Automate Irrigation, Updated Apr 15, 2020 15:52:05 GMT
Post by papa on Apr 15, 2020 15:52:05 GMT
Automate Irrigation, Updated
For openHAB 2.5.x & Otherwise I'm Updating This Thread
"Automate Irrigation Based on Soil Moisture & Weather"
Perhaps like me, you've been interested in using OpenHAB & nodes to automate irrigation. In 2017, I created a Soil Moisture & Soil Temperature End Node that I wanted to use for Irrigation Automation.
Studying this, this, & this, I saw a good start on how I might irrigate my garden beds. These versions rely on weather data & (predetermined, but adjustable) watering periods. I wanted to include the weather data. However, instead of watering by timers, I wanted to use my soil moisture end node to trigger watering when the soil was drying out & stop when adequate moisure was achieved.
The following irrigation automation assumes one has these working: OpenHAB, MQTT, & computourist-style gateway. (I believe a ESP8266 wifi node could also be used without a gateway.) I've used various versions of openHAB from OpenHAB2 to currently OH 2.5.4
Also assumed is a Soil Moisture End Node in the garden bed & something like a DHT End Node. The DHT End Node will toggle a electrically activated water valve via a DC to AC solid state relay. The following also assumes an irrigation system (sprinklers, drip, ??) which includes water valves that open via AC electricity supplied by a 24 VAC transformer.
Clicking the node's User Interface or physical switch will (for maybe a minute) toggle the state of the valve open or closed before the state reverts to its state before the attempted switch.
This setup was successfully tested later in a real garden (see below). Initially it was tested successfully with soil probes inserted into a plant pot. When the pot's soil dried below the moisture threshold, the node triggered the relay to turn on an AC light. Even with DHT sensor, push button, soil moisture sensor, & soil temp sensor running, the node had enough current to trigger the relay to switch on an AC device.
Originally, I thought I might mount the irrigation node on a stake in a garden bed & for protection, cap it with a liter bottle whose bottom has been removed. Later (see starting at this post), I installed the irrigation node in a sealed project box.