system that reduces the common limitations of single energy storage
systems to achieve near perpetual operation. We present our design choices, tradeoffs, circuit
evaluations, performance analysis, and models. We discuss the relationships between system
components and identify optimal hardware choices to meet an application’s needs. Finally we
present our implementation of a real system that uses solar energy to power Berkeley’s Telos
Mote. Our analysis predicts the system will operate for 43 years under 1% load, 4 years under
10% load, and 1 year under 100% load. Our implementation uses a two stage storage system
consisting of super capacitors (primary buffer) and a lithium rechargeable battery (secondary
buffer). The mote has full knowledge of power levels and intelligently manages energy transfer
to maximize lifetime.
CHAPTER2
BLOCK DIAGRAM
CHAPTER 3
COMPONENTS DETAILS
SOLAR PANEL
A solar panel is a set of solar photovoltaic modules electrically connected and mounted on a
supporting structure. A photovoltaic module is a packaged, connected assembly of solar cells.
The solar panel can be used as a component of a larger photovoltaic system to generate and
supply electricity in commercial and residential applications.
WORKING PRINCIPLE
The working principle of all today solar cells is essentially the same. It is based on
the photovoltaic effect. In general, the photovoltaic effect means the generation of a potential
difference at the junction of two different materials in response to visible or other radiation.
The basic processes behind the photovoltaic effect are:
1. Generation of the charge carriers due to the absorption of photons in the materials that form a
junction
2. Subsequent separation of the photo-generated charge carriers in the junction
3. Collection of the photo-generated charge carriers at the terminals of the junction
SPECIFICATIONS

Typical Power: 15 W

Optimum operating voltage (Vmp): 17.6

Optimum operating current (Imp): 0.82

Short circuit current: 3.65

Dimensions: 12 x 15x 1 in.

Weight: 1.5Kg

Dimensions: 12x15x1 in.

