DIY 4-Channel Automatic Watering Kit - Capacitive Soil Sensor & 5V Relay Module

The capacitive soil moisture sensors operate on a wide DC voltage range from 3.3V to 5.5V, making them directly compatible with 3.3V logic systems like ESP32 or Raspberry Pi GPIO, as well as standard 5V Arduino boards without requiring a level shifter.

Connect the sensor's analog output pin to an Arduino analog input (e.g., A0) to read the 0-3.0V moisture signal. The 4-channel relay module is controlled via digital output pins. Your Arduino sketch should read the sensor value and trigger the corresponding relay to turn its pump ON or OFF based on your defined moisture threshold.

Capacitive sensors, like those in this kit, measure soil moisture by detecting changes in dielectric constant, which prevents electrode corrosion. Resistive sensors measure conductivity between two exposed probes, which can degrade over time due to electrolysis. Capacitive sensors generally offer better long-term stability.

No. While the pumps are rated for 3-5V, they can draw 70-120mA each, which exceeds the current rating of a standard Arduino GPIO pin. The pumps must be powered by a separate 5V supply (like a wall adapter or battery pack) and controlled through the provided relay module, which isolates the high-current pump circuit from the microcontroller.