The document provides an overview of embedded systems, including their definition, characteristics, and application areas. Some key points: - Embedded systems are computing devices that perform specific tasks, unlike general purpose computers. They have limited resources and fixed functionality. - Embedded systems are widely used in consumer electronics, industrial automation, medical devices, networking equipment, wireless technologies, testing/measurement, security, and finance. Nearly all processors are used in embedded systems. - The typical architecture of an embedded system includes a central processing unit, memory, input/output devices, communication interfaces, and application-specific circuitry running embedded software. Smaller systems may not require an operating system.

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CHAPTER-1
INTRODUCTION TO EMBEDDED SYSTEM
An embedded system can be defined as a computing device that does
a specific focused job. Appliances such as the air-conditioner, VCD player,
DVD player, printer, fax machine, mobile phone etc. are examples of
embedded systems. Each of these appliances will have a processor and
special hardware to meet the specific requirement of the application along
with the embedded software that is executed by the processor for meeting
that specific requirement. The embedded software is also called “firm
ware”. The desktop/laptop computer is a general purpose computer. You
can use it for a variety of applications such as playing games, word
processing, accounting, software development and so on. In contrast, the
software in the embedded systems is always fixed listed below:
· Embedded systems do a very specific task; they cannot be
programmed to do different things. . Embedded systems have very limited
resources, particularly the memory. Generally, they do not have secondary
storage devices such as the CDROM or the floppy disk. Embedded systems
have to work against some deadlines. A specific job has to be completed
within a specific time. In some embedded systems, called real-time systems,
the deadlines are stringent. Missing a deadline may cause a catastrophe-loss
of life or damage to property. Embedded systems are constrained for power.
As many embedded systems operate through a battery, the power
consumption has to be very low.
· Some embedded systems have to operate in extreme environmental
conditions such as very high temperatures and humidity.
1.1 Application Areas
Nearly 99 per cent of the processors manufactured end up in
embedded systems. The embedded system market is one of the highest
growth areas as these systems are used in very market segment- consumer

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electronics, office automation, industrial automation, biomedical
engineering, wireless communication, data communication,
telecommunications, transportation, military and so on.
1.2 Consumer appliances
At home we use a number of embedded systems which include
digital camera, digital diary, DVD player, electronic toys, microwave oven,
remote controls for TV and air-conditioner, VCO player, video game
consoles, video recorders etc. Today’s high-tech car has about 20 embedded
systems for transmission control, engine spark control, air-conditioning,
navigation etc. Even wristwatches are now becoming embedded systems.
The palmtops are powerful embedded systems using which we can carry
out many general-purpose tasks such as playing games and word
processing.
1.3 Office Automation
The office automation products using embedded systems are
copying machine, fax machine, key telephone, modem, printer, scanner etc.
1.4 Industrial Automation
Today a lot of industries use embedded systems for process control.
These include pharmaceutical, cement, sugar, oil exploration, nuclear
energy, electricity generation and transmission. The embedded systems for
industrial use are designed to carry out specific tasks such as monitoring the
temperature, pressure, humidity, voltage, current etc., and then take
appropriate action based on the monitored levels to control other devices or
to send information to a centralized monitoring station. In hazardous
industrial environment, where human presence has to be avoided, robots are
used, which are programmed to do specific jobs. The robots are now
becoming very powerful and carry out many interesting and complicated
tasks such as hardware assembly.

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1.5 Medical Electronics
Almost every medical equipment in the hospital is an embedded
system. These equipments include diagnostic aids such as ECG, EEG,
blood pressure measuring devices, X-ray scanners; equipment used in blood
analysis, radiation, colonoscopy, endoscopy etc. Developments in medical
electronics have paved way for more accurate diagnosis of diseases.
1.6 Computer Networking
Computer networking products such as bridges, routers, Integrated
Services Digital Networks (ISDN), Asynchronous Transfer Mode (ATM),
X.25 and frame relay switches are embedded systems which implement the
necessary data communication protocols. For example, a router
interconnects two networks. The two networks may be running different
protocol stacks. The router’s function is to obtain the data packets from
incoming pores, analyze the packets and send them towards the destination
after doing necessary protocol conversion. Most networking equipments,
other than the end systems (desktop computers) we use to access the
networks, are embedded systems.
1.7 Telecommunications
In the field of telecommunications, the embedded systems can be
categorized as subscriber terminals and network equipment. The subscriber
terminals such as key telephones, ISDN phones, terminal adapters, web
cameras are embedded systems. The network equipment includes
multiplexers, multiple access systems, Packet Assemblers Dissemblers
(PADs), sate11ite modems etc. IP phone, IP gateway, IP gatekeeper etc. are
the latest embedded systems that provide very low-cost voice
communication over the Internet.
1.8 Wireless Technologies
Advances in mobile communications are paving way for many
interesting applications using embedded systems. The mobile phone is one
of the marvels of the last decade of the 20’h century. It is a very powerful

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embedded system that provides voice communication while we are on the
move. The Personal Digital Assistants and the palmtops can now be used to
access multimedia service over the Internet. Mobile communication
infrastructure such as base station controllers, mobile switching centers are
also powerful embedded systems.
1.9 Insemination
Testing and measurement are the fundamental requirements in all
scientific and engineering activities. The measuring equipment we use in
laboratories to measure parameters such as weight, temperature, pressure,
humidity, voltage, current etc. are all embedded systems. Test equipment
such as oscilloscope, spectrum analyzer, logic analyzer, protocol analyzer,
radio communication test set etc. are embedded systems built around
powerful processors. Thank to miniaturization, the test and measuring
equipment are now becoming portable facilitating easy testing and
measurement in the field by field-personnel.
1.10 Security
Security of persons and information has always been a major issue.
We need to protect our homes and offices; and also the information we
transmit and store. Developing embedded systems for security applications
is one of the most lucrative businesses nowadays. Security devices at
homes, offices, airports etc. for authentication and verification are
embedded systems. Encryption devices are nearly 99 per cent of the
processors that are manufactured end up in~ embedded systems. Embedded
systems find applications in every industrial segment- consumer electronics,
transportation, avionics, biomedical engineering, manufacturing, process
control and industrial automation, data communication, telecommunication,
defence, security etc. Used to encrypt the data/voice being transmitted on
communication links such as telephone lines. Biometric systems using
fingerprint and face recognition are now being extensively used for user
authentication in banking applications as well as for access control in high
security buildings.

