final year embedded systems projects in chennai

http://www.embeddedinnovationlab.com ABSTRACT

Final year embedded systems projects in chennai . Nowadays energy and power are the one of the basic necessities regarding this modern world. As the demand of energy is increasing day by day, so the ultimate solution to deal with these sorts of problems is just to implement the renewable sources of energy. But these renewable energy sources must have to be adopted in practical manner by keeping an eye on all aspects regarding the research work. Final year ece projects in chennai .So then these techniques should be applied in order to get the desired output. In case of our project we have used the technique of power generation through footsteps as a source of renewable energy that we can obtained while walking on to the certain arrangements like footpaths, stairs, plate forms and these systems can be install elsewhere specially in the dense populated areas.final year eee projects in chennai .

The basic working principle of our project ‘footstep power generation system’ is based on the piezoelectric sensor. Final year mechanical projects in chennai.So in order to implement this foot step power generation system we adjust the wooden plates above and below the sensors and moveable springs, when we walk on the mat than automatically force is applied and as a result magnet fixed under the top wooden sheet and moves into the cavity. As this cavity is fixed at bottom wooden sheet of mat so between the moveable springs adjusted between the top and bottom sheets.final year engineering projects in chennai

As a result of completing the above procedure or technique we made ourselves able to design such compatible system through which we could run our home appliances through AC output. As our main purpose was to charge the battery through DC output and then by inverting it into AC for normal common usage.

Thus as a result we have concluded that these types of designs and techniques of power generating systems are very useful and handy in order to match the supply and demand of energy globally as well.

http://www.embeddedinnovationlab.com


CHEPTER 1

INTRODUCTION

Energy surrounds us in all aspects of life, it’s up to us weather we use it

constructively for the benefit of mankind or


we use it destructively to harm others. Alternative energy resources are not based

on fossils fuels or atom distribution.

The alternatives are

Solar energy

Wind power

Geothermal

Hydroelectric

Nuclear

We are introducing a new way to overcome the increasing demand of energy.

We are utilizing human force and we named it FSGS (Foot Step Generating

System). Final year eee projects in bangalore

1.1 Motivation

Man is hunter of energy from the starting of human being. First he started in

the form of food i.e. to get energy from animals and plants. Then man started

cultivation of land to get food and he gave a new trend to energy by training

animals for his help in doing job. Demand is always increasing day by day and

year by year so he started to use wind for driving ships in the sea and falling water

to turn water wheel. Final year projects in chennai

1.1.1 Defining the problem


http://www.embeddedinnovationlab.com/

http://www.embeddedinnovationlab.com In Pakistan the demand is more than the daily energy produced so we are

facing power-cut after approximate 1 hour and industries are in hell these days.

People uses rechargeable batteries (UPS) or diesel/petrol engine to fulfill their

demands. The use of stand by generator is common in industries and large offices.

1.2 Objective of project

“Final year mechanical engineering projects in chennai .” Our aim is to

produce energy by a source that has no negative effect on environment and its

output can be used to overcome the crises in Pakistan.


1.3 Principle of project

The principle of project has few steps in it regarding which generate power

through footsteps using piezoelectric sensor. We start with the proper arrangement

of electrical components and equipment which transforms the mechanical energy

in to electrical energy.

The second part of piezoelectric sensor is mechanical part, which involves

spring connection to piezo, so by movement of footsteps up and down spring is

giving vibration to piezo which generate electrical power and this power will be in

the form of electric current. And these two arrangements electrical and mechanical

combined together which transforms mechanical energy to electrical energy.

When producing power with footsteps on piezo there is some load placed at the

end which used power, then power stored in battery is decreased so more footsteps

on spring which vibrate the step and due to vibration force power generated.

“Final year engineering projects in bangalore. “ Voltages which produced

from piezoelectric sensor is A.C voltages while we need D.C voltages to store in

the battery, so for this purpose rectifier circuit is used. In rectifier circuit we can

used either half wave rectifier or full wave rectifier. Our concern is with full wave


http://www.embeddedinnovationlab.com/

http://www.embeddedinnovationlab.comrectifier because it gives full value. So now A.C voltages are converted in to D.C

voltages. Now by placing next the battery charger circuit and battery, battery

charger circuit is charging the battery and this D.C voltages is stored in the lead

acid battery of 12 volt. Final year be projects in chennai.

