Build a Simple Water Level Indicator Using Arduino
Learn how to build a basic water level indicator using Arduino and metal probes. Ideal for science fair projects or home automation.
Never worry about an overflowing or empty water tank again! In this project, we’ll build a simple yet effective Arduino water level indicator using a water-level sensor and indicator LEDs (plus an optional buzzer). It’s perfect for science fairs, MakerBox challenges, and real-world home use.
Materials Needed Part Purpose Arduino Uno (or compatible) Processing data Water level sensor (analog, three-pin) Detect water level 3× LEDs (red/yellow/green) Visual level indicators 3× 220 Ω resistors Limit LED current Buzzer (optional) Overflow alarm Breadboard & jumper wires For circuit setup 5V power source Arduino and sensor power
Wiring Diagram Here's how to wire the sensor and LEDs: • Sensor VCC → 5 V, GND → GND, Signal → A0 • LEDs: Red → D2, Yellow → D3, Green → D4 (all cathodes to GND via resistor) • Optional Buzzer on D5 In this setup, each LED lights up as water rises: green (low), yellow (medium), red (high/full).
Arduino Code
// Pin definitions const int sensorPin = A0; const int ledLow = 2, ledMid = 3, ledHigh = 4; const int buzzer = 5;
void setup() { Serial.begin(9600); pinMode(ledLow, OUTPUT); pinMode(ledMid, OUTPUT); pinMode(ledHigh, OUTPUT); pinMode(buzzer, OUTPUT); }
void loop() { int value = analogRead(sensorPin); Serial.print("Level: "); Serial.println(value);
digitalWrite(ledLow, value > 300); digitalWrite(ledMid, value > 500); digitalWrite(ledHigh, value > 700);
digitalWrite(buzzer, value > 700); delay(500); }
How It Works • Sensor Operation: Water bridges sensor traces; the more submerged, the higher the analog voltage . • Arduino Reads Voltage: analogRead() gives a 0–1023 value (0–5 V) that correlates with water immersion. • Threshold Logic: If value crosses set thresholds, relevant LEDs light up and buzzer may sound.
Safety Considerations • Use 5 V supply only to avoid shocks • Insulate probes and wires to prevent corrosion and short circuits. • For pumps or mains use, always use isolated relays with Arduino control.
Calibration Tips • Dry sensor read might be ~0; fully submerged may be ~800–1000 — run AnalogReadSerial to test • Set thresholds dynamically based on your water and tank depth.
Next Steps & Upgrades • Connect a relay and pump to automate filling (like advanced tutorials on circuitdigest.com) • Add LCD or OLED display for live numeric readings. • Add IoT notifications with ESP32 or Ethernet shield.