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1.11 Finance
Financial dealing through cash and cheques are now slowly paving
way for transactions using smart cards and ATM (Automatic Teller
Machine, also expanded as Any Time Money) machines. Smart card, of the
size of a credit card, has a small micro-controller and memory; and it
interacts with the smart card reader! ATM machine and acts as an electronic
wallet. Smart card technology has the capability of ushering in a cashless
society. Well, the list goes on. It is no exaggeration to say that eyes
wherever you go, you can see, or at least feel, the work of an embedded
system.
1.12 Overview of Embedded System Architecture
Every embedded system consists of custom-built hardware built
around a Central Processing Unit (CPU). This hardware also contains
memory chips onto which the software is loaded. The software residing on
the memory chip is also called the ‘firmware’. The embedded system
architecture can be represented as a layered architecture as shown in Fig.
The operating system runs above the hardware, and the application software
runs above the
FIG 1.1.LAYOUT ARCHITECTURE OF AN EMBEDDED SYSTEM
operating system. The same architecture is applicable to any computer
including a desktop computer. However, there are significant differences. It

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is not compulsory to have an operating system in every embedded system.
For small appliances such as remote control units, air conditioners, toys
etc., there is no need for an operating system and you can write only the
software specific to that application. For applications involving complex
processing, it is advisable to have an operating system. In such a case, you
need to integrate the application software with the operating system and
then transfer the entire software on to the memory chip. Once the software
is transferred to the memory chip, the software will continue to run for a
long time you don’t need to reload new software.
Now, let us see the details of the various building blocks of the
hardware of an embedded system. As shown in Fig. the building blocks are;
· Central Processing Unit (CPU)
· Memory (Read-only Memory and Random Access Memory)
· Input Devices
· Output devices
· Communication interfaces
· Application-specific circuitry
FIG 1.2.HARDWARE OF AN EMBEDDED SYSTEM

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1.13 Central Processing Unit (CPU)
The Central Processing Unit (processor, in short) can be any of the
following: microcontroller, microprocessor or Digital Signal Processor
(DSP). A micro-controller is a low-cost processor. Its main attraction is that
on the chip itself, there will be many other components such as memory,
serial communication interface, analog-to digital converter etc. So, for
small applications, a micro-controller is the best choice as the number of
external components required will be very less. On the other hand,
microprocessors are more powerful, but you need to use many external
components with them. D5P is used mainly for applications in which signal
processing is involved such as audio and video processing.
1.14 Memory
The memory is categorized as Random Access 11emory (RAM) and
Read Only Memory (ROM). The contents of the RAM will be erased if
power is switched off to the chip, whereas ROM retains the contents even if
the power is switched off. So, the firmware is stored in the ROM. When
power is switched on, the processor reads the ROM; the program is
program is executed.
1.15 Input Devices
Unlike the desktops, the input devices to an embedded system have
very limited capability. There will be no keyboard or a mouse, and hence
interacting with the embedded system is no easy task. Many embedded
systems will have a small keypad-you press one key to give a specific
command. A keypad may be used to input only the digits. Many embedded
systems used in process control do not have any input device for user
interaction; they take inputs from sensors or transducers 1’fnd produce
electrical signals that are in turn fed to other systems.

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1.16 Output Devices
The output devices of the embedded systems also have very limited
capability. Some embedded systems will have a few Light Emitting Diodes
(LEDs) to indicate the health status of the system modules, or for visual
indication of alarms. A small Liquid Crystal Display (LCD) may also be
used to display some important parameters.
1.17 Communication Interfaces
The embedded systems may need to, interact with other embedded
systems at they may have to transmit data to a desktop. To facilitate this,
the embedded systems are provided with one or a few communication
interfaces such as RS232, RS422, RS485, Universal Serial Bus (USB),
IEEE 1394, Ethernet etc.
1.18 Application-Specific Circuitry
Sensors, transducers, special processing and control circuitry may
be required fat an embedded system, depending on its application. This
circuitry interacts with the processor to carry out the necessary work. The
entire hardware has to be given power supply either through the 230 volts
main supply or through a battery. The hardware has to design in such a way
that the power consumption is minimized.

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CHAPTER-2
PROJECT INTRODUCTION
2.1 ABSTRACT
Man has needed and used energy at an increasing rate for his
sustenance and well-being ever since he came on the earth a few million
years ago. Due to this a lot of energy resources have been exhausted and
wasted. Proposal for the utilization of waste energy of foot power with
human locomotion is very much relevant and important for highly
populated countries like India and China where the roads, railway stations,
bus stands, temples, etc. are all over crowded and millions of people move
around the clock. This whole human/ bio-energy being wasted if it can be
made possible for utilization it will be great invention and crowd energy
farms will be very useful energy sources in crowded countries. In this project
the conversion of the force energy in to electrical energy. The control mechanism
carries the piezoelectric sensor, A.C ripples neutralizer, unidirectional current
controller and 12V, 1.3Amp lead acid dc rechargeable battery and an inverter is
used to drive AC/DC loads. The battery is connected to the inverter. This
inverter is used to convert the 12 Volt D.C to the 230 Volt A.C. This 230
Volt A.C voltage is used to activate the loads

