Michael ErwinRoss Martin (Team Leader)Tao NguyenClifton WengUrsula Zangrilli

Dr. Chun and Prof. Dougherty

OverviewOverview

IntroductionIntroduction ObjectivesObjectives Ideas and ResultsIdeas and Results EconomicsEconomics Case StudiesCase Studies Final ThoughtsFinal Thoughts

Intro and ObjectivesIntro and Objectives

Tao NguyenTao Nguyen

IntroductionIntroduction

Almost Everyone Uses Portable ElectronicsAlmost Everyone Uses Portable Electronics

Palm Pilot (200 mW), MP3 Players (110 mW), Palm Pilot (200 mW), MP3 Players (110 mW), Laptops (10 W) Laptops (10 W)

All run out of power in a matter of hoursAll run out of power in a matter of hours

Power EstimatesPower Estimates

Breathing – 0.42 W Breathing – 0.42 W Blood pressure – 0.37 W Blood pressure – 0.37 W Exhalation – 0.40 W Exhalation – 0.40 W Footsteps – 5 W Footsteps – 5 W

ChallengesChallenges

How do we generate power?How do we generate power?

How can we harness it?How can we harness it?

State of the ArtState of the Art Hand crank/Shake FlashlightsHand crank/Shake Flashlights

Kinetic watchesKinetic watches Swatch Automatic/AutoquartzSwatch Automatic/Autoquartz Seiko KineticSeiko Kinetic

Seiko Thermic watches Seiko Thermic watches

ObjectivesObjectives

Design a device to generate electrical Design a device to generate electrical power from the human bodypower from the human body Various devices that convert human mechanical to Various devices that convert human mechanical to

electrical energyelectrical energy A circuit to harness this energyA circuit to harness this energy

Use this power to charge the batteries of Use this power to charge the batteries of portable electronicsportable electronics

Harness enough electrical power to charge Harness enough electrical power to charge a cell phone batterya cell phone battery

The Design IdeaThe Design Idea

Ross MartinRoss Martin

The IdeaThe Idea Shoe based generatorShoe based generator

Incorporates piezoelectric stripsIncorporates piezoelectric strips Strips generate electricity through Strips generate electricity through

polarization induced by stretching of the polarization induced by stretching of the fibersfibers

Screen printed silver electrodes provide Screen printed silver electrodes provide electrical contactselectrical contacts

The IdeaThe Idea Each strip produces:Each strip produces:

40 volts peak-to-peak per pulse 40 volts peak-to-peak per pulse 6-9 uAmps per pulse6-9 uAmps per pulse

Final output is an AC voltageFinal output is an AC voltage

The IdeaThe Idea AC->DC ConversionAC->DC Conversion

Pass AC wave through transformer rectifierPass AC wave through transformer rectifier Capacitor filter smoothes the wave even Capacitor filter smoothes the wave even

furtherfurther Voltage regulationVoltage regulation

Maintain a steady output voltage between Maintain a steady output voltage between 3.7 and 4.1V3.7 and 4.1V

As high a current output as possibleAs high a current output as possible

The IdeaThe Idea

Circuit tucked under heel in sealed Circuit tucked under heel in sealed packagepackage

Wire feeds power to battery being Wire feeds power to battery being chargedcharged

Standard charging plug for phoneStandard charging plug for phone Phone held in modified holder on Phone held in modified holder on

ankleankle

Research ResultsResearch Results

ResultsResults

Initial design was as shown aboveInitial design was as shown above Converter to 555 timing chip to batteryConverter to 555 timing chip to battery

ResultsResults

Eliminated due toEliminated due to No need for timing with low currentNo need for timing with low current 3 pole transformer introduces 3 pole transformer introduces

unnecessary complexityunnecessary complexity Large number of components lower Large number of components lower

outputoutput

ResultsResults

Second design: Dedicated charging Second design: Dedicated charging chipchip Use of LM3658 to control chargingUse of LM3658 to control charging

Pros: introduces layers of battery safety Pros: introduces layers of battery safety Cons: 4.5v-6v input voltage range, 50mA Cons: 4.5v-6v input voltage range, 50mA

minimum currentminimum current Put to the side, pending higher current Put to the side, pending higher current

and better voltage controland better voltage control

ResultsResults

Re-evaluation of design strategyRe-evaluation of design strategy Focus on sustainable voltage levelsFocus on sustainable voltage levels Plans for intelligent charging continued Plans for intelligent charging continued

as a second goal for post experiment as a second goal for post experiment workwork

