Tamagotchi
A virtual pet that lives, grows, and misses you when you're away
Author: Vasile Delia
GitHub Project Link: https://github.com/UPB-PMRust-Students/fils-project-2026-deliavasile
Description
A Tamagotchi (digital pet) built on the STM32 NUCLEO-U545RE-Q microcontroller, programmed entirely in Rust. The system uses a finite state machine with concurrent async tasks. It provides visual feedback via an OLED screen, audio feedback via a PWM-driven passive buzzer, and accepts input via three physical buttons (Feed, Play, Sleep). The pet's state (hunger, happiness, fatigue) degrades over time using the microcontroller's internal RTC, so the pet continues to age even when the device is idle.
Motivation
I chose this project because it combines several embedded systems concepts (async Rust, I2C, PWM, state machines) in a fun and interactive way. It also presents a real challenge: managing time-based state changes using the internal RTC of the microcontroller.
Architecture
The main components of the system are:
- STM32 NUCLEO-U545RE-Q — main microcontroller with internal RTC running Embassy/Rust
- SSD1306 OLED screen — displays the pet's current state via I2C
- 3 push buttons — user input (Feed, Play, Sleep) via EXTI interrupts
- Passive buzzer + transistor — audio feedback via hardware PWM
Log
Week 5 - 6
Brainstormed project ideas and consulted with the lab professor to decide on the final concept.
Week 7
Project got approved. Ordered the necessary hardware components.
Week 8 - 9
Set up the development environment and started experimenting with Embassy on the NUCLEO board.
Week 10 - 11
Developed the KiCad schematic and assembled the prototype for the project.
Hardware
The project uses the STM32 NUCLEO-U545RE-Q as the main microcontroller. An SSD1306 OLED screen is connected via I2C. Three push buttons handle user input and a passive buzzer driven by a transistor provides audio feedback. Time tracking is handled by the microcontroller's built-in RTC.
Schematics
Bill of Materials
| Device | Usage | Price |
|---|---|---|
| STM32 NUCLEO-U545RE-Q | Main microcontroller | — |
| SSD1306 OLED screen | Graphical interface | 20 RON |
| 3x Push buttons | User input (Feed/Play/Sleep) | 5 RON |
| Passive buzzer + transistor | Audio feedback | 6 RON |
| Jumper wires + breadboard | Assembly | 15 RON |
Software
| Library | Description | Usage |
|---|---|---|
embassy-stm32 | Async HAL for STM32 | I2C, EXTI, Timers, RTC |
embassy-time | Async time management | Managing concurrent tasks |
embedded-graphics | 2D graphics library | Drawing to the OLED display |
ssd1306 | Display driver for SSD1306 | Used for the OLED screen |
defmt | Logging framework | Debugging |