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2.2 INTRODUCTIONOF THE PROJECT
In this project we are generating electrical power as non-
conventional method by simply walking or running on the foot step. Non-
conventional energy system is very essential at this time to our nation.
Non-conventional energy using foot step is converting mechanical energy
into the electrical energy. This project uses piezoelectric sensor.
In this project the conversion of the force energy in to electrical
energy. The control mechanism carries the piezoelectric sensor, A.C ripples
neutralizer, unidirectional current controller and 12V, 1.3Amp lead acid dc
rechargeable battery and an inverter is used to drive AC/DC loads. The
battery is connected to the inverter. This inverter is used to convert the 12
Volt D.C to the 230 Volt A.C. This 230 Volt A.C voltage is used to activate
the loads.
This project uses regulated 5V, 500mA power supply. 7805 three
terminal voltage regulator is used for voltage regulation. Bridge type full
wave rectifier is used to rectify the ac output of secondary of 230/12V step
down transformer

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CHAPTER-3
PROJECT DESCRIPTION
3.1 BLOCK DIAGRAM
Fig 3.1 BLOCKS DIAGRAM OF FOOT STEP POWER
GENERATION SYSTEM TO RUN AC AND DC LOADS

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3.2 WORKING
1. By using Foot step power generation project we can generate the D.C voltage
and store it in the rechargeable battery.
2. This voltage we are converting into the AC voltage by using converter. And
we can operate AC loads also.
3. Foot step board it consist of a 16 piezoelectric sensors which are connected
in parallel.
4. When the pressure is applied on the sensors, the sensors will convert
mechanical energy into electrical energy.
5. This electrical energy will be storing into the 12v rechargeable battery.
6. This voltage we are giving to the inverter.
7. Inverter is used to converts DC voltage to AC voltage.
8. By using this AC voltage we can operate AC loads.
FIG 3.2 CIRCUIT DIAGRAM

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CHAPTER-4
COMPONENTS DESCRIPTION
4.1 SENSOR
A sensor is a device that measures a physical quantity and converts
it into a signal which can be read by an observer or by an instrument. For
example, mercury converts the measured temperature into expansion and
contraction of a liquid which can be read on a calibrated glass tube. At
thermocouple converts temperature to an output voltage which can be read
by a voltmeter. For accuracy, most sensors are calibrated against known
standards.
Sensors are sophisticated devices that are frequently used to detect and
respond to electrical or optical signals. A Sensor converts the physical
parameter (for example: temperature, blood pressure, humidity, speed, etc.)
into a signal which can be measured electrically. Let’s explain the example
of temperature. The mercury in the glass thermometer expands and
contracts the liquid to convert the measured temperature which can be read
by a viewer on the calibrated glass tube.
Sensor is the device which converts any physical quantity to its
equivalent electrical signal. There are different types of sensor are available
there are: Temperature sensor, Light sensor, Voltage sensor, Smoke Sensor,
Gas sensor, Fire sensor, Magnetic Sensors, etc.
Criteria to choose a Sensor
There are certain features which have to be considered when we choose a
sensor. They are as given below:
1. Accuracy
2. Environmental condition - usually has limits for temperature/ humidity

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3. Range - Measurement limit of sensor
4. Calibration - Essential for most of the measuring devices as the readings
changes with time
5. Resolution - Smallest increment detected by the sensor
6. Cost
7. Repeatability - The reading that varies is repeatedly measured under
the same environment
Classification of measurement errors
A good sensor obeys the following rules:
 Is sensitive to the measured property
 Is insensitive to any other property likely to be encountered in its application
 Does not influence the measured property
Ideal sensors are designed to be linear or linear to some simple
mathematical function of the measurement, typically logarithmic. The
output signal of such a sensor is linearly proportional to the value or simple
function of the measured property. The sensitivity is then defined as the
ratio between output signal and measured property. For example, if a sensor
measures temperature and has a voltage output, the sensitivity is a constant
with the unit [V/K]; this sensor is linear because the ratio is constant at all
points of measurement.
Sensor deviations
If the sensor is not ideal, several types of deviations can be observed:
 The sensitivity may in practice differ from the value specified. This is called
a sensitivity error, but the sensor is still linear.
 Since the range of the output signal is always limited, the output signal will
eventually reach a minimum or maximum when the measured property
exceeds the limits. The full scale range defines the maximum and minimum
values of the measured property.
 If the output signal is not zero when the measured property is zero, the sensor
has an offset or bias. This is defined as the output of the sensor at zero
input.

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 If the sensitivity is not constant over the range of the sensor, this is called
nonlinearity. Usually this is defined by the amount the output differs from
ideal behaviour over the full range of the sensor, often noted as a
percentage of the full range.
 If the deviation is caused by a rapid change of the measured property over
time, there is a dynamic error. Often, this behaviour is described with a
bode plot showing sensitivity error and phase shift as function of the
frequency of a periodic input signal.
 If the output signal slowly changes independent of the measured property,
this is defined as drift (telecommunication).
 Long term drift usually indicates a slow degradation of sensor properties
over a long period of time.
 Noise is a random deviation of the signal that varies in time.
 Hysteresis is an error caused by when the measured property reverses
direction, but there is some finite lag in time for the sensor to respond,
creating a different offset error in one direction than in the other.
 If the sensor has a digital output, the output is essentially an approximation
of the measured property. The approximation error is also called
digitization error.
 If the signal is monitored digitally, limitation of the sampling frequency also
can cause a dynamic error, or if the variable or added noise changes
periodically at a frequency near a multiple of the sampling rate may induce
aliasing errors.
 The sensor may to some extent be sensitive to properties other than the
property being measured. For example, most sensors are influenced by the
temperature of their environment. All these deviations can be classified as
systematic errors or random errors. Systematic errors can sometimes be
compensated for by means of some kind of calibration strategy. Noise is a random
error that can be reduced by signal processing, such as filtering, usually at the
expense of the dynamic behaviour of the sensor.

