Lesson 3D Printed Strain Sensors

Learning Objectives

After this lesson, students should be able to:

• Explain the basics of electrical resistance.
• List the advantages of 3D printed strain sensors.
• Explain the societal uses of 3D printed strain sensors.

Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

NGSS: Next Generation Science Standards - Science

International Technology and Engineering Educators Association - Technology

Worksheets and Attachments

Introduction/Motivation

Let us start this lesson with a question: why might it be better to 3D print a technology if it is possible to do so? (Give the students a few minutes to write down possible answers.) 3D printing is a technology that is rapidly accelerating as a novel way to manufacture products. Did you guess any of the following answers to the question? For starters, 3D printing is highly customizable; designers can print objects and customize them, practically on the fly by tweaking code. 3D printing also allows designers to quick print lightweight products. Also, the nature of 3D printing means it is easy to share a design with other engineers and manufacturers.

Let’s take a look at a technology that is easily produces because of 3D printers the strain sensor. (Lead students through 3D Printed Strain Sensors Lesson PowerPoint).

Lesson Background and Concepts for Teachers

Electrical resistance is how difficult it is for electricity to pass through a substance. Electrical resistance is related to the other variables of electricity through Ohm’s law. The website Rapid Tables details electrical resistance and Ohm’s law if you are unfamiliar.

A strain sensor is a sensor that works by measuring electrical resistance as a sensor is put through strains that deform the sensor. Also called a strain gauge, the most common type consists of an insulating flexible backing which supports a metallic foil pattern. The gauge is attached to the object by a suitable adhesive and as the object is deformed, the foil is deformed, causing its electrical resistance to change.

Associated Activities

• Constructing and Testing a 3D Printed Glove with Strain Sensors - Students learn how to integrate 3D printed strain sensors into a glove. They investigate how the sensors work in relation to the feedback that they provide.

Lesson Closure

Are there any questions? We will now take a quick quiz about 3D printed strain sensors.

Vocabulary/Definitions

3D printing: The act of creating something using a 3D printer, which works by creating a product by adding material (such as a filament) to a base using a program until the product is finished. 3D printing is the opposite of machining, in which an object is carved out of piece of raw material.

electrical resistance: The measurement of how well electrons flow through a substance.

resolution: The level of detail in a print.

strain sensor: A sensor that detects differences of movement or deformation through changes in electrical resistance; also known as a strain gauge.

Assessment

Pre-Lesson Assessment:

Question: Have students answer this question in writing: “Why can it be better to 3D print a technology if it is possible?”

Introduction Assessment:

Discussion: Lead a classroom discussion about what the students have written from the Pre-Assessment and about what students know about 3D printing.

Lesson Summary Assessment:

Quiz: Have students take the 3D Printed Strain Sensor Quiz individually. Check student answers using the 3D Printed Strain Sensor Quiz Answer Key.

References

Copyright

Contributors

Supporting Program

Acknowledgements

This material is based upon work supported by the National Science Foundation under grant no. CNS-1854985—a Research Experience for Teachers program titled “Multidisciplinary Computational Solutions to Smart Sensors and Sensing Systems” at Michigan State University. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation.