ME424 Engineering DesignME424 Engineering DesignPhase VI PresentationPhase VI Presentation

Group 11Group 11

Jim WatermanJim WatermanScott HamiltonScott HamiltonEric McCormickEric McCormick

Shingo MatsubaraShingo MatsubaraDavid ManningDavid Manning

Advisor: Frank FisherAdvisor: Frank Fisher

Piezoelectric‐Based Application

Updated Project ObjectivesUpdated Project Objectives►► 1) Utilize the unique properties of PZT (lead 1) Utilize the unique properties of PZT (lead zirconatezirconate

titanatetitanate) fiber) fiber--based piezoelectric materials developed based piezoelectric materials developed by Advanced by Advanced CerametricsCerametrics Company to design and Company to design and develop a floor tile that harvests energy from foot develop a floor tile that harvests energy from foot strikes.strikes.

►► 2) Use the harvested energy as the sole source of 2) Use the harvested energy as the sole source of power to transmit wireless signals for building power to transmit wireless signals for building surveillance.surveillance.

►► Advanced Advanced CerametricsCerametrics Inc. flexible PZT composite Inc. flexible PZT composite piezopiezo stripsstrips

►► Features:Features:►►10X more power than ceramic 10X more power than ceramic piezospiezos►►Eliminate battery replacement Eliminate battery replacement ►►Tested to over 1 billion cycles with virtually no output degradaTested to over 1 billion cycles with virtually no output degradation.tion.►►Convert up to 70% of energy from ambient vibration to electricalConvert up to 70% of energy from ambient vibration to electrical

powerpower►►Most efficient transducer material available today; piezoelectriMost efficient transducer material available today; piezoelectric active c active

fibersfibers

What Makes this Project What Makes this Project Possible?Possible?

►► Advanced Advanced CerametricsCerametrics Inc. flexible PZT composite Inc. flexible PZT composite piezopiezo stripsstrips

►► Features:Features:►►10X more power than ceramic 10X more power than ceramic piezospiezos►►Eliminate battery replacement Eliminate battery replacement ►►Tested to over 1 billion cycles with virtually no output degradaTested to over 1 billion cycles with virtually no output degradation.tion.►►Convert up to 70% of energy from ambient vibration to electricalConvert up to 70% of energy from ambient vibration to electrical

powerpower►►Most efficient transducer material available today; piezoelectriMost efficient transducer material available today; piezoelectric active c active

fibersfibers

What Makes this Project What Makes this Project Possible?Possible?

+-

Initial IdeasInitial Ideas

►► Initially chose medical device application:Initially chose medical device application:AutoAuto--Stiffening Knee BraceStiffening Knee Brace

►► Other ideasOther ideasGame or Toy Application Game or Toy Application Sensing/Monitoring Application Sensing/Monitoring Application Buoy Light or Ocean/Wave ApplicationBuoy Light or Ocean/Wave ApplicationSports Device Sports Device –– Golf Club Training AidGolf Club Training Aid

►► Replaced by floor tile idea due to the following Replaced by floor tile idea due to the following reasons:reasons:

Functional specification too difficultFunctional specification too difficultScope too largeScope too largeNeeded advanced medical knowledgeNeeded advanced medical knowledgeSolution looking for a problem, not a problem looking for a soluSolution looking for a problem, not a problem looking for a solutiontion

Piezoelectric Surveillance Floor TilePiezoelectric Surveillance Floor Tile

►► Invisible Fence for building Invisible Fence for building securitysecurity

►► Sends wireless Sends wireless transmission upon foot transmission upon foot strikestrike

►► Completely selfCompletely self--poweredpowered►► Modular (can implement Modular (can implement

one or several tiles)one or several tiles)►► State of the art: others State of the art: others

have tried creating such have tried creating such systems with little successsystems with little success

Tile Design EvolutionTile Design EvolutionKey Design Characteristics:

• Exterior made of Lexan Plastic

• Constructed using L-brackets and corner brackets

• Mounting Block located in middle of tile

• Mass attached to the end of each Piezoelectric Strip

Actuation SystemActuation System

►► SubfloorSubfloor DevelopmentDevelopmentFoam Foam SubfloorSubfloor not not sufficient for strip vibrationsufficient for strip vibrationActuation System neededActuation System needed

►► Spring Loaded Actuation Spring Loaded Actuation SystemSystem

Tile placed in system with Tile placed in system with four springs at the cornersfour springs at the cornersActuation bar responsible Actuation bar responsible for flicking stripsfor flicking strips

►► Key CharacteristicsKey Characteristics2 vibrations / footstep2 vibrations / footstepVariable displacementVariable displacementAdjustable Actuation BarAdjustable Actuation Bar