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Resolution
The resolution of a sensor is the smallest change it can detect in the quantity
that it is measuring. Often in a digital display, the least significant digit will
fluctuate, indicating that changes of that magnitude are only just resolved.
The resolution is related to the precision with which the measurement is
made. For example, a scanning tunneling probe (a fine tip near a surface
collects an electron tunneling current) can resolve atoms and molecules.
Different Types Sensor:
1] Acoustic, sound, vibration
 Geophone
 Hydrophone
2] Automotive, transportation
 Air-fuel ratio meter
 Crank sensor
3] Chemical
 Breathalyzer and Alcohol Sensor
 Carbon dioxide sensor
4] Electric current, electric potential, magnetic, radio
 Ammeter
 Current sensor
5] Environment, weather, moisture, humidity
 Bedwetting alarm
 Dew warning
6] Flow, fluid velocity
 Air flow meter
 Anemometer

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7] Ionizing radiation, subatomic particles
 Bubble chamber
 Cloud chamber
8] Navigation instruments
 Air speed indicator
 Altimeter
9] Position, angle, displacement, distance, speed, acceleration
 Accelerometer
 Capacitive displacement sensor
10] Optical, light, imaging
 Charge-coupled device
 Colorimeter
11] Pressure
 Barograph
 Barometer
12] Force, density, level
 Bhangmeter
 Hydrometer
13] Thermal, heat, temperature
Bolometer
Calorimeter
14] Proximity, presence
 Alarm sensor
 Motion detector

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4.1.1 PIEZOELECTRIC SENSOR-
A piezoelectric sensor is a device that uses the piezoelectric
effect to measure pressure, acceleration, strain or force by converting them
to an electrical signal.
Piezoelectric sensors have proven to be versatile tools for the
measurement of various processes. They are used for quality
assurance, process control and for research and development in many
different industries it was only in the 1950s that the piezoelectric effect
started to be used for industrial sensing applications. Since then, this
measuring principle has been increasingly used and can be regarded as a
mature technology with an outstanding inherent reliability. It has been
successfully used in various applications, such as in medical,
aerospace, nuclear instrumentation, and as a pressure sensor in the touch
pads of mobile phones. In the automotive industry, piezoelectric elements
are used to monitor combustion when developing internal combustion
engines. The sensors are either directly mounted into additional holes into
the cylinder head or the spark/glow plug is equipped with a built in
miniature piezoelectric sensor.
FIG 4.1 PEIZOELECTRIC SENSOR
One disadvantage of piezoelectric sensors is that they cannot
be used for truly static measurements. A static force will result in a fixed
amount of charges on the piezoelectric material. While working with
conventional readout electronics, imperfect insulating materials, and
reduction in internal sensor resistance will result in a constant loss

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of electrons, and yield a decreasing signal. Elevated temperatures cause an
additional drop in internal resistance and sensitivity. The main effect on the
piezoelectric effect is that with increasing pressure loads and temperature,
the sensitivity is reduced due to twin-formation. While quartz sensors need
to be cooled during measurements at temperatures above 300°C, special
types of crystals like GaPO4 gallium phosphate do not show any twin
formation up to the melting point of the material itself.
FIG 4.2 SYMBOL OF PIEZOELECTRIC SENSOR
4.2 BATTERY
Battery (electricity), an array of electrochemical cells for
electricity storage, either individually linked or individually linked and
housed in a single unit. An electrical battery is a combination of one or
more electrochemical cells, used to convert stored chemical energy into
electrical energy. Batteries may be used once and discarded, or recharged
for years as in standby power applications. Miniature cells are used to
power devices such as hearing aids and wristwatches; larger batteries
provide standby power for telephone exchanges or computer data centers.

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FIG 4.3 VARIOUS BATTERIES (TOP-LEFT TO BOTTOM-
RIGHT): TWO AA, ONE D, ONE HANDHELD HAM RADIO
BATTERY, TWO 9-VOLT PP3, TWO AAA, ONE C, ONE
CAMCORDER BATTERY, ONE CORDLESS PHONE BATTERY.
4.2.1How batteries work-
A battery is a device that converts chemical energy directly to
electrical energy. It consists of a number of voltaic cells; each voltaic cell
consists of two half cells connected in series by a conductive electrolyte
containing anions and cations. One half-cell includes electrolyte and the
electrode to which anions (negatively-charged ions) migrate, i.e. the anode
or negative electrode; the other half-cell includes electrolyte and the
electrode to which cations (positively-charged ions) migrate, i.e. the
cathode or positive electrode. In the redox reaction that powers the battery,
reduction (addition of electrons) occurs to cations at the cathode, while
oxidation (removal of electrons) occurs to anions at the anode. The
electrodes do not touch each other but are electrically connected by the
electrolyte. Many cells use two half-cells with different electrolytes. In that
case each half-cell is enclosed in a container, and a separator that is porous
to ions but not the bulk of the electrolytes prevents mixing.
Each half cell has an electromotive force (or emf), determined by its
ability to drive electric current from the interior to the exterior of the cell.
The net emf of the cell is the difference between the emfs of its half-cells,

21. 21
as first recognized by Volta. Therefore, if the electrodes have emfs E1 and
E2 and, then the net emf is E2 - E1; in other words, the net emf is the
difference between the reduction potentials of the half-reactions.
The electrical driving force or across the terminals of a cell
is known as the terminal voltage (difference) and is measured in volts. The
terminal voltage of a cell that is neither charging nor discharging is called
the open-circuit voltage and equals the emf of the cell. Because of internal
resistance, the terminal voltage of a cell that is discharging is smaller in
magnitude than the open-circuit voltage and the terminal voltage of a cell
that is charging exceeds the open-circuit voltage. An ideal cell has
negligible internal resistance, so it would maintain a constant terminal
voltage of until exhausted, then dropping to zero. If such a cell
maintained 1.5 volts and stored a charge of one Coulomb then on complete
discharge it would perform 1.5 Joule of work. In actual cells, the internal
resistance increases under discharge, and the open circuit voltage also
decreases under discharge. If the voltage and resistance are plotted against
time, the resulting graphs typically are a curve; the shape of the curve varies
according to the chemistry and internal arrangement employed.
As stated above, the voltage developed across a cell's terminals
depends on the energy release of the chemical reactions of its electrodes
and electrolyte. Alkaline and carbon-zinc cells have different chemistries
but approximately the same emf of 1.5 volts; likewise NiCd and NiMH
cells have different chemistries, but approximately the same emf of 1.2
volts. On the other hand the high electrochemical potential changes in the
reactions of lithium compounds give lithium cells emfs of 3 volts or more.
4.2.2 Categories and types of batteries-
Batteries are classified into two broad categories, each type with
advantages and disadvantages.

