1. Energy Scavenging from Vibrations – Summary Lecture

2. Problem Review

3. Energy Harvesting
Wind
Water
Solar
Temperature
Vibration

4. Energy Scavenging through Vibration

5. Piezoelectric
Piezoelectricity is the ability of certain materials to produce a voltage when subjected to mechanical stress.
Piezoelectric materials also show the opposite effect, where application of an electrical field creates mechanical stress (size modification) in the crystal.

6. Piezoelectric Frequency Response

7. Components Provided

8. Methods for Solving the Problem

9. Rotary-to-Reciprocating Motion
Continuous rotary motion can be generated using motors.
Conversion between rotary motion to reciprocating motion can be achieved using an asymmetric cam .

10. Rectifying Circuit
A rectifier circuit can be used to convert an AC electric signal to a DC signal.
A four diode bridge can be used as a rectifier.

11. Capacitor A capacitor is a device that can store electrical charge.
In a capacitor equal amounts of positive and negative charges are stored on two separate conductors.

12. Charging Circuit
A super capacitor (0.47F 5.5v) is used to store electric charge.
A Zener diode (BZX85-C5V6) is used to protect the super capacitor .

13. Engineering Principles and Concepts

14. DC Motor (Speed vs. Voltage)
The induced force (F) is perpendicular to the direction of the current (I) and of the electromagnetic flux (B).
The speed of the motor is approximately proportional to the input voltage. V e R

15. Gear Ratio A B
driving
driven

16. Gear Train Simple gear train Compound gear train driving idler drivenB C A B C D

17. AC vs. DC
In alternating current (AC) the movement (or flow) of electric charge periodically reverses direction.
In direct current (DC) the movement of electric charge doesn’t change direction.

18. Diode Diodes allow the electric current to flow in only one direction.v i v i

19. 4 Diode Bridge

20. The Meaning of Frequency
Frequency means the number of times something occurs within a given time period. Frequency for waves is usually measured per second. The unit for frequency is Hertz (Hz), which means per second.

21. Spectrum Decomposition

22. Design Trade-offs
Two types of testing stations that generate vibrations for the piezo buzzer are designed, with/without a gearbox .
The gearbox provides the flexibility to tune the vibration frequency to match the resonant frequency of the piezo buzzer.
The more complex the design is, the longer the time and higher the costs it takes to implement it, but the more chance that it should provide better results.

23. Engineering Design Process
Identify the need or problem
Research the need or problem
Modify to improve the design if needed
Develop possible solutions
Test and evaluate the prototype
Select the best solutions
Construct a prototype

24. Design of a Lateral Saddle1
Gathering information
Identify constraints and design variables
Preliminary design
1 Freshman Engineering Project. Department of Civil and Environmental Engineering. Polytechnic University of Puerto Rico

25. Design of Lateral Saddle (cont.)
Evaluation and selection of preferred solution
Preparation of plan and specification
Implementation of the design
Test and evaluation

26. Reflective Problem Solving Strategies
define the problem
Test, evaluate, and improve the design
analyze the problem
reflect
identify design variables
Implement the design
propose solutions

27. Societal Impact
Energy harvesting or the process of acquiring energy from the surrounding environment has been a continuous human endeavor throughout history.

28. Societal Impact
Piezoelectric materials, such as the lead zirconate titanate (PZT), are great candidates for energy harvesting using vibrations from the surrounding environment.

29. Self-powered Wireless Corrosion Sensor
Application Areas
Wireless corrosion monitoring systems
Biomechanical Energy Harvester
vehicle
vibrating structure
frequency
Accel. PSD
mechanical energy
Self-powered Wireless Corrosion Sensor
low power
wireless transceiver
corrosion sensor
energy harvester

30. References
M. Raju, “Energy Harvesting, ULP meets energy harvesting: A game-changing combination for design engineers,” Texas Instrument White Paper, Nov. 2008
R.J.M. Vullers, V. Leonov, T. Sterken, A. Schmitz, “Energy Scavengers For Wireless Intelligent Microsystems,” Special Report in Microsystems & Nanosystems, OnBoard Technology, June 2006
Imec, “Design for analog and RF technologies and systems,”
Imec, “Micropower generation and storage,”
F. Whetten, “Energy Harvesting Sensor Systems – A Proposed Application for f, ” DOC: IEEE / f
C. Cossio, “Harvest energy using a piezoelectric buzzer,” EDN, pg.94-96, March 20, 2008