Section 1 – Introduction

Energy is a considerable issue in today’s world. Coal and oil are becoming more expensive and the emissions from it cause huge problems for the environment. In the past few decades a “Green” movement has begun to take place. The movement’s goal is to lower carbon emissions and provide more renewable energy. The “Green” Movement is today on the forefront of the media as well as academia. It is very important for the United States to stop relying on foreign oil and polluting the environment. This leads to a push to harness energy elsewhere. The purpose of the groups design is to harness energy from a person, enough to power a handheld or other device that does not require a substantial amount of power.

The human body releases a considerable amount of energy regularly. This energy comes in the form of body heat and movement of the person. Body heat is difficult to harness as the human body does not reach extreme temperatures. Movement however is a different story. In gyms all over the country today you can see a plenty of people exerting a lot of their energy in the name of exercise. Runners in particular exert a great amount of energy while exercising. If this energy were to be harnessed a handheld device such as an IPod can be charged simply by a person running. To harness this energy the group decided to use a piezoelectric

Piezoelectric has been shown to be useful in harnessing energy from the motion of a person. Piezoelectric materials are different from other ceramics because their dielectric constant decreases with an applied mechanical load and Young’s Modulus, the stiffness of a material, changes with an applied voltage. The change in the dielectric constant is of interest. The plates of a normal capacitor become charged with the application of voltage, however with a piezoelectric capacitor the plates become charged when stress is applied. Due to the decrease in the dielectric constant the power is released when a mechanical stress is present. One necessary property of piezoelectric is that the material must be formed as a single crystal. This poses a problem as ceramics have a multi-crystalline structure. The impurities of the grains cancel out the piezoelectric effect. In order to align the grains a process called poling takes place. During poling the material is introduced to a DC voltage which aligns the grains of the materials. Not all grains align; the amount of grains that align depends on aspects such as voltage, temperature and time. During poling the material changes shape due to the applied voltage, it increases in size between the electrodes and decreases in parallel. The poles during poling determine the poles of the piezoelectric once a force is applied. Piezoelectric can harness energy from a number of different sources including, human motion, low-frequency seismic vibration and acoustic noise. The current project will focus on harnessing energy from human motion.

Previous research has been done exploring the harnessing energy of Piezoelectric. MIT has done some research on harnessing power from Piezoelectric which will be discussed later in this report. During their research they were able to harness enough energy to send out an RFID signal, however not enough to power a handheld device. DARPA has also funded some research into harnessing energy from piezoelectric. Previous research has shown that piezoelectric shoe generators can produce energy on the order of miliwatts. This is not enough to power a handheld device so the design must be improved upon. The testing was also done on a person walking casually and not running like someone who is exercising would be. The group wants to improve the design as well as test it on someone running versus walking.

Even though previous research has been done it is stated that more research is needed for piezoelectric power harnessing. MIT labs have completed some research on shoe-mounted piezoelectric, the research only got enough power to transmit an RFID signal. It was stated in the paper that with additional research more power can be produced.

The purpose of this design is to harness energy from the human footstep to be able to eventually provide a person with energy to power a handheld device, sensors or transmitters. The original goal was to power a handheld device, however since that proved unlikely the group researched some alternatives. Charging a battery during movement was the best alternative the group came up with. This could be used outside of people exercising and with rescue personnel/adventurers to use when they are in remote locations. This would rid people of the extra weight and allow them to complete numerous tasks that require electrical energy.

There are numerous applications for the device being designed. The most promising of the applications are people that are in remote locations with no access to an electrical grid. This includes military personnel, rescue personnel and extreme hikers. The design is useful to these people because they do not have to carry around extra weight, generating the power they will use themselves. Another possible application is people exercising, not only can this design power a device they are using it can also power sensors to judge their workouts. Mobile medical personnel can also benefit from this design as well as people with a need for personal navigation.

Section 2: Technical Information

2.1: Functional Description of the Design and its Components

The primary objective of this project is to generate power equivalent to that of a USB port. Both the difficulty and innovation are found in the process by which this will be achieved as the limiting factor in many previous piezoelectric harvesting endeavors has been the generation of sufficient energy. This endeavor will use the force exerted by the human footstep to deform a piezoelectric sheet, and thus generate electric energy.