ResultsResults

Third design: Converter with Third design: Converter with capacitorcapacitor 2 versions: half and full wave2 versions: half and full wave

Half wave yielded moderate voltages of up Half wave yielded moderate voltages of up to 6Vto 6V

Required unrealistic strip movementsRequired unrealistic strip movements Acceptable, but not idealAcceptable, but not ideal

ResultsResults

Full wave produces voltages in excess of Full wave produces voltages in excess of 15V15V

Uses diode bridge rather than paired setUses diode bridge rather than paired set Easily obtainable via normal movementsEasily obtainable via normal movements Full rectification gives twice as many pulses Full rectification gives twice as many pulses

within acceptable voltage rangewithin acceptable voltage range

ResultsResults

Voltage output of Diode BridgeVoltage output of Diode Bridge

ResultsResults Addition of capacitors reduce ripple between Addition of capacitors reduce ripple between

pulsespulses

ResultsResults

Results of designResults of design Working converter circuitWorking converter circuit Ample voltage for chargingAmple voltage for charging Insufficient currentInsufficient current

EconomicsEconomics

Tess ZangrilliTess Zangrilli

Costs for PrototypeCosts for Prototype

Piezoelectric strips(3):$25 per stripPiezoelectric strips(3):$25 per strip Circuit components:about $1Circuit components:about $1 Phone Plug: $1Phone Plug: $1 Inserts: $5Inserts: $5 Total=$82Total=$82

Costs to Mass ProduceCosts to Mass Produce StartupStartup

CustomizationsCustomizations

Per unit costs:Per unit costs: $5-10 per strip$5-10 per strip Circuit components: <$1Circuit components: <$1 Phone Plug: <$1Phone Plug: <$1 Insert: <$1Insert: <$1

Independent Case StudiesIndependent Case Studies

Cliff WengCliff Weng

Case Study #1: InductorCase Study #1: Inductor

Slug Velocity: 1.3 m/s

Number of turns: 100,000

Total Length: 8 cm

Coil Diameter: 2 cm

Current Produced: 0.015 amps

Inductor

Piezo stripscircuit

Case Study #2: WindmillCase Study #2: Windmill

Bellows Dimensions:2.5 cm x 1.3 cm x 5 cm

Bellows Nozzle Diameter:0.5 cm

Air Velocity:19 m/s

Turbine Speed:4 RPMs

Turbine

Piezo strips circuit

Final Thoughts Final Thoughts

Mike ErwinMike Erwin

Were our Goals Achieved?Were our Goals Achieved?

Design a device to generate electrical Design a device to generate electrical power from the human bodypower from the human body SucceededSucceeded

Use this power to charge the Use this power to charge the batteries of portable electronicsbatteries of portable electronics Not possible using available suppliesNot possible using available supplies

Harness enough electrical power to Harness enough electrical power to charge a cell phone batterycharge a cell phone battery Proved to be possible. - NokiaProved to be possible. - Nokia

Lessons Learned Lessons Learned

Test Testing EquipmentTest Testing Equipment Simple is BetterSimple is Better More Specific is BetterMore Specific is Better Allow plenty of time for ComplicationsAllow plenty of time for Complications

Items in the MailItems in the Mail Mixed Group ComplicationsMixed Group Complications

Main Focus EE Main Focus EE Piezo stripsPiezo strips

ME Case Studies ME Case Studies other possibilities could have allowed MEs to other possibilities could have allowed MEs to

contribute morecontribute more

Future Group PossibilitiesFuture Group Possibilities

Improve current designImprove current design Using Specially Designed StripsUsing Specially Designed Strips

Implement Case StudiesImplement Case Studies Move Beyond the PhoneMove Beyond the Phone

With improved design(s), possible to charge With improved design(s), possible to charge other electronicsother electronics

I-PodI-Pod Palm PilotPalm Pilot LaptopLaptop

Special thanks go to Special thanks go to

Dr Chun and Prof DoughertyDr Chun and Prof Dougherty

Advanced CerametricsAdvanced Cerametrics

New Balance ShoesNew Balance Shoes

Questions?Questions?