signalk-barometer-trend

Calculate pressure trend and get weather predictions from a barometer over time. Are there foul weather on the way?

Prerequisites

• A barometer, i.e. the bme280, outputting 'environment.outside.pressure' to SignalK
• Optional: GPS-coordinates to determinate if located in northern | southern hemisphere (default: northern)
• Optional: Temperature sensor and GPS-altitude for increased precision

Install & setup

Install the plugin through the SignalK plugin interface. 'Enable' it through the Plugin Config interface.

• Sample Rate: More | fewer readings. This may result in a more | less "jumpy" barometer-trend. (Default = 60).
• Altitude Offset: Ajust for any differences between your sensor altitude to GPS-altitude. (Default = 0).

Use

It might take a couple of minutes before the plugin show any data, as it need to collect pressure readings to calculate a trend. The plugin will not change the pressure readings you observe in SignalK - only internally for calculations.

The plugin outputs several new SignalK-values, such as:

'environment.outside.pressure.trend.tendency'
'environment.outside.pressure.trend.severity'
'environment.outside.pressure.prediction.pressureOnly'
...

The plugin saves all barometer readings every 3 minutes and when the plugin is disabled. Within a timeframe of 3 hours it should be able to read meaningful data when the plugin is started again.

Alarms

Based on the severity value it's possible to set an alarm, using the Simple Notification-plugin (see severity table below).

'environment.outside.pressure.trend.severity'

FALLING: | RISING: ------------ | ------------- (0) FALLING.STEADY | (0) RISING.STEADY (-1) FALLING.SLOW | (1) RISING.SLOW (-2) FALLING.CHANGING | (2) RISING.CHANGING (-3) FALLING.QUICKLY | (3) RISING.QUICKLY (-4) FALLING.RAPIDLY | (4) RISING.RAPIDLY

Contribute

Please feel free to contribute to this plugin by creating an issue and/or a Pull Request including test code.

Disclaimer

• See all disclaimers by reading the README at the GitHub project 'barometer-trend', also by the same author, to understand the limitations of this plugin.

External links

• GitHub: barometer-trend
• SignalK

Real world example

This is actual data while developing the plugin. A tropical wave, OT-48, was moving through the Caribbean creating local heavy rainfall and stormy winds in Guadeloupe.

The above GIF-animation is actual radar image from Meteo France at the time.
The above satelitte photo animation is from NOAA.