The human footstep transfers the full weight of a human being each time a step is taken. This comparatively tremendous force, has many times the energy necessary to provide power at the USB standard. This statement can be proved with the simplified potential energy equation:

Epotential=mg(∆h)

This equation describes the correlation between mass, height and potential energy. To theoretically determine the energy potential of a footstep, this equation is modified as such:

g=9.8m /s2

FFootstep=mhuman∗g

Ework=F(∆ D)

Therefore: EFootstep=mhuman∗g∗(∆h )

And:EFootstepmeter

=mhuman∗g

These equations state that the energy derived from a human footstep is based upon the mass of the human stepping, the height his foot travels relative to the ground, and the gravitational

constant g. To better quantify this energy potential, the mass of the human stepping must be determined. From the US Census Bureau the following statistical information was used to determine the energy potential of a male, age 20-29, residing in the United States in 2007. This information was used to generate a graph showing the potential energy of a single footstep falling from a height of 1 centimeter.

The chart (right) shows the weighted average of the weight of a US male age 20-29. From this information the average weight is derived to be between 180 and 190 pounds.

http://www.census.gov/compendia/statab/2011/tables/11s0206.xls

With this information it can be mathematically determined that the average energy generated from a single footstep of 0.01 meters is between 17.64 and 18.62 Joules. These values represent the theoretical maximum one could harvest from a footstep, assuming the most ideal conditions. From a technical perspective these values would be adjusted based on the efficiency of the piezo device in question, however it is evident that even at a fraction of the theoretical, substantial energy is possible.

To further quantify the feasibility of such a power harvesting endeavor, the power or energy per unit time must be considered. The generation of power through the deformation of a piezoelectric material presents many challenges, and these challenges become increasingly difficult as the frequency of generation decreases. A study performed by MIT has shown that the heel of the shoe offers the best source of piezoelectric generation, as the quick impact of the heel during the beginning of a new step offers more energy than the slow curving of the sole. The study also outlines graphically the type of power developed by an average weight person walking at a slightly brisk pace (2 footsteps per second).

From the results of the MIT experiment it was shown that the “heel strike” offers greater than 5 times the power produced by the sole of the shoe. While the power generated by was small, other experiments have sought ways of reconfiguring the design to allow for increased usable production from the same stepping force. Experiments performed at Virginia Tech showed that by using smaller piezoelectric crystals arranged in parallel the time required to charge equivalently sized batteries decreased dramatically.

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“To demonstrate the power harvesting advantage, 40 and 80 mAhr Nickel Metal Hydride batteries are charged with each individual actuator then charged with both actuators connected in parallel. For a 1.4 Hz frequency (a brisk walking pace), the parallel combination charges two 40 mAhr batteries in 3.09 hours, and two 80 mAhr batteries in 5.64 hours. The individual actuators require 16.1 hours to charge a 40 mAhr battery, and 22.7 hours to charge an 80 mAhr battery.”

This experiment did not use a real shoe, as with the MIT counterpart, but instead developed a consistent, easily repeatable, mechanical model. While the results of this model may not be seen quite as dramatically in the shoe itself it is reasonable to assume that by using paralleled piezoelectric crystals more usable energy can be derived from a step, and that the addition of further paralleled crystals would yield further decreased battery charging times. As this is the purpose of the project in question (to provide USB charging power), it stands to reason that a grid design using many paralleled piezoelectric materials would be the most efficient route of deriving useful energy from the human step.

