You end up with something that feels like a time capsule and a technical achievement at once
In the quiet space between nostalgia and invention, a maker known as Chaos Theory has reconstructed a small but meaningful artifact of 1990s childhood: the Tamagotchi. Using an Arduino Nano, an OLED display, and a 3D-printed shell, the CassaGotchi runs authentic emulator firmware to recreate not just the look, but the lived experience of caring for a digital creature. It is a reminder that the most compelling technology is sometimes not the newest, but the most faithfully remembered — and that open-source culture turns personal projects into shared foundations.
- The pull of genuine tactile nostalgia — not an app, but a physical device you hold — drives the entire motivation behind this build.
- The project's main friction point is its honest skill ceiling: Arduino coding, basic circuitry, and 3D modeling experience are all quietly required.
- A modest but specific bill of materials — Arduino Nano, LiPo battery, OLED display, 3D printer access — keeps the barrier to entry real but not prohibitive.
- The creator openly admits beginner-level 3D modeling skills and invites the community to improve the design files, signaling this is a starting point, not a finished product.
- With documentation on Instructables and GPL-licensed firmware, the CassaGotchi is already positioned as a living project that other makers can fork, refine, and evolve.
There is something quietly compelling about holding a working Tamagotchi again — not a phone app, but an actual device with weight and buttons. A maker known as Chaos Theory built exactly that: the CassaGotchi, a fully functional Tamagotchi emulator running on an Arduino Nano inside a 3D-printed shell designed to echo the original toy's charm.
The project adapts ArduinoGotchi, an open-source firmware created by Gary Kwok under a GPL license, specifically for the Arduino Nano's constraints. This is not a new game or a custom pet simulator — it is a genuine emulation of the software that ran on the handheld devices millions of people carried in the 1990s. The same mechanics, the same digital creature to nurture, rebuilt from modern components.
The bill of materials is modest: an Arduino Nano, a 3.7-volt LiPo battery, a 168-by-64-pixel OLED display, and access to a 3D printer for the custom shell and chassis. Basic tools — screws, a multimeter, hot glue — round out the build. The real prerequisite is a working familiarity with Arduino coding, basic circuitry, and some 3D modeling experience.
Chaos Theory is candid about the project's rough edges, describing themselves as a beginner at 3D modeling and openly inviting others to improve the files. The CassaGotchi is a proof of concept, not a polished kit — but for makers at the right skill level, it delivers something genuinely rewarding: a pocket-sized time capsule running authentic 90s software, built entirely by hand.
The project lives on Instructables with open-source files ready to be forked, refined, and adapted. That openness is the point — the CassaGotchi is less a finished object than a foundation, an invitation for the maker community to carry it further.
There's something magnetic about the idea of holding a working Tamagotchi in your pocket again—not a phone app, not a nostalgia-tinged simulation, but an actual device that feels like the real thing from the 1990s. A maker known as Chaos Theory figured out how to build exactly that, and the result is called the CassaGotchi: a fully functional Tamagotchi emulator running on an Arduino Nano, housed in a 3D-printed shell that captures the charm of the original toy.
The project takes an existing piece of open-source firmware called ArduinoGotchi, which was originally created by Gary Kwok under a GPL license, and adapts it specifically for the Arduino Nano's constraints. This isn't a new game or a custom pet simulator—it's an emulation of the actual software that ran on the handheld devices millions of people carried in their pockets decades ago. The appeal is straightforward: you get the authentic experience, the same mechanics, the same digital creature to nurture, but in a modern build that you made yourself.
What makes this project approachable for hobbyists is that the bill of materials is surprisingly modest. You'll need an Arduino Nano as the brain, a 3.7-volt lithium polymer battery for power, and a 168-by-64-pixel OLED display to see your pet. Beyond that, you're looking at basic hardware: screws, a micro-screwdriver, a multimeter for testing connections, and some hot glue to hold things together. The real requirement is access to a 3D printer, since the shell and chassis are custom-designed pieces that give the device its distinctive look and feel.
Chaos Theory is candid about the limitations of the design. The creator describes themselves as a complete beginner at 3D modeling and explicitly invites improvements to the files. This isn't a polished, production-ready kit—it's a working proof of concept that assumes you have at least a passing familiarity with Arduino coding, basic circuitry, and ideally some experience with 3D modeling software. For makers at that skill level, though, the project offers something genuinely rewarding: a functional retro device you built from scratch, running authentic 90s software on modern components.
The CassaGotchi represents a particular kind of maker appeal. It's not about inventing something entirely new; it's about faithfully recreating something beloved using contemporary tools. The 3D-printed shell mimics the original toy's form factor and aesthetic, while the OLED display is a genuine upgrade over the original's dot-matrix screen. You end up with something that feels like a time capsule and a technical achievement at once—a pocket-sized device that lets you experience what it actually felt like to own and care for a Tamagotchi, without relying on emulation software running on a computer or smartphone.
For anyone interested in pursuing this build, the project documentation is available on Instructables, and the firmware is open-source, which means the design can evolve. Other makers can fork the files, improve the 3D models, optimize the code, or adapt the concept for different microcontrollers. That openness is part of what makes maker culture compelling—the project isn't a finished product to be consumed, but a foundation to be built upon, modified, and shared.
Notable Quotes
I am a total 3D-modelling noob and expect that many improvements could be made to these files— Chaos Theory, CassaGotchi creator
I would only recommend attempting this project if you have a passing knowledge of Arduino coding, circuitry, and 3D modelling— Chaos Theory, on project prerequisites
The Hearth Conversation Another angle on the story
Why does this matter? There are Tamagotchi apps everywhere now. Why build a physical device?
Because an app on your phone isn't the same thing. The original Tamagotchi was a specific tactile experience—you carried a small object, you pressed physical buttons, you checked on it throughout the day. An app gets buried in notifications. This device is intentionally limited and focused.
So it's purely nostalgia?
Not purely. It's also about understanding how the original worked. When you build it yourself, you're learning the hardware and software that made that toy function. You're not just using nostalgia; you're reconstructing it.
The creator says they're a 3D modeling beginner. Doesn't that limit the quality?
It actually makes it more interesting. The design is functional but imperfect, which invites others to improve it. It's a starting point, not a finished product. That's the whole point of open-source hardware.
What's the hardest part of building one?
Probably the soldering and getting the OLED display wired correctly. The 3D printing is straightforward if you have access to a printer. The coding is already done for you.
Could someone with no electronics experience do this?
Not really. The creator is explicit about that. You need to understand circuitry basics and be comfortable reading Arduino code. It's not a beginner project, but it's not advanced either—it's intermediate maker work.
What happens after you build it?
You have a working Tamagotchi that runs the actual 1990s software. You feed it, play with it, watch it grow. It's the real experience, just in a device you made.