A tiny wristwatch built around MSP430FR4133IG48, RV-3028-C7 RTC, and a GDC0209 passive LCD powered by a CR2032.
hardware is done, firmware/enclosure are next. I’m keeping it clean + easy to follow so future-me (and anyone curious) can jump in.
- ✅ Schematic + PCB: done
- ✅ LCD mapping confirmed:
- COM0–COM3 → L0–L3
- SEG0–SEG8 → L10–L18
- ✅ RTC: RV-3028-C7 over I2C
- ⏳ Firmware: not started yet
- ⏳ Enclosure: not started yet
MCU: MSP430FR4133IG48
RTC: RV-3028-C7 (I2C)
LCD: GDC0209 passive LCD (4 COM, 9 SEG used)
Power: CR2032
Programming: MSP-FET430UIF (SBW)
- Schematic PDF:
hardware/schematic/export/ - Gerbers:
hardware/pcb/gerbers/ - BOM:
hardware/bom/
Quick note: MSP430FR4133 has an on-chip LCD driver, perfect for low-power segments.
hardware/→ schematic, PCB, gerbers, BOMdocs/→ mapping tables, bring-up notes, decisionsfirmware/→ (future) code + driversenclosure/→ (future) CAD + prints
- Start with
docs/overview.md - Check
docs/lcd-mapping.mdfor segment mapping - Hardware files are in
hardware/ - Firmware will live in
firmware/(coming soon)
If you want to help before firmware exists:
- suggest a clean low-power firmware architecture
- RV-3028 register config ideas (alarms, 1Hz, timestamp, etc.)
- LCD segment table organization / generator script ideas
- v0.1 Bring-up
- I2C scan + RTC read/write
- Basic timekeeping + 1Hz tick
- LCD “all segments” test + segment map validation
- v0.2 Watch Functions
- show HH:MM
- button handling (minutes/hours adjust)
- low-power loop strategy
- v0.3 Quality
- calibration / drift notes
- power measurements
- enclosure draft
Issues and PRs are welcome — especially:
- low-power tips for MSP430FR4133
- RV-3028-C7 setup patterns
- LCD driver code structure
- test ideas + bring-up checklists
Keep PRs small and focused. If you change behavior, add a short note in docs/bringup-notes.md.
MIT License – see LICENSE file.
If you build something similar or spot an improvement, please open an issue — I’d love to learn from it.