Making the assumption that such increased efficiency could be achieved, and a high power output generated, the next solution to be designed is the rectification and filtering of the generated energy into that which as USB device could utilize. As per the USB 2.0 standard kept at USB.org one USB port must be capable of supplying 500 milli-Amps at precisely 5 Volts, or a total of 2.5 watts of continuous power. From previous calculations, the per-step theoretical energy is at most 17.64 joules for a 180 pound male (the average in the US as of 2007). From the MIT experimentation a brisk walking pace is considered to be 1 step per second. Therefore:

P=17.64 ( Joulesstep )∗1( stepsecond )=17.64 ( joulessecond )=17.64watts

This power value represents the maximum generation possible from a 1cm footstep, by a statistically average male, in the target age group, at an average walking pace. As the required power to support a USB device is significantly lower, it is reasonable to say that such a venture is technically feasible. Furthermore it can be mathematically derived that the overall system efficiency can be no less than

Efficiency system=requiredavailalbe

∗100= 2.5watts17.64watts

∗100=14.17 %

In order to generate USB compatible power, the end to end system efficiency would need to be greater than or equal to 14.17%. This assessment includes the piezoelectric deformation generation, and the filtering circuitry incorporated for power conversion.

Efficient, low loss conversion is therefore a significant obstacle to be addressed. From the MIT experiments it was seen that voltages up to 200 volts were produced with a 500 kilo-Ohm load. Additionally the bipolar production of the piezoelectric system must be considered as the current produced is not direct. As the heel first strikes occurs deformation of the crystalline material produces a voltage across the material which will always be in the same direction relative to the circuit (assuming the type of step is consistent). However, as the “heel strike” completes, the

material returns to its original shape and dimensions, and generates a voltage opposite, and greatly less than the initial. This phenomenon is found in the original MIT experiment and can be seen in this representation.

The voltage spike at approximately 0.9 seconds represents the heel first striking the surface below the shoe. The next spike is the rolling of the heel, and the return of the material to its original shape. The MIT researchers chose to view this information as the absolute value of the voltage, but from the perspective of power generation it is also useful to view the bipolar voltage production. It should also be noted that the while the initial spike is of greater amplitude, the area under underneath the initial and secondary generations is approximately equal. Power generated in this fashion is incompatible with a USB device, as voltage transients would likely be harmful to the device, and the inconsistent output would not be realizable as charging energy.

Power conversion is therefore an interfacing requirement between the piezoelectric generation point and the end user USB device. Such conversion can be achieved with this functional outline:

The system above will convert the electric power generated by the periodic stepping of a human into power which is defined as acceptable by the USB 2.0 standard. From an input to output perspective, the input will be a human footstep of approximately 1 hertz (net, from 2 separate shoes); the system will convert this periodic event into electrical power at a given standard; the system will output power consistent with the USB 2.0 standard.

The output of this system will be routed to the commonplace USB female adapter, and will therefore be compatible with any fixed or portable device that is intended to plug into a USB port. This port would be installed into a small plastic device small

enough to fit into a pant pocket, thus allowing for the mobile generation of USB equivalent power through the conversion of only the human footstep.

2.2: Technical Description of the Design and its Components

The first component involved in such a system would be the piezoelectric heels affixed to the wearer’s shoes. Ideally this heel would be removable and transferrable, allowing it to be produced separate from the shoe. This heal would contain a grid formation of piezoelectric crystals aligned so as to generate the maximum possible current from the downward deformation of the heel. Thus as each step is taken the piezoelectric crystal deformation will develop charge potential across the piezo-grid. Small wires will carry this charge from the generation point to an apparatus containing the conversion circuitry. The volume of such a device would ideally be less than one cubic inch, and would have a slim profile, allowing the wearer to store it in a pocket.

The specific attributes of the charge will be strictly dependent on the characteristics of the piezo electric grid, as well as the true deformation achieved by the human footstep. As no information presently exists to more accurately predict the prototype grid’s output, it must be assumed that the output from such a device would very nearly mimic that which was seen in the previous MIT experiments. Components required to convert the power as previously prescribed will be based upon this data.

Regardless of the total energy produced by the step, the voltage derived from the system must be uniformly in the same direction, and have a value of 5 Volts. Therefore the system would need to first proportionately decrease the voltage, whilst increasing the current produced (equal energy). This could be achieved through the use of a diode switching transistor system. Such a design would convert the spikes to DC at near the voltage generated, and store the energy in capacitors to be pulsed to the rest of the system by digitally controlled transistors. This design would work best in a larger more complex converter, but this method is far too complicated for a prototype of such a small footprint. Additionally high voltage diodes and storage capacitors would be more expensive and physically larger. A small transformer, could instead be implemented to decrease the voltage to approximately 12 volts (about 1/30th the initial voltage).

