tomodachi
Summary
Concept
Sketch
I started out by sketching what the device would look like and i went through a bunch of iterations and CAD-ed two of my top choices.
What do I need?
I wanted it to be a circular keychain, so that I could carry it around. I also know I needed a microcontroller that had a type-C port. I want it to be as energy efficient as possible with a tiny battery. With all those information, I built my list:
Design
It’s a prototype, so I wanted it to be really simple. After my parts came in, it was time to figure out how to build the device.
Circuit Design
With the help of previous physics knowledge, i sketched the diagram and tried it out on my breadboard. I spent an hour or two, trying to figure this out. Once I finally got it working, I connected it all!
Visual Design
I was inspired by the Tamagotchi and its resurgence on the web, and I wanted to make something close to that so I thought of the word “Tomodachi.” I also liked the show Smiling Friends, so I thought it would be a great idea to mesh the two and have the tomodachi switch faces when the user interacts (or doesn’t!) with the app. So, I animated four sprites with different colors and emotions for the display.
App Design
PCB Design
This was the version I submitted for the project, however, I wanted to take it to the next level and design my own PCB, so I decided to learn KiCAD for this. After many youtube videos and articles, I designed my first PCB!
Case Design
So, it was time to piece everything together and 3d print the case. This case is going to be a simple one, with a type-c hole. At first, I wanted it to look like the house from Smiling Friends, but I realized it was too bulky and I would not want to carry it like that. So, it took me five revisions until I was satisfied with how it looked like.
And after I got the custom pcb, I needed to refine the case design again.
Challenges
- The colors were off at first and I was stuck for a while, and I implemented a fix in the arduino and it worked.
- Designing a case and working with the components was a challenge! Greg, my mentor and Head of the MakerLab, helped me out a lot and answered my questions.
- I ordered the wrong display without the touch layer. However, upon evaluation, having a companion app was better since the screen was small and I wanted it to be a keychain.
Conclusion
Tomodachi was a fun project that taught me how to design a product end to end. I’d definitely make other tomodachi’s in the future. For instance, a Claude and Codex tomodachi signals me whenever my agents needed input or permissions.