Foot step power generation system for rural energy application to run AC and DC loads

TECHNICAL SPECIFICATIONS

Technical Specifications:

Title of the project : Foot step power generation system for rural energy

Application to run AC and DC loads

Domain : Renewable Energy Management, Energy System

Power Supply : +5V, 500mA Regulated Power Supply and 12V lead acid

Battery

Source : Piezo electric transducers array

Inverter : 1

Applications : Metros, Rural Applications etc.,

Developed By : M/S Wine Yard Technologies

Phone : 040- 6464 6363,

Web site : www.WineYardProjects.com

INDEX1. TECHNICAL SPECIFICATION

2. ABSTRACT

3. BLOCK DIAGRAM

4. INTRODUCTION OF THE PROJECT

5. INTRODUCTION OF SENSORS

6. PIEZO ELECTRIC SENSOR

7. LEAD AICD BATTERY

8. LIGHT EMITTING DIODE

9. HARDWARE EXPLANATION

10. UNIDIRECTIONAL CURRENT CONTROLLER

11. INVERTER

12. BULB

13. WORKING PROCEDURE

14. ADVANTAGES

15. APPLICATIONS

16. CONCLUSION

17. REFERENCES

ABSTRACT

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 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 piezo electric 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. We are using conventional battery

charging unit also for giving supply to the circuitry.

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

out put of secondary of 230/12V step down transformer.

Block Diagram

Rechargeable Battery

Block Diagram:

Piezo electric transducers

arrayAC ripple

neutralizer

Unidirectional Current Controller

Conventional Battery Charger Unit

Step down

T/F

Bridge Rectifier

Filter Circuit Regulator

Unidirectional Current

Controller

Block Diagram: Foot step power generation system for rural energy application to run AC and DC loads

InverterON/ OFF control switchAC 230V

Load

Protector sheet made from soft core material

INTRODUCTION TO PROJECT INTRODUCTION TO PROJECT

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

Walking is the most common activity in day to day life. When a person

walks, he loses energy to the road surface in the form of impact, vibration, sound etc, due to the

transfer of his weight on to the road surface, through foot falls on the ground during every step.

This energy can be tapped and converted in the usable form such as in electrical form.

In this project the main role is played by piezoelectric sensor. These sensors

convert the mechanical energy into electrical energy. This energy is stored in rechargeable

battery and this energy is used for operating A.C and D.C.

INTRODUCTION TO SENSOR

What is sensor?

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.

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

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 

Definition:

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, a mercury-in-glass thermometer converts

the measured temperature into expansion and contraction of a liquid which can be read on a

calibrated glass tube. A thermocouple converts temperature to an output voltage which can be

read by a voltmeter. For accuracy, all sensors need to be calibrated against known standards

(OR)

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.

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.

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 behavior 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 behavior 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 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 behavior of the sensor.

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

Lace Sensor a guitar pickup

Microphone

Seismometer

Accelerometer

2] Automotive, transportation

Air-fuel ratio meter

Crank sensor

Curb feeler , used to warn driver of curbs

Defect detector , used on railroads to detect axle and signal problems in passing trains

Engine coolant temperature sensor , or ECT sensor, used to measure the engine

temperature

Hall effect sensor , used to time the speed of wheels and shafts

MAP sensor , Manifold Absolute Pressure, used in regulating fuel metering.

Mass flow sensor , or mass airflow (MAF) sensor, used to tell the ECU the mass of air

entering the engine

Oxygen sensor , used to monitor the amount of oxygen in the exhaust

Parking sensors , used to alert the driver of unseen obstacles during parking manoeuvres

Radar gun , used to detect the speed of other objects

Speedometer , used measure the instantaneous speed of a land vehicle

Speed sensor , used to detect the speed of an object

Throttle position sensor , used to monitor the position of the throttle in an internal

combustion engine

Tire-pressure monitoring sensor , used to monitor the air pressure inside the tires