This AC power would next flow through a full bridge rectifier and bring the voltage to approximately 10 volts. Both methods would work, at different degrees of efficiency and cost. The first method involves high voltage diodes, high voltage capacitors, and digital controller to operate, adding significant cost to the system. The transformer however can accomplish the same task of lowering the voltage and increasing the current, and can convert this lower voltage power to DC with the rectifier diodes at a fraction of the cost. Even for a prototype the estimated costs of such a transformer and diode system would be under 15 USD (source: www.RadioShack.com).

To further convert this DC power, the pulses would need to be stored, and slowly distributed to the final power regulation phase. These two components must be matched, so that the power

entering the inline regulator is compatible to its internal circuitry. The final regulator is the last opportunity to refine the power before it would be used by our USB device. This meant the produced power must not, even minutely, deviate from 5 Volts and it would need to be continuous and free of distortion. To store the energy from the diodes, a small 12volt capacitor could be implemented, in combination with a resistor to create a low pass filter. This circuit would dampen the heel strike voltage further, and slowly deliver a lower voltage to the final stage Integrated Circuit - 5 Volt Inline Voltage Regulator.

Again several options could be employed, including a slew of discrete filtering systems, but this would only increase cost, complexity, size, and may even lower overall efficiency. Instead a small, reliable, inexpensive IC inline voltage regulator could perform the same function and would be the most simplistic approach. The IC is priced at under $4.59 USD, and widely available. This regulator is able to convert and filter input voltages from 4-30 Volts, to a fixed output of 5 volts, so long as the inputted power is greater than the output power by an amount equal to the heat loss (inefficiency) of the IC. Information regarding the output characteristics of the LT1076-5 integrated circuit can be found from the manufactorer’s website (source: http://www.datasheetcatalog.org/datasheet/lineartechnology/10765fbs.pdf).

This final stage would produce 5 volts at a predetermined maximum current that could easily be utilized by a USB charging device. Thus the final circuit would resemble the following:

The output of this circuit would be connected to USB female recepticol, recessed in the device and would accept standard USB 2.0 compatible cables. Overall system performance will vary greatly based on the walking speed of the user, the particular USB device’s power draw specifications, and the piezoelectric grid. However, in order to generate sufficient power to supply a standard USB power, a person need only step with his or her body weight (assuming a statistically average weight) with a frequency of one hertz to generate, with an overall conversion efficiency of less than 15%. As such the excess potential generation would simply ensure continuous stable output at the port, and thus creates a factory of safety capable of offsetting concerns in the variances of the aformentioned system variables.

Step Down Transformer and

Full Bridge Rectifier

5V Inline Regulator from

Linear Tech

Storage and Filtering

2.3: Mathematical of Other Principles Embedded in the Project

In order to use the electricity produced by the piezoelectric material we had to investigate different types of circuits that would rectify, step-down, and regulate the voltage. Since the voltage would be relatively high (>50V) and the current would be very low (>2mA) coming from the piezoelectric material we needed to find a way to lower the voltage and raise the current to levels that would be more usable. We found researched that showed a multilayered piezoelectric material actually delivered voltage and current levels that were much more in line with what we were looking for. N-layer multilayer ceramics decreased the voltage but increased the current N times. The impedance of the multilayer ceramics are matched to 1 kΩ which is similar to the impedance of general electrical devices, so the multilayer piezoelectric generator could possibly be directly employed for electrical devices without the additional electrical circuit in order to improve the efficiency of the energy generation.

When the same amount of force was applied to the piezoelectric material, the generated voltage should be linearly proportional to the thickness of each layer.

where E is the generated electrical field, V is the voltage, l is the

thickness of each layer, d31 is the piezoelectric constant, ᵋ0 is the vacuum permittivity, K is the dielectric constant of the material, F is the applied force and A is the area of the electrode of the piezoelectrics. Since the output voltages are different for the different number of layers, and the researchers tested the three different number of layers in the same manner, the generated power should be the same to satisfy the principle of energy conservation. It was seen that for

the N layer piezoelectrics that the capacitance was N2 times that of a single layer, so the output energy should have different electrical quantities even though the total energy is the same. Since electrical power, p, can be expressed as p=i * V, the higher voltage sample should have the lower generated current. The following equations are useful for determining the generated current for a certain number of layers of piezoelectric material.

