Mfr Part # KT-PR0058
NORTH AMERICA ONLY - LULZBOT TAZ
LulzBot
Acoustic Amplification Creations
2
Courtesy of Lulzbot
Guide by Lulzbot
Acoustic Amplification Creations
Description
Have you ever considered why acoustic guitars are louder without the use of electricity? Or why putting a phone in a glass cup makes the music playing louder? These instances are examples of manipulating and directing sound waves, something we do with our speakers, with our hands, and in our everyday lives! But can we design an acoustic device to do this intentionally?
Introduction
Lesson Overview:
Through this lesson, we will investigate the fundamental properties of sound waves and how they travel through the air. After considering what creates sound, we will determine how we can create devices to manipulate it!
Utilizing an engineering design process, students will research, brainstorm, design, and fabricate their own amplification devices within a variety of specifications and constraints through a real world design challenge! We’ve all made efforts to both dampen and increase sounds in the world around us, from muting an alarm clock to cupping our hands over our mouth to help us shout. In this lesson, students will create technology that can assist in such a situation!
Through their research and designed solutions, students will utilize computer aided design software, or CAD, to assist in creating a model prototype solution that will be produced using 3D printers! Students will then have the opportunity to test and evaluate their solutions under real-world specifications and constraints of a design challenge. Through this activity, our students will not only learn about sound, but also create devices that interact with it!
Utilizing an Engineering Design Process:
An Engineering Design Process, or design loop, is a method used by scientists, designers, and engineers to develop solutions to our everyday problems. Through a design loop, students will develop skills in problem solving as they brainstorm solutions and work to create a prototype through hands-on activities.
Design loops come in many shapes and sizes, but none are ever truly ending. The “last” step of any design loop is redesign, or reflection, where we look at what we’ve learned in our developed prototype to improve upon its design. Not being afraid of failure is a powerful concept that leads to greater success and implementation of problem solving.
Assorted 3D Printed Amplification Prototype Examples and a LulzBot TAZ SideKick 747 3D Printer
Lesson Objectives:
- Students will identify the properties of sound waves and how sound travels through the air
- Students will identify a situation where sound amplification may be needed or changed
- Students will create an acoustic or mechanical device that amplifies sound waves
- Students will utilize an engineering design process to develop their own solutions to a real-world problem
- Students will utilize computer aided design (CAD) software to create a 3D model that can be produced on a 3D printer
- Students will understand how 3D printers work and how they are used in an industrial setting
- Students will be able to safely apply prototyping techniques to construct designed solutions to real-world problems
Materials:
This is a list of materials each student will need to complete this lesson:
- Pencils, rulers, drawing paper
- Computer or tablet with Internet access
- Computer Aided Design (CAD) software
- 3D Printer and Filament
- Assorted non-3D printed materials to include in prototyping such as hot glue, tape, cardboard tubes, plastic cups, or rubber bands (optional)
- Click here for sample models shown throughout this lesson
Modifications:
In addition to this lesson plan, see our One Page Brief [PDF] that can be used to guide students through the lesson. Additional examples as to how this lesson could be modified are:
- Offer additional tools and materials to construct prototypes such as cardboard tubes, paper cups, or hot glue to combine with 3D printed parts
- Students could be challenged to create a prototype for a specific device, like their own phone - or a more generic situation, like any phone - to reflect real-world product design situations and decision making
- Incorporating electronic measuring equipment like a decibel meter or programmed micro controllers such as a microbit or Arduino to interact with sound may allow greater cross-curricular connections to be made
- Students could design a various assortment of amplification devices, choose constraints to foster creativity and cater to the available resources within your instructional space!
Considerations:
Based upon the age of your students, introduce the concepts of amplitude, pitch, frequency, sound waves, and rapid prototyping techniques using terms and concepts familiar to their prior experiences and needs.
Offering opportunities to allow for personal interest and passions to be included in prototype design may foster higher engagement and interest among students. Consider creating real-world scenarios, such as wishing our phones were louder when playing audio in a large room or creating devices to amplify our voices in a crowd, to provide students with ideas and content they can relate to. Choose constraints and content that fit the needs and interests of your students.
Proper safety procedures should be introduced to students when working in any makerspace or lab environment. When students are around machines such as 3D printers, or using tools to cut or glue materials, students must be informed of potential hazards and taught how to use these resources safely. For reference, see the safety resources offered by ITEEA.
