TERM PAPER On WALKING CHARGER USING PIEZO-ELECTRIC MATERIAL

1. WALKING CHARGER USING PIEZO-ELECTRIC MATERIAL
Department of Electrical Engineering,
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TERM PAPER
On
WALKING CHARGER USING
PIEZO-ELECTRIC MATERIAL
ELECTRICAL ENGINEERING DEPARTMENT
ACKNOWLEDGEMENT

2. WALKING CHARGER USING PIEZO-ELECTRIC MATERIAL
Department of Electrical Engineering,
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I WOULD LIKE TO THANK dr. Manisha sharma for helping me studying
and researching on this topic. I would also like to thank my department
of electrical engineering for giving me a good opportunity on STUDYING
on such a NICE topic of ‘WALKING CHARGER USING PIEZO-ELECTRIC
MATERIAL.
I would also like to mention the help of my parents and friends who
helped in the topic from other side.
SUBMISSION DATE – 15/11/2019
Abstract: Due to our hectic and torpid lifestyles, health has been on the receiving end. Herein
we discuss a device using piezoelectric material that furnishes as an alternate means for
powering mobile devices, etc. Additionally, it can also be intended for emergency lighting
solutions like flashlights and emergency torch. Noting that it is an energy regeneration device

3. WALKING CHARGER USING PIEZO-ELECTRIC MATERIAL
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it encourages walking and thus can also be acknowledged as an electrical health gadget
which endorses physical fitness. One more feature which has been incorporated into this
gadget is a battery bank which is used to store the charge when the phone is 100 percent
charged or there is no need for emergency lighting. The piezoelectric crystals are incubated
into the sole and the heel of the shoes as they are considered as the maximum pressure points
and via trotter moment and vibrations on the crystals they generate voltage pulses and minute
quantities of current.
Keywords: Piezoelectric materials, Nanogenerators, walking charger, emergency lighting.
I. INTRODUCTION
A phone isnolongeran itemusedonlyforcommunication,ithasbecome smart.Thusitrequiresa
largerbatteryto keepitrunningthroughoutthe day.But since itisnot at all feasible toexpandthe mAh
value of a batteryendlessly,thereforewe needtosupplementitandwhatbetterthanrechargingit with
a renewable resource.Thus,hereinwe are designinga portable chargerwhose energywill be equal to
the numberof stepswe take.The gadgetwill thenharnessthe voltage generatedacrossapiezoelectric
material keptwithinashoe moreover,store itinthe batterywhichcanbe utilizedtocharge the cellular
phone usinganyUSB wire wheneverneeded.Itwill be adevice weighingaround200 grams whichcan
be strappedaroundour ankle.Andwill provideischarge onthe go. It’sa perfecttraveler’sequipment
whichfocusesoncapturingthe renewable andwaste energypresentaroundus.
II. LITERATUREREVIEW
“Global conference Wikimedia 2014 London states that 97 out of 100 total members are cell phone
users”.But due to the urbanizationgoingandthe dependence on life increasing so rapidly, the battery
research has been unable to keep up. Thus the problem of fast discharging batteries and mobiles
runningoutof charge in approximately8hoursas comparedto previousphonesthatusedtolast3 days.
Thus nowchargingmobile phonesand making sure that it lasts a sufficient time period requires user a
lot more user attention as the conventional or the age old method requires appropriate socket and
electrical connectivity.Butthe problemarisesspecificallyfortourists,mountaineersorin remote places
like villageswherethe electrical supplyisn’tthere or even if it’s there the assurance of 24*7 supplies is
not there thus this offers specific limitations in charging mobile phones. These hindrances are mostly
observedinchargingmobile phoneoftendue toincrease battery drainage in our smartphones. A lot of
alternate measures have been suggested and there implementation has been tried out to make
available emergency power for charging mobile phones and moreover renewable and sustainable
measures has engrossed an increasing interest in last few years. One of the many such means is the