Lead acid battery of 12 volt which is charged is now further connected to the

inverter. As we have D.C voltages stored in the battery but we need A.C voltages

because mostly load need A.C voltages so by using the inverter circuit which is

such designed that it inverts the voltages from battery which is 12 volt D.C to 220

volt A.C voltages.final year vlsi projects in chennai and bangalore

So this A.C voltage is used in different appliances such as for charging the

laptop battery and also to charge the handset, it can also be used to lightening up

the energy savor. If we need more power from this technique then used more steps

for more electric current, final year ece projects in chennai.and also increase the

connection of piezoelectric sensor which is connected parallel and series

combination and by vibrating with the help of footsteps gives electrical power

which is in the form of electric current. Then ability of battery and inverter should

be increased, battery should be of high current and voltages and inverter is such

designed that it convert that electrical power to A.C voltages and also no loss in it,

then output power will be increased and can be used more electrical appliances and

also can be used such appliances which need more electric current..final year ece

projects in bangalore.

1.4 Renewable energy resources

Due to global warming and worldwide heating now globe is stirring to

renewable energy resources. Other alternative resources which are using for

generating electrical power are very expensive and either their units are shut down

in Pakistan. Maintenance of already existing energy sources caused huge amount


http://www.embeddedinnovationlab.comof cost, so much cost is due to the heavy machinery involving in it which need

maintenance and also the labor and engineering work. These existing energy

sources are also harmful for humans, the rays from nuclear generator caused cancer

to the nearer city, and final year mechanical projects in bangaore.hydroelectric

projects caused flood to cities and also damaged the fields. So due to these

problems globe is stirring to renewable energy resources which are fairly low cost,

efficient while using, reliable and caused no uneasiness to human nature. The

renewable energy resources such as solar panels, wind turbine, geo thermal, bio

gas etc. they all used natural things for generating electrical power so the danger to

human will be no more as in the case of nuclear energy. The maintenance costs of

these plants are very low. These plants do not contain any heavy machinery for

generating electrical power. So when these plants are out of working or some error

in it and it needs maintenance then the maintenance cost is not so much high and

also it don’t need labor works because it is not involving any heavy machinery in it

and it only requires engineering work in it. Final year eee projects in chennai.So

that’s why our project is of renewable energy resources and we generate electrical

power by footsteps and it is fairly low cost and efficient technique.

1.5 Energy crises in Pakistan

Power is the mainly central basis in support of financial increase of a state.

There will be main power crises that must look Pakistan in future for next two to

three years in power, oil and natural gas. Now Pakistan is suffering energy crises in

all most every field. So that’s why Pakistan gross domestic product is low because

due to industrial shut down, shut down of local factories as well domestic factories.

Today mostly everything every business is depended upon power. Now power is

the backbone of every country and in Pakistan which is also nuclear country is

suffering too much problem of energy from last five to seven years.


http://www.embeddedinnovationlab.com Energy crises in Pakistan have a lot of reasons. Recession is one of them

Pakistan is suffering recession and economic crises from last seven years. Inflation

is increased to its higher value, so that’s why investment from foreigner is

decreased to great extent. Due to all these problems Pakistan is suffering the

energy crises. Final year eee projects in bangalore.

The other reason of short fall is that money not giving to independent power

producers. So these independent power producers not deliver full power and also

they mostly shut down their units. And also money is no giving to oil delivers and

oil producers. Money also doesn’t give to Pakistan state oil which delivers oil to

power plants. When they don’t have money then they don’t deliver oil and oil is

necessary for power plant so short fall increases. Pakistan has also loan on it so

they don’t get any loan from World Bank. So that’s why energy is not producing in

the plants and they shut down their units and our economic growth is decreased. If

they don’t have power industrial and domestic structure will be finished.

Further reason of energy crises in Pakistan are not constructed the new

dams and new power plants units. “Final year mechanical projects in chennai.”

Kala bagh dam is constructed in past not completely but the feasibility report of

this dam is completed and equipment for this dam is also purchased and also it

fulfills all our electricity needs but due to political reasons this dam is not started

and its work is stopped so that’s why short fall increases day by day. Huge amount

of money is also wasted on this dam while there is no output also caused a lot of

problems. So if we are not constructed new dams and wasting the money then the

short fall increases and energy crises also increases to great extent. So construct

new dams to fulfill the need of energy.


The other reason for energy crises in Pakistan is not maintaining the

already build power plants once the power plant is damaged due to any reason then


http://www.embeddedinnovationlab.comthat unit will be completely shut down. And burden on other units increase which

in turns increase the short fall. Also the staffs don’t take care of power plants. So

this is also very bad aspect of energy crises in Pakistan. This can be reduced by

taking proper caring of power plants and maintained at right time. So in this case

short fall can be reduced. final year vlsi projects in chennai.

