The Earth Unit is a Sensor for measuring Humidity in Soil or Similar Materials. The Soil Moisture Sensor is quite simple to use. The two large stake-type sensors act as probes for the sensor, acting together as a variable resistance. The higher the moisture in the soil, the better the conductivity between the two, so that the sensor results in less resistance and higher GIS output.

You can read the moisture in the soil through ADC. Within this unit, there is an extra potentiometer to change the measurement range.

IR is an Infrared Photoelectric Sensor. The infrared remote control is widely used in consumer electronics; it can be used to operate devices such as televisions, DVD players or other household appliances within a short distance. Since this unit comes with a transmitter and receiver, you can practice not only IR encoding, but also IR decoding.

Angle is a 10K potentiometer that can be used for continuous control, such as volume, brightness or engine speed. A potentiometer is a manually adjustable variable resistance with three terminals. Two terminals are connected to a resistive element, the third terminal is connected to an adjustable cleaner. The position of the wiper determines the output voltage. The output voltage is captured and converted by AD in ESP32 on portB.