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Primary batteries irreversibly (within limits of practicality)
transform chemical energy to electrical energy. When the initial supply of
reactants is exhausted, energy cannot be readily restored to the battery by
electrical means.
Secondary batteries can be recharged; that is, they can have their
chemical reactions reversed by supplying electrical energy to the cell,
restoring their original composition.
Historically, some types of primary batteries used, for example, for
telegraph circuits, were restored to operation by replacing the components
of the battery consumed by the chemical reaction. Secondary batteries are
not indefinitely rechargeable due to dissipation of the active materials, loss
of electrolyte and internal corrosion.
Fig 4.4 batteries
4.2.3. Primary batteries-
Primary batteries can produce current immediately on assembly.
Disposable batteries are intended to be used once and discarded. These are
most commonly used in portable devices that have low current drain, are
only used intermittently, or are used well away from an alternative power
source, such as in alarm and communication circuits where other electric
power is only intermittently available. Disposable primary cells cannot be
reliably recharged, since the chemical reactions are not easily reversible and
active materials may not return to their original forms. Battery
manufacturers recommend against attempting to recharge primary cells.

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Common types of disposable batteries include zinc-carbon batteries
and alkaline batteries. Generally, these have higher energy densities than
rechargeable batteries, but disposable batteries do not fare well under high-
drain applications with loads under 75 ohms (75 Ω).
4.2.4. Secondary batteries-
Secondary batteries must be charged before use; they are usually
assembled with active materials in the discharged state. Rechargeable
batteries or secondary cells can be recharged by applying electrical current,
which reverses the chemical reactions that occur during its use. Devices to
supply the appropriate current are called chargers or rechargers.
The oldest form of rechargeable battery is the lead-acid battery.
This battery is notable in that it contains a liquid in an unsealed container,
requiring that the battery be kept upright and the area be well ventilated to
ensure safe dispersal of the hydrogen gas produced by these batteries during
overcharging. The lead-acid battery is also very heavy for the amount of
electrical energy it can supply. Despite this, its low manufacturing cost and
its high surge current levels make its use common where a large capacity
(over approximately 10Ah) is required or where the weight and ease of
handling are not concerns.
A common form of the lead-acid battery is the modern car battery,
which can generally deliver a peak current of 450 amperes. An improved
type of liquid electrolyte battery is the sealed valve regulated lead acid
(VRLA) battery, popular in the automotive industry as a replacement for
the lead-acid wet cell. The VRLA battery uses an immobilized sulfuric acid
electrolyte, reducing the chance of leakage and extending shelf life. VRLA
batteries have the electrolyte immobilized, usually by one of two means:
Gel batteries (or "gel cell") contain a semi-solid electrolyte to prevent
spillage.

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Absorbed Glass Mat (AGM) batteries absorb the electrolyte in special
fiberglass matting.
Other portable rechargeable batteries include several "dry cell"
types, which are sealed units and are therefore useful in appliances such as
mobile phones and laptop computers. Cells of this type (in order of
increasing power density and cost) include nickel-cadmium (NiCd), nickel-
zinc (NiZn), nickel metal hydride (NiMH) and lithium-ion (Li-ion) cells.
By far, Li-ion has the highest share of the dry cell rechargeable market.
Meanwhile, NiMH has replaced NiCd in most applications due to its higher
capacity, but NiCd remains in use in power tools, two-way radios, and
medical equipment. NiZn is a new technology that is not yet well
established commercially.
Recent developments include batteries with embedded functionality
such as USBCELL, with a built-in charger and USB connector within the
AA format, enabling the battery to be charged by plugging into a USB port
without a charger, and low self-discharge (LSD) mix chemistries such as
Hybrio, ReCyko, and Eneloop, where cells are precharged prior to shipping.
4.2.5. Lead-acid battery-
Lead-acid batteries are the most common in PV systems because
their initial cost is lower and because they are readily available nearly
everywhere in the world. There are many different sizes and designs of
lead-acid batteries, but the most important designation is that they are deep
cycle batteries. Lead-acid batteries are available in both wet-cell (requires
maintenance) and sealed no-maintenance versions. AGM and Gel-cell deep-
cycle batteries are also popular because they are maintenance free and they
last a lot longer.
Lead acid batteries are reliable and cost effective with an
exceptionally long life. The Lead acid batteries have high reliability
because of their ability to withstand overcharge, over discharge vibration
and shock. The use of special sealing techniques ensures that our

25. 25
batteriesare leak proof and non-spillable. Other critical features include the
ability to withstand relatively deeper discharge, faster recovery and more
chances of survival if subjected to overcharge. The batteries have
exceptional charge acceptance, large electrolyte volume and low self-
discharge, which make them ideal as zero-maintenance batteries.
Lead acid batteries are manufactured/ tested using CAD (Computer
Aided Design). These batteries are used in Inverter & UPS Systems and
have the proven ability to perform under extreme conditions. The batteries
have electrolyte volume, use PE Separators and are sealed in sturdy
containers, which give them excellent protection against leakage and
corrosion.
FIG 4.5 LEAD ACID BATTERY
Features
 Manufactured/tested using CAD
 Electrolyte volume
 PE Separators
 Protection against leakage
Number of batteries needed:
If you use the numbers from the sample load numbers link at the end
of the page, you turn out needing 6310W peak and a total of 20950Wh/day.
This comes out at 51 Amps peak and a total of 174 Amp Hours in a day at
120 Volts. To handle these peak loads, it is important to use electrical
wiring of the correct gauge to carry the current. 51 Amps @ 120 Volts (or
526 Amps@12vDC) is hazardous. One should not forget that batteries have
a limited life span. Any system should be designed such that you can easily

