Interface Water Level Sensor with Arduino UNO – Circuit, Code & Working

This project utilizes an Arduino Mega 2560 board to monitor liquid depth by interfacing a resistive water level sensor module and driving visual feedback through 5mm LEDs. The water level sensor operates on a series of exposed parallel conductive traces. When immersed in liquid, the water acts as a variable resistor bridging the traces, altering the conductivity between them. This produces an analog voltage output corresponding to the depth of the liquid, which is read by one of the Arduino's analog input pins. The Arduino processes this incoming analog value within its firmware running via the Arduino IDE. Depending on the measured water level thresholds, the microcontroller sends output signals to digital pins connected to 5mm LEDs. Each LED is paired with a 220-ohm current-limiting resistor to ensure safe operating currents and prevent component damage. As the liquid level rises or falls, different combinations or thresholds of LEDs illuminate, providing a direct visual representation of the water depth on a breadboard. The system is interconnected using jumper wires and powered via a USB cable connected to the Arduino Mega 2560.