In this tutorial we will use one soil hygrometer module to measure soil moisture of a pot.
The module can give us a digital signal when the soil need watering and this output can be adjusted by the potentiometer. Or it can give us an analog signal of current soil moisture!
The DHT-11 is a digital-output relative humidity and temperature sensor. It uses a capacitive humidity sensor and a thermistor to measure the surrounding air. Compared to the DHT22, this sensor is less precise, less accurate and works in a smaller range of temperature and humidity, but its smaller and less expensive.