26. 26
replace batteries without disrupting much of your load. You may need to
diagnose to determine what batteries have lost their ability to retain a
charge.
4.3 RECTIFIER
The output from the transformer is fed to the rectifier. It converts
A.C. into pulsating D.C. The rectifier may be a half wave or a full wave
rectifier. In this project, a bridge rectifier is used because of its merits like
good stability and full wave rectification.
The Bridge rectifier is a circuit, which converts an ac voltage to dc
voltage using both half cycles of the input ac voltage. The Bridge rectifier
circuit is shown in the figure. The circuit has four diodes connected to form
a bridge. The ac input voltage is applied to the diagonally opposite ends of
the bridge. The load resistance is connected between the other two ends of
the bridge.
FIG 4.6 RECTIFIER CIRCUIT
For the positive half cycle of the input ac voltage, diodes D1 and D3
conduct, whereas diodes D2 and D4 remain in the OFF state. The
conducting diodes will be in series with the load resistance RL and hence
the load current flows through RL.
For the negative half cycle of the input ac voltage, diodes D2 and
D4 conduct whereas, D1 and D3 remain OFF. The conducting diodes D2
and D4 will be in series with the load resistance RL and hence the current
flows through RL in the same direction as in the previous half cycle. Thus a
bi-directional wave is converted into a unidirectional wave.

27. 27
FIG 4.7 RECTIFIER OUTPUT WAVEFORMS
4.4 FILTER
Capacitive filter is used in this project. It removes the ripples from
the output of rectifier and smoothens the D.C. Output received from this
filter is constant until the mains voltage and load is maintained constant.
However, if either of the two is varied, D.C. voltage received at this point
changes. Therefore a regulator is applied at the output stage.
4.5 VOLTAGE REGULATOR
As the name itself implies, it regulates the input applied to it. A voltage
regulator is an electrical regulator designed to automatically maintain a
constant voltage level.
FIG 4.8 VOLTAGE REGULATOR

28. 28
In this project, power supply of 5V and 12V are required. In order to obtain
these voltage levels, 7805 and 7812 voltage regulators are to be used. The
first number 78 represents positive supply and the numbers 05, 12 represent
the required output voltage levels. The L78xx series of three-terminal
positive regulators is available in TO-220, TO-220FP, TO-3, D2PAK and
DPAK packages and several fixed output voltages, making it useful in a
wide range of applications. These regulators can provide local on-card
regulation, eliminating the distribution problems associated with single
point regulation. Each type employs internal current limiting, thermal shut-
down and safe area protection, making it essentially indestructible. If
adequate heat sinking is provided, they can deliver over 1 A output current.
Although designed primarily as fixed voltage regulators, these devices can
be used with external components to obtain adjustable voltage and currents.
FIG 4.9 7805 VOLTAGE REGULATOR
4.6 INVERTER
FIG 4.10 INVERTER CIRCUIT

29. 29
An inverter is an electrical device that converts direct current (DC)
to alternating current (AC); the converted AC can be at any required
voltage and frequency with the use of appropriate transformers, switching,
and control circuits.
Solid-state inverters have no moving parts and are used in a wide
range of applications, from small switching power supplies in computers, to
large electric utility high-voltage direct current applications that transport
bulk power. Inverters are commonly used to supply AC power from DC
sources such as solar panels or batteries.
There are two main types of inverter. The output of a modified sine
wave inverter is similar to a square wave output except that the output goes
to zero volts for a time before switching positive or negative. It is simple
and low cost and is compatible with most electronic devices, except for
sensitive or specialized equipment, for example certain laser printers.
A pure sine wave inverter produces a nearly perfect sine wave output
(<3% total harmonic distortion) that is essentially the same as utility-
supplied grid power. Thus it is compatible with all AC electronic devices.
This is the type used in grid-tie inverters. Its design is more complex, and
costs 5 or 10 times more per unit power. The electrical inverter is a high-
power electronic oscillator. It is so named because early mechanical AC to
DC converters was made to work in reverse, and thus was "inverted", to
convert DC to AC.
The inverter performs the opposite function of a rectifier.
FIG 4.11 INVERTER

30. 30
FIG 4.12 CIRCUIT DESCRIPTION
In one simple inverter circuit, DC power is connected to
a transformer through the centre tap of the primary winding. A switch is
rapidly switched back and forth to allow current to flow back to the DC
source following two alternate paths through one end of the primary
winding and then the other. The alternation of the direction of current in the
primary winding of the transformer produces alternating current (AC) in the
secondary circuit.
The electromechanical version of the switching device includes two
stationary contacts and a spring supported moving contact. The spring holds
the movable contact against one of the stationary contacts and an
electromagnet pulls the movable contact to the opposite stationary contact.
The current in the electromagnet is interrupted by the action of the switch
so that the switch continually switches rapidly back and forth. This type of
electromechanical inverter switch, called a vibrator or buzzer, was once
used in vacuum tube automobile radios. A similar mechanism has been
used in door bells, buzzers and tattoo guns.

31. 31
As they became available with adequate power
ratings, transistors and various other types of semiconductor switches have
been incorporated into inverter circuit designs.
4.7 SWITCHES
FIG 4.13 SWITCHES
4.7.1. Definition of switch-
In a telecommunications network, a switch is a device that channels
incoming data from any of multiple input ports to the specific output port
that will take the data toward its intended destination. In the traditional
circuit-switched telephone network, one or more switches are used to set up
a dedicated though temporary connection or circuit for an exchange
between two or more parties. On an Ethernet local area network (LAN), a
switch determines from the physical device (Media Access Control or
MAC) address in each incoming message frame which output port to
forward it to and out of. In a wide area packet-switched network such as the
Internet, a switch determines from the IP address in each packet which
output port to use for the next part of its trip to the intended destination.
4.7.2. Special types-
Switches can be designed to respond to any type of mechanical
stimulus: for example, vibration (the trembler switch), tilt, air pressure,
fluid level (the float switch), the turning of a key (key switch), linear or

32. 32
rotary movement (the limit switch or micro switch), or presence of a
magnetic field.
4.7.2.1. Mercury tilt switch:
The mercury switch consists of a drop of mercury inside a glass
bulb with 2 or more contacts. The two contacts pass through the glass, and
are connected by the mercury when the bulb is tilted to make the mercury
roll on to them. This type of switch performs much better than the ball tilt
switch, as the liquid metal connection is unaffected by dirt, debris and
oxidation, it wets the contacts ensuring a very low resistance bounce-free
connection, and movement and vibration do not produce a poor contact.
These types can be used for precision works.
4.7.2.2. Knife switch:
Knife switches consist of a flat metal blade, hinged at one end,
with an insulating handle for operation, and a fixed contact. When the
switch is closed, current flows through the hinged pivot and blade and
through the fixed contact. Such switches are usually not enclosed. The parts
may be mounted on an insulating base with terminals for wiring, or may be
directly bolted to an insulated switch board in a large assembly. Since the
electrical contacts are exposed, the switch is used only where people cannot
accidentally come in contact with the switch.
4.7.2.3. Intermediate switch:
A DPDT switch has six connections, but since polarity reversal is a
very common usage of DPDT switches, some variations of the DPDT
switch are internally wired specifically for polarity reversal. These
crossover switches only have four terminals rather than six. Two of the
terminals are inputs and two are outputs. When connected to a battery or
other DC source, the 4-way switch selects from either normal or reversed
polarity. Intermediate switches are also an important part of multi way
switching systems with more than two switches (see next section).

33. 33
4.7.2.4. Power switching:
When a switch is designed to switch significant power, the
transitional state of the switch as well as the ability to stand continuous
operating currents must be considered. When a switch is in the on state its
resistance is near zero and very little power is dropped in the contacts; when
a switch is in the off state its resistance is extremely high and even less
power is dropped in the contacts. However when the switch is flicked the
resistance must pass through a state where briefly a quarter (or worse if the
load is not purely resistive) of the load's rated power is dropped in the
switch.
Power switches usually come in two types. A momentary on-off
switch (such as on a laser pointer) usually takes the form of a button and
only closes the circuit when the button is depressed. A regular on-off switch
(such as on a flashlight) has a constant on-off feature. Dual-action switches
incorporate both of these features.
4.7.2.5. Inductive loads:
When a strongly inductive load such as an electric motor is switched
off, the current cannot drop instantaneously to zero; a spark will jump
across the opening contacts. Switches for inductive loads must be rated to
handle these cases. The spark will cause electromagnetic interference if not
suppressed; a snubber network of a resistor and capacitor in series will quell
the spark.
FIG 4.14 A DIAGRAM OF A DUAL-ACTION SWITCH SYSTEM

34. 34
4.8. BULB
FIG 4.15 BULB
A bulb is a short stem with fleshy leaves or leaf bases. The leaves
often function as food storage organs during dormancy.
A bulb's leaf bases generally do not support leaves, but contain food
reserves to enable the plant to survive adverse conditions. The leaf bases
may resemble scales, or they may overlap and surround the center of the
bulb as with the onion. A modified stem forms the base of the bulb, and
plant growth occurs from this basal plate. Roots emerge from the underside
of the base, and new stems and leaves from the upper side.
4.8.1Incandescent-
These are the standard bulbs that most people are familiar with.
Incandescent bulbs work by using electricity to heat a tungsten filament in
the bulb until it glows. The filament is either in a vacuum or in a mixture of
argon/nitrogen gas. Most of the energy consumed by the bulb is given off as
heat, causing its Lumens per Watt performance to be low. Because of the
filament's high temperature, the tungsten tends to evaporate and collect on
the sides of the bulb. The inherent imperfections in the filament causes it to
become thinner unevenly. When a bulb is turned on, the sudden surge of

35. 35
energy can cause the thin areas to heat up much faster than the rest of the
filament, which in turn causes the filament to break and the bulb to burn
out.
Incandescent bulbs produce a steady warm, light that is good for most
household applications. A standard incandescent bulb can last for 700-1000
hours, and can be used with a dimmer. Soft white bulbs use a special
coating inside the glass bulb to better diffuse the light; but the light color is
not changed.
4.8.2. Halogen-
Halogen bulbs are a variation of incandescent bulb technology.
These bulbs work by passing electricity through a tungsten filament, which
is enclosed in a tube containing halogen gas. This halogen gas causes a
chemical reaction to take place which removes the tungsten from the wall
of the glass and deposits it back onto the filament. This extends the life of
the bulb. In order for the chemical reaction to take place, the filament needs
to be hotter than what is needed for incandescent bulbs. The good news is
that a hotter filament produces a brilliant white light and is more efficient
(more lumens per watt).
The bad news is that a hotter filament means that the tungsten is
evaporating that much faster. Therefore a denser, more expensive fill gas
(krypton), and a higher pressure, are used to slow down the evaporation.
This means that a thicker, but smaller glass bulb (envelope) is needed,
which translates to a higher cost. Due to the smaller glass envelope (bulb),
the halogen bulb gets much hotter than other bulbs. A 300 watt bulb can

