Connection setup for iSpindel

BrewPiLess supports iSpindel by accepting data from iSpindel and acting an AP for iSpindel to connect to, BrewPiLess and iSpindel can connect to the same router. To support softAP, set the correct settings in System configuration. Please note that the password(passphrase) should be at least 8 characters. The same password(pass phrase) is used for setting and for connection certification. Default value is brewpiless.

Setting	Description
iSpindel	To enable iSpindel support.
Offset	the offset between reported gravity and “real” gravity”
Calculated by BPL	Do the conversion from tilt angle to gravity by BrewPiLess. If this option is OFF, all the following options are not used.
Calibration points	Calibration data.
Coefficients	The coefficients of the formula to calculate gravity. The formula is derived based on calibration points. It is not editable.
LowPass Filter Coefficient	0~1. See following description
Gravity Stability Threshold	Integer value. 1 point = 0.001.

Offset will be “added” to reported gravity to derive the result gravity. If calculated by BPL is enabled, offset is ignored. To enable calculation, at least two points of calibration points should be entered.

After version 4.4, the calibration data survives through brews. The coefficients(formula) is derived from the calibration data.

iSpindel Settting

• Select Generic HTTP
• Server address set to 192.168.4.1 if iSpindel connect to the AP created by BrewPiless. or use the ip of BrewPiless if iSpindel connects the AP that BrewPiLess connects to.
• set url to /gravity

BrewPiLess accept post if it contains the following keys/values:

• name
• temperature
• angle
• RSSI
• gravity

For other iSpindel setting, like network settting, please refer to iSpindel project.

About low Pass Filter

The coefficient defines the ‘a’ in this LPF: y = y[i-1] + a ( x - y[i-1] ) It is usually set to 1/f. So, 1/60 for one minute reporting period, and 1/6 for 10 minute reporteing period.

calibrationSG.htm in /extra folder is an utility HTML file which can be used to derive the coefficients instead of using the excel from iSpindel.

iSpindel Dedicated Display

The information displayed are

• 1st line: SG and tempemperature
• 2nd line: battery, tilt value, and WiFi signal strength of iSpindel
• 3rd line: time since last seen
• 4th line: IP address and WiFi singal strenth of BPL