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Energy Scavenging - An Introductory Engineering Project

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2014 ASEE Annual Conference & Exposition


Indianapolis, Indiana

Publication Date

June 15, 2014

Start Date

June 15, 2014

End Date

June 18, 2014



Conference Session

FPD 9: First-Year Projects

Tagged Division

First-Year Programs

Page Count


Page Numbers

24.482.1 - 24.482.16



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Paper Authors


S. Scott Moor Indiana University Purdue University, Fort Wayne

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Scott Moor is an Associate Professor of engineering and Coordinator of First-year Engineering at Indiana University-Purdue University, Fort Wayne. He received a B.S. and M.S. in chemical engineering from MIT. After more than a decade in industry, he returned to academia at the University of California,
Berkeley, where he received a Ph.D. in chemical engineering and an M.A. in statistics. He is a registered Professional Chemical Engineer in California. His research interests include engineering education with an emphasis on developing and testing educational materials and learning spaces that stimulate serious play.

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Stephen Heindel Indiana University-Purdue University Fort Wayne

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Stephen Heindel is pursuing a Bachelors of Science in Computer Engineering with a minor in Computer Science and Mathematics at Indiana University-Purdue University Fort Wayne (IPFW). Stephen has been the Teaching Assistant for the introductory engineering course at IPFW since the Spring semester of 2012. He has been actively involved in new student outreach events for the engineering department.

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Yanfei Liu Indiana University Purdue University, Fort Wayne

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Yanfei Liu received a BS (1996) in Electrical Engineering from Shandong Institute of Architecture and Engineering, Jinan, China, a MS (1999) in Electrical Engineering from the Institute of Automation, Chinese Academy of Sciences, Beijing, China, and a PhD (2004) in Electrical Engineering from Clemson University in South Carolina. In 2005 she joined the Department of Engineering at Indiana University – Purdue University Fort Wayne (IPFW), where she currently is an associate professor of electrical and computer engineering. She is the author/co-author of more than 30 publications in technical journals and conferences. Her Ph.D. work was on vision guided dynamic manipulation for industrial robots. Her current research focuses on autonomous mobile robots and distributed sensing. She is also particularly interested in distributed sensing through low-cost, low-power consumption smart cameras with wireless capabilities.
Professor Liu is the recipient of the IEEE Real World Engineering Award in 2010, for the freshmen engineering project “Energy Scavenging through Vibrations.”

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Energy Scavenging - an Introductory Engineering ProjectA project in a general first-year engineering course should be engaging, contemporary andsufficiently broad so as to address multiple facets of engineering including multiple engineeringtopics and important soft-skills. The project needs to be challenging while being understood bythe typical student. An energy scavenging project that incorporates multiple facets ofengineering one project has been refined over several years. The project consists of designing amechanical system that harnesses the power of a motor to vibrate piezoelectric buzzer creatingan electrical current 1. The output current is rectified and used to charge a micro-battery.The project is organized into three phases to help scaffold the project as shown in Table 1.Phase I: Mechanical Design - Student groups brainstorm multiple concepts for converting therotational motion of a motor to vibration of a piezoelectric crystal. These design concepts arediscussed in class. Using a drag and drop LEGO® CAD program2, students prepare detaileddesigns. Two memos are required in this phase from each group: 1) reviewing three generalvibration design concepts and 2) detailing two LEGO design implementations. Students arechallenged to come up with mechanical designs that are both effective and original.Phase II: Mechanical Construction and Testing - Students built their LEGO design, measuretheir rotational speeds and test the electrical output signal from the piezoelectric buzzer. Forrotational speed an optical tachometer is used. For electoral output a sound card signal analyzeris used. This custom MATLAB program captures the input into a microphone port, the signalfrequency is analyzed with a Fast Fourier Transform (FFT) and the charging capability estimatedusing a special duty cycle calculation (see Figure 1).Phase III Electrical Circuit and Final Testing - Students construct a full-wave rectificationcircuit. The output of this circuit is tested using the same sound-card software. Finally, studentsconnect a micro-battery to their output of their charging circuit and measure the charging of thebattery over time using a multimeter.At the end of the projects students individually write a reflection memo.This project is accessible and engaging to first-year students as well as being practical andeconomic to implement. By using Legos® for the mechanical assemblies and solderlessbreadboards for the electrical assemblies, students can easily design and redesign their systemswithout excessive cost or build time. The CAD software used for the Lego® designs is free andthe oscilloscope/measurement software is written in MATLAB, software that many universitiesalready possess. This energy scavenging project incorporates mechanical, electrical, andsoftware elements and introduces a range of soft skills including teamwork, communication,design process, and experimentation.The sound card software is one of the keys to this project. It helps the students understand theconcepts being taught without getting bogged down in learning a full oscilloscope interface. Thesimple initial interface of this scope is shown in Figure 1. The software also calculates aspecially developed duty-cycle number that effectively predicts the charging capability of theirdesign. This allows the students to test and modify their ideas quickly.This paper covers the details of the project setup including details about assignments, rubrics,equipment, and software. It also includes the overall design and performance of the MATLABsound card oscilloscope/signal analyzer program. The overall assessment of the project iscovered in two major areas. The first how students are engaged in the course; this is assessedusing a Student Course Engagement Questionnaire (SCEQ), developed at the University ofColorado at Denver3. The second is a review of the actual student’s technical results, includingoverall quality of the signal and the results of the charge time; this shows that the project goalsare attainable by the students. Both outcomes show that the overall project approach andemphasis encourages student learning and successfully demonstrates engineering principles.Table 1: Energy Scavenging Project Phases and Associated ToolsWeek Phase Deliverable Tools Used 1 I. Mechanical Design Concepts Memo MLCad Software 2 Design Design Implementation Memo 3 II. Mechanical Optical Tach., Power Supply, 4 Construct & Test Initial Measurements Memo MATLAB Signal Analyzer 5 III. Electrical Circuit Power Supply, Multimeter 6 and Final Testing Technical Memo MATLAB Signal AnalyzerFigure 1: Sound Card Analyzer Software. The “Record” button toggles to turn recording on andoff. Clicking on “Analyze” button opens a second window with a Fourier Power Spectrum,RMS voltage and a special Duty Cycle Number of the chosen segment.Bibliography1. C. Cossio, “Harvest energy using a piezoelectric buzzer,” EDN, pg.94-96, March 20, 20082. Michael Lachmann, MLCAD Mike’s LEGO® CAD, n.d.,, accessed 10/2013.3. Handelsman, M. M., W. L. Briggs, N. Sullivan, A. Towler, “A Measure of College Student Course Engagement,” The Journal of Educational Research, 98(3), pp. 184-191, (2005)

Moor, S. S., & Heindel, S., & Liu, Y. (2014, June), Energy Scavenging - An Introductory Engineering Project Paper presented at 2014 ASEE Annual Conference & Exposition, Indianapolis, Indiana. 10.18260/1-2--20373

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