Transmission fluid temperature sensor , used to measure the temperature of the

transmission fluid

Turbine speed sensor (TSS), or input speed sensor (ISS), used to measure the rotational

speed of the input shaft or torque converter

Variable reluctance sensor , used to measure position and speed of moving metal

components

Vehicle speed sensor (VSS), used to measure the speed of the vehicle

Water sensor or water-in-fuel sensor, used to indicate the presence of water in fuel

Wheel speed sensor , used for reading the speed of a vehicle's wheel rotation

3] Chemical

Breathalyzer and Alcohol Sensor

Carbon dioxide sensor

Carbon monoxide detector

Catalytic bead sensor

Chemical field-effect transistor

Electrochemical gas sensor

Electronic nose

Electrolyte–insulator–semiconductor sensor

Hydrogen sensor

Hydrogen sulfide sensor

Infrared point sensor

Ion-selective electrode

Nondispersive infrared sensor

Microwave chemistry sensor

Nitrogen oxide sensor

Olfactometer

Optode

Oxygen sensor

Pellistor

pH glass electrode

Potentiometric sensor

Redox electrode

Smoke detector

Zinc oxide nanorod sensor

4] Electric current, electric potential, magnetic, radio

Ammeter

Current sensor

Galvanometer

Hall effect sensor

Hall probe

Leaf electroscope

Magnetic anomaly detector

Magnetometer

Metal detector

Multi-meter

Ohmmeter

Radio direction finder

Telescope

Voltmeter

Voltage detector

Watt-hour meter

5] Environment, weather, moisture, humidity

Bedwetting alarm

Dew warning

Fish counter

Gas detector

Hook gauge evaporimeter

Hygrometer

Leaf sensor

Pyranometer

Pyrgeometer

Psychrometer

Rain gauge

Rain sensor

Seismometers

Snow gauge

Soil moisture sensor

Stream gauge

Tide gauge

6] Flow, fluid velocity

Air flow meter

Anemometer

Flow sensor

Gas meter

Mass flow sensor

Water meter

7] Ionizing radiation, subatomic particles

Bubble chamber

Cloud chamber

Geiger counter

Neutron detection

Particle detector

Scintillation counter

Scintillator

Wire chamber

8] Navigation instruments

Air speed indicator

Altimeter

Attitude indicator

Depth gauge

Fluxgate compass

Gyroscope

Inertial reference unit

Magnetic compass

MHD sensor

Ring laser gyroscope

Turn coordinator

Variometer

Vibrating structure gyroscope

Yaw rate sensor

9] Position, angle, displacement, distance, speed, acceleration

Accelerometer

Capacitive displacement sensor

Free fall sensor

Gravimeter

Inclinometer

Laser rangefinder

Linear encoder

Linear variable differential transformer (LVDT)