Frame Material: Aluminum with plastic edge caps
CHARGE CONTROLLERS
Most stand-alone solar power systems will need a charge controller. The purpose of this is to
ensure that the battery is never overcharged, by diverting power away from it once it is fully
charged. Only if a very small solar panel such as a battery saver is used to charge a large battery
is it possible to do without a controller. Most charge controllers also incorporate a low-voltage
disconnect function, which prevents the battery from being damaged by being completely
discharged. It does this by switching off any DC appliances when the battery voltage falls
dangerously low.
HIGH VOLTAGE
SENSOR
CHARGE
CONTROLLER
BATTERY
LOW VOLTAGE
SENSOR
WORKING PRINCIPLE
The principle behind a solar charge controller is simple. There is a circuit to measure the battery
voltage, which operates a switch to divert power away from the battery when it is fully charged.
Because solar cells are not damaged by being short or open-circuits, either of these methods can
be used to stop power reaching the battery.
BATTERY
An electric battery is a collection of one or more electrochemical cells in which stored
chemical energy is converted into electrical energy. The principles of operation haven’t changed
much since the time of Volta. Each cell consists of two half cells connected in series through an
electrolytic solution. One half cell houses the Anode to which the positive ions migrate from
the Electrolyte and the other houses the Cathode to which the negative ones drift. The two cells
are may be connected via a semi permeable membranous structure allowing ions to flow but not
the mixing of electrolytes as in the case of most primary cells or in the same solution as in
secondary cells.
WORKING PRINCIPLE
The energy released during accepting an electron by a neutral atom is
known as electron affinity. As the atomic structure for different materials are different, the
electron affinity of different materials will differ. If two different kinds of metals or metallic
compounds are immersed in the same electrolyte solution, one of them will gain electrons and
the other will release electrons. Which metal (or metallic compound) will gain electrons and
which will lose them depends upon the electron affinities of these metals or metallic compounds.
The metal with low electron affinity will gain electrons from the negative ions of the electrolyte
solution. On the other hand, the metal with high electron affinity will release electrons and these
electrons come out into the electrolyte solution and are added to the positive ions of the solution.
In this way, one of these metals or compounds gains electrons and another one loses electrons.
As a result, there will be a difference in electron concentration between these two metals. This
difference of electron concentration causes an electrical potential difference to develop between the
metals. This electrical potential difference or emf can be utilized as a source of voltage in any electronics
or electrical circuit. This is a general and basic principle of battery .
BATTERY CONNECTION BLOCK DIAGRAM
SPECIFICATIONS
Nominal Voltage
12V
Internal Impedance
0.25 Ω
Charging Cut Off Voltage
13.3 V
Discharging Cut Off Voltage
10.5
Operating Temperature
charging
0oC ~ 45oC
discharging
-0oC ~ 55oC
Chemistry
Lead Acid
Capacity
7Ah
Rating Whr
84
Length
5.95 inches
Width
2.56 inches
Height
3.7 inches
Weight
1 Kg
INVERTER
A power inverter, or inverter, is an electronic device or circuitry that changes direct current (DC)
to alternating
current (AC).The
input voltage,
output
voltage
and
frequency,
and
overall power handling depend on the design of the specific device or circuitry. The inverter does
not produce any power; the power is provided by the DC source. A power inverter can be
entirely electronic or may be a combination of mechanical effects (such as a rotary apparatus)
and electronic circuitry. Static inverters do not use moving parts in the conversion process.
WORKING PRINCIPLE
The PWM inverter correct the output voltage according to the value of the
load connected at the output. This is accomplished by changing the width of the switching
frequency generated by the oscillator section. The AC voltage at the output depend on the width
of the switching pulse. The process is achieved by feed backing a part of the inverter output to
the PWM controller section (PWM controller IC).Based on this feedback voltage the PWM
controller will make necessary corrections in the pulse width of the switching pulse generated at
oscillator section. This change in the pulse width of the switching pulse will cancel the changes
in the output voltage and the inverter output will stay constant irrespective of the load variations.
SOLAR POWER SUPPLY BOARD MODULE
Working Types and History of Wind Turbine
How wind turbine works? We all are aware of wind energy that is converted into
electrical energy by a wind turbine. But it is very interesting how wind turbine converts kinetic
energy from the wind into electrical energy and what are the major parts of a wind turbine.
Major Parts of Wind Turbine
Tower of Wind Turbine
Tower is very crucial part of wind turbine that supports all the other parts. It is not only support
the parts but raise the wind turbine so that its blades safely clear the ground and so it can reach
the stronger winds at higher elevations. The height of tower depends upon the power capacity of
wind turbines. Larger turbines usually mounted on tower ranging from 40 meter to 100 meter.
Nacelle of Wind Turbine
Nacelle is big box that sits on the tower and house all the components in a wind turbine. It
houses Power Converter, Shaft, Gearbox, Generator, Turbine controller, Cables, Yaw drive.
Rotor Blades of Wind turbine
Blades are the mechanical part of wind turbine that converts wind kinetic energy into mechanical
energy. When the wind forces the blades to move, it transfers some of its energy to the shaft.
Blades are shaped like airplane wings blades can be as long as 150 feet.
Shaft of Wind Turbine
The shaft is connected to the rotor. When the rotor spins, the shaft spins as well. In this way, the
rotor transfers its mechanical, rotational energy to shaft which enters to an electrical generator on
the other end.
Gearbox
The rotor turns the shaft at low speed ex. 20 rpm but for generator to generate electricity we need
higher speed. Gearbox increases the speed to much higher value required by most generator to
produce electricity. For example, if Gearbox ratio is 1:80 and if rotor speed is 15 rpm then
gearbox will increase the speed to 15 × 80 = 1200 rpm that is given to generator shaft.
Generator
Generator is electrical device that converts mechanical energy received from shaft into electrical
energy. It works on electromagnetic induction to produce electrical voltage or electrical current. A
simple generator consists of magnets and a conductor. The conductor is typically a coiled wire.
Inside the generator shaft connects to an assembly of permanent magnets that surrounded by
magnets and one of those parts is rotating relative to the other, it induce the voltage in the
conductor. When the rotor spins to the shaft, the shaft spins the assembly of magnets and
generate voltage in the coil of wire.
Power Converter
Because wind is not always constant so electrical potential generated from generator is not
constant but we need a very stable voltage to feed the grid. Power converter is an electrical
device that stabilizes the output alternating voltage transferred to the grid.
Turbine Controller
Turbine controller is a computer (PLC) that controls the entire turbine. It starts and stops the
turbine and runs self diagnostic in case of any error in the turbine.
Anemometer
It measures the wind speed and passes the speed information to PLC to control the turbine
power.
Wind Vane
It senses the direction of wind and passes the direction to PLC then PLC faces the blades in such
a way that it cuts the maximum wind.
Pitch Drive
Pitch drive motors control the angle of blades whenever wind changes it rotates the angle of
blades to cut the maximum wind, which is called pitching of blades.
Yaw Drive
Blades and other components in wind turbine is housed in Nacelle , whenever any change in
wind direction is there Nacelle has to move in the direction of wind to extract the maximum
energy from wind. For this purpose yaw drive motor are used to rotate the nacelle .It is
controlled by PLC that uses the wind vane information to sense the wind direction.
Working of Wind Turbine
When the wind strikes the rotor blades, blades start to rotating. Rotor is directly
connected to high speed gearbox. Gearbox converts the rotor rotation into high speed which
rotates the electrical generator.
An exciter is needed to give the required excitation to the coil so that it can generate required
voltage. The exciter current is controlled by a turbine controller which senses the wind speed
based on that it calculate the power what we can achieve at that particular wind speed. Then
output voltage of electrical generator is given to a rectifier and rectifier output is given to line
converter unit to stabilities the output ac that is feed to the grid by a high voltage transformer. An
extra units is used to give the power to internal auxiliaries of wind turbine (like motor, battery
etc.), this is called Internal Supply unit. ISU can take the power from grid as well as from wind.
Chopper is used to dissipate extra energy from the RU for safety purpose. Internal Block diagram
of wind turbine
Types of Wind Turbine
There are generally two kinds of wind turbines. Horizontal axis and vertical axis. Horizontal axis
is divided as upwind and downwind whereas vertical axis is divided as a drag based and lift
based as shown in below.