Due to corruption while running the power plants is also increase the

energy crises. As the corruption ratio in Pakistan is very high especially in

government sectors. So due to bad management and corrupt staff as well as

illegible officers working in power plants caused energy crises in Pakistan. Miss

management also causes problem while running the power plants. If power plant

unit is not turn off and turn on completely at specific time will increased energy

crises and short fall will be increased and this all happens in Pakistan.final year

engineering projects in chennai

Pakistan is also have very high demand of gas, industries and factories needs gas to

great extent but in Pakistan availability of gas is very low, some of the power plant

unit also works on gas but of not continuous supply of gas some of unit shut down

so that’s why short fall increases and energy crises also increases.

Solution: above mention we write all crises in Pakistan about energy so the

economy is low so we should find a way to generate electricity which is cheapest

and efficient. If we install our system to 300ft and 2500 men walk through that

area four times in a day then we can produce 0.7MegaWatt in a day. If we need

more energy area should increased.


1.6 Footstep power generation resources

There are various resources of power generation through which we can

generate the power with footsteps. It is unique and different type of power


http://www.embeddedinnovationlab.comgeneration system it requires a technology and huge amount of research work that

is why this type of generation system is mostly in use of developed countries.

This type of power generation can be done through various techniques and

methods like piezoelectric sensors, through mechanical arrangement like fly wheel

and gear wheel, pedal and springs type arrangement, staircase energy generating

system by rotating the generator, then also by implementing the faraday’s law of

electromagnetic induction by moving magnet into the coil through spring system.

Our project is based on piezoelectric sensors we have designed structure

like mathere large number of sensors are placed in series and parallel connection.

The springs are placed between the sheets of sensors and springs have enough

tensile strength that they can bear the weight. . This type of footsteps power

generation system are eligible to be installed in crowded places and rural areas

cities in the places like railway stations, airports, footpaths where there is a rush of

pedestrians.

CHAPTER 2

LITERATURE SURVEY

2.1 Purpose

There are few methods to generate electrical energy from footsteps. Gear wheel and fly wheel are techniques to generate electrical power. This method also work on this principle and in it mechanical part are used because it is placed on where the number of peoples are more and energy produced by their movement on the floor.

Power would generated by footsteps of crowd on the floor. Piezo plate scheme is located beneath the floor then the then there will be sheet covering the piezo plate and also spring will be there for vibration force on piezo. The piezo plate will be in chunks in the floor. This plate will generate power in the type of electric current.


http://www.embeddedinnovationlab.comThe power produced by pedestrians can also be used as additional features such as to lightning up street light or the light that used at that place for pedestrians. So the pedestrians should give credit the energy which produced by their movement.

2.2 Literature Analysis

To generate electrical power using footsteps one step will be enough at this level to produced electrical energy.

As studied few methods from which power is generated. Following are the steps of fly and gear wheel method. As piezo plate is also involves these steps.

First step is by proper arrangement of electrical components and equipment which transforms the mechanical energy in to electrical energy.

After the arrangement of electrical system which transforms mechanical energy to electrical energy, then the spring is attached with sheet to piezo so the spring arrangement is done, spring vibrate the piezo.

When load using the power then this spring is used to vibrate the step by force then power is produced. Final year ece projects in chennai.

Then the voltage that produced through steps is rectified and after battery charger circuit this D.C voltage is stored in the lead acid battery of 12 volt.

This lead acid battery is further attached to the inverter. The invert is such designed that it inverts the voltage from battery which is 12 volt D.C to 230 volt A.C.

So this A.C voltage is used in different appliances such as for charging the laptop battery and also to charge the handset, final year embedded system projects in chennai. it can also be used to lightening up the energy savor. If we need more power from this technique then used more steps for more electric current and also then ability of battery and inverter should be increased then output power will be increased.

2.2.1 Uses

The electrical power that is produced by footsteps is mostly suitable at where the numbers of pedestrians are more and also crowdie places.


http://www.embeddedinnovationlab.comThe places such as:

Universities

Bus Stands

Arrival and departure of passengers at air ports

Shopping Mall

Food streets

Footpath

Markets

Final year ece projects in bangalore. Pedestrian bridges this is the finest purpose of generating power by footsteps. Its cost is very low. This power then used for lights on bridge, street light, also light used for traffic purpose.

Public places final year mechanical projects in bangalore

These all are the places where just planting of system cost matter and as this cost is fairly low so unlimited input and high power will produce.

2.2.2 Aspects

Main feature of footstep power generation through piezoelectric is that electrical power produced by transforming mechanical energy to electrical energy of the movement of people on the floor where piezo plate is placed.

