This low cost conductivity sensor can be used to detect the moisture in soil. Applications range from plant soil monitoring to forest moisture research.
The sensor uses two probes to pass a current through the soil then the resistance is measured. More water means conduct electricity more easily (less resistance), while dry soil conducts electricity poorly (more resistance). This resistenace measurement is then converted into an analog voltage output signal. Since not all setup is the same, you'll need to do some calibration to convert the voltage into a meaningful mositure reading.
- Supply voltage: 3.3V or 5V
- Output voltage signal: 0 - 4.2V
- Current: 35mA