Horizontal Axis Wind Turbine or HAWT – Up wind

Horizontal Axis Wind Turbine or HAWT – Down wind

Vertical Axis Wind Turbine or VAWT – Drag based

Vertical Axis Wind Turbine or VAWT – Lift based
In Horizontal Axis Up Wind turbine, the shaft of turbine and alternator both are aligned
horizontally and the turbine blades are placed at the front of the turbine that means air strikes the
turbine blades before the tower. In the case of Vertical Axis Down Wind turbine the shafts of the
rotor and generator are also placed horizontally but turbine blades are placed after the turbine
that means the wind strikes the tower before the blades.
If we observe VAWT drag based turbine, the generator shaft is located vertically with the blades
positioning up and the turbines are normally mounted on the ground or on a tiny tower. This type
is also called the Savonius turbine, after its inventor, S.I. Savonius. In the case of VAWT lift
based turbine, the generator shaft is placed vertically with the blade's position is up. Now days
Horizontal axis wind turbines are most popular because of high efficiency. Since the blades
always move perpendicularly to the wind, and receive power through the whole rotation.
History of Wind Turbine
Using wind energy is not a new concept. It was being using from long past but for
different purposes other than producing electricity. It was long before invention of electricity, the
Chinese and Persian people used windmill for pumping water, breaking up grain and sawing
lumber etc. It was long before invention of electricity. There are mainly two types of wind
turbine, namely vertical axis and horizontal axis turbine. The first wind turbine was designed as
vertical axis where a number of sails attached around the vertical axes produce ration of rotor
along the vertical axis of the system. The figure below shows a very old design of vertical axis
wind turbine.
After that horizontal axis wind mill was designed in the British Isles, Northern Europe.
Horizontal axis wind mills were most popularly utilized in Holland in 14th century. These
windmills carried out lots of tasks for example timber milling, pumping water for farming etc.
Netherlands is another European country which utilized windmill popularly at that time.
In the late 19th century in the American mid-west farmers came to put your faith in a leaner
design characteristic a trestle tower topped by wooden or steel paddle-type blades. Between 1850
and 1970, more than six million mostly small means 1 horsepower or less mechanical output
wind turbines were installed in the U.S. only and the most important use was water-pumping and
the major purpose were store water for home water needs. In 1891 Danish meteorologist, Poul
La Cour designed an electrical output wind turbine replicating the aerodynamic design principles
that were used in European tower mills. In Denmark, 1900 the biggest machines were on 24
meter (79 ft) tower with four-bladed 23 meter (75 ft) diameter rotors and generating 30 MW. In
the 1920s, wind generated electrical systems began to follow the design of airplane propellers
and monoplane wings. In 1950’s the world’s first alternating current wind turbines comes in the
picture and credit goes to Johannes Juul, he is the best student of Paul La Cour (great scientist
and known as his work on wind power). After that John Brown & Company in 1951, developed
a first convenience grid-connected wind turbine which operated in the UK (United Kingdom).
An over view about wind turbines. The figure given below contains some components of wind
turbines.
Aurdino
Audio is an open-source electronics prototyping platform based on flexible, easy-to use
hardware and software. It’s intended for artists, designers, hobbyists, and anyone interested in creating
interactive objects or environments. Aurdino can sense the environment by receiving input from a
variety of sensors and can affect its surroundings by controlling lights, motors, and other actuators. The
microcontroller on the board is programmed using the Aurdino programming language and the Aurdino
Development Environment. Aurdino projects can be stand-alone, or they can communicate with
software running on a computer.
There are plenty of other microcontrollers available. So you may be asking, why choose the Audio?
Aurdino really simplifies the process of building projects on a microcontroller making it a great
platform for amateurs. You can easily start working on one with no previous electronics experience.
That is what this Aurdino guide is about.
In addition to Aurdino’s simplicity, it is also inexpensive, cross-platform and open source.
The Aurdino is based on Atmel’s ATMEGA8 and ATMEGA168 microcontrollers. The plans for the
modules are published under a Creative Commons license, so experienced hobbyists and professionals
can make their own version of the Aurdino, extending it and improving it.
Believe it or not, even relatively inexperienced users can build a version of the Audio module on a
breadboard in order to understand how it works and save a little bit of money.
What Can You Do With an Audio?
There is a lot you can do with an Audio. An Audio can basically do anything by interfacing sensors