A further aspect of piezoelectric power generation system is that it is safe and secure to use, still this system is working, make no problem and no discomfort for the people, and it is totally risk free method.final year vlsi projects in bangalore

Footstep power generation through piezoelectric have mechanical part as well as electrical part but this system has not so many losses, also this system is not damaged completely by any sort of thing and this system has very low cost of equipments and components so if system is damaged then the cost of the system is very low, this is also the feature of footstep power generating system through


http://www.embeddedinnovationlab.compiezoelectric. This system also has the capability to store the electrical power in storage battery.

This system generate electricity to lightening up the lights used in streets, also for traffic purpose, sign boards of roads, the power which will be left behind is given to national grid for electricity purpose.final year projects in chennai

This system footstep power generating system through footstep is cheap, efficient and reliable method.

upcoming extent

Now globe is stirring to the renewable resources due to the worldwide heating so this project footstep power generation through piezoelectric has a vast extent. Other renewable resources are also used such as solar sterling plant, bio gas, wind turbine etc. but if contrast with footstep power generation through piezoelectric sensor is fairly low cost means to say inexpensive, useful, efficient and reliable than these renewable resources.

2.3 Block diagram



Figure 2.1 Footstep general block diagram 2.3.1 Components / parts

Piezoelectric sensor mat

Battery charger circuit

Lead Acid Battery

Inverter

Load

2.3.1.1 Timber Pieces


http://www.cheers4all.com/2013/08/footstep-power-generation-system/2-40/

http://www.embeddedinnovationlab.com We made timber pieces for footsteps on which force will apply. In footstep power generation through piezoelectric sensor project designing a plate consist of piezo which is connected in series and parallel arrangement. There are three timber pieces each has width and length of 1ft. Final year eee projects in chennai

2.3.1.2 Springs

Spring is used on the top of each piezo sensor, while applying force on spring it gives vibration to piezo and power produced in the form of electric current.

3.0 THEORETICAL DESCRIPTION

3.1 Introduction

We mostly relay on our hydro source which is not as much enough as we required or maybe our country is not utilizing it in a good manner so it is primary need of the country that power may produce by any source so that they can fulfill the need of the people and industries as well because without providing power to industries we are not able to make people happy. To start new large projects first we need lot of money i.e. nuclear power, hydro need much more money. Lot of energy is wasted daily coming from some natural sources. The idea of this project live behind that human walking is a natural process which can’t be stopped, so why we waste it knowing the fact that this energy is useful for producing energy. We can use it in highly populated country like china but also in our country in which energy crises are headline of the day. We are erasing this problem on cheap and small projects implementation.

FOOT STEP POWER GENERATION USING PIEZOELECTRIC MATERIAL

Foot Step Power Generation Using Piezoelectric Material



In this project the conversion of the force energy in to electrical energy. The control mechanism carries the piezoelectric sensor, A.C ripples neutralizer,


http://www.embeddedinnovationlab.comunidirectional 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. Here we are using 16X2 LCD to display the voltage values of the rechargeable battery using AT89S52.

"An average person, weighing 60 kg, will generate only 0.1 watt in the single second required to take two steps across the tile," said Yoshiaki Takuya, a planner with Sound power Corp. "But when they are covering a large area of floor space and thousands of people are stepping or jumping on them, then we can generate significant amounts of power."Stored in capacitors, the power can be channeled to energy-hungry parts of the station, he said, including the electrical lighting system and the ticket gates. Final year eee projects in chennai

.

If by the grace of ALLAH we become successful in the project then human energy that is wasted all the day in all life could be made useful for mankind. The best implementation of this idea will be at railway stations, crowded malls, universities, colleges, schools, government offices and areas with large crowd daily.final year engineering projects in chennai

In this project we are producing electricity by simply walking or running or by vehicles which is non conventional source of energy and at this stage non-conventional energy is very needed for our country. We can make it possible through mechanical design or through electrically. We are using piezo electric sensor to do it. Some researchers also win this game by coil and magnet arrangement but we are not discussing it because it not our job, it is totally mechanically. In this some people make stair-case arrangement.

This project converts the vibration energy in to electrical energy. The control mechanism carries the piezo electric sensor, current controller and 12V, 1.2Amp 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 220 Volt A.C. This 220 Volt A.C voltage is used to activate the


http://www.embeddedinnovationlab.comloads. We are using conventional battery charging unit also for giving supply to the circuitry.

3.2 Sensor

A sensor is a device that measures a physical quantity and converts it into waveform which can be read by an observer. Like mercury which shows the temperature of the body by the liquid expansion. Sensors are calibrated by a scale which is easy for observer.

3.3 Piezo Electric Sensors

A device which measures the force, pressure, strain and vibration and converts it into electrical signals is known as piezo electric sensor. These materials exhibit a property known as piezo electric effect in which force or vibration is produced an electric field is created which causes a potential difference across these materials and hence current start flowing through it.