Assessments:
Opportunities for formative assessments will take place through observations and discussions between students as they interact with the content in this lesson. For summative assessment, we recommend utilizing a rubric to assess how a student was able to apply the engineering design process to solve an open-ended problem. Example Rubric - PDF
Essential Questions:
- How does sound travel through the air?
- Why does sound get louder or quieter depending on physical materials it passes through or around?
- How can we create an acoustic device that changes the volume from an instrument, electronic device, or our own voices?
- How can we use technology to design a solution to a real-world problem?
This prototype solution is designed to reduced or muffle the amplification of an acoustic guitar rather than increase it!
Printed on a LulzBot TAZ SideKick 747 using Flexible TPE Filament
Identify the Problem
How Does Sound Travel?
We are surrounded by sounds. From the soft clicking of our keyboards to the alarms and sirens of an emergency vehicle, objects create and emit sound that we can hear and recognize. In the Acoustic Amplification Creations challenge, students will be creating unplugged, acoustic devices that can manipulate and change the amplification of sound waves!
Sound travels through a medium, such as air or water, as a wave. These sound waves travel by shaking, or vibrating, atoms or molecules as they travel. While all sound waves cause these vibrations as they travel, there are differences between them which is why we hear different sounds, tones, and volumes!
Each sound wave has its own unique pattern that can usually be described by its amplitude, or height of the wave, which determines how loud the sound is to us when we hear it. Amplitude is measured in decibels (dBA). A wave can also be described by its frequency or pitch, which changes the tone we can hear as our ears interact with the sound wave. The frequency of a sound wave is defined by the number of waves that pass by a point within a second. Frequency is measured in hertz (Hz).
Sound waves are sometimes called compression waves because they create areas of compression and rarefaction as they change pressure levels while traveling through the air. Waves with a higher amplitude have greater energy as they travel which makes them louder across a longer distance. When a sound wave collides with a solid object, the waves can either be reflected, diffused, or absorbed. This means that sound is a physical reaction which relies on movement of molecules, something that can be manipulated using physical devices, like your hands! Through the physical properties of sound, we can create devices that manipulate the amplitude of a sound wave to make it louder or quieter as we develop our own prototype solutions!
Identify the Problem
Have you ever tried to make your phone louder by putting it in a glass cup? Or cupped your hands over your mouth as you tried to get someone’s attention from across the room? These physical actions are attempts to change the amplitude of a sound wave, just like a hollow-body acoustic guitar!
Using an engineering design process and modern prototyping techniques, can you create a device that changes the amplification of a mobile device, instrument, or your voice more effectively and with greater ease? Consider ergonomic and aesthetic factors in your design, as well as the following constraints to guide you through this challenge:
- Your prototype must change the amplifications of sound waves from a chosen real-word situation (a mobile phone, voice, instrument, etc.)
- Your prototype solution should consider ergonomics and aesthetics in the design as you create a prototype solution that reflects real-world product design
- Your 3D Model build volume may not exceed 36 in3
- You have 1 day to brainstorm, 3 days to build, and 1 day to test & evaluate
Resources:
Offer examples of different sound waves to compare how we hear amplitude and frequency.
Objectives:
- Students will identify the properties of sound waves
- Students will identify how sound waves travel through the air and interact with the objects around us
- Students will identify how sound waves can be created, or manipulated
Teacher Instructions:
Encourage open discussion as students explore how sound works and how sound waves travel through the air. Creating sound can be fun, as can manipulating it using different materials and objects!
The concepts of amplitude, frequency, and sound can be differentiated to fit the understandings, abilities, and needs of any age group. Consider appropriate definitions and labs for your students as you introduce fundamental topics. See the “Modifications” and “Considerations” sections in the lesson introduction for more info and ideas.
Objectives:
Students will be able to identify the role specifications and constraints play in a real-world design challenge.
Teacher Instructions:
There is no one answer to any solution, nor is there one specific set of constraints for any design challenge. See examples for how to adapt and modify the specifications and constraints of this design challenge under the “Modifications” and “Considerations” section of the lesson introduction.
Prototype Megaphone Amplification Device
printed on a LulzBot Mini 2 using PLA
Brainstorm Possible Solutions
Why Solutions and Not Solution?
The second step of our Engineering Design Process is “Brainstorm Possible Solutions.” A key part of this step is solutions being plural, meaning more than one. Why do designers and engineers think of more than one way to solve a problem?