Liquid capacitive inclinometers

Odometer

Piezoelectric accelerometer

Position sensor

Rotary encoder

Rotary variable differential transformer

Selsyn

Sudden Motion Sensor

Tilt sensor

Tachometer

Ultrasonic thickness gauge

10] Optical, light, imaging

Charge-coupled device

Colorimeter

Contact image sensor

Electro-optical sensor

Flame detector

Infra-red sensor

LED as light sensor

Nichols radiometer

Fiber optic sensors

Photodetector

Photodiode

Photomultiplier tubes

Phototransistor

Photoelectric sensor

Photoionization detector

Photomultiplier

Photoresistor

Photoswitch

Phototube

Proximity sensor

Scintillometer

Shack-Hartmann

Wavefront sensor

11] Pressure

Barograph

Barometer

Boost gauge

Bourdon gauge

Hot filament ionization gauge

Ionization gauge

McLeod gauge

Oscillating U-tube

Permanent Downhole Gauge

Pirani gauge

Pressure sensor

Pressure gauge

Tactile sensor

Time pressure gauge

12] Force, density, level

Bhangmeter

Hydrometer

Force gauge

Level sensor

Load cell

Magnetic level gauge

Nuclear density gauge

Piezoelectric sensor

Strain gauge

Torque sensor

Viscometer

13] Thermal, heat, temperature

Bolometer

Calorimeter

Exhaust gas temperature gauge

Gardon gauge

Heat flux sensor

Infrared thermometer

Microbolometer

Microwave radiometer

Net radiometer

Resistance temperature detector

Resistance thermometer

Silicon bandgap temperature sensor

Temperature gauge

Thermistor

Thermocouple

Thermometer

14] Proximity, presence

Alarm sensor

Motion detector

Occupancy sensor

Passive infrared sensor

Reed switch

Stud finder

Triangulation sensor

Touch switch

Wired glove

Doppler radar

Piezoelectric sensor

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 .

The rise of piezoelectric technology is directly related to a

set of inherent advantages. The high modulus of elasticity of

many piezoelectric materials is comparable to that of many

metals and goes up to 10e6 N/m²[Even though piezoelectric

sensors are electromechanical systems that react to compression,

the sensing elements show almost zero deflection. This is the

reason why piezoelectric sensors are so rugged, have an extremely high natural frequency and an

excellent linearity over a wide amplitude range. Additionally, piezoelectric technology is

insensitive to electromagnetic fields and radiation, enabling measurements under harsh

conditions. Some materials used (especially gallium phosphate or tourmaline) have an extreme

stability even at high temperature, enabling sensors to have a working range of up to 1000°C.

Tourmaline shows pyroelectricity in addition to the piezoelectric effect; this is the ability to

generate an electrical signal when the temperature of the crystal changes. This effect is also

common to piezoceramic materials.

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 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.

Symbol of Piezo electric sensor

LEAD ACID BATTERY

Lead-acid batteries:

These 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 batteries

are 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.

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 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.

Battery connections:

Lead-acid batteries are normally available in blocks of 2V, 6V or 12V. In most cases, to

generate the necessary operating voltage and the capacity of the batteries for the Solar Inverter,

many batteries have to be connected together in parallel and/or in series. Following three

examples are shown:

Parallel Connection:

Series Connection:

Parallel-Series Connection:

LIGHT EMITTING DIODE

LED (Light emitting diode):

A light-emitting diode (LED) is a semiconductor light source.[3] LEDs are used as indicator

lamps in many devices and are increasingly used for otherlighting. Introduced as a practical electronic

component in 1962,[4] early LEDs emitted low-intensity red light, but modern versions are available

across thevisible, ultraviolet, and infrared wavelengths, with very high brightness.

When a light-emitting diode is forward-biased (switched on), electrons are able

to recombine with electron holes within the device, releasing energy in the form of photons. This effect is

called electroluminescence and the color of the light (corresponding to the energy of the photon) is

determined by the energy gap of the semiconductor. LEDs are often small in area (less than 1 mm2), and

integrated optical components may be used to shape its radiation pattern. [5] LEDs present

many advantages over incandescent light sources including lower energy consumption, longer lifetime,

improved robustness, smaller size, and faster switching. LEDs powerful enough for room lighting are

relatively expensive and require more precise current and heat managementthan compact fluorescent

lamp sources of comparable output.

Light-emitting diodes are used in applications as diverse as aviation lighting, automotive lighting,

advertising, general lighting, and traffic signals. LEDs have allowed new text, video displays, and sensors

to be developed, while their high switching rates are also useful in advanced communications technology.

Infrared LEDs are also used in the remote control units of many commercial products including

televisions, DVD players, and other domestic appliances.

Hardware Explanation :

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.

Colour Code:

CAPACITOR:

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 -.

Examples:  

DIODES:

Diodes allow electricity to flow in only one direction. The arrow of the circuit symbol shows the

direction in which the current can flow. Diodes are the electrical version of a valve and early diodes were

actually called valves.

Circuit symbol:   

Diodes must be connected the correct way round, the diagram may be 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 labeled with their code in small print; you may need

a magnifying glass to read this on small signal diodes.