Final year embedded system projects in chennai Piezoelectricity is from Greek word which means pressure electricity. There are many crystals like Lead Zirconate Titanate that produce electric charges when pressure is applied on them or they vibrate when subjected to potential difference. The amount of charges depends upon the frequency of vibration. AC voltage vibrates the piezo electric material at the same frequency at which we are providing AC.

Quartz is the best example of piezo material. The materials with ABO3 have the strong property of piezo electricity, where ‘A’ denotes large divalent ion (lead) while ‘B’ is for small tetravalent ion (titanium).

Piezoelectric technology rises due to set of inherent advantages i.e.

High modulus of elasticity ( N/) Piezo material is very rugged Have very high natural frequency Linear over amplitude Insensitive to EM radiation (can be used in every conditions ) No effect of radiations Tourmaline is stable at high temperature also (even sensor works at 1000°C) As piezo material is sensitive to pressure, some are also sensitive to

temperature they are called as pyroelectrical.



Figure 3.1 Piezo sensor

The piezoelectric sensor shown in figure 3.2 is of tourmaline material. It is very effective for daily usage because it can bear high temperature; it is rough and is linear over amplitude. The material with no centre of symmetry then it will exhibit the property of piezoelectricity.

3.3.1 Geometry

Everyone thinks that a simple material having ordinary crystal has a property of producing electrical spike, what it has that make him doing such a wonderful job. Questions arises in mind that

What make it different from other materials? Are any free electrons present in its atom? Is this material exhibit the property of magnet and coil?

The answer to these questions is present in the structure of the piezoelectric material. The answer to why an electric spike produces when subjected to pressure lives behind its structure of crystal.final year matlab projects in chennai

Most piezoelectric material is ionic salts containing cat ions and anions, these ions form a unit cell. The crystal of piezoelectric material contains three dimensional array of unit cell. The unit cell has a positive charge centre and negative charge centre. If these centre are at same place i.e. centre coincide then there will be no electrical dipole and hence no spike. But if their centres do not



http://www.embeddedinnovationlab.comcoincide then the electrical spike value will be according to the magnitude of charges and distance of positive and negative charges. There are symmetric and asymmetric unit cell and vibration or strain causes every unit cell to distort but the symmetric cell’s centre will continue to coincide after stress. In case of asymmetric cell, force will cause the centre of positive and negative changes which will create electrical voltage. There are 32 unit cells from which 20 have piezoelectric property because they are asymmetric.

3.3.1.1 Constant of piezoelectricity

It is defined as the ratio of strain (pressure/length) over applied electric field i.e.

d = ————————– 3.1

Its units are

i.e. meter per volts.

Quartz (SI) has d = 3×

It will change its thickness up to 3nm when kilovolts are applied across its faces.

3.3.1.2 Electromechanical coupling constant

Electromechanical coupling constant K, this constant shows the conversion of electrical energy to mechanical energy or vice versa, so we can check the piezo electric effect by this constant also.

3.3.1.3 Materials

There are many materials which has the property of piezo electricity i.e.

Quartz SI Ammonium dihydrogenphosphate ADPN Potassium sodium tartrate KNa Rochelle salt


http://www.embeddedinnovationlab.comExcept quartz all others have strong piezo electric effect and are used in low cost project because their strength is weak.

3.3.2 Working of piezoelectric sensor

This effect is due to its geometry which contains a unit cell. The unit cell of

piezoelectric material has a cubic shape which contain positive charges at all its

ends as shown in figure 3.3(a). In this figure we are discussing only those materials

which has asymmetric nature because otherwise no voltage spike will produce and

no working will be there. We actually want to produce electric charges or field

from movement of charges so it is our prime objective to produce voltage and

current. Now we are going towards working principle

Initially no pressure is applied on the unit cell so positive charge is at centre

and length between positive and negative is same. When stress, pressure or

vibration is applied to material then the spacing between the positive and negative

charge increases which cause a voltage to produce and we will sense it by any

device or we will use it for our benefit or power requirements. The Figure 2(b)

shows the unit cell after stress is appliedIt’s clear in above picture that the positive

charge has been misplaces from its original position which means the spacing

between them changes. Space change shows the voltage spike which means its

comfortable to use them as power generation.

3.3.3 Usage of piezoelectric sensor

Due to his property it canbe used in many applications i.e.

