Measuring soil moisture requires to translate frequency to a certain water level.
The easiest one is to set minimum and maximum of water to a certain frequency.

This was done experimental; in future, there will be a calibration function, that tracks the optimal values aswell.

Currently we use:

- "Air with 40% humidity"  ~  +-9350 HZ
- "Sensor complete in water"  ~  +- 800 HZ