Example:       

LIGHT-EMITTING DIODE (LED):

The longer lead is the anode (+) and the shorter lead is the cathode (&minus). In the schematic

symbol for an LED (bottom), the anode is on the left and the cathode is on the right.

Lighemitting diodes are elements for light signalization in electronics.

They are manufactured in different shapes, colors and sizes. For their low price, low

consumption and simple use, they have almost completely pushed aside other light sources-

bulbs at first place.

It is important to know that each diode will be immediately destroyed unless its current is

limited. This means that a conductor must be connected in parallel to a diode. In order to

correctly determine value of this conductor, it is necessary to know diode’s voltage drop in

forward direction, which depends on what material a diode is made of and what colors it is.

Values typical for the most frequently used diodes are shown in table below: As seen, there are

three main types of LEDs. Standard ones get full brightness at current of 20mA. Low Current

diodes get full brightness at ten time’s lower current while Super Bright diodes produce more

intensive light than Standard ones.

Since the 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).

Switches and Pushbuttons:

A push button switch is used to either close or open an electrical circuit depending on the

application. Push button switches are used in various applications such as industrial equipment control

handles, outdoor controls, mobile communication terminals, and medical equipment, and etc. Push button

switches generally include a push button disposed within a housing. The push button may be depressed to

cause movement of the push button relative to the housing for directly or indirectly changing the state of

an electrical contact to open or close the contact. Also included in a pushbutton switch may be an

actuator, driver, or plunger of some type that is situated within a switch housing having at least two

contacts in communication with an electrical circuit within which the switch is incorporated.

Typical actuators used for contact switches include spring loaded force cap actuators that reciprocate

within a sleeve disposed within the canister. The actuator is typically coupled to the movement of the cap

assembly, such that the actuator translates in a direction that is parallel with the cap. A push button switch

for a data input unit for a mobile communication device such as a cellular phone, a key board for

a personal computer or the like is generally constructed by mounting a cover member directly on a circuit

board. Printed circuit board (PCB) mounted pushbutton switches are an inexpensive means of providing

an operator interface on industrial control products. In such push button switches, a substrate which

includes a plurality of movable sections is formed of a rubber elastomeric. The key top is formed on a top

surface thereof with a figure, a character or the like by printing, to thereby provide a cover member. Push

button switches incorporating lighted displays have been used in a variety of applications. Such switches

are typically comprised of a pushbutton, an opaque legend plate, and a back light to illuminate the legend

plate.

Block Diagram For Regulated Power Supply (RPS):

Figure: Power Supply

Description :

Transformer

A transformer is a device that transfers electrical energy from one circuit to another through

inductively coupled conductors—the transformer's coils. A varying current in the first or primary

winding creates a varying magnetic flux in the transformer's core, and thus a varying magnetic

field through the secondary winding. This varying magnetic field induces a varying

electromotive force (EMF) or "voltage" in the secondary winding. This effect is called mutual

induction.

Figure: Transformer Symbol

(or)

Transformer is a device that converts the one form energy to another form of energy like a

transducer.

Figure: Transformer

Basic Principle

A transformer makes use of Faraday's law and the ferromagnetic properties of an iron core to

efficiently raise or lower AC voltages. It of course cannot increase power so that if the voltage is

raised, the current is proportionally lowered and vice versa.

Figure: Basic Principle

Transformer Working

A transformer consists of two coils (often called 'windings') linked by an iron core, as shown in

figure below. There is no electrical connection between the coils; instead they are linked by a

magnetic field created in the core.

Figure: Basic Transformer

Transformers are used to convert electricity from one voltage to another with minimal loss of

power. They only work with AC (alternating current) because they require a changing magnetic

field to be created in their core. Transformers can increase voltage (step-up) as well as reduce

voltage (step-down).

Alternating current flowing in the primary (input) coil creates a continually changing magnetic

field in the iron core. This field also passes through the secondary (output) coil and the changing

strength of the magnetic field induces an alternating voltage in the secondary coil. If the

secondary coil is connected to a load the induced voltage will make an induced current flow. The

correct term for the induced voltage is 'induced electromotive force' which is usually abbreviated

to induced e.m.f.