with a computer. This would allow you to take any sensor and have any action applied with the
readings. For example (in one of our projects) we will read the level of light in a room and adjust an
LED’s brightness to react based on that input. This of course is a simple example of what you can do
with an Audio. A more complicated example would be to read from multiple sensors and use that data
to affect other outputs. Think of the possibility of wiring your house with all sorts of different sensors
(photocells, oxygen sensors, thermometers) and having it adjust your blinds, air conditioner and
furnace and make your house a more comfortable place.Hackers have used Arduinos to create some
amazing electronics projects. Things like:
Robots
Breathalyzers
Remote controlled cars
3d printers
Video games
Home automation systems
What Is Inside an Aurdino?
Although there are many different types of Arduino boards available, this manual focuses on the
Arduino Uno. This is the most popular Arduino board around. So what makes this thing tick? Here are
the specifications:
Processor: 16 Mhz ATmega328
Flash memory: 32 KB
Ram: 2kb
Operating Voltage: 5V
Input Voltage: 7-12 V
Number of analog inputs: 6
Number of digital I/O: 14 (6 of them pwm)
The specs may seem meager compared to your desktop computer, but remember that the
Arduino is an embedded device. We have a lot less to process than your desktop.Another wonderful
feature of the Arduino is the ability to use what are called “Shields”. Although we will not be covering
shields in this manual, an Arduino shield will give you crazy functionality like you wouldn’t believe.
Check out this list of some really cool Arduino shields to take your projects to the next level. The Top
4 Arduino Shields To Superpower Your Projects The Top 4 Arduino Shields To Superpower Your
Projects You’ve bought an Arduino starter kit, you’ve followed all the basic guides, but now you’ve hit
a stumbling block - you need more bits and bobs to realise your electronics dream. Luckily, if you have
What You Will Need For This Guide
Below you will find a shopping list of the components we will use for this manual. All these
components should come in under $50.00 USD. This listing should be enough to give you a good
understanding of basic electronics and have enough components to build some pretty cool projects
using this or any other Arduino guide.
1x Arduino Uno Microcontroller
1 x USB A-B Cable (same as your printer takes)
1x Breadboard
2 x LEDs
1 x Photo Resistor
1 x Tactile Switch
1 x Piezo Speaker
1 x 10 k-Ohm Resistors
1 x 2 k-Ohm Resistors
2 x 1 K-Ohm Resistors
1 x Jumper Wire Kit
Electrical Component Overview
What is a Breadboard?
Breadboards are blocks of plastic with holes into which wires can be inserted. The
holes are connected electrically, so that wires stuck in the connected holes are also connected
electrically. The connected holes are arranged in rows, in groups of five, so that up to five parts can be
quickly connected just by plugging their leads into connected holes in the breadboard. When you want
to rearrange a circuit, just pull the wire or part out of the hole, and move it or replace it. The
breadboard I recommended also includes power and ground lanes on each side for easy power
management.
What is an LED?
An LED, short for Light Emitting Diode, is a semiconductor light source. LEDs are
typically used as visual indicators. For instance, your new Arduino microcontroller has an LED on pin
13 that we frequently use to indicate an action or event.
5.3 What is a Photo Resistor?
A photo resistor allows us to measure light by decreasing its resistance when it detects an increase of
light intensity.
5.4 What is a Tactile Switch?
A tactile switch is an electric switch that controls the flow of electricity. When pressed, the switch
completes the circuit. Basically, it is a button.
5.5 What is a Piezo Speaker?
A piezo speaker is a single frequency beeper that converts an electrical signal into
a tone. This will allow your Arduino to sing to you.
5.6 What is a Resistor?
A resistor is an electrical component that limits or regulates the flow of electricity.
5.7 What are Jumper Wires?
Jumper wires are short wires that are used for prototyping circuits. These are what
you will use to connect the various components electrically to your Arduino.
Mobile Cell phone Battery Charging
A mobile battery charger circuit is a device that can automatically recharge a mobile phone’s
battery when the power in it gets low. Nowadays mobile phones have become an integral part of
everyone’s life and hence require frequent charging of battery owing to longer duration usage.
Battery chargers come as simple, trickle, timer based, intelligent, universal battery chargeranalyzers, fast, pulse, inductive, USB based, solar chargers and motion powered chargers. These
battery chargers also vary depending on the applications like mobile phone charger, battery
charger for vehicles, electric vehicle batteries chargers and charge stations.
Charging methods are classified into two categories: fast charge method and slow charge
method. Fast charge is a system used to recharge a battery in about two hours or less than this,
and the slow charge is a system used to recharge a battery throughout the night. Slow charging is
