A Data Transfer Tool for More Accurate G-SHOCK Tide Predictions
GitHub - MatthieuCresh/better-tides-casio-gshock: Better tides on your Casio G-Shock GBX-100: accurate 60-constituent harmonic tide data (SHOM, NOAA…) uploaded over Bluetooth LE. Marées précises sur GBX-100.
Image: Matthieu Girard
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MIT（リポジトリのライセンスが画像にも適用されるとの今回の運用上の仮定）A new tool improves tide predictions on the Casio G-SHOCK GBX-100 without changing its firmware. In Saint-Malo, France, the watch's original data produced average high- and low-tide timing errors of 29 minutes, with a worst case of two hours and five minutes.
Creator Matthieu Girard found that the watch can calculate tides using 60 harmonic constituents, but the official app supplied only a small four-constituent set for Saint-Malo. He calculated a fuller set from official measurements and transferred it via Bluetooth. Average error against 2025 observations fell to five minutes.
Details： Matthieu Girard ↗
The watch could already handle 60 pieces of tide data, but its app only handed over four. Fixing the watch meant giving it better homework, not new hardware.