The iron core is laminated to prevent 'eddy currents' flowing in the core. These are currents

produced by the alternating magnetic field inducing a small voltage in the core, just like that

induced in the secondary coil. Eddy currents waste power by needlessly heating up the core but

they are reduced to a negligible amount by laminating the iron because this increases the

electrical resistance of the core without affecting its magnetic properties.

Transformers have two great advantages over other methods of changing voltage:

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.

Classification of Transformer

Step-Up Transformer

Step-Down Transformer

Step-Down Transformer

Step down transformers are designed to reduce electrical voltage. Their primary voltage is

greater than their secondary voltage. This kind of transformer "steps down" the voltage applied

to it. For instance, a step down transformer is needed to use a 110v product in a country with a

220v supply.

Step down transformers convert electrical voltage from one level or phase configuration usually

down to a lower level. They can include features for electrical isolation, power distribution, and

control and instrumentation applications. Step down transformers typically rely on the principle

of magnetic induction between coils to convert voltage and/or current levels.

Step down transformers are made from two or more coils of insulated wire wound around a core

made of iron. When voltage is applied to one coil (frequently called the primary or input) it

magnetizes the iron core, which induces a voltage in the other coil, (frequently called the

secondary or output). The turn’s ratio of the two sets of windings determines the amount of

voltage transformation.

Figure: Step-Down Transformer

An example of this would be: 100 turns on the primary and 50 turns on the secondary, a ratio of 2 to 1.

Step down transformers can be considered nothing more than a voltage ratio device.

With step down transformers the voltage ratio between primary and secondary will mirror the

"turn’s ratio" (except for single phase smaller than 1 kva which have compensated secondary). A

practical application of this 2 to 1 turn’s ratio would be a 480 to 240 voltage step down. Note that

if the input were 440 volts then the output would be 220 volts. The ratio between input and

output voltage will stay constant. Transformers should not be operated at voltages higher than

the nameplate rating, but may be operated at lower voltages than rated. Because of this it is

possible to do some non-standard applications using standard transformers.

Single phase step down transformers 1 kva and larger may also be reverse connected to step-

down or step-up voltages. (Note: single phase step up or step down transformers sized less than 1

KVA should not be reverse connected because the secondary windings have additional turns to

overcome a voltage drop when the load is applied. If reverse connected, the output voltage will

be less than desired.)

Step-Up Transformer

A step up transformer has more turns of wire on the secondary coil, which makes a larger

induced voltage in the secondary coil. It is called a step up transformer because the voltage

output is larger than the voltage input.

Step-up transformer 110v 220v design is one whose secondary voltage is greater than its primary

voltage. This kind of transformer "steps up" the voltage applied to it. For instance, a step up

transformer is needed to use a 220v product in a country with a 110v supply.

A step up transformer 110v 220v converts alternating current (AC) from one voltage to another

voltage. It has no moving parts and works on a magnetic induction principle; it can be designed

to "step-up" or "step-down" voltage. So a step up transformer increases the voltage and a step

down transformer decreases the voltage.

The primary components for voltage transformation are the step up transformer core and coil.

The insulation is placed between the turns of wire to prevent shorting to one another or to

ground. This is typically comprised of Mylar, nomex, Kraft paper, varnish, or other materials. As

a transformer has no moving parts, it will typically have a life expectancy between 20 and 25

years.

Figure: Step-Up Transformer

Applications :

Generally these Step-Up Transformers are used in industries applications only.

Types of Transformer

Mains Transformers

Mains transformers are the most common type.  They are designed to reduce the AC mains

supply voltage (230-240V in the UK or 115-120V in some countries) to a safer low voltage.

The standard mains supply voltages are officially 115V and 230V, but 120V and 240V are the

values usually quoted and the difference is of no significance in most cases.

Figure: Main Transformer

   

To allow for the two supply voltages mains transformers usually have two separate primary coils

(windings) labeled 0-120V and 0-120V. The two coils are connected in series for 240V (figure

2a) and in parallel for 120V (figure 2b). They must be wired the correct way round as shown in

the diagrams because the coils must be connected in the correct sense (direction):

Most mains transformers have two separate secondary coils (e.g. labeled 0-9V, 0-9V) which may

be used separately to give two independent supplies, or connected in series to create a centre-

tapped coil (see below) or one coil with double the voltage.

Some mains transformers have a centre-tap halfway through the secondary coil and they are

labeled 9-0-9V for example. They can be used to produce full-wave rectified DC with just two

diodes, unlike a standard secondary coil which requires four diodes to produce full-wave

rectified DC.

A mains transformer is specified by:

1. Its secondary (output) voltages Vs.

2. Its maximum power, Pmax, which the transformer can pass, quoted in VA (volt-amp). This

determines the maximum output (secondary) current, Imax...

...where Vs is the secondary voltage.  If there are two secondary coils the maximum

power should be halved to give the maximum for each coil.

3. Its construction - it may be PCB-mounting, chassis mounting (with solder tag

connections) or toroidal (a high quality design).

Audio Transformers

Audio transformers are used to convert the moderate voltage, low current output of an audio

amplifier to the low voltage, high current required by a loudspeaker.  This use is called

'impedance matching' because it is matching the high impedance output of the amplifier to the

low impedance of the loudspeaker.

Figure: Audio transformer

Radio Transformers

Radio transformers are used in tuning circuits. They are smaller than mains and audio

transformers and they have adjustable ferrite cores made of iron dust. The ferrite cores can be

adjusted with a non-magnetic plastic tool like a small screwdriver. The whole transformer is

enclosed in an aluminum can which acts as a shield, preventing the transformer radiating too

much electrical noise to other parts of the circuit.

Figure: Radio Transformer

Turns Ratio and Voltage

The ratio of the number of turns on the primary and secondary coils determines the ratio of the

voltages...

...where Vp is the primary (input) voltage, Vs is the secondary (output) voltage, Np is the number

of turns on the primary coil, and Ns is the number of turns on the secondary coil.

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.

Figure: Diode Symbol

A diode is a device which only allows current to flow through it in one direction.  In this

direction, the diode is said to be 'forward-biased' and the only effect on the signal is that there

will be a voltage loss of around 0.7V.  In the opposite direction, the diode is said to be 'reverse-

biased' and no current will flow through it.

Rectifier

The purpose of a rectifier is to convert an AC waveform into a DC waveform (OR) Rectifier

converts AC current or voltages into DC current or voltage.  There are two different rectification

circuits, known as 'half-wave' and 'full-wave' rectifiers.  Both use components called diodes to

convert AC into DC.

The Half-wave Rectifier

The half-wave rectifier is the simplest type of rectifier since it only uses one diode, as shown in

figure.

Figure: Half Wave Rectifier

Figure 2 shows the AC input waveform to this circuit and the resulting output.  As you can see,

when the AC input is positive, the diode is forward-biased and lets the current through.  When

the AC input is negative, the diode is reverse-biased and the diode does not let any current

through, meaning the output is 0V.  Because there is a 0.7V voltage loss across the diode, the

peak output voltage will be 0.7V less than Vs.

Figure: Half-Wave Rectification

While the output of the half-wave rectifier is DC (it is all positive), it would not be suitable as a

power supply for a circuit.  Firstly, the output voltage continually varies between 0V and Vs-

0.7V, and secondly, for half the time there is no output at all. 

The Full-wave Rectifier

The circuit in figure 3 addresses the second of these problems since at no time is the output

voltage 0V.  This time four diodes are arranged so that both the positive and negative parts of the

AC waveform are converted to DC.  The resulting waveform is shown in figure 4.

Figure: Full-Wave Rectifier

Figure: Full-Wave Rectification

When the AC input is positive, diodes A and B are forward-biased, while diodes C and D are

reverse-biased.  When the AC input is negative, the opposite is true - diodes C and D are

forward-biased, while diodes A and B are reverse-biased.