(1) (2) substitute 1 into 2 -> (3)

(4), where t is time. Equation 4 can show that the generated current is linearly proportional to the number of layers, piezoelectric constant of the material, and mechanical vibration condition. If we consider that the piezoelectric constant of the material can be increased by searching for new compositions, which is a time consuming task, and that the mechanical vibration condition is also determined by the vibration source, it is easy to come to the conclusion that the multilayer piezoelectric approach is a very effective way to increase the generated current.

The researchers concluded that multilayered piezoelectric materials were able to successfully generate a larger current by scarifying the voltage, and that the electrical current was increased in proportion to the number of layers. They also noted that the impedance of the piezoelectric generator was decreased as the number of layers increased which showed promising for using the generator with general electronic devices. If the impedance could be brought down to a low enough level then the addition of circuitry to lower the impedance would be unnecessary which would improve the efficiency power generation.

For our electrical circuitry that would condition the voltage and current for use with a battery, we started off simple with the following circuit.

The four diodes work together to create a rectifier bridge which would convert the alternating current coming from the piezoelectric material into a direct current that would then be used to charge a capacitor which would then periodically charge the battery hooked up to it. Since we knew that we would have to create a more complex circuit to sufficiently condition the voltage and current we explored other circuits that already existed on the marketplace. The following circuit takes a high input voltage (in the order of what is present in a typical wall outlet) and then steps it down to five Watts of power at a constant voltage and constant current in order to charge a cell phone or similar consumer electronics device.

This engineering chart describes a five-Watt constant voltage/constant current (CV/CC) universal-input power supply for cell phone or similar charger applications. This reference design is based on the LinkSwitch-II family product LNK616PG.

This helped us to decide against powering a device directly because it was clear that the power generated from the piezoelectric materials would not be sufficient. Looking at this and other similar circuits we created the following circuit that we predict will be able to charge a small Lithium-ion battery with the highest efficiency possible.

2.4: Performance Expectations/Objectives

Our group's main objective was to create a system that would be capable of harvesting energy from a piezoelectric generator and then use that energy to charge a small Lithium-ion battery in order to provide an emergency supply of power for a USB powered device. This would be useful for users who do not have access to a conventional power grid like military personnel, rescue personnel, and extreme sports enthusiasts. In an attempt to determine if this project was even feasible, we conducted research into piezoelectric energy harvesting along with what kind of circuitry would be needed to condition the output from the piezoelectric material. During our research, we decided that we would need to set certain performance expectations so that we would be able to tell if our efforts were successful or not.

First of all, we needed to determine how to get more current and less voltage out of the piezoelectric material because based on our research piezoelectrics traditionally generated high voltages at micro amp levels. When charging a thin film battery or capacitor for an electrical device, a larger current is needed to shorten the charging time. In order to increase the current in the piezoelectric energy harvesting, multilayer ceramics were looked into. N-layer multilayer ceramics decreased the voltage but increased the current N times. We decided that we would use a multilayered piezoelectric material in our design so that we could have less conditioning circuitry which would increase our power production efficiency. Ideally we wanted a piezoelectric that would output voltage in the range of one to twenty volts with a current in the range of one hundred milliamps to one amp.

Then we looked into what kind of circuitry we would need in order to step down the voltage and increase the current to levels that would trickle charge our battery. Our finding showed that we would need to convert the alternating current to direct current with a rectifier diode bridge. Then we would need to step down the voltage by utilizing a voltage regulator and a capacitor in order to bring the voltage down to five volts and the current in the range of half an amp to one amp. This output specification would allow us to trickle charge a Lithium-ion battery in a reasonable amount of time depending on the size of the battery.

