The soil moisture sensor - an easy-to-use sensor to detect the humidity of the soil in which it is placed. It will convey information regarding insufficient or excessive watering of your lawn or garden's plants.
A small voltage is generated between the two electrodes if the soil is dry. If the soil is dry, the resistance will high and the current will be low. If the soil is wet, resistance will be low and the current will be high. According to the resultant signal the degree of soil humidity can be measured.
The contact surfaces of the sensor are coated with gold to prevent corrosion when the sensor is off. It is impossible to get rid of the electrolytic corrosion caused by leakage current, therefore it is recommended to power the sensor through via a mosfet (turn it on only when you need it).
The sensor consumes about 35 mA during operation, where supply voltage is 3.3 V — 5 V. The resultant signal (when powered from a 5 V source) is between 0 - 4.2 V. You can display these values over a 10-bit range by using the following approximations:
Connect the sensor via 3-pin jumper cable to receive a signal from the scanner. The 3-pin jumper cable needed for the connection is included in the kit.
There are several different ways to wire this module:
Troyka Shield. The most straightforward method. Connect the module to a pin group on Troyka Shield with the 3-pin jumper cable and you’re ready to interface with it from your Arduino.
Troyka Slot Shield. The best choice for quick prototyping. Using slots on the shield, you can get rid of cables. The module will be held securely in place using both pin headers.
Breadboard. For advanced use. Troyka pin headers have 0.1” spacing which is compatible with any breadboard. Simply wire the module like you would do with any IC.