Water Level Indicator

Published: January 15, 2026

A water level indicator that lights up a series of LEDs based on how much water the sensor is submerged in — the more water, the more LEDs turn on.

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📸 Preview

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⚙️ How It Works:

• The water level sensor outputs an analog signal depending on how deep it’s submerged.
• The Arduino reads this analog value using analogRead().
• The value is mapped to a range of 0 to 8 (for 8 LEDs).
• More submerged = more LEDs turned on, bottom to top.
• Acts like a battery meter to show water depth visually.

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📦 Components Used:

Component	Purpose
Arduino UNO	Main controller
Water Level Sensor	Detects water depth
8 LEDs	Display water level visually
8x 220Ω Resistors	Limit current for LEDs
Breadboard + jumper wires	Connections
Passive Buzzer	For tone alert when full

Disclaimer: Some Amazon links may be affiliate links. This means I may earn a small commission at no extra cost to you.

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🔌 Wiring Instructions

🌊 Water Level Sensor

Sensor Pin	Connect To
VCC	5V
GND	GND
A0	A0 on Arduino

🔊 Passive Buzzer

Component	Connect to
Buzzer +	D10
Buzzer –	GND

💡 LEDs (x8)

LED #	Color	Pin	Note
1	Green	D2	Lowest water level
2	Green	D3
3	Green	D4
4	Yellow	D5	Mid-level
5	Yellow	D6
6	Yellow	D7
7	Red	D8	Warning level
8	Red	D9	Tank full

Each LED's anode (long leg) connects to Arduino via a 220Ω resistor. Each cathode (short leg) → GND rail.

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✅ Code

Language: C++

const int sensorPin = A0;  // Water level sensor analog output

// LED pins from D2 to D9
const int ledPins[] = {2, 3, 4, 5, 6, 7, 8, 9};
const int numLEDs = 8;
const int buzzerPin = 10;

void setup() {
  pinMode(buzzerPin, OUTPUT);

  for (int i = 0; i < numLEDs; i++) {
    pinMode(ledPins[i], OUTPUT);
  }
  Serial.begin(9600); // For debugging water level
}

void loop() {
  int sensorValue = analogRead(sensorPin); // Read water level (0–1023)
  Serial.println(sensorValue);             // Optional: view sensor output

  // Map sensor value to number of LEDs (0–8)
  int level = map(sensorValue, 100, 350, 0, numLEDs);
  level = constrain(level, 0, numLEDs); // Keep within LED range

  // Light up LEDs based on water level
  for (int i = 0; i < numLEDs; i++) {
    digitalWrite(ledPins[i], i < level ? HIGH : LOW);
  }

  // Turn on buzzer if water level is too high
  if (level >= 8) { // Top 2 LEDs lit
    tone(buzzerPin, 1000);  // 1kHz beep
  } else {
    noTone(buzzerPin);
  }

  delay(100);
}

🚀 Uploading the Code

• Open Arduino IDE
• Paste the code
• Select your Arduino UNO board and port
• Click Upload ↑

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