Teacher Instructions:
Adapt key phrases, concepts, and terms to best fit your students’ needs. Main idea is there is NEVER any one solution to a problem. If possible, provide an example that relates to your students’ lives, like all of their different shoes, or phones, or video game consoles. Emphasize the importance of variety and why we must, as designers, think of as many ideas as possible.
Brainstorming Our Solutions
As we work to think of different ways to solve this problem, there are a few things we can consider assisting in our design. The first is to determine what sound wave we wish to amplify. Do you want to make your phone louder when playing music? Or perhaps amplify a movie being played on a tablet? What about making your voice louder at a sporting event? Or perhaps reduce or change the amplification of your musical instrument? Any of these real-world scenarios could be improved through the creation of your prototype solution!
An effective strategy to designing a solution is to research and learn from existing solutions. Investigate existing devices that serve a similar purpose to the one you wish to create, as well as consider how they could be changed or improved.
After researching existing solutions, begin to design your own unique amplification device! Remember to consider the specifications and constraints of the design challenge as you brainstorm different potential prototype solutions to this problem. The constraints may not only guide your decision making, but also ensure you have a viable solution to solve the identified problem.
Thumbnail sketches are a great way to think of many ideas quickly without getting caught up on the details. Once you’ve completed the thumbnail sketches, narrow your choices down as you create your final design. For your final sketch, create a clear design that is neat and labeled. Consider drawing your design from multiple views (front, top, side, or isometric) to better portray your ideas.
Teacher Instructions:
Emphasize coming up with as many ideas as possible as students will tend to want to go with their first idea. Also reiterate the real-world specifications and constraints of the design challenge and ensure students are factoring them into their designed solution. The detail in technical drawings can be modified based on age and prior skill of students, as can resources provided to students in order to support the brainstorming stage. Offering additional materials to work with, such as cardboard tubes or paper cups, may foster greater creativity while also offering mediums students are familiar with. Inform students of what materials they can use as they begin to design their prototype solutions. See the “Modifications” and “Considerations” section of the lesson introduction for more examples on how to modify this design challenge to cater to available resources.
Objectives:
Students will obtain a greater understanding of how the engineering design processed is used to solve real-world problems.
Brainstorming different possible solutions using the lesson one page design brief document
Resources:
- One Page Design Brief Document [PDF]
- Thumbnail Sketching Document [PDF]
- Technical Drawing Paper [PDF]
Objectives:
- Students will be able to identify various situations sound could or should be amplified
- Students will apply research and brainstorming techniques to develop multiple solutions
- Students may consider increase or decreasing amplification in a real-world setting
- Students will use technical drawing skills to plan and share their ideas with others
Develop A Prototype
What is 3D Printing?
Step 3 of the engineering design process is all about constructing our prototype solution! In this step, we are going to get hands-on with software and machinery to create our final designs.
One of the key prototyping machines used by today’s professional designers, engineers, and scientists is a 3D printer. There are a lot of different types of 3D printers out there, but all 3D printers create physical objects you can touch, and hold based on a 3D design or digital model. Some 3D printers melt rolls of plastic into the model, while others use light to harden a liquid resin. There are even 3D printers that can print concrete, metal, or living cell tissue!
LulzBot 3D printers use the fused deposition modeling process (FDM) that feeds and melts spools of plastic through a nozzle, kind of like glue traveling through a hot glue gun. The plastic is fed, or extruded, layer by layer to create the model designed in computer aided design (CAD) software. Once we design our amplification device models in CAD software, we will be able to send them to 3D printers to be manufactured!
Teacher Instructions:
Introducing and over viewing the resources available for prototyping before beginning construction is key. Make sure your students know what resources are available, as well as how to use them safely. Introduce any additional resources available for prototyping during this step (see Modifications in lesson introduction.)
Developing our 3D Models
Now that we’ve brainstormed our prototype amplification devices, it is time to begin to fabricate them! But before we can 3D print our parts; we need a 3D design. To create this, we will use computer aided design software, or CAD. There’s plenty of great free CAD programs out there, we recommend Tinkercad, FreeCAD, Fusion360, or OnShape for students.
As you are creating a prototype that changes the amplification of a particular device or instance, like a phone for example, it is important your prototype can fit the device you wish to interact with. One way to ensure this is by taking accurate measurements, or dimensions, and including them in your design. If you want a phone to fit into a stand, or to be able comfortably hold your prototype in your hands, take accurate measurements of objects to ensure they fit within your design. Also consider creating a mock simulated assembly of all 3D printed and non-3D printed parts in CAD software before production.
It’s also always a good idea to include tolerances, or “wiggle room”, in your design too! Tolerances can be added to your dimensions to ensure things fit together or are not too tight after printing as 3D printer material tends to shrink during production. In general, adding 1/16” to dimensions acts as a general tolerance when working with PLA. Note, model shrinking and required tolerances can vary based on filament, printer, printing conditions, and print orientation.
Objectives:
Students will be able to identify how 3D printers work, and how to use them safely.
Resources:
- Computer or Tablet
- USB Mouse (Recommended)
- CAD Software & Guiding Tutorials
Objectives:
Students will utilize CAD Software to create a 3D model of their designed solutions.
Teacher Instructions:
Students may better understand the purpose of CAD after being initially introduced to rapid prototyping production machinery. For beginners, experimentation is key when learning the basics of CAD software. Encourage patience and offer tutorials or techniques to support learners. Working with a USB mouse often makes CAD easier to use.
3D Printing Modular Components for a Hybrid Amplification Prototype on a LulzBotTAZ SideKick 747 using PLA
Simulating a mock assembly of a hybrid amplification prototype using shape generators in the Tinkercad design application
Develop A Prototype
Printing!
Once students have completed their designs, it’s time to download and prepare them to use Cura. Cura is not a CAD program in that it allows you to design your models. Instead, Cura “slices” models’ layer by layer to create a program file, or Gcode file, for the 3D printer to read. This Gcode file is a set of directions that the 3D printer follows as it prints your model.
In general, we recommend PLA filament for most classroom uses as it’s a safe plastic to print in schools and prints easily in nearly any setting. PLA works well for most applications, but you may also want to consider TPU or TPE filament to create flexible parts devices that interact with musical instruments or need to be durable and particularly strong. LulzBot 3D printers are able to print countless types of rigid and flexible filaments right out the box! In addition to considering filament choices, we must also optimize our print settings to fit the needs of our student’s models. The first consideration is print quality:
- High Speed has a default layer height of 0.38mm and works best to create models that do not require lots of detail quickly
- Standard has a default layer height of 0.25mm and is the best compromise between speed and detail for parts that need to fit together at a faster speed
- High Detail has a default layer height of 0.18mm and is best for printing detailed and delicate models slowly.
Additionally, if you students have any overhangs, you should consider Support Material and Bed Adhesion settings. Support material is automatically drawn by Cura to fill any gaps or structural flaws while bed adhesion will allow for greater contact to be made between the part and print bed by increasing surface area. After the model is printed, supports and brims can be carefully removed by peeling it off of the model.
Constructing our Prototypes
In the final part of this stage in the engineering design process, we must construct our prototypes after all parts have been 3D printed. Depending on available resources and the specifications and constraints of the challenge, this step may involve assembling 3D printed parts together, cutting and creating sound horns from paper cups, or gluing 3D printed parts to non-3D printed materials.
Time needed for construction will vary based on the available resources and materials students have to build with.
Remember, proper safety procedures should be introduced to students when working in any makerspace or lab environment. When students are around machines such as 3D printers, or using tools to cut or glue materials, students must be informed of potential hazards and taught how to use these resources safely. For reference, see the safety resources offered by ITEEA.
Objectives:
Students will understand how 3D models designed in CAD are prepared and sent to 3D printers for manufacturing.
Teacher Instructions:
Depending on your student age group and classroom resources, the teacher may need to slice the models for the students. Ensure proper settings are chosen for selected filament and model quality. Reference LulzBot guides and tutorials for assistance.
Discussing Gcode is a good lesson in itself! Gcode is a list of directions for the machines to follow and can be read using a basic text program. Did you know early CNC machines required people to write Gcode manually? Luckily, we have Cura for that now!
Resources:
Materials and tools for prototype construction.
Objectives:
Students will use available resources and apply proper safety techniques to construct their prototype solutions.
Teacher Instructions:
Available resources and additional materials will vary based upon the specifications and constraints of the design challenge. Consider offering cardboard tubes, paper cups, popsicle sticks, or hot glue to enhance amplification device design and creation in an open-ended design challenge. For more examples, see the “Modifications” and “Considerations” sections in the lesson introduction.
Safety is key. Ensure all students have been trained to use any available tools or resources and organize your room to ensure these resources can be monitored accordingly.