While the full-wave rectifier is an improvement on the half-wave rectifier, its output still isn't

suitable as a power supply for most circuits since the output voltage still varies between 0V and

Vs-1.4V.  So, if you put 12V AC in, you will 10.6V DC out.

Capacitor Filter

The capacitor-input filter, also called "Pi" filter due to its shape that looks like the Greek letter

pi, is a type of electronic filter. Filter circuits are used to remove unwanted or undesired

frequencies from a signal.

Figure: Capacitor Filter

A typical capacitor input filter consists of a filter capacitor C1, connected across the rectifier

output, an inductor L, in series and another filter capacitor connected across the load.

1. The capacitor C1 offers low reactance to the AC component of the rectifier output while

it offers infinite reactance to the DC component. As a result the capacitor shunts an

appreciable amount of the AC component while the DC component continues its journey

to the inductor L

2. The inductor L offers high reactance to the AC component but it offers almost zero

reactance to the DC component. As a result the DC component flows through the

inductor while the AC component is blocked.

3. The capacitor C2 bypasses the AC component which the inductor had failed to block. As

a result only the DC component appears across the load RL.

Figure: Centered Tapped Full-Wave Rectifier with a Capacitor Filter

Voltage Regulator

A voltage regulator is an electrical regulator designed to automatically maintain a constant

voltage level. It may use an electromechanical mechanism, or passive or active electronic

components. Depending on the design, it may be used to regulate one or more AC or DC

voltages. There are two types of regulator are they.

Positive Voltage Series (78xx) and

Negative Voltage Series (79xx)

78xx:

’78’ indicate the positive series and ‘xx’indicates the voltage rating. Suppose 7805 produces

the maximum 5V.’05’indicates the regulator output is 5V.

79xx:

’78’ indicate the negative series and ‘xx’indicates the voltage rating. Suppose 7905

produces the maximum -5V.’05’indicates the regulator output is -5V.

These regulators consists the three pins there are

Pin1: It is used for input pin.

Pin2: This is ground pin for regulator

Pin3: It is used for output pin. Through this pin we get the output.

Figure: Regulator

UNIDIRECTIONAL CURRENT CONTROLLER :

Here in the place of unidirectional current controller we are using diodes which 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.

Figure: Diode Symbol

A diode is a device which only allows current to flow through it in one direction.  In this

direction, the diode is said to be 'forward-biased' and the only effect on the signal is that there

will be a voltage loss of around 0.7V.  In the opposite direction, the diode is said to be 'reverse-

biased' and no current will flow through it. By connecting this device the current cannot flow in

reverse direction from battery.

IINVERTERNVERTER

Inverter:

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 were made to work in

reverse, and thus were "inverted", to convert DC to AC.

The inverter performs the opposite function of a rectifier.

Symbol of Inverter

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.

As they became available with adequate power ratings, transistors and various other types

of semiconductor switches have been incorporated into inverter circuit designs.

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.

Other types of storage organs (such as corms, rhizomes, and tubers) are sometimes

erroneously referred to as bulbs. The correct term for plants that form underground storage

organs, including bulbs as well as tubers and corms, is geophytes.

Some epiphytic orchids (family Orchidaceous) form above-ground storage organs called pseudo

bulbs that superficially resemble bulbs.

Incandescent:

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 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.

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 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.

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 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 ballasts need 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 vapor

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.

WORKING PROCEDURE:

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 piezo electric 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.

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

Applications:

Foot step generated power can be used for agricultural, home applications, streeght-lightining.

Foot step power generation can be used in emergency power failure situations.

Metros, Rural Applications etc.,

CONCLUSION

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 piezo electric sensor.

REFERENCE:

www.howstuffworks.com

www.answers.com

EMBEDDED SYSTEM BY RAJ KAMAL

Magazines:

www.Electronics for you.com

www.Electrikindia.com