36. 36
reach over 300 degrees C. Therefore attention must be paid to where
halogen bulbs are used, so that they don't accidentally come in contact with
flammable materials, or burn those passing by.
Care must be taken not to touch the glass part of the bulb with our
fingers. The oils from our fingers will weaken the glass and shorten the
bulb’s life. Many times this causes the bulb to burst when the filament
finally burns out.
To summarize, the halogen has the advantage of being more
efficient (although not by much) and having longer life than the
incandescent bulb. They are relatively small in size and are dimmable. The
disadvantages are that they are more expensive, and burn at a much higher
temperature, which could possibly be a fire hazard in certain areas.
4.8.3. Fluorescent
These bulbs work by passing a current through a tube filled with
argon gas and mercury. This produces ultraviolet radiation that bombards
the phosphorous coating causing it to emit light (see: “How Fluorescents
Work”). Bulb life is very long - 10,000 to 20,000 hours. Fluorescent bulbs
are also very efficient, producing very little heat. A common misconception
is that all fluorescent lamps are neutral or cool in color appearance and do
not have very good color-rendering ability. This is largely due to the fact
that historically the "cool white" fluorescent lamp was the industry
standard. It had a very cool color appearance (4200K) and poor CRI rating.
This is simply no longer the case. Regarding color, a wide variety of
fluorescent lamps , using rare-earth tri-phosphor technology, offer superior

37. 37
color rendition and a wide range of color temperature choices (from 2700K
to 5000K and higher). Fluorescent bulbs are ideal for lighting large areas
where little detail work will be done (e.g. basements, storage lockers, etc.).
With the new type bulbs, and style of fixtures coming out, fluorescents can
be used in most places around the home. Most fluorescent bulb cannot be
used with dimmers.
That fluorescent bulb need components called ballasts to provide
the right amount of voltage. There are primarily two types - magnetic and
electronic. Electronic ballasts solve some of the flickering and humming
problems associated with magnetic ballast, and are more efficient, but cost
more to purchase. Some ballast needs a “starter” to work along with it.
Starters are sort of small mechanical timers, needed to cause a stream of
electrons to flow across the tube and ionize the mercury vapour.
On tube type fluorescent bulbs, the letter T designates that the bulb is
tubular in shape. The number after it expresses the diameter of the bulb in
eighths of an inch.

38. 38
CHAPTER 5
HARDWARE EXPLANATION
5.1 RESISTOR:
Resistors "Resist" the flow of electrical current. The higher the value of
resistance (measured in ohms) the lower the current will be. Resistance is the
property of a component which restricts 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.
FIG 5.1 RESISTOR
5.2 CAPACITORS:
Capacitors store electric charge. They are used with resistors
in timing circuits because it takes time for a capacitor to fill with charge. They are
used to smooth varying 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 and they must be connected the
correct way round, at least one of their leads will be marked + or -.
FIG 5.2 CAPACITOR

39. 39
5.3 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
labeled a or + for anode and k or - for cathode (yes, it really is k, not c, for
cathode!). The cathode is marked by a line painted on the body. Diodes are
labelled with their code in small print; you may need a magnifying glass to read
this on small signal diodes.
FIG 5.3 DIODE
5.4 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. Light emitting diodes are elements
for light signalization in electronics.
FIG 5.4 LED (LIGHT EMITTING DIODE)

40. 40
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.
FIG 5.4.1 TYPES OF LED’S
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 8051 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).
5.5 Block DiagramForRegulatedPowerSupply (RPS):
FIG 5.5 POWER SUPPLY

41. 41
5.6Transformer
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.
FIGURE5.6: TRANSFORMER SYMBOL
(or)
Transformer is a device that converts the one form energy to another form
of energy like a transducer.
FIGURE 5.6.1: TRANSFORMER
5.6.1 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

42. 42
course cannot increase power so that if the voltage is raised, the current is
proportionally lowered and vice versa.
FIGURE5.6.2: BASIC PRINCIPLE
5.6.2Transformer 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.

43. 43
FIGURE 5.6.3: 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.

44. 44
Transformers have two great advantages over other methods of
changing voltage:
1. 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.
2. Almost no power is wasted in a transformer. They have a high efficiency
(power out / power in) of 95% or more.
5.6.3Classification of Transformer
Step-Up Transformer
Step-Down Transformer
5.6.3.1 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.

45. 45
FIGURE 5.6.4: 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.)
5.6.3.2 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.

46. 46
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 5.6.5: STEP-UP TRANSFORMER

47. 47
CHAPTER-6
6.1 ADVANTAGES
 Reliable, Economical, Eco-Friendly.
 Less consumption of Non- renewable energies.
 Power generation is simply walking on the step
 Power also generated by running or exercising on the step.
 No need fuel input
 This is a Non-conventional system.
 Battery is used to store the generated power.
 Extremely wide dynamic range, almost free of noise
 Compact yet highly sensitive
 Self generating – no external power required.
6.2 DIS-ADVANTAGES
 Initial cost of this arrangement is high.
 Mechanical moving parts is high
6.3 APPLICATIONS
Foot step generated power can be used for agricultural, home applications,
street-lightning.
Foot step power generation can be used in emergency power failure
situations
 Metros, Rural Applications etc.,

48. 48
CHAPTER-7
7.1. CONCLUSION
The project “FOOT STEP POWER GENERATION FOR
RURAL ENERGY APPLICATION TO RUN A.C. AND D.C. LOADS”
is successfully tested and implemented which is the best economical,
affordable energy solution to common people. This can be used for many
applications in rural areas where power availability is less or totally
absence. As India is a developing country, where energy management is a
big challenge for huge population. By using this project we can drive both
A.C. as well as D.C loads according to the force we applied on the
piezoelectric sensor.
7.2 FUTURE SCOPE
Man has needed and used energy at an increasing rat
e for his sustenance and well being ever since he came on the earth
a few million years ago. Due to this a lot of energy resource save been
exhausted and wasted. Proposal for the utilization of waste energy of foot
power with human locomotion is very much relevant and important for
highly populated countries like India and China in future.
7.3 REFERENCE
www.howstuffworks.com
www.answers.com
EMBEDDED SYSTEM BY RAJ KAMAL
Magazines:
Electrical4u.com
Electrikindia