Preparing a prototype to be 3D printed on a LulzBot Mini 2 in PLA with a brim using the Cura LulzBot Edition slicing application
Constructing a prototype amplification device using a variety of materials in combination with 3D printed components
Testing Criteria
In this stage of the design process, it is time to get hands-on with our designed prototype solutions in order to determine their effectiveness in solving the defined problem of the Acoustic Amplification Creations design challenge!
During the testing stages of the engineering design process, we must place our prototype solutions into a real-world environment to determine how they perform. Testing situations may vary between amplification devices as each student created their own unique designs for various circumstances. In any testing situation, it is important to get a baseline to compare our prototypes to in order to determine their success. Using a decibel measuring device, such as a decibel meter, a DIY device coded using a micro controller, or a decibel measuring app on a smart phone, measure the pre-existing amplitude prior to implementing your prototype solution. Once recorded, incorporate your prototype device into the testing environment and measure the amplitude again. Did it increase or decrease as expected?
During this stage, consider making multiple attempts from various simulated situations to obtain an average baseline, as well as to get a more accurate sense of how your prototype performs. Consider manipulating or modifying your prototype during testing to get the best possible results.
Evaluation Criteria
After the real-world testing stages have concluded, we must review the data collected and determine if our prototype solution was successful in manipulating the amplification of sound waves. Consider the following questions:
- Did the sound waves increase or decrease in amplitude as expected during testing?
- Were you able to interact with your prototype through a real-world setting as expected?
These guiding questions may allow for students to consider the successes of their designed solutions as well as areas that can be improved upon in a more meaningful manner.
Offer an opportunity for students to present their findings to their classmates, as well as an opportunity to receive suggestions from their peers as to how their prototype solutions could be changed or improved in terms of performance, ergonomics, and aesthetics. Offer guidelines and expectations for sharing feedback to help guide students through productive and meaningful conversations as needed. Emphasize that there is no one way to solve any problem, as we discovered in the early stages of this lesson when looking at existing solutions. Each student found their own unique way to solve this problem.
Resources:
Planning document [PDF], or notebook to record findings and discoveries during testing stages of the design process.
Objectives:
Students will apply the engineering design process as they test the performance of their design prototype solutions.
Teacher Instructions:
Challenge students to think critically as they compare their designed solutions to the identified problem, as well as existing solutions. Remind students that these are PROTOTYPES, not finished models and that failure or room for improvement is expected and GOOD when designing solutions to real-world problems.
Resources:
Planning document, Notebook, or presentation software and Internet-enabled devices.
Objectives:
- Students consider the data collected during testing to determine the effectiveness of their designed prototype solutions
- Students will review and share their data with their peers as they provide and collect constructive feedback with one another
Teacher Instructions:
Create connections between the constructed prototype solutions existing solutions in the real world. Encourage students to think critically as to how their prototypes compare to these products.
Testing the performance of an acoustic amplification speaker using a smart phone and decibel measuring device
Printed on a LulzBot TAZ SideKick 747 using PLA
Redesign
No design is perfect, nor is it ever truly finished. As new technology is developed, improvements like cost, speed, performance, or aesthetics can always be made. When considering redesign, we must look at both the successes and failures of our prototypes. A failed design does not mean we failed; it means we have room to improve upon for the next prototype solution!
Consider collected data from testing and evaluating your prototype amplification devices, as well the feedback obtained through observations and from your peers. What worked well? What could be improved? Could you improve its ergonomics or aesthetics to make it better reflect a professional quality product? Record your thoughts and create a sketch of an improved prototype design with changes you would make to allow your prototype to better meet the evaluation criteria and solve our real-world problem more effectively. Your sketch should be neat and label the changes you are making to improve your solution’s performance.
Resources:
- Planning document or Drawing Paper [PDF]
Objectives:
Students will utilize the engineering design process to reflect and improve upon their designs as they create a proposed redesigned solution.
Teacher Instructions:
Stress the importance of failure in design and engineering. No one enjoys failing, or not doing well, but the redesign step is a chance to reflect on both the good and bad of our designed solutions. Additionally, we can use observations made from other solutions as we create a proposed redesign with everything we’ve learned.
Drawn and written redesign activities both work well with varying learning styles, we recommend a combination of the two. If time permits, students may use CAD to make a 3D model of their redesigned solution or even attempt to create a new solution entirely.
Removing the brim off of a 3D printed prototype model
printed on a LulzBot Mini 2 using PLA
Have questions or comments? Continue the conversation on TechForum, DigiKey's online community and technical resource.