Springs (4X)

Actuation Bar Assembly(Stationary)

PZT StripsAluminum Mounting

Block

Threaded Rod (4X)- controls height/spring

pre-load

LexanSidewalls

(reduce friction)

Energy Harvesting

Circuit

¾” Wood Board (2X)Allowable

Displacement (0<do<1.5”)

do

SubassembliesSubassemblies

►► Actuation Bar CharacteristicsActuation Bar CharacteristicsStationary bar connected to two threaded rodsStationary bar connected to two threaded rodsRounded edge for smooth actuationRounded edge for smooth actuationSlots for adjustable interferenceSlots for adjustable interference

►► Holding Block CharacteristicsHolding Block CharacteristicsTwo piece block to clamp stripsTwo piece block to clamp stripsHouses multiple Houses multiple piezopiezo stripsstripsConnected directly to base of tileConnected directly to base of tile

►► Spring Loaded System CharacteristicsSpring Loaded System CharacteristicsSprings slotted in two wood boardsSprings slotted in two wood boardsLexanLexan walls to reduce frictionwalls to reduce frictionAdjustable displacement (0” < d < 1.5”)Adjustable displacement (0” < d < 1.5”)

Prototype BuildingPrototype Building►► Point Mass increases duration of Point Mass increases duration of

vibration but limits frequencyvibration but limits frequencyOriginal Point Masses too largeOriginal Point Masses too largeMagnets achieve goal while Magnets achieve goal while maintaining frequencymaintaining frequency

►► Uneven Tile DisplacementUneven Tile Displacement1/8” Gap between tile and side 1/8” Gap between tile and side wallswallsStraight down displacement Straight down displacement only if force is located in tile only if force is located in tile centercenterGap Closers added to ensure Gap Closers added to ensure only vertical displacementonly vertical displacement

►► Final PrototypeFinal PrototypePlatform with tile in centerPlatform with tile in centerAllows ability to walk across tileAllows ability to walk across tile

Electrical SystemElectrical System

Electrical SystemElectrical System

Energy Harvesting Circuit

Input from Piezo Strips

Output

Rectifiers

Electrical Circuit DiagramElectrical Circuit Diagram

Iterative Testing ProcedureIterative Testing Procedure

Setup Actuation System

Measure # of footstrikes to charge circuit

Judge relative feasibility of the test condition

Test Variables• # of PZT strips

• # of magnets

• Location of triggering mechanism

• Spring pre-load

• Weight of test subject

Choose Final Configuration

Multimeter

Test RunsTest Runs►► The following test conditions were run:The following test conditions were run:

No point mass, 1 No point mass, 1 piezopiezo stripstripNo point mass, 4 No point mass, 4 piezopiezo stripsstrips1 magnet, 1 1 magnet, 1 piezopiezo stripsstrips1 magnet, 4 1 magnet, 4 piezopiezo stripsstrips2 magnets, 1 2 magnets, 1 piezopiezo stripstrip2 magnets, 4 2 magnets, 4 piezopiezo stripsstrips

►► Data collection performed with Data collection performed with AgilentAgilent brand brand multimetermultimeterMeasured DC voltage across the leads of the 1000uF capacitor in Measured DC voltage across the leads of the 1000uF capacitor in the the EH301 Energy Harvesting Circuit.EH301 Energy Harvesting Circuit.

Stored VoltageStored Voltage

Stored Voltage vs. # of steps

01000200030004000500060007000

0 10 20 30 40 50 60

# of steps

Volta

ge (m

V), 1

000u

F ca

p

no magnets

1 magnet

2 magnets

Upper VoltageThreshold

Lower VoltageThreshold

8.3mJ useful output

Stored EnergyStored Energy

Stored Energy vs. # of steps

0369

121518

0 10 20 30 40 50 60

# of steps

Ener

gy (m

J), 1

000u

F ca

p

no magnets

1 magnet

2 magnets

Upper EnergyThreshold

Lower EnergyThreshold

8.3mJ useful output

Capacitor Leakage Rate (no load)Capacitor Leakage Rate (no load)

Capacitor Leakage Rate (no load)

01000

20003000

40005000

6000

0 1 2 3

Days

Volta

ge (m

V)

Upper VoltageThresholdLeakage/dayEnergy Harvesting

Circuit holds charge for 3 days!

