2017-06-10, 10:23 AM
Well it's hard to tell because it depends on the persons skills... I have just finished a simplified solution that is working for me but it took me some hours because all of this stuff is not my daily routine and it always takes me some time to get into it.
My test setup is a Wemos D1 mini, which is flashed with ESP Easy. It measures air pressure via a BME280 sensor and forwards the data to a MQTT broker running on my RPi. Node red (also on the RPi) collects the data and writes it to a MySQL database. For the test I've used my own online server but you can run MariaDB or something similar on your pi for an offline version or use a txt-file (but I would prefer a DB). Now select the data from one and three hours ago from the DB and compare them to your live data. To smoothen your data you can use some basic statistical analysis methods like a linear regression. The slope of the regression line tells you how fast the air pressure is changing. You can transform your values e.g. 1,3hPa/h to a certain slope of the line and use the values for alerts as well. Of course this reacts slower to quickly dropping air pressure than the comparison of the raw values. It's just a simple idea for a different approach to analyse your data.
All this can be done in node red but you have to be able to set up a basic database and communicate with it.
My test setup is a Wemos D1 mini, which is flashed with ESP Easy. It measures air pressure via a BME280 sensor and forwards the data to a MQTT broker running on my RPi. Node red (also on the RPi) collects the data and writes it to a MySQL database. For the test I've used my own online server but you can run MariaDB or something similar on your pi for an offline version or use a txt-file (but I would prefer a DB). Now select the data from one and three hours ago from the DB and compare them to your live data. To smoothen your data you can use some basic statistical analysis methods like a linear regression. The slope of the regression line tells you how fast the air pressure is changing. You can transform your values e.g. 1,3hPa/h to a certain slope of the line and use the values for alerts as well. Of course this reacts slower to quickly dropping air pressure than the comparison of the raw values. It's just a simple idea for a different approach to analyse your data.
All this can be done in node red but you have to be able to set up a basic database and communicate with it.