The final part of our system would be the battery pack, which would store the energy generated from our piezoelectric generators. Li-ion battery technology is currently the standard technology for portable computer batteries. The charging schemes for these batteries are usually stated for the maximum recommended voltage and current due to the instability of Lithium-ion batteries at elevated temperatures. Piezoelectrics are well suited for charging Li-ion batteries due to the low currents generated, accompanied by sufficient voltages to trickle charge the battery. This allows the battery to be charged safely at a slow rate, while maintaining the charge accumulated.

After the electricity generated goes through processing it will be ready to charge a small battery pack that accepts 5V and up to 1 amp, that would act as a way to recharge USB devices. This battery pack could act mainly as a backup battery in case you need to recharge your cell phone or mp3 player. Since the battery accepts the standard USB voltage specification it would be possible for us to instead of charging a backup battery have the power go directly to a USB device if the user is running for instance since the energy produced by

running is much more consistent than walking. Based on an experiment done at Virginia Tech where the piezoelectric generators efficiency was low (in the range of 1 to 4%) it took between 1 to 22 hours to fully charge different sized batteries.

If we can increase the efficiency of our piezoelectric generation along with our conditioning circuitry we could conceivably have faster charging times. Looking at the data they acquired we can determine the size of the battery that we will use depending on how long we want it to take to charge our backup battery. A battery with a capacity of about 200 to 300 mAh would be a good compromise since it does not take too long to charge and it will provide enough charge to increase the life of a USB powered device.

One of the most important factors that would determine the success of our product would be how comfortable it is to wear and use. The system would have to be integrated into the sole of the shoe without affecting the usability of the sole. It would have to remain supportive of the user's foot and be able to withstand the forces that will be put on it due to walking, running, hiking, and other human motions. It would be ideal to fit the conditioning circuitry inside of the shoe as well in order to keep the complexity for the user low. Wires would then come out of the shoes to connect to a small Lithium-ion battery that is stored in the users pants or shirt in some kind of pocket that would keep the battery safe from unnecessary wear and tear while also making it easy for the user to connect USB devices to the battery.

We have set our expectation relatively high for this product since we can see the possible lifesaving possibilities it can provide. Let's say a hiker is lost and he has a small GPS device that sends a signal to 911 services. Unfortunately the device is out of power, our goal is to allow him to plug in the GPS to the battery pack which would provide enough charge to allow the GPS to operate for around five minutes in order for him to send out an SOS signal that could mean the difference between life and death for him.

Section 3: Critical Evaluation of Project

3.1: The “Good”

One of the best aspects about this project is working with environmentally friendly technology. If this project is eventually mass-marketed it, it could significantly reduce the carbon footprint of many peoples technology need. This design could be used in areas where access to a power grid is not an option such as military missions and extended hikes. It could also be used to monitor athletic performance. Today’s society is attached to hand-held devices and being able to power them through personal motion would be an important breakthrough.

The Design is fairly simple and would be accomplishable in a year. One circuit-board is needed for each device, and fairly inexpensive components are required for the circuit. Other than the circuit a battery and piezoelectric crystals are needed.

3.2: The “Scary”

There are various challenging parts of this project. Firstly producing a substantial amount of energy from piezoelectric has been shown to be difficult. To charge a battery takes a minimum amount of energy and that will be required of the design. Finding a battery which is small and powerful enough is a challenge. Engineers from other disciplines will need to be utilized to achieve this. Mechanical engineers would probably be best to assist in this application. Also the circuitry must work for all different speed of footsteps. A filter that works for steps at a casual pace might not be ideal for a person jogging.

Another critical issue of this design is comfort for the user. The piezoelectric will need to fit into the shoe in a way that it does not provide substantial discomfort to the person using it. If it is not comfortable there will be no market for the product. Some of the research done by DARPA funding has shown that some of the designs were extremely uncomfortable to the people using them.

3.3: The “Fun”

There are many fun aspects of this project. Primarily is the fact that much research is still to be done in this area which opens up many doors to funding and applications. The group will need to engage some forward-thinkers for this project to be completed. There are many areas of improvement needed. Firstly, the improvement of the mechanics, MIT research has stated that more rigorous research must be developed. The mechanics of exciting a transducer from foot dynamics is of utmost importance. Exciting the material at its resonance frequency could prove to provide a larger amount of energy.