4. WALKING CHARGER USING PIEZO-ELECTRIC MATERIAL
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extractionof humanpowerusingaNano-generatorlikepiezoelectric transducers etc. Previously, many
such humanpower-drivengeneratorsandhumandrivenharvesting system had been proposed but the
uniqueness of this paper is that it gives extra importance to the actual development and
implementationof the E-Health gadget. When a person actual walks or runs there is sufficient amount
of inherentkineticenergygenerateddue tohisactionandharvesting this is really favorable because of
plentiful motion and vibration in the ankle which is capable of producing produces moderate power
renewably.Althoughutilizationof the energygenerated by the sun in the form of solar energy is also a
veryexcitingprospectbutitsusage isnotequivalenttothat of these Nano-generatorsasitisdependent
source,itdependsonthe intensityandthe areaof the solar panel and is thus more complicated way of
generating renewable energy and even if we by some proper research and developments we are
somehow able to overcome the above drawbacks, one major thing which we would never be able to
eliminate will be its limited time availability as the sun can maximum provide energy for around 15
hoursin a day.Thus inrecentyears,lotsof developmentandresearcheshave beenmade about ways of
generatingpowerfromvibrational energy.Alsosince byusing piezoelectric polymer transducer energy
is harvested from human walk without affecting user’s gate it proposes a solution that can be easily
implementedwiththe existingshoe. The piezo transducer is capable of generating up to 2 V in a single
press and by proper placing and designing we can rectify and regulate the voltage to 5V. But, it serves
only an independent implementation of piezoelectric material without any amplification circuitry
attachedmakesa portable mobile phonewith a lesser efficiency, thus there is a need for an amplifier.
Also in some previous related work, minimalistic mobile electronic systems such as biomedical drug
deliveryimplants or the acceleration and pressure monitoring sensors have been suggested. But they
have short operational lives due to the deficiency of storage space but in the application discussed in
this paper there is sufficient space to provide an external battery pack thereby increasing its
applicability.
III. DESIGNANDDEVELOPMENT
A. PRINCIPLE
The elementaryprincipleinvolvedisthe transformationof humanmechanical powerintoelectrical
signals.The mechanical powergeneratedisdue tothe trottermomentof ourankle.Whena personis
walkingorrunninghe possessacertainamountof kineticenergyandthusappliessome amountof

5. WALKING CHARGER USING PIEZO-ELECTRIC MATERIAL
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pressure onthe groundvia the shoe andthisis the pressure we are concerned withandare utilizingin
our productdevelopment.Thismechanical energyintermsof vibrationsisfedtothe piezoelectricdisc
transducerwhichcausesthe piezocrystalstovibrate;thisexcitationwhentakenwithreference tothe
base plate generatesavoltage.Infigure 1the goldenlayeristhe groundplate andthe crystals are
embeddedinthe centerasshown.The voltage yieldof thistransduceristhenattachedtoan amplifier,
rectifieranditisthensynchronizedtoa value adequate enoughtocharge a mobile phone battery.
Figure 1 – Piezoelectric transducerdisc
The circuit of the device chieflyaDarlingtontransistor(Figure 2),anamplifier(dual op-amp)(Figure 3),
a full wave rectificationcircuit(Figure4),regulatingICnamely7805 to make a constant voltage of 5V
and a switch.A capacitor (1000 uF) isused to stockthe electriccharge sothat whenthe personisnot in
motionthe poweriscontinuallysupplied.The piezoelectricdiscisattachedamidthe upperandlower
part of the sole.The external circuitryisfabricatedandfittedtothe backpart of the shoe and dissimilar
connectorsoutspreadforchargingthe phone batteries.The control of the chargeris giventothe user
viaa switchsothat he can decide whenhe wantstocharge the phone and whennotand whenitisnot
chargingthe mobile phone the powerisstoredinthe batterywhichcanbe usedwheneverneeded.

