Brew and Calibrate iSpindel
If this feature is enabled, BPL will record the TILT angles from iSpindel, expect the gravity data from user, and derive formula to calculate the gravity automatically. The procedure to use "Brew and Calibrate" is
- Setup iSpindel to make it report to BPL.
- Get the Tilt value in water(SG:1.0) before dropping it into the fermenter.
- Measure the Original Gravity.
- Enable "Calibrate iSpindel" and enter the Tilt value in water at the Gravity Device pages. This must be done before startting logging.
- Start local logging.
- Input SG, which is the value of Original Gravity. Note: You should usually input the same value as OG. The required data is SG here.
- Measure SG as usual or more frequently. Input the measured SG.
BPL will derive the formula by the Tilt values and gravity data input. If the number of data pairs is less than 3, then linear(x) formula is used. Second order polynomial(x^2) will be derived if the number of pairs is equal to 3. If 4 or more gravity readings are available, 3 order polynomial will be derived. At the beginning, there should be two readings, 1.0 and OG. Even though you can't expect precise and correct gravity readings from the chart from the beginning, the change of gravity can be deduced by the change of Tilt values.
The gravity reading to input shoud be NON temperature-corrected. The wort used to measure gravity shoud be at the same temperature as the fermenting wort. The data used to calibrate iSpindel is from the iSpindle in the fermenting wort and the gravity input. The derived formula will be used to calculate the gravity value. Temperature correction is applied on the calculated values.
Note: The formula coefficients might be different from the value input or calculated. It is due to the precision of float point. The difference of calculated gravity should be within 0.0001. Therefore, it should be fine.
If BPL is in calibrating mode, there will be a lower case "f" at the bottom of the legend block. Click the "f" will bring out the calibration points and formula used.
