Developing optical devices and projects for teaching engineering

Nathan Lemke; John McCauley; Tristan Noble; Grace Riermann; Ellesa St. George; Nathan Lindquist; Keith Stein; Karen Rogers

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Conference: 2022 ASEE Annual Conference & Exposition
Location: Minneapolis, MN
Publication Date: August 23, 2022
Start Date: June 26, 2022
End Date: June 29, 2022
Conference Session: NSF Grantees Poster Session
Page Count: 5
DOI: 10.18260/1-2--42008
Permanent URL: https://strategy.asee.org/42008
Download Count: 219

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Nathan Lemke

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Nathan Lemke is Associate Professor of Physics and Engineering at Bethel University (St. Paul MN). He holds a Ph.D. in Physics from the University of Colorado. His research interests include atomic clocks, optical time transfer, atomic vapor cells, and laser stabilization technologies. Recently he has become interested in improving STEM education with student-led projects.

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Keith Stein is a professor in the Department of Physics & Engineering at Bethel University. He has a Ph.D. in Aerospace Engineering, with past research activities focusing on the modeling of parachute dynamics and fluid-structure interactions. He is currently involved in student-faculty studies utilizing advanced optical and high-speed video imaging techniques to study a number of applications involving compressible flows, shock waves, and thermal convection.

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Grace Riermann

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Ellesa St. George

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Tristan Noble

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John McCauley

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Abstract

We are creating a suite of tools and techniques based on optics to be used for teaching a variety of engineering topics. Each tool is intended for non-expert use and without the need for high-end equipment such as vibration-free optical tables. Here we report progress on three such tools: image-plane digital holography for measuring mechanical deformation; schlieren imaging of convective flows using a smart phone; and a simple optical communication protocol using LabVIEW. We will present the designs of the tools and preliminary results from teaching engineering labs and projects with these tools. Specific courses impacted to date include Fluid Dynamics, Mechanical Systems and Measurements, and Physical Optics.

We use digital holography for rapid and precise imaging of mechanical deformation. Digital holography uses a laser and beamsplitter to create an interference pattern and image it with a digital camera. One of the beams reflects off a metal bar that we can mechanically load and deform. The small deformation creates a phase shift to the interference pattern, which can be readily and precisely analyzed after numerically reconstructing the hologram, typically performed in Matlab. Sub-micron precision is observed, in accordance with the wavelength of visible light.

Schlieren imaging is a powerful technique for fluid visualization. In our setup, a single curved mirror is used to image a point source onto a screen or detector. The light source is the flash of a smart phone camera, and the detector is the smart phone camera. Near the curved mirror, a convection source such as a lit candle is placed. A stop is used to block a portion of the field, enabling the refraction caused by the flow’s density variations to create an image of the flow. We will report the design of a compact and portable setup to hold and position the mirror and phone. The parts are 3-D printable or otherwise commercially available.

Laser communication uses either amplitude, frequency, or phase steps of the laser field to encode information. Here we focus on amplitude- and frequency-shift communications, using simple diode lasers along with a standard computer data acquisition card. We demonstrate high fidelity communications at several hundred kbps speeds, including the ability to post messages to social media sites via the laser protocol.

This work is supported by the NSF Division of Undergraduate Education

Citation
Format

Lemke, N., & Rogers, K., & Lindquist, N., & Stein, K., & Riermann, G., & St. George, E., & Noble, T., & McCauley, J. (2022, August), Developing optical devices and projects for teaching engineering Paper presented at 2022 ASEE Annual Conference & Exposition, Minneapolis, MN. 10.18260/1-2--42008

TY - CPAPER
AB - We are creating a suite of tools and techniques based on optics to be used for teaching a variety of engineering topics. Each tool is intended for non-expert use and without the need for high-end equipment such as vibration-free optical tables. Here we report progress on three such tools: image-plane digital holography for measuring mechanical deformation; schlieren imaging of convective flows using a smart phone; and a simple optical communication protocol using LabVIEW. We will present the designs of the tools and preliminary results from teaching engineering labs and projects with these tools. Specific courses impacted to date include Fluid Dynamics, Mechanical Systems and Measurements, and Physical Optics.

We use digital holography for rapid and precise imaging of mechanical deformation. Digital holography uses a laser and beamsplitter to create an interference pattern and image it with a digital camera. One of the beams reflects off a metal bar that we can mechanically load and deform. The small deformation creates a phase shift to the interference pattern, which can be readily and precisely analyzed after numerically reconstructing the hologram, typically performed in Matlab. Sub-micron precision is observed, in accordance with the wavelength of visible light.

Schlieren imaging is a powerful technique for fluid visualization. In our setup, a single curved mirror is used to image a point source onto a screen or detector. The light source is the flash of a smart phone camera, and the detector is the smart phone camera. Near the curved mirror, a convection source such as a lit candle is placed. A stop is used to block a portion of the field, enabling the refraction caused by the flow’s density variations to create an image of the flow. We will report the design of a compact and portable setup to hold and position the mirror and phone. The parts are 3-D printable or otherwise commercially available.

Laser communication uses either amplitude, frequency, or phase steps of the laser field to encode information. Here we focus on amplitude- and frequency-shift communications, using simple diode lasers along with a standard computer data acquisition card. We demonstrate high fidelity communications at several hundred kbps speeds, including the ability to post messages to social media sites via the laser protocol.

This work is supported by the NSF Division of Undergraduate Education

AU - Nathan Lemke
AU - Karen Rogers
AU - Nathan Lindquist
AU - Keith Stein
AU - Grace Riermann
AU - Ellesa St. George
AU - Tristan Noble
AU - John McCauley
CY - Minneapolis, MN
DA - 2022/08/23
PB - ASEE Conferences
TI - Developing optical devices and projects for teaching engineering
UR - https://strategy.asee.org/42008
DO - 10.18260/1-2--42008
ER -