The electrical aspect of the project will also be fun. Improvements in the electrical design will yield higher power output. Testing out different Integrated Circuits and filtering techniques will be researched for this project.

3.4: Funding of Project

The project does not require a lot of funding at its initial stages. There is an abundance of free software available for the design of the circuitry. The piezoelectric crystals are also fairly inexpensive.

However, moving forward with the project some funding might be needed. This funding can be obtained from a variety of power companies. Ryan Wilson has worked at Hess and has

seen interest from them in a project like this. Any company in the business of selling energy has a vested interest in this project. Another source of funding could be the DOD and the US military. Many operations that the military engages in are in hostile territory with no access to a local power grid. The majority of soldiers in recent wars have been killed while transporting power to the bases. Harnessing the energy from the soldiers themselves will reduce the amount of energy needed to be delivered to the bases and will in turn decrease the amount of casualties abroad.

Section 4: Summary

In summary the group is very optimistic about this project for several reasons. The project has great potential for interesting research as well as a variety of applications where it can be applied. Even though past research has shown that not enough energy is produced, working with an interdisciplinary group might yield different results.

Many things will need to be researched for this project to be successful. Firstly, the electrical circuitry must be evaluated further. Such things as the frequency of steps for given application must be considered. The loss of the system must be analyzed to maximize the power output. The mechanics of the footstep must also be further researched. Depending on the users activity (walking or running) the energy is placed at different spots of the foot. A design balance between power output and comfort must be considered. Also, the closer the mechanical excitation frequency is to the materials resonant frequency the more power will be produced.

The group is optimistic about this project because of the numerous applications where it can be used. People that are in desolate locations with no access to a power grid can greatly benefit from this design. Such persons are military, rescue and hikers. This could also be used for athletes to power their devices as well as power sensors to track their progress. Mobile medical personnel can also use this. This project has a large amount of applications.

Sources:

“Energy Scavenging with Shoe-Mounted Piezoelectrics” – MIT Research found via IEEE Explore

“Parasitic power harvesting in shoes” – MIT Research found via IEEE Explore

http://designs.digikey.com/library/4294959904/4294959874/271

http://homepage.ntu.edu.tw/~ yichung/power_harvesting-jmm-2006.pdf

http://www.springerlink.com/content/9v23732061q6847t /

http://www.memsinvestorjournal.com/2010/04/microstructured-piezoelectric-shoe-power-generator-outperforms-batteries.html#more

http://www.piezo.com /

http://www.usb.org/developers/docs /

http://www.eetimes.com/electronics-news/4197064/Piezoelectric-Technology-A-Primer

http://www.cimss.vt.edu/pdf/Conference%20Papers/Park/C20.pdf

http://ece.uncc.edu/~smbobbio/ifa/ifa.html

http://www.writing.eng.vt.edu/urs/simmers1.pdf

http://homepage.ntu.edu.tw/~yichung/power_harvesting-jmm-2006.pdf

http://www.usb.org/developers/docs/

http://www.radioshack.com/product/index.jsp?productId=2062599

Biographies:

Mikhail Itenberg

Mikhail Itenberg was born on February 1st, 1989 in Moscow, Russia. He lived in Moscow until the age of 8 and finished first grade there. Mikhail moved to the United States in 1997 to Fair Lawn, New Jersey where he currently resides. He attended public schools during his life in the United States, and graduated from Fair Lawn High School in 2007. During his time in School Mikhail was a stellar student and was involved in numerous extracurricular activities

As a student Mikhail finished at the top of his class and completed various AP courses, including Calculus, Physics, Economics and Statistics. For extracurricular activities he was involved in sports as well as after-school clubs. Mikhail was a 4-year varsity swimmer and also played Lacrosse for 3 years. Mr. Itenberg was also a member of the Math Club and JETS (Junior Engineering Technical Society) where he regularly competed in the various competitions between schools.

In August of 2007 Mikhail began his education at Stevens Institute of Technology, where he is currently working towards his Bachelors of Engineering in Electrical Engineering. At Stevens Mikhail joined the Theta Xi fraternity, where he is currently an active brother. Throughout his years as a Theta Xi brother he has held the position of Scholarship Chair and has been involved with the numerous philanthropy events the fraternity takes part in.

