General
dynamic irrigation control
There are no clear specifications or guidelines on how to implement dynamic weather control.
In principle, that is OpenSprinkler just the tool, you have to work. That means trying until it fits.
Up to now there was a good possibility to dynamically implement a weather-dependent control with the weather service and the adjustment type “carpenter” or “evapotranspiration”.
Due to the incredibly large number of parameters such as water permeability of the soil, plant type and composition, sun intensity and shadows, pH value, nutrients, soil temperature, humidity and much more, it is not possible to make any definable specifications. You could only do this if you not only observed, but also measured values.
Because one thing is missing in their configuration: A measuring instrument for the actual soil moisture. And that is exactly what is now with the new "Analog Sensor Board" and the soil moisture sensors from Truebner is possible.
These measurements were created by my system, OpenSprinkler can create the graphic directly.
Basically, there are two steps:
1. You continue to water as usual, but measure the soil values, eg over a period of a few months
Here's an example, but it's about avenue trees: https://www.kassel.de/einrichtungen/aurea/sensoren-am-auepark/sensor-bodenFeucht-fuer-alleebaeume.php
2. You determine the optimum humidity range based on the measurement data, e.g. 15%-22% (this is just an example!)
You can then use these values to perform a linear program fit in OpenSprinkler enter
There is a new function “Program adjustments” for this purpose:
SMT50 soil moisture values briefly explained:
– 0% corresponds to completely dry soil
– 50% corresponds to the same amount of water as earth. The SMT50 is limited to 50%, only the SMT100 can measure up to 100%. In nature, however, a maximum of 60% occurs, but this corresponds more to a swamp and is therefore irrelevant.
Setting explained:
– If soil moisture is 15% or less, we increase irrigation up to a factor of 1,5 (150%)
– If it is higher than 22%, we reduce it to a factor of 0,5 (50%).
– Between 15% and 22% is scaled linearly, so at 18,5% it would be 100%
Combined with the weather-dependent watering, this results in the optimum watering time for the desired soil moisture range.
If you observe this again over a period of time, you should be able to get an idea of whether the soil moisture can be kept constant or whether it still needs to be improved.
Hello from Portugal! I've been using OS for many years and just came across your(?) adaptation to the soil moisture sensor system. Exactly what I was missing! However, I use LoRa moisture sensors at a depth of 30cm for our tree plantings. You already have Modbus at the start, how about http-GET or MQTT values?
Greetings Gregory
Hi,
With the API you can read out all sensor values and log data via http-get. The documentation is in the Github repo.
Mqqt also outputs the sensor data.