Tide Clock

A battery-powered e-paper display showing tide times. Configurable for any coastal location. This device does not need an internet or bluetooth connection as all data is calculated on the device itself from a given time and location. Thanks to the display type and slow refreshrate with long sleep cycles this device can operate on two AA-batteries for at least 3 years.

Features

• Tide prediction - Next high/low tide times using a 31-constituent harmonic model
• Moon phase - Current phase with upcoming full/new moon dates
• Sunrise/Sunset - Daily times with 24-hour daylight visualization bar
• Special messages - Solstices, equinoxes, eclipses, meteor showers, holidays
• Offline operation - Pure mathematical models, no internet required
• Multi-year battery life - 15-minute wake cycles with deep sleep between updates

Hardware

• MCU: STM32F411RET6 (ARM Cortex-M4)
• Display: 2.9" e-paper (296x128, SSD1680 controller)
• RTC: DS3231MZ+ with alarm wake
• Power: AA batteries with TPS61099 boost converter

Project Structure

tidal-clock/
├── firmware/          # STM32 firmware (Rev A & B)
├── simulator/         # SDL2 simulator for testing
├── scripts/           # Location config generation
│   └── harmonic_fitting/  # Tide model fitting
├── kicad/             # PCB designs
└── manual/            # User manual

Each folder has its own README with detailed instructions.

Quick Start

Simulator

cd simulator
sudo apt install libsdl2-dev
git clone https://github.com/olikraus/u8g2.git
make && ./tide_sim

Firmware

cd firmware/revA  # or revB
cd lib && git clone https://github.com/olikraus/u8g2.git && cd ..
pio run --target upload

Customizing Location

Configure for any coastal location. See scripts/README.md for details.

US locations (using NOAA API):

cd scripts
python3 generate_location.py --noaa 9414290 --name "San Francisco" --tz US_PACIFIC

Other locations (fit your own model):

python3 generate_location.py --json harmonic_fitting/model.json --name "Location" --tz UK

License

MIT