Piezoelectric sensors is perfect contrivance for the measurement of various processes. They are used for eminence assertion, progression manage and for research and development in many different industries. It was only in the 1950s that the piezoelectric effect on track for industrial usage. Since then it can be


http://www.embeddedinnovationlab.comregarded as a grown-up technology with an stupendous steadfastness. It has been fruitfully used in various applcations such as

Medical Aerospace In nuclear instrumentation Touch pads of cell phones Power generations In Toys In microphone and ultrasound detector Convert oscillations of diaphragm(caused by wave) into electrical signal Iginition devices Electronics lighter Iginition system for gas stoves

The block explanation of a single piezoelectric sensor which is used to convert force or pressure into electrical spike. As clear from figure that when pressure from up or down is applied on the sensor then analog voltmeter or galvanometer shows the deflection of few volts. If vibration is severed then it may give spike up to 15V or in some case 30 V. This single has very low power rating because its current is low so we combined them to make desired output. The working of this sensor is easily understood by the block diagram in figure 3.4.

Figure 3.3 Piezo voltage checking

3.4 Already developed systems



http://www.embeddedinnovationlab.com Fly wheel and gear arrangement Stair case and faraday’s law arrangement Rack & Pinion and chain Sprocket arrangement

3.5 Proposed system

Our proposed system contains following parts

Piezo electric sensor Full-wave bridge rectifier Battery charger unit 12 V, 1.2 Amp Lead battery Inverter Transformer AC loads DC loads

We are using piezo sensor of tourmaline material shown in figure 3.2, the output of this single sensor was not as much as we need so make a series and parallel combinations of piezo electric sensor. But making this become a challenge because it involve mechanical design also like to press all piezo sensors together we need springs and wooden sheets. So the parts of piezo electric sensor are

3.5.1 Piezo electric sensor

Instead of making tiles we use wooden sheets like shown in above figure (taken by camera) for the purpose of stepping. All four sides of two sheets are connected by nut and bolt. Piezo sensors are placed on the bottom plate on which holes of diameter 0.5mm less than piezo diameter are drilled. 80 piezo sensors like shown in figure3.2 are placed on the lower plate which upper plate also has holes of diameter equal to diameter of spring. These spring are unguided and are placed on the piezo to provide stress them so that they vibrate and we get the required output.

There will be third plate on these two plates on which we place step or drive the tire of vehicle so that it can press the bundles of spring which would cause the piezo to presses and we would get required output.


http://www.embeddedinnovationlab.comActually we make three same sets of plates which are as similar to tiles of floor so that by simply walking on them we get the required output.

We are using spring to make our sensor works because we are using 80 piezo sensors so we cannot press them simultaneously by foot, we tried much to get rid of these springs but we were not able to get good output without these springs so we are using spring of much tensile strength so that they can bear the weight of a person and also has not much compressive force so that first we have to provide enough force to overcome spring force.

Piezo

These are piezo sensors which are in amount of 80 and are on the lower plate and a spring from the upper plate is place on this piezo which is compressed by the third plate on which we step. These piezo plates are pasted on the lower plate which a hole of diameter slightly less than the diameter of the piezo sensor as shown above.

Rectifier

The piezo sensor produces AC spikes so we have to rectify it before sending to battery because battery stores only DC. We tried half wave rectification by simple diode but we cannot get output because already current was very low by clipping one cycle the power rating becomes half and hence we are in loss. Then we tried full-wave bridge rectifier and got the result. But the problem was that we have to connect bridge rectifier with every piezo sensor which was a challenge but we made it.

Battery charger circuit

To charge a battery we need a charge controller which is important part of electronics portion of our project and will be discussed clearly later as we will start electronics chapter. LM 338 and LM 358 are ICs used in this circuit.

Battery

We are using Lead Acid battery of 12 V and current of 1.2 Amp. We want to store charges so that we can use the power generated by foot step not only in busy hour but also in other part of the day.

Inverter


http://www.embeddedinnovationlab.com Inverter is used to run AC loads and we are storing in battery which stores DC but our load is AC so we use inverter. TIP 122 and TIP 127 are main ICs of our circuit.

Transformer

Transformer is part of inverter. We are using center tape transformer of 12+12 V / 220 V.

4.0 BATTERY CHARGER CONTROL CIRCUITRY

We have arrangement of piezo sensors so that we want to control charging and discharging of the battery. In other words we want to protect the battery from over charging effects which could damage the battery.

Actually we used 12V Lead acid battery in this project. We set specific voltages for battery charging and after indication of full battery; there is cut-off system to remove the battery from charging circuitry.

4.1 Schematic diagram



Figure 4.1 Schematic diagram of battery charger circuit

4.1.1 List of components

LM358 Capacitor 100n Potentiometer 5k Resistor 10k Transistor 2N2219 Capacitor 100u Zener diode 1N5233B LM338 LED Resistor 4.7k

4.1.2 Working principle of LM358

This IC contains dual low noise amplifiers which operate on single power supply.

