To help colleagues at my FH course, here is an example-code for measuring soil humidity.
The basic concept is that an analog reading of the hygrometer sensor is taken and sent via MQTT to a central server. From there, Node Red is used to collect data and send notifications if the level dips down too low.
Version "internal ADC, 1 sensor": Hygrometer - Single
Version "external ADC, 4 sensors": Hygrometer - Quad
Used for the project:
- Arduino IDE
- ADS1115 I2C ADC (for the quad version)
- MQTT server for data transport