During college Mikhail joined the Cooperative Education program and has completed 4 work terms for Credit Agricole Investment Bank in New York, NY. At Credit Agricole he worked in the IT Infrastructure and IT Security Groups. His specific positions include IT Help Desk, IT Security Administrator and IT Security Engineer. For his fifth term Mikhail will be working at ACC (Automated Control Concepts) in Neptune, NJ.

Ryan Wilson:

Majoring in computer engineering at Stevens Institute of Technology he is currently finishing his junior year. As a fourth year member of the Varsity Men's Tennis team, most of his free time is spent training and practicing in the spring semester. His hobbies include playing video games, watching culturally enriching television programming and working on his car. Born and raised in Toms River, New Jersey he attended Toms River High School East where

he was a member of the tennis team, National Honor Society, French club, and the indoor track team.

Also participating in the impressive Stevens Cooperative Education Program, Ryan has worked for three large global corporations during his time at Stevens.

His first job was at the now infamous Lehman Brothers banking institute where he worked for the Information Technology Infrastructure department. This job gave him an insight into the corporate world and how it runs. Much was learned at Lehman Brothers, from inventory management to pc upgrades to organizing removal of outdated technology equipment. When Lehman Brothers went bankrupt, Ryan saw the ugly side of the corporate world. Seeing grown men crying over lost livelihoods and department managers reduced to assisting him install pc's, Ryan witnessed what happens when greed takes over in the corporate world. When Barclay's Capital swooped in and purchased Lehman Brothers and all of its assets, Ryan took over the role of Head PC Lab Coordinator. He was now in charge of the other co-op students that were previously working alongside him. This provided a great opportunity for him to develop his leadership skills and prove that he could manage a team.

His second job was at Amerada Hess Corporation, where he worked for the Information Services department in Application Development. During his time at Hess, he developed an automated solution for the marketing team that generated reports for them that were previously excel spreadsheets that had to be filled in by hand every month. The main skills he learned here include working with a team of individuals to accomplish a task, gathering project requirements, and learning to integrate different corporate systems using SQL Server.

His most recent work experience was at Mindray North America, where he assisted the Software Engineering department with their design documentation. Heart rate monitors and other life monitoring systems are vital to the operation of any modern hospital and Mindray North America strived to produce innovative monitors that would make the jobs of nurses and doctors easier in the high stress environment of a hospital. Documentation and document control was not as glamorous as the previous jobs that Ryan had held so at the end of his semester with Mindray he decided that he would pursue returning to Amerada Hess for his final co-op experience.

Thomas Radziewicz

G3 Technologies Incorporated, New Providence New JerseyCo-op CDMA Support Engineer: 5/10-12/10 Assembled Multi-Base Station CDMA micro cells Load and performance tested CDMA 850MHz and 1900MHz Voice (1xRTT) and Data (EVDO)

systems using in-house testing software. Enhanced cellular phone performance using modified ROMs and Post Production Software Developed and maintained component inventory and tracking system. Communicated with outside contractors in acquisition of parts and materials. Purchased, stocked and maintained critical lab and office supplies. Planned and coordinated office events and sales demonstrations Designed and created in-house custom communication circuits (including soldering).Created circuit and utility layout of New Providence location.

Zimmer Trabecular Metal Technology, Parsippany New JerseyCo-op Plant Engineer: 1/09-5/09 and 08/09-12/09 Validation: Developed thorough testing procedures to test, validate, and verify machine

functionality and performance. Performed testing, compiled results, and coordinated meetings to present findings. Wrote

final validation reports. Setup and integrated electronic control systems Programmed automation systems using C-more and DirectSOFT proprietary software. Debugged and corrected malfunction in existing automation systems Redesigned critical gas detection system. Identified inefficient and erroneous coding,

rewrote and refined. Acted as Plant Engineering representative at Material Review Board (MRB)

Electronics, Microprocessor System Design, Automobiles, Renewable Energy, Cabinetry, Music, Computer Programming, Personal Health and Fitness, New Technology.

House Manager of the Theta Xi Fraternity, Greek Intramural Sports, Sailing.