I’ve built an ESP8266 based device which I am going to use to auto-water my greenhouse plants based upon data from it’s ‘soil humidity’ & ‘Temperature’ sensors.
The device regularly sends data via MQTT to node-red, and node-red then determines if, when & how much water to administer. Node-red then sends a MQTT message to the device, telling it how long to switch on the irrigation pump.
For example; greenhouse/control 65
…would activate the pump on for 65 seconds.
All good, installed & working so far as a POC…
However I need to work some more on the calculation used by node-red to determine the pump timing as there are 3 influencing factors;
- Time of Day - I want watering to be reduced during the night
- Soil Humidity - more water to be available if soil humidity is low
- Temperature - as the temperature rises, I can be more generous with water
I realise that the actual timings will need to be tweaked by trial & error, but has anyone any ideas what would be the best way to perform a three way calculation such as this?