WIP: A 3D-printed speaker and audio system project for teaching interdisciplinary engineering design

Brian Scott Krongold; Gavin Buskes; Bagus Nugroho

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Conference: 14th Annual First-Year Engineering Experience (FYEE) Conference
Location: University of Tennessee in Knoxville, Tennessee
Publication Date: July 30, 2023
Start Date: July 30, 2023
End Date: August 1, 2023
Page Count: 4
DOI: 10.18260/1-2--44853
Permanent URL: https://strategy.asee.org/44853
Download Count: 62

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Paper Authors

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Brian Scott Krongold University of Melbourne orcid.org/0000-0003-1619-3516

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Brian Krongold received the B.S., M.S., and Ph.D. degrees in electrical engineering in 1995, 1997 and 2001, respectively, from the University of Illinois at Urbana-Champaign. He joined the University of Melbourne in late 2001 as a Research Fellow and was later awarded an ARC Postdoctoral Research Fellowship. He is currently an Associate Professor of electrical engineering and has served as Assistant Dean Teaching & Learning and as a Senior Academic Advisor. He is on sabbatical during the Fall 2023 semester at Olin College and Northeastern University.

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Gavin Buskes The University of Melbourne orcid.org/0000-0002-7920-8052

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Gavin is an Associate Professor and Deputy Head (Academic) in the Department of Electrical and Electrical Engineering at the University of Melbourne, Australia. He teaches a wide range of engineering subjects and has research interests in optimal control, idea generation, prior knowledge and developing professional skills. He also holds the role of Assistant Dean (Teaching and Learning) in the Faculty of Engineering and Information Technology.

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Bagus Nugroho The University of Melbourne

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Dr Bagus Nugroho is a Lecturer at the Dept of Mechanical Engineering, The University of Melbourne, and part of the fluid mechanics research group. His research is centered around wall-bounded turbulent flow and flow control. He is also an ITC (Infrared Training Center) Level 2 Thermographer, and a member of the accredited Thermography professional training team at the University of Melbourne. Dr Nugroho teaches/coordinates various engineering subjects at the university at both undergraduate and postgraduate levels such as engineering mechanics, engineering modeling and design, manufacturing processes and technology, and final-year capstone project.

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Abstract

This work-in-progress paper details an innovative and newly-taught design project within the first-year course ENGR10006 Engineering Modelling and Design at the University of Melbourne. This course’s goal is to develop students’ understanding of the modelling and design processes by taking them through the life cycle of a real-world engineering project, using a combination of lectures and integrated hands-on workshop sessions. Students work in teams of three and choose one of three possible projects at the start of semester.

Our students have no declared major during their first year, and a majority need some experience to help determine their pathway going forward. The only course prerequisite is standard high school mathematics, and student backgrounds can range from little or no physics to those having previously studied mechanics and electricity and magnetism. With these issues in mind, we asked ourselves: how can first-year students learn core aspects of both electrical and mechanical engineering through a unique, fun and engaging design project? Our solution was the interdisciplinary “speaker project”, which had as its focus the important physical principle of energy conversion from electrical to mechanical; namely, Faraday’s Law resulting in speaker cone movement to generate acoustic waves. As speakers are common consumer products, students could readily relate what they were doing to concrete, real-world examples.

On the mechanical engineering side, students designed and built a physical speaker (driver plus enclosure) comprised mainly of 3D-printed parts, magnets, fabric, wire, and laser-cut MDF for an enclosure. The cone, due to weight and surface issues, was pre-made using injection moulding of plastic. Students used CAD software (SolidWorks) to draw their design, 3D-print some parts, and laser cut an enclosure that could house their speaker. On the electrical engineering side, students designed circuits for an audio equalizer, stereo-to-mono mixing, crossover unit, and some additional analog filtering. Students then built and tested these circuits on breadboards. A small battery-powered amplifier module was provided to them to boost the audio power for their speaker. Students learned to measure their speakers’ performance using a sound-isolation box, measurement microphone and software. Using frequency response plots of their constructed midrange driver and a provided tweeter, students chose a crossover frequency and designed the crossover circuit. Due to the varied student backgrounds, in-depth theory could not be taught, and alternative approaches that abstract away some details were instead employed. For example, only very basic circuit theory concepts (KVL, KCL, voltage division) were taught, while more advanced concepts, such as active and passive filters and op amps, were taught with a “functional depth”. Students learned a systems-based approach, whereby they view filters and summers as basic sub-system blocks that can be designed and interconnected provided loading effects are properly minimized.