advantageous as it does not require any charge detection circuit. Moreover, it is cheap as well.
The only drawback of this charging system is that it takes maximum time to recharge a battery.
Auto-Turn off Battery Charger
The aim of this project is to automatically disconnect a battery from the mains when the battery
gets fully charged. This system can be used to charge partially discharged cells as well. The
circuit is simple and consists of AC-DC converter, relay drivers and charge stations.
Mobile Battery Charger Circuit
Circuit Description
In an AC-DC converter section, the transformer step-downs the available AC
supply to 9v AC at 75omA which is rectified by using a full wave rectifier, and then filtered by
the capacitor. The 12v DC charging voltage is provided by the regulator and when the switch S1
is pressed, the charger starts working and the power on LED glows to indicate the charger is
‘on’. The relay driver section consists of PNP transistors to energize the electromagnetic relay.
This relay is connected to the collector of first transistor and it is driven by a second PNP
transistor which in turn is driven by the PNP transistor. In the charging section, regulator IC is
biased to give about 7.35V. To adjust the bias voltage, preset VR1 is used. A D6 diode is
connected between the output of the IC and a limiting output voltage of the battery up to 6.7V is
used for charging the battery. When the Switch is pushed, it latches relay and starts charging the
battery. As the voltage per cell increases beyond 1.3V, the voltage drop starts decreasing at R4.
When the voltage falls below 650 mV, then the T3 transistor cuts off and drives to T2 transistor
and in turn cuts off transistor T3. As a result, relay RL1 gets de-energized to cut off the charger
and red LED1 is turned off. The charging voltage, depending on the NiCd cell, can be
determined with the specifications provided by the manufacturer. The charging voltage is set at
7.35V for four 1.5V cells. Currently 700mAH cells, which can be charged at 70 mA for ten
hours, are available in the market. The voltage of the open circuit is about 1.3V.The shut-off
voltage point is determined by charging the four cells fully (at 70 mA for fourteen hours) and
adding the diode drop (up to 0.65V) after measuring the voltage and bias LM317 accordingly. In
addition to the above simple circuit, the real time implementation of this circuit based on the
solar power projects are discussed below.
Solar Power Charge Controller
The main objective of this solar power charge controller project is to charge a battery
by using solar panels. This project deals with a mechanism of charge controlling that will also do
over charge, deep discharge and under voltage protection of the battery. In this system, by using
photo voltaic cells, solar energy is converted into electrical energy.
Solar Power Charge Controller
This project comprises hardware components like solar panel, Op-amps, MOSFET, diodes,
LEDs, potentiometer and battery. Solar panels are used to convert sun light energy into electrical
energy. This energy is stored in a battery during day time and makes use of it during night time.
A set of OP-AMPS are used as comparators for monitoring of panel voltage and lead current
continuously.
LEDS are used as indicators and by glowing green, indicates the battery as fully charged.
Similarly, if the battery is under charged or over loaded, they glow red LED. The Charge
controller makes use of MOSFET – a power semiconductor switch to cutoff the load when the
battery is low or in overload condition. A transistor is used to bypass the solar energy into a
dummy load when the battery is fully charged and it protects the battery from getting over
charged.
Microcontroller Based Photovoltaic MPPT Charge Controller
The aim of this project is to design a charge controller with a maximum power point tracking
based on a microcontroller.
The major components used in this project are solar panel, battery, inverter, wireless transceiver,
LCD, current sensor and temperature sensor. The power from the solar panels is fed to the charge
controller which is then given as output into battery and is allowed for energy storage. The
output of the battery is connected to an inverter that provides outlets for the user to access the
stored energy.
The solar panel, battery and inverter are bought as the off shell parts while the MPPT charge
controller is designed and built by solar knights. A LCD screen is provided for displaying storage
power and other alert messages. The output voltage is varied by pulse width modulation from the
microcontroller to MOSFET drivers. The way to track a maximum power point by using MPPT
algorithm implementation in controller ensures that the battery is charged at maximum power
from the solar panel.
This is how one can make one’s own battery charger for the mobile phones. The two examples
mentioned here can make the process easier for you. Moreover, if you have any doubts and need
help for implementing real-time projects and industrial battery charger circuits, you can
comment in the comment section below.
Photo Credits
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Mobile Battery Charger Circuit by ggpht