It is a versatile, rugged workhorse with a thousand uses, from amplifying signal from variety of transducers or any other op-amp function.

4.1.2.1 Features

It has large DC voltage gain up to 100dB.



http://www.embeddedinnovationlab.com Its response bandwidth is up to 1MHz (temperature compensated). Its supply assortment is broad, For single supply 3VDC to 32vDC For double supply 1.5VDC to 16VDC

Its input offset voltage and current is low

4.1.2.2 Applications

All conventional op-amp circuits. Transducers amplifier.

4.1.3 Capacitor

There are basically two types of capacitors

Polar capacitor

Non-polar capacitor

Polar capacitors are that capacitors who have proper polarity mean positive and negative terminals. In other words we can say that they have embedded polarity as shown in figure 4.3 and they have effect on circuitry of their terminals but in case of non-polar capacitors don’t have specific positive and negative terminals as shown in figure 4.4, we can connect them in circuit without taking any care of terminals.

4.1.4 Transistor

Transistor is basically a semiconductor device consist of three layers either two p- and one n-type layer or one n- and two p-type layers called pnp and npn transistor respectively.

4.1.4.1 Types of transistor

There are basically three types (configurations) of bipolar transistor,

1. Common base configuration2. Common collector configuration3. Common emitter configuration


http://www.embeddedinnovationlab.comEach configuration has its own properties and results used in different kinds of circuits according to the requirement. While field effect transistor, terminals are gate, drain and source. Voltage at gate is resolute by current among drain and source.

4.1.4.2 Transistor as switch

When the transistor is biased in the saturation or cut-off region then it can be used as switch.http://www.embeddedinnovationlab.com

Figure 4.5 Characteristic graph of transistor

In cutoff mode transistor is fully off and its working state of affairs are zero base current, zero collector current and maximum collector to emitter voltage.

4.1.4.3 Advantages

Vacuum tube, transistor and integrated circuits More trustworthy Lesser in volume Less power utilization Lower voltages



http://www.embeddedinnovationlab.com Less heat More strong

4.1.4.4 Limitations

Transistor has limited power handling capabilities. In use temperature range of transistor is kept usually 50-60 degree Celsius. The least signal that can be functional to transistor is restricted by the

interior noise ended by the transistor. The minimum collector current have to be bigger than the saturation current

Ico, which is noticeably less than 100 microamperes in the majority junction types.

4.1.5 Zener diode

Figure 4.7 Zener diode

4.1.5.1 Working principle

The zener region of figure 4.8 is shown below. The attribute drops in an almost straight down method at a reverse bias potential denoted by Vz. The reality that arch drops down and away from the horizontal axis before up and away for the positive voltage Vf area reveals that the current in the zener region has a path reverse tothat of a forward biased diode. http://www.embeddedinnovationlab.com




Figure 4.8 Characteristic graph of zener diode

The minor gradient to the curve in the zener region reveals that there is an intensity of resistance to be connected with the zener diode in conduction mode.

4.1.6 Working principle of LM338

It is positive voltage regulator of 12V.

It has capability to supply current of 5A.

4.1.6.1 Features

Output is short-circuited sheltered

Thermal regulation

Modifiable yield along to 1.2V

Current limit stable with temperature

4.1.6.2 Applications

Adjustable power supplies

Battery charger circuits

Constant current regulators

4.2 How does it work???



http://www.embeddedinnovationlab.com For battery charging we use positive voltage regulator of 12V. We are using voltage divider at adjust pin of the regulator, by using this we adjust 14V for battery charging. Then we use LM358 as comparator configuration.

When battery will charge up to 14V then comparator circuit will active and battery charging will cutoff through transistor which will act like switch here.

In comparator circuit we use a zener diode of 5.1V as a reference and second signal of 5.3V. As the battery will fully charged then comparator circuit will activate and will cut off the battery from charging. http://www.embeddedinnovationlab.com

5.0 BATTERY

Battery consists of electrochemical cells to store electricity house in a single unit. In battery stored chemical energy is transformed into electrical energy. Some batteries are used once and some of them are rechargeable. Large batteries also provide stand by operation i.e. mobile, laptops etc.

5.1 Types of batteries

Mainly batteries are divided into two categories

1. Primary batteries2. Secondary batteries

5.1.1 Primary batteries

Primary batteries can produce current immediately on meeting. Disposable batteries are planned to be used once and useless. These are most usually used in handy devices that have low current drain, are only used occasionally, or are used well away from a different power source, such as in alarm and communication circuits where other electric power is only occasionally available. Disposable primary cells cannot be constantly recharged, since the chemical reactions are not easily reversible and active materials may not return to their original forms. Battery manufacturers propose against attempting recharging primary cells.

