tl;dr This is not a full mouse, just the interior made more square and symmetric to make it easier to design your own exterior. It can be used as a fun, practical way to teach or learn about CAD and 3d printing.
Are you looking for a fun project to practice some CAD skills? - a project that will leave you with a functional, useful product?
Are you an instructor looking for a CAD project that your students will be excited about? - a project that will teach them about CAD skills, engineering communication, prototyping and 3d printing?
The challenge is simple: design and print an exterior shell that makes this interior into a working mouse. The CAD files are provided for the interior of the mouse using the BambuLabs kit 002. My design for it is based off the official one with a few changees making it easier to work with in a parametric CAD program.
My interior is symmetric with the scroll wheel centered.My interior has more flat (and orthogonal) faces so making sketches is mutch easier
This design challenge can be used to personally learn about CAD and design for 3d printing, or - if you are a teacher - you can assign it as a design project. I have done that and my 50+ students have gone from zero CAD experience to having designed and printed their own mouse in just a few weeks. They have loved having a real-world project to learn CAD, design, and prototyping skills.
There are three different levels for this challenge and I have had success with students doing each of them. It just depends on what you want to learn/teach.
Level 1 - Use the provided .stp files to design your own exterior
Import the “Complex Interior.stp” in the CAD program of your choice and examine what components will be necessary to design a successful exterior. This file has the three pieces printed of the interior as well as all of the hardware components in kit 002.
Use that file or the “Simplified Interior.stp” to design your own exterior. The simplified model is a single body with all of the same necessary details so it may be simple to use when CADing your own design.
Modify the base to have your own name on it.
Print the three pieces of the interior and your custom exterior. Then assemble with the kit to make your amazing mouse.
Redesign and reprint your exterior. It will never work the first time, so identify the problem, fix it, and try again. THIS IS THE MOST IMPORTANT STEP!
This is the most straightforward way to do the challenge and the most appropriate for those with no CAD experience. See the design considerations section below for general advice on designing your exterior.
Level 2 - Print the interior and design your exterior from measurements of it
Designing from physical measurements is a practical skill
Modify the base to have your own name on it.
Print the three pieces of the interior and assemble it with the kit. If you don't have the kit yet then print the “Simplified Interior.stp”.
Use measurements from the printed interior to design to make a simplified model of it. This will be similar to “siplified interior.stp” but you are free to make whatever/as many simplifications as you want. All you need are the critical dimensions (total width and button placement to name two) so omit any details that will be unneccesary for designing your exterior.
Design your exterior. The previous step may be considered unneccessary, but it is extremely benefitial when designing to fit something that you have a CAD model of that something.
Print your exterior and assemble with the kit to make your amazing mouse.
Redesign and reprint your exterior. It will never work the first time, so identify the problem, fix it, and try again. THIS IS THE MOST IMPORTANT STEP!
Replicating a physical model is a skill that students automatically recognize as being practical. More abstract (and I think more important as a general skill) is the ability to identify the critical details and simplify the unnecessary ones. This is slightly more involved but will teach you more tangeable skills than just the CAD. See the design considerations section below for general advice on designing your exterior.
Level 3 - Design from an Engineering Drawing
Full drawings are included in documentation
Download the engineering drawings provided and use them to create a CAD model of the simplified interior
Design your exterior. Modelling the interior may be skipped, but it is extremely benefitial when designing to fit something that you have a CAD model of that something.
Modify the base to have your own name on it.
Print the three pieces of the interior and your custom exterior. Then assemble with the kit to make your amazing mouse.
Redesign and reprint your exterior. It will never work the first time, so identify the problem, fix it, and try again. THIS IS THE MOST IMPORTANT STEP!
This is a fantastic opportunity to teach/learn about identifying critical details like with Level 2 (there are far more numbers on the drawing than you will type into your CAD model, which ones is up to you). It is also a great exposure to technical documentation of parts. See the design considerations section below for general advice on designing your exterior.
Design Considerations
Most people will not find use in the sensitivity toggle button so you might want to simplify your exterior design by ignoring it if you don't think you will use it.
If you are a teacher, you may not want to share this information with your students and let them figure it out themselves. I usually have a mix of skill levels in my classes so Iend up dishing out these things on an individual basis where they are not figuring it out themselves.
There are three main mechanisms for attaching your exterior to the pre-designed interior:
Your exterior needs a ledge across the front to catch the lip created by an overhang of the top over the base of the interior
Your exterior needs two pins to accept screws at the back (the hole for accepting the screws should be 1.825mm diameter this is smaller than the hole through the base of the interior)
Your exterior should press down on the thin rim along the sides of the interior
Two other important details your exterior needs to have:
The scroll wheel must still be accessible when your exterior is attached
There needs to be a way to push on your exterior and for the buttons to get clicked (there are many ways to do that)
Figure out each of these things and you should be ready to start prototyping. Here are a few more general tips that may be helpful:
Make sure you know how to ‘Project’ or ‘Use’ geometry in your CAD program
1.5mm is a good thickness to start with for the walls of your exterior
A pin with exactly the same diameter as a hole will most likely not fit when printed
The lens must be 2.4 mm above the desktop which is acheived when the pads are stuck on the bottom (this is only necessary to worry about if you modify the base or where the mouse contacts the table)
Design things to print without supports wherever possible
Watch the GIF above to see how everything fits together with an example mouse (We Are!)
That's the challenge: make a custom, awesome mouse. I have just started the work for you.
Whether you are just someone looking for a CAD design project or a professor looking for an engaging project - one that will excite students and and prompt discussions on creativity, design, manufacturing, communication, documentation, compliant mechanisms, 3d printing, and more - try out this design challenge and make yourself an awesome mouse!
I made all of these materials as a project for my students because I believe it is an effective and fun way to help them develop into effective designers and engineers. I would be thrilled if anyone else can do the same so I am sharing them here. I don't know if this will reach the right audience for this so share it with whomever it may be useful.
Good luck and have fun designing your very own mouse!
Noah