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Figure 2 – Darlington Configuration
B. Working
The applicationof thisgadgetisentirelybasedonhumanpressure andtrottermovementof
our ankle;here the mechanical stressesandvoltagesare usedtogenerate powerviathe
piezoelectrictransducerswhichare putinour shoe.Thisvibrational energyischangedinto
electrical energybythe transducer.The productivityof the transducersystemisthenfedinto
a modifierciruitarythat consistsof 4 subsystem, voltageamplification(byadjustingthe
voltage gain),rectification(DC-DCconverter)–whichconvertspulsatedDCtofixedDC,and
currentamplification –thisincreasesthe currenttoa value 20X the value.Inwalkingcondition
for a 70 Kg man the discproducesa voltage of 1.75V-2V. Thisvoltage isimprovedupto8V by
usinga suitable resistance arrangementof 20 ohm and5 ohm.With the helpof this non-
invertingconfigrationwe setthe voltage gainof 4.This amplification isthenputintoa
rectificationcircuitforconvertingpulsatingdcsignalstopure continuousform.Once we get
continuousDC,thenthe currentismagnefiedabout20 timesusingthe Darlingtontransistor
and lastlyvoltage isregulatedto5V by usinga regulatingIC7805. Thisoutputafterregulation
issufficientenoughtocharge the mobile phone andtopowerthe small electronicdevices.
IV. EQUATIONS
Voltage developed
Voltage = Papp*Tp*C (1)

7. WALKING CHARGER USING PIEZO-ELECTRIC MATERIAL
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Where Papp= Pressure appliedonpiezo,Tp = Thicknessof
the piezoandC = piezorating
AMPLICICATION MODEL
The voltage gaindependsonthe impedancesconnectedacrossthe pnptransistor inthe Darlington
pair.
Here,rf = resistance inparallel,ri = resistance inseries.
VI. CONCLUSION
Thispaper,we about discussabouta piezo-material basedgadgetwhichusestrottermoment
to generate sufficientvoltage whichiscapable of chargingourmobile phone batteriesat
remote placeswhere plugpointisn’tlocatedat5V DC. Since the gadgetinvolvesactual
walkingthe gadgetwasfabricatedandactual data has beenrecordedabove.The major
conclusiondrawnbythisisthat Nano-generatorasanonlypowersource aren’tcapable of
producingenoughcurrenttobe of any plausibleapplication,thuswe needaDarlingtonpairto
amplifythisvalue.Itwasalsonoted thatthe voltage variedincreasedwhenthe personstarted
runningandtime takento charge the phone declined.Thus,the gadgetalsoprovestobe a
benefitforhumanhealthbyreassuringanacclaimedfitnessexercise like walkingandrunning.
So the gadgetmakesfor a potentrenewablegadgetwhichcanspeciallybe usedinremote
placeslackingelectrical supply.
VII. SCOPEFOR THEFUTURE
Piezoelectricmaterialscanbe placedunderthe flooroN variousbusyareasandcan be usedas
a renewable energy source forlightingsystempresentaround.Itcanalso be placedunderthe
floorof discosas a large amountof pressure isappliedonthe floorsthere while jumping.

8. WALKING CHARGER USING PIEZO-ELECTRIC MATERIAL
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NOTES & CONCLUSION
The establishmentof aHospital isa mixedenergyconsumingInstitution. Limitation of access and usage
pattern makes the situation more vulnerable from energy consumption point of view.
In the currentendeavor,measurementsatimportantpointshave beentaken,vis-à-vis,electricity,water
and gas consumption. But, unfortunately, absence of proper consumption meter did deter the job of
proper understanding of the consumption pattern and daily/monthly/yearly consumption. Merely
studying the consumption at a point of time is not sufficient to visualize the situation as a whole.
It isimportantto connectmeasuringmeters,evendue to situational advantages, the raw materials are
of little value. But, everybody should come across the level of consumption at any point.
The present level of energy audit is indeed a right step in right direction. It is, though, a beginning.