===== Calibration Formula Instructions =====
{{ :formula.mp4 |}}

=== Working Principle ===
  - The electronic hydrometer contains a built-in gyroscope. It generates different tilt angles based on the density of the liquid, which are then converted into specific gravity values using a fitting formula.

=== Online Calibration ===
  - The Cuckoo management platform offers an online calibration feature, allowing instant calibration at any time.

=== Calibration Requirements ===
  - A minimum of 2 data sets is required to generate a formula.
  - Formulas derived from 3 or more data sets will be more accurate.
  - It is recommended to use the highest and lowest points from the brewing batch to create the formula.
  - If the error is significant, click "Restore Defaults" to obtain an original formula and clear existing calibration data. New data can then be added to generate a new formula based on this default.

=== Restart Calibration (Performing a full calibration through a complete fermentation process will yield greater accuracy) ===
  - Click "Restore Defaults" to clear all data.
  - Place the hydrometer in pure water. After receiving at least 2 new data sets and confirming angle stability, click the "Pure Water" marker and save.
  - Place the hydrometer in the initial wort. After receiving at least 2 new data sets and confirming angle stability, click the "Initial Calibration" marker and generate a new formula. This will create a basic formula.
  - (Optional) During fermentation, take a sample, remove carbon dioxide, measure the specific gravity (with temperature compensation), and obtain a gravity value. Click "Process Point"; in the pop-up dialog, the angle will show the latest data. Enter the measured gravity value and generate a new formula. This will produce a more accurate formula. Click "Add" in the upper left to include more process points.
  - At the end of fermentation, sediment such as yeast residue may adhere to the hydrometer, causing lower gravity readings. Calibrate the final gravity by measuring the beer using the same method as for process points. Click the "Final Gravity" marker, enter the measured final gravity value, and update the formula. This will invalidate the pure water value.

=== Calibration Guidance ===
To improve formula calibration, several validation criteria have been added:
  - Data will be invalid if the value is 0 or lacks angle/gravity values.
  - Data will be invalid if the angle and gravity values are too concentrated.
  - Gravity values should increase as the angle increases. If the angle increases but gravity decreases, check and remove the erroneous data.
  - New data with excessive deviation (observable in the calibration curve) should be checked and removed.
  - After adding a final gravity value, the pure water value will become invalid.
  - If gravity errors are detected in later batches, individual data points can be updated or replaced.