Muffin
M5Stack CoreS3 + Module-LLM
- Listens to its name + offline AI
- Front camera + selfies
- Web radio
- Touch UI
Your handmade virtual pet
Open-source virtual pets for M5Stack devices — playful for kids, inspectable for parents and hackable for makers.
✨ The flagship pet, Muffin, hears you call its name and understands what you ask — fully offline, running its own small AI on a Module-LLM expansion.
M5
Try poking my forehead, cheeks or nose.
Three pets, one accessory
Same source tree. Pick the pet that matches your hardware — and optionally add a Pip as a pocket-sized companion device that pairs with any of them.
Visu
M5Stack CoreS3 (no module)
- Front camera + selfies
- Web radio
- Touch UI
- Same hardware as Muffin, no LLM module
Goo-Goo
M5Stack Core2
- Hard buttons (BtnA/B/C)
- Web radio
- Touch UI
- Most affordable variant
Pip
M5StickC PLUS2
- Pocket companion for any of the three pets
- Pick a treat (Apple / Carrot / Bone) with BtnA
- Wrist-flick throws it via ESP-NOW
- Home pet eats it within ~200 ms
Note: the pet illustrations above are stylised demos. Real screenshots from the actual hardware are below.
Pick your pet animal
Each pet renders one of three animals on screen — Bear, Cat or Dog. You pick during first-run setup; you can switch any time in Settings. Real screenshots from a Goo-Goo (Core2):
In real life
What you need to buy
Pick one pet kit, plus optionally a Pip as accessory. All from the official M5Stack store; no soldering, all USB-C.
Pets — pick one
- Muffin — M5Stack CoreS3 + Module LLM (AX630C) + Battery Module 13.2 (the LLM module is sold separately from the battery; you need both. Battery 13.2 = 1500 mAh, fits under the CoreS3 stack)
- Visu — M5Stack CoreS3 + M5GO Battery Bottom3 (500 mAh, the official CoreS3 battery base)
- Goo-Goo — M5Stack Core2 (500 mAh battery built in, nothing else needed)
Accessory — optional
- Pip — M5StickC PLUS2 (200 mAh battery built in, pocket-sized; pairs with any of the three pets above)
What it does
Eleven moods
Pip: 5 basics
Idle, happy, excited, in love, sleepy, asleep, sad, startled, laughing, eating, speaking — driven by needs and interaction. Pip has the basic five (idle / happy / excited / sleeping / startled).
Voice control
Muffin only
Muffin listens for its own name. Call “Muffin!”, then tell it what to do — “eat something”, “let’s play”, “go to sleep”, “turn on the radio”, “let’s dance”. The pet understands plain sentences and triggers the matching action. Everything runs offline on a small built-in AI: speech-to-text by Whisper, intent classification by Qwen3-0.6B, both on the Module-LLM expansion. No cloud, no microphone leaving the device.
Singing + applause
All pets
Tilt the device upright, then left and right within five seconds — the pet bursts into song for eight seconds, then opens its ear and listens for applause. Loud clapping rewards a happy reaction; silence gets a small disappointment. The pet uses its built-in microphone to measure peak loudness.
Proximity wake-up
Muffin / Visu only
The front camera runs a lightweight skin-tone detector. When you walk past or lean in, the pet greets you with a happy face and a chirpy sound — once per cooldown so it doesn't get annoying. The detector goes silent while the pet is sleeping, listening for voice or playing radio.
Selfies + gallery
Muffin / Visu only
Open the camera in the media menu, the pet shows up in the bottom-left corner of the live preview. Tap the round shutter button on the right edge to capture; the gallery shows up to five photos as a thumbnail grid, tap a thumb to view it big with the pet alongside.
Kid-friendly web radio
Muffin / Visu / Goo-Goo
WDR Die Maus on German, Fun Kids UK on English. The pet sways to the music with little notes drifting up. No tracking; the stations are public broadcasters.
Pet friendships
Muffin / Visu / Goo-Goo
Two pets in radio range can swap gifts, hearts, food and toys via ESP-NOW. Both kids tap a big “Verabreden” button at the same time to pair up, then the four send buttons appear. No internet, no accounts.
Mini-games
Muffin / Visu / Goo-Goo
Sport mode (squats, jumps, yoga via IMU), foraging for food, toy play with five toys, scene travel between bedroom, meadow, forest, beach, city, desert and space — each scene with its own activity.
Real weather + moon
Muffin / Visu / Goo-Goo
The bedroom window mirrors your local weather and the night scene shows the actual moon phase. Location is resolved once via IP, then cached for a day.
Parental session limit
Muffin / Visu / Goo-Goo
Defaults to 30 minutes per power-on, configurable 5–120 minutes via a parent web page. After the limit the pet plays a bedtime animation and shuts down with a 30-minute lockout.
Treat thrower (Pip → home pet)
Pip + Muffin / Visu / Goo-Goo
Pip cycles through five pages with BtnA — an empty “pick one” safe-carry page, Apple / Carrot / Bone treats, and Tricks. On a treat page a wrist-flick throws it via ESP-NOW; within ~200 ms the home pet eats it with the matching face and a happy sound. No router needed; enable “Pip mode” in the home pet's Settings to receive.
Tricks (Pip → home pet)
Pip + Muffin / Visu / Goo-Goo
On the Tricks page each up-or-down flick of Pip counts a peak. After a short pause the count is sent to the home pet, which hops that many times in a row — laughing face, giggle sound and a heart per landing. The kid is teaching it a quick trick.
A father-and-son project
Pixel Pets was made together by Justus (10) and his dad Marcel. Justus brought the ideas, tested every build tirelessly and made the design calls — how the pet should feel, which mini-games belong in which scene, which animations stay. Dad's job was to “translate” this input for the AI doing the coding, and to add a bit of technical know-how on the side. The first beta was finished on a Sunday afternoon, sitting next to Justus on the sofa; the boring polish (CI, partition tables, README rewrites) was dad's evening work. Every line of firmware came from Claude (Anthropic) under our direction.
For parents
No cloud, no account
Everything runs on the device. The only network calls are an optional weather lookup and the kid-friendly web radio stream — both you can turn off.
Open source, you can read it
MIT-licensed firmware on GitHub. Every interaction the pet has is in the source. No hidden behaviour, no telemetry.
Built-in time limit
The pet decides when bedtime is. After the configured session length, it plays a sleep animation and shuts down — even if your kid wants “five more minutes”.
Quiet by default
Volume and brightness are configurable. The pet babbles softly when idle but never shouts; the wake-up sounds are short pet noises, not human speech.
Get started
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1. Pick a board
The most polished experience is on the M5Stack CoreS3 with the Module-LLM (Muffin). On a budget, an M5Stack Core2 (Goo-Goo) is enough. For a pocket-sized stick, get the M5StickC Plus 2 (Pip).
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2. Clone the repo
git clone https://github.com/marceld23/Pixel-Pets.git cd pixel-pets -
3. Install PlatformIO
Either as a VSCode extension or as a CLI:
pip install platformio -
4. Build and flash
pio run -e cores3 -t upload # Muffin (CoreS3 + Module-LLM) pio run -e visu -t upload # Visu (CoreS3 alone) pio run -e core2 -t upload # Goo-Goo (Core2) pio run -e pip -t upload # Pip (StickC Plus 2)Detailed hardware notes (COM-port quirks, Module-LLM ADB workflow, Qwen3 pitfalls) are in the docs: