Tictac is a smartwatch prototype built on STM32G4, featuring heart rate monitoring, step counting and Bluetooth time sync on an e-ink display.
Tictac is built around an e-ink display, a PPG heart rate sensor, a 6-axis accelerometer and a Bluetooth module, all packed into a custom-routed PCB and a fully 3D-printed enclosure.
The project spans embedded C on STM32G4, signal processing prototyped in MATLAB, PCB design in Altium Designer, mechanical design in Fusion 360, and a companion Android app; all developed from scratch over one semester.
- What : A smartwatch prototype with heart rate monitoring, step counting, time display and Bluetooth sync.
- Why : We wanted a project that was both technically ambitious and tangible; something you can actually wear and demo.
- Context : Embedded systems student project, two-person team.
- ⚙️ Hardware Architecture: Component list, pin mapping and wiring
- 🛠️ Firmware: STM32G4, state machines, code architecture
- 📶 Connectivity: Bluetooth usage and handling
- 💓 Heart-Rate Measurement: PPG acquisition, bandpass filtering and BPM calculation
- 👟 Step Counter: Accelerometer-based step detection and distance estimation
- 👤 Human-Machine Interface: E-ink display, rotary encoder and menu navigation
- 🔌
Electronics: Altium schematic, PCB routing, JLCPCB validation - 📐 Mechanical Design: 3D-printed enclosure, pulse sensor jaw, dial and screen housing
├── hardware/ # Altium schematics, PCB
├── firmware/ # Source code
├── matlab/ # Signal processing scripts (PPG, pedometer)
├── docs/ # Documentation, conception notes
├── assets/ # Images, schematics and illustrations
└── case/ # 3D models