5.1.2 Secondary batteries


http://www.embeddedinnovationlab.com These batteries are charged before use. Charging is done by applying current which reverse the chemical reaction that take place for the period of use. The devices which are used to charge this type of batteries which provide rated value of current known as charger.

The oldest form of rechargeable battery is the lead-acid battery. This battery is prominent in that it consists of a liquid in an unsealed pot requiring that the battery be kept standing and the area be well ventilated to make certain safe spreading of the hydrogen gas formed by these batteries throughout overcharging. The lead-acid battery is also very heavy for the amount of electrical energy it can supply. Although, it’s low built-up cost and its high flow current levels make its use common.

6.0 INVERTER

Inverter is a combination of such components which converts DC signal into AC signal.

In this project we designed inverter which consists of following parts

1. Sine wave oscillator2. Drive circuitry3. Transformer

6.1 Sine wave oscillator

We designed this oscillator such that it gives us pure sinusoidal wave form. That wave form has 10Vp-p of frequency 50Hz. In this oscillator we can vary the frequency according to our own requirement but up to some extent.

Schematic diagram

PCB Layout

Components

Battery

LM358N

Capacitor 1u

Zener diode 1N5223B


http://www.embeddedinnovationlab.com Resistor 330k

Potentiometer 50k

Resistor 10k

Capacitor 5p

Resistor 51ohm

Potentiometer 1k

Capacitor 470n

Resistor 100k

6.2 Drive circuitry

The output comes from sine wave oscillator is given to the drive circuitry which consist of TIP122 and TIP127. By using these two components we increase the overall current of that wave form.

6.2.1 Schematic diagram

Figure 6.4 Drive circuitry of inverter

6.2.2 Components



http://www.embeddedinnovationlab.com Resistor 4.7k TIP 122 TIP 127

6.2.2.1 Working of TIP122

TIP122 pin configuration Its base current is 120mA, its mean that it works only for positive cycle of

the wave. When it becomes active it behaves like short circuit. At negative cycle voltage appear across collector.

6.2.2.2 Working of TIP127

Its base current is -120mA, its mean that it works only for negative cycle of the wave.

When it becomes active it behaves like short circuit. At positive cycle voltage appear across collector.

6.3 Transformer

Transformer is a device which is used to step up and step down the voltages according to our own requirement without changing frequency.

6.3.1 Working principle

Transformer has two types of winding as shown in figure 6.5

1. Primary winding2. Secondary winding

Mainly transformer work on the principle of mutual induction

6.3.1.1 Mutual induction

When alternating current pass through the primary winding then it produces the changing flux due to the production of magnetic field in the primary winding. As the amplitude of current increases, flux will increase. Then this changing flux will pass through the secondary winding of the transformer due to which current will induce in the secondary winding. This whole process is known as mutual induction.


http://www.embeddedinnovationlab.comThe voltage induced across the secondary is due to Faraday’s law of electromagnetic induction, which states that “Rate of change of flux linkage is equal to the induced emf.”

E=N ——————————- 6.1

Where ‘E’ is the induced emf and ‘N’ is the number of turns in equation 1.

6.3.2 Centre tapped Transformer

We use centre tap transformer as shown in figure 6.6 in the project of following rating

Voltage 12+12V to 220V

Current 1.2 Amperes

A centre tapped transformer works when a magnetic field is generated about the winding as alternating current passes during it. Alternating current occurs when a secondary winding is come within the magnetic field producing an alternating current inside this winding. Within the primary winding, alternating current induces an alternating magnetic flux. The flux flows in the region of the ferromagnetic core as it varies direction with each cycle. Another alternating current is then created in every turn of the secondary windings by the alternating flux in the core. In our project we use this transformer to transform 12V to 220V.

7.0 RECTIFIER

Rectification is the process in which input signal is being clipped or removed after passing through the arrangement of diodes. This process is known as rectification.

There are two types of rectification

1. Half wave rectification2. Full wave rectification

7.1 Half wave rectification


http://www.embeddedinnovationlab.com In this process half wave of the input signal is clipped after passing through the diodes as shown in figure 7.1

As we see in the figure 7.1 that only negative cycle of the input signal is eliminated that’s why we call this process half wave rectification.

7.2 Full wave rectification

In this process full wave of the input signal is moved toward positive side after passing through the diodes as shown in figure 7.2

As we see in whole input signal is diverted into positive side of the voltage.

In our project we use full wave rectifier after each piezoelectric sensor. Because sensor give us AC spikes so we use full wave rectifier to covert the AC voltage to DC voltage. We did this transformation of voltage for storage purpose in the battery because battery can store only DC voltages.



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