Leakage Rate =72mV/hour

Summary of ResultsSummary of Results►► The best energy generating condition is the two The best energy generating condition is the two

magnet conditionmagnet condition►► 8.3mJ of useful output can be generated in just 20 8.3mJ of useful output can be generated in just 20

footsteps on the floor tile!footsteps on the floor tile!►► Four piezoelectric stripsFour piezoelectric strips

2 magnets mounted on each strip2 magnets mounted on each strip

Steps to charge circuit from 0-5.2V 50

Steps to charge circuit in operating range (3.1-5.2V) for 8.3mJ useful power

20

Stored Energy/step in 3.1-5.2V range 0.42mJ/step

Capacitive Discharge with no load 72mV/hr (in 1000uF capacitor)

Footstep rate for zero net energy transfer

0.72 footstep/hr

Wireless Transmission CapabilityWireless Transmission Capability

Useful Energy Output 8.3mJ

Energy Required/Wireless Transmission 1.44mJ

Wireless Transmission Capability 5.76 signals

►► Therefore, 20 footsteps generate enough Therefore, 20 footsteps generate enough power to send 5 wireless signals.power to send 5 wireless signals.

Suggestions for ImprovementSuggestions for Improvement

►► Mechanical mechanismMechanical mechanismReduce displacementReduce displacementTransfer EnergyTransfer EnergySmoother operation for transparent operationSmoother operation for transparent operation

►► Networked system of tiles Networked system of tiles -- surveillance systemsurveillance system►► Manufacturability Manufacturability -- reduce part countreduce part count►► Lithium Ion batteries Lithium Ion batteries -- store excess energystore excess energy►► Improve Energy Harvesting EfficiencyImprove Energy Harvesting Efficiency

High performance, low power rectifiersHigh performance, low power rectifiersPCB PCB -- reduce footprint reduce footprint

►► Gaskets Gaskets -- for waterproofing for waterproofing

Alternate ApplicationsAlternate Applications

►► LightLight--up gaming up gaming applicationapplication

►► Location monitoringLocation monitoringCars/Industrial Cars/Industrial EquiptEquiptPedestrianPedestrianAnimalsAnimals

►► Traffic lightsTraffic lights►► Dance floor Dance floor LEDsLEDs►► Electronics powering Electronics powering

shoe applicationshoe application

Piezoelectric Surveillance Floor TilePiezoelectric Surveillance Floor Tile

Only 20 Steps Allows for Multiple Surveillance Signals at Night!!!

Stevens Mechanical Design Team :Jim Waterman Eric McCormickScott Hamilton Shingo MatsubaraDavid ManningStevens Electrical Design Team:Michael Ivey Neil PatelMark Vitzhum Arturo DizonAdvisors:

Professors Frank Fisher and Bruce McNairBud Cass, President Advanced Cerametrics Inc.Farhad Mohammadi, Director R&D Advanced Cerametrics Inc.

Springs (4X)

Actuation Bar Assembly(Stationary)

PZT StripsAluminum Mounting

Block

Threaded Rod (4X)- controls height/spring

pre-load

LexanSidewalls

(reduce friction)

Energy Harvesting

Circuit

¾” Wood Board (2X)Allowable

Displacement (0<do<1.5”)

do

Utilize the unique properties of PZT (lead zirconate titanate) fiber-based piezoelectric materials developed by Advanced Cerametrics Company to design and develop a floor tile that harvests energy from a foot strike.Use the harvested energy as the sole source of power to transmit wireless signals for building surveillance.

Piezoelectric materials create electrical charge when mechanically stressed. The converse effect is also true for these materials, meaning application of an electrical force can cause mechanical movement. The below diagram summarizes this unique material property.

Introduction to Piezoelectricity

Test Results

Stored Voltage vs. # of steps

01000200030004000500060007000

0 10 20 30 40 50 60

# of steps

Volta

ge (m

V), 1

000u

F ca

p

no magnets

1 magnet

2 magnets

Upper VoltageThreshold

Lower VoltageThreshold

8.3mJ useful energy

Principle of Operation

Input Sinusoidal Oscillation

Beam Displacement Beam Stress

Output VoltageHarvest EnergyUse Energy to Send Wireless

Signal

Causes Creates

How the Tile Works:1. Footstep to exert force on tile system2. Tile deflects and returns due to spring system3. Strip vibration initiated by contact with actuation bar4. Oscillation of strips creates AC signal output5. Output of each strip is rectified and connected in parallel6. Combined electrical output stored in capacitor7. Microprocessor defines when tile should be in detection mode8. Wireless signal sent when footstep is detected , using power

generated during daytime foot strikes

Stevens Mechanical Design Team :Jim Waterman Eric McCormickScott Hamilton Shingo MatsubaraDavid ManningStevens Electrical Design Team:Michael Ivey Neil PatelMark Vitzhum Arturo DizonAdvisors:Professors Frank Fisher and Bruce McNairBud Cass, President Advanced Cerametrics Inc.Farhad Mohammadi, Director R&D Advanced Cerametrics Inc.