Photovoltaic MPPT Charge Controller by eecs
Mobile Phones – Principle of operation
A cellular/mobile system provides standard telephone operation by full-duplex two-way
radio at remote locations. It provides a wireless connection to the Public Switched Telephone
Network (PSTN) from any user location within the radio range of the system.
The basic concept behind the cellular radio system is that rather than serving a given
geographical area within a single transmitter and receiver, the system divides the service area
into many small areas known as cells, as shown in Fig. below. The typical cell covers only
several square kilometers and contains its own receiver and low-power transmitter. The cell area
shown in Fig. below is ideal hexagon. However, in reality they will have circular or other
geometric shapes. These areas may overlap, and cells may be of different sizes.
Basic cellular system consists of mobile stations, base stations and a mobile switching center
(MSC). The MSC is also known as Mobile Telephone Switching Office (MTSO). The MTSO
controls ’11 the cells and provides the interface between each cell and the main telephone office.
Each mobile communicates via radio with one of the base stations and may be handed off
(switched from one cell to another) to any other base station throughout the duration of the call.
Each mobile station consists of a transceiver, an antenna and control circuitry. The base station
consists of several transmitters and receivers which simultaneously handle full duplex
communication and generally have towers which support several transmitting and receiving
antennas. The base station serves as a bridge between all mobile users in the cell and connects
the simultaneous mobile calls via telephone lines or microwave link to the MSC. The MSC coordinates the activities of all the base stations and connects the entire cellular system to the
PSTN, most of the cellular system also provide a service known as roaming.
The cellular system operates in the 800-900 MHz range. The newer digital cellular systems have
even greater capacity. Some of these systems operate in 1.7-1.8 GHz bands.
Cellular Telephone Unit
The block diagram of a cellular mobile radio unit. The unit consists of five major sections:
Transmitter, receiver, synthesizer, logic unit, and control unit. The mobile unit contains built-in
rechargeable batteries to Provide operating power. The transmitter and receiver in the unit share
the common antenna.
CHAPTER4
CONCLUSION
This paper suggests the use of a solar energy and wind energy harvester in mobile phone
devices. The following remarks could be extracted from the current work:
1. It is possible to use solar energy to supply mobile phones batteries with the necessary power.
2. Indoor artificial light could be used to enhance the charge of the battery.
3. Our design was implemented using simple and cost effective circuit.