The first offering was in the latter half of 2022, and along with some success, there were some underperforming groups and unexpected issues. Discussions at the final demonstration showed a majority of students grasped the core design concepts. Further outcomes and lessons learned in the development and teaching of this project will be discussed.

Citation
Format

Krongold, B. S., & Buskes, G., & Nugroho, B. (2023, July), WIP: A 3D-printed speaker and audio system project for teaching interdisciplinary engineering design Paper presented at 14th Annual First-Year Engineering Experience (FYEE) Conference, University of Tennessee in Knoxville, Tennessee. 10.18260/1-2--44853

TY - CPAPER
AB - This work-in-progress paper details an innovative and newly-taught design project within the first-year course ENGR10006 Engineering Modelling and Design at the University of Melbourne. This course’s goal is to develop students’ understanding of the modelling and design processes by taking them through the life cycle of a real-world engineering project, using a combination of lectures and integrated hands-on workshop sessions. Students work in teams of three and choose one of three possible projects at the start of semester.

Our students have no declared major during their first year, and a majority need some experience to help determine their pathway going forward. The only course prerequisite is standard high school mathematics, and student backgrounds can range from little or no physics to those having previously studied mechanics and electricity and magnetism. With these issues in mind, we asked ourselves: how can first-year students learn core aspects of both electrical and mechanical engineering through a unique, fun and engaging design project? Our solution was the interdisciplinary “speaker project”, which had as its focus the important physical principle of energy conversion from electrical to mechanical; namely, Faraday’s Law resulting in speaker cone movement to generate acoustic waves. As speakers are common consumer products, students could readily relate what they were doing to concrete, real-world examples.

On the mechanical engineering side, students designed and built a physical speaker (driver plus enclosure) comprised mainly of 3D-printed parts, magnets, fabric, wire, and laser-cut MDF for an enclosure. The cone, due to weight and surface issues, was pre-made using injection moulding of plastic. Students used CAD software (SolidWorks) to draw their design, 3D-print some parts, and laser cut an enclosure that could house their speaker. On the electrical engineering side, students designed circuits for an audio equalizer, stereo-to-mono mixing, crossover unit, and some additional analog filtering. Students then built and tested these circuits on breadboards. A small battery-powered amplifier module was provided to them to boost the audio power for their speaker. Students learned to measure their speakers’ performance using a sound-isolation box, measurement microphone and software. Using frequency response plots of their constructed midrange driver and a provided tweeter, students chose a crossover frequency and designed the crossover circuit. Due to the varied student backgrounds, in-depth theory could not be taught, and alternative approaches that abstract away some details were instead employed. For example, only very basic circuit theory concepts (KVL, KCL, voltage division) were taught, while more advanced concepts, such as active and passive filters and op amps, were taught with a “functional depth”. Students learned a systems-based approach, whereby they view filters and summers as basic sub-system blocks that can be designed and interconnected provided loading effects are properly minimized.

The first offering was in the latter half of 2022, and along with some success, there were some underperforming groups and unexpected issues. Discussions at the final demonstration showed a majority of students grasped the core design concepts. Further outcomes and lessons learned in the development and teaching of this project will be discussed.

AU - Brian Scott Krongold
AU - Gavin Buskes
AU - Bagus Nugroho
CY - University of Tennessee in Knoxville, Tennessee
DA - 2023/07/30
PB - ASEE Conferences
TI - WIP: A 3D-printed speaker and audio system project for teaching interdisciplinary engineering design
UR - https://strategy.asee.org/44853
DO - 10.18260/1-2--44853
ER -