Arduino Uno Multi-Electrode Water Level Controller

Professional 5-electrode stainless steel water level sensor deploys conductive sensing between common ground probe and 4 level electrodes (EMPTY/LOW/MEDIUM/HIGH/OVERFLOW) measuring >1MΩ dry → <10kΩ wet resistance threshold. Multi-point detection enables precise tank state classification with 2cm resolution.

Digital pins 2-6 monitor individual levels with 50kΩ pull-up resistors providing stable HIGH=DRY / LOW=WET logic levels. Hysteresis via software debounce prevents relay chatter at boundaries. 5V operation, IP68 probes survive indefinite submersion.

Production Fluid Level Components

Arduino UNO R3 digital GPIO (pins 2-6)
5-Electrode Water Level Sensor (316L SS)
50kΩ pull-up resistors x5 (1/4W)
Male-to-male jumper wires (12 pieces)
12V submersible pump + relay module
IP68 junction box + cable glands

Multi-Point Resistive Level Interface

COMMON (GND): Arduino GND

EMPTY: Digital Pin 2 (tank bottom)

LOW: Digital Pin 3 (25% level)

MED: Digital Pin 4 (50% level)

HIGH: Digital Pin 5 (75% level)

OVERFLOW: Digital Pin 6 (alarm level)

Program: Arduino Uno Water Level - Automatic Pump Controller

// Arduino Uno 5-Electrode Water Level - Industrial Tank Management
// Pins 2-6: EMPTY/LOW/MED/HIGH/OVERFLOW | Hysteresis control
const int levelPins[] = {2,3,4,5,6};
const int pumpRelay = 7;
const int overflowAlarm = 8;
const int levels[] = {0,25,50,75,100};  // % levels

String levelStatus[] = {"EMPTY", "LOW", "MEDIUM", "HIGH", "OVERFLOW"};

void setup() {
  Serial.begin(9600);
  for(int i=0; i<5; i++) {
    pinMode(levelPins[i], INPUT_PULLUP);  // 50kΩ internal
  }
  pinMode(pumpRelay, OUTPUT);
  pinMode(overflowAlarm, OUTPUT);
  digitalWrite(pumpRelay, HIGH);  // Pump OFF
  
  Serial.println("=== 5-Electrode Water Level Controller Active ===");
  Serial.println("Level | Status | Pump | Alarm");
  Serial.println("---------------------------------------");
}

void loop() {
  int highestLevel = 0;
  for(int i=0; i<5; i++) {
    if(digitalRead(levelPins[i]) == LOW) {  // Wet = LOW
      highestLevel = i;
    }
  }
  
  float percentage = levels[highestLevel];
  Serial.printf("Level: %3d%% | %s | ", (int)percentage, levelStatus[highestLevel]);
  
  // Automatic pump control with hysteresis
  if(highestLevel <= 1) {  // <25% → PUMP ON
    digitalWrite(pumpRelay, LOW);
    Serial.print("PUMP:ON ");
  } else if(highestLevel >= 3) {  // >50% → PUMP OFF
    digitalWrite(pumpRelay, HIGH);
    Serial.print("pump:off ");
  } else {
    Serial.print("pump:hold ");
  }
  
  // Overflow protection
  if(highestLevel == 4) {
    digitalWrite(overflowAlarm, HIGH);
    tone(9, 1500, 500);
    Serial.println("*** OVERFLOW ALARM! ***");
  } else {
    digitalWrite(overflowAlarm, LOW);
    Serial.println("OK");
  }
  
  delay(1000);
}

Multi-Level Production Deployment

Upload automatic tank controller. Submerge probes verifying EMPTY→OVERFLOW progression. 25%/50% pump hysteresis.

Serial + alarm relay provide complete level management.

Advanced Continuous Level & Pump Cycling

Program: Arduino Uno Capacitive Continuous Level

// Analog capacitive strip (A0: 0-1023 = 0-100%)
int rawLevel = analogRead(A0);
float percentage = map(rawLevel, 100, 900, 0, 100);
percentage = constrain(percentage, 0, 100);

Serial.printf("Continuous: %.1f%% | Pump: %s\n",
  percentage,
  (percentage < 20) ? "ON" : (percentage > 70) ? "OFF" : "HOLD");

if(percentage < 20) digitalWrite(7, LOW);
else if(percentage > 70) digitalWrite(7, HIGH);

5-Electrode Sensor Specifications

316L stainless probes; >1MΩ dry / <10kΩ wet; 2cm resolution; IP68 submersion; 5V logic; unlimited probes.

Industrial Fluid Management Applications

Rainwater cistern auto-refill

Sump pump overflow protection

Boiler feedwater control

Program: Arduino Uno Water Level - Pump Duty Cycle Logger

// Pump run hours + level trending
static unsigned long pumpStart = 0;
static float pumpHours = 0;

void loop() {
  if(digitalRead(pumpRelay) == LOW && pumpStart == 0) {
    pumpStart = millis();
  } else if(digitalRead(pumpRelay) == HIGH && pumpStart > 0) {
    pumpHours += (millis() - pumpStart) / 3600000.0;
    pumpStart = 0;
    Serial.printf("Pump runtime: %.1fhours\n", pumpHours);
  }
}

Production Level Specifications

25%/50%/75% discrete levels
2cm electrode spacing
50kΩ pull-up hysteresis
316L stainless corrosion proof
IP68 full submersion
Unlimited parallel channels

Advanced Float Switch & Ultrasonic Hybrid

Program: Arduino Uno Hybrid Level Validation

// Cross-check discrete + continuous
int discreteLevel = getDiscreteLevel();
float ultrasonicLevel = getUltrasonicDistance();

float discretePercent = levels[discreteLevel];
float diff = abs(discretePercent - ultrasonicLevel);

if(diff > 10) {
  Serial.println("*** LEVEL DISCREPANCY DETECTED ***");
  digitalWrite(9, HIGH);  // Fault relay
} else {
  Serial.printf("Validated: %.0f%%\n", (discretePercent + ultrasonicLevel)/2);
}

Installation & Maintenance Protocol

Vertical probes (max tilt 5°). 10cm above pump intake (LOW level). Weekly debris cleaning. Distilled water testing. Stainless 316L prevents corrosion. IP68 junction box mandatory.

Conductivity Considerations

>10μS/cm tap water: Excellent
1-10μS/cm distilled: Poor
Brackish/seawater: Very good
Oils/glycols: Non-conductive