“TinyMoisture monitors the soil moisture of your plants and gives an alarm if you forget to water them again.
TinyMoisture uses the resistance measurement method to determine the soil moisture. The two probes together with the substrate form a variable resistor. The more humid the soil, the better its conductivity and the lower the electrical resistance. Together with the 10k fixed resistor, a voltage divider is formed. This voltage can be measured by the ADC of the microcontroller. The circuit is based on the SparkFun Soil Moisture Sensor.”