Springs (4X)

Actuation Bar Assembly(Stationary)

PZT StripsAluminum Mounting

Block

Threaded Rod (4X)- controls height/spring

pre-load

LexanSidewalls

(reduce friction)

Energy Harvesting

Circuit

¾” Wood Board (2X)Allowable

Displacement (0<do<1.5”)

do

Utilize the unique properties of PZT (lead zirconate titanate) fiber-based piezoelectric materials developed by Advanced Cerametrics Company to design and develop a floor tile that harvests energy from a foot strike.Use the harvested energy as the sole source of power to transmit wireless signals for building surveillance.

Piezoelectric materials create electrical charge when mechanically stressed. The converse effect is also true for these materials, meaning application of an electrical force can cause mechanical movement. The below diagram summarizes this unique material property.

Introduction to PiezoelectricityPiezoelectric materials create electrical charge when mechanically stressed. The converse effect is also true for these materials, meaning application of an electrical force can cause mechanical movement. The below diagram summarizes this unique material property.

Introduction to Piezoelectricity

Test Results

Stored Voltage vs. # of steps

01000200030004000500060007000

0 10 20 30 40 50 60

# of steps

Volta

ge (m

V), 1

000u

F ca

p

no magnets

1 magnet

2 magnets

Upper VoltageThreshold

Lower VoltageThreshold

8.3mJ useful energy

Principle of Operation

Input Sinusoidal Oscillation

Beam Displacement Beam Stress

Output VoltageHarvest EnergyUse Energy to Send Wireless

Signal

Causes Creates

How the Tile Works:1. Footstep to exert force on tile system2. Tile deflects and returns due to spring system3. Strip vibration initiated by contact with actuation bar4. Oscillation of strips creates AC signal output5. Output of each strip is rectified and connected in parallel6. Combined electrical output stored in capacitor7. Microprocessor defines when tile should be in detection mode8. Wireless signal sent when footstep is detected , using power

generated during daytime foot strikes

Questions?Questions?

►► Energy Energy HarvestorHarvestor BoxBoxOnboard electrical energy Onboard electrical energy storage in capacitorstorage in capacitor

►► FiberFiber--Powered Wireless Powered Wireless SensorSensor

Wireless Temperature Wireless Temperature sensor powered exclusively sensor powered exclusively by fiber stripsby fiber strips

+

Piezoelectric Strips

Capacitive Storage Circuit

Project InspirationProject Inspiration

Electrical SystemElectrical System

1.1. Four piezoelectric strips mounted in the floor tile Four piezoelectric strips mounted in the floor tile ––output AC voltageoutput AC voltage

2.2. Full wave bridge rectifiers Full wave bridge rectifiers –– to rectify each AC output to to rectify each AC output to DCDC

3.3. ALD EH301 Energy Harvesting Circuit ALD EH301 Energy Harvesting Circuit –– to store energyto store energy4.4. PIC16F877a Microprocessor PIC16F877a Microprocessor –– powered by energy powered by energy

harvesting circuit, programmed to wake up harvesting circuit, programmed to wake up ZigbeeZigbeeTransmitterTransmitter

5.5. ZigbeeZigbee Transmitter Transmitter –– to send signalsto send signals6.6. ZigbeeZigbee Receiver Receiver –– to receive signalsto receive signals7.7. PC Terminal with Graphical User Interface (GUI) to PC Terminal with Graphical User Interface (GUI) to

provide a provide a ““WARNINGWARNING”” alertalert

RecommendationsRecommendations

►► Importance of electrical engineering supportImportance of electrical engineering support►►Understand the relationship between frequency Understand the relationship between frequency

and amplitude with respect to voltageand amplitude with respect to voltage►►No need to frequency match with No need to frequency match with

discontinuous vibrationdiscontinuous vibration►►When using a discontinuous forced vibration, When using a discontinuous forced vibration,

an actuation system is essential.an actuation system is essential.

ALD Energy Harvesting CircuitALD Energy Harvesting Circuit

Output Waveform

Spring SelectionSpring Selection

Spring OD 0.875 inSpring Length 3.0625 inMaterial Music WireCompressed Length 1.14 inDeflection @Load 1.92 inLoad Pounds 41.2 lbSpring Constant (k) 20.50 lb/inkequiv (parallel) 82 lb/in

Max Displacement = 1.5”Max Force = 123lb

Actuation Distance = 0.75”Actuation Force = 61.5lb

Max Force = 123lb

Spring Design Considerations1. Correct Free Length2. Right Load Characteristics3. Deflection @Load > 1.5”4. Compressed Length < 1.5”

Note: During walking, experimental data indicates 1.2W< Fstep <1.8W