(Thanks to Israel21c) Israel’s CommonSensor wireless smart water filter registers how much water is in the soil, rather than measuring pressure or humidity. It then controls irrigation when the plant needs it without any human intervention. Distributors are sought for the new version.
http://israel21c.org/headlines/smart-watering-that-lets-plants-decide-when-to-drink/
https://www.youtube.com/watch?v=8bNj-wh9mkM