Automatic Water Dispenser

Automatic Water Dispenser

Image: Orange and Apple infused water dispenser.jpg by Grandmaster Huon via Wikimedia Commons, CC0

How It Works

• An ultrasonic sensor aimed downward at the spout area continuously measures distance to whatever's below it.
• When a container is placed within range, the measured distance drops below a threshold, which the controller interprets as "container present."
• The controller then energizes a relay driving a small submersible pump for a fixed duration (or until the container is removed), dispensing a measured amount of water.
• Removing the container restores the longer baseline distance reading, and the pump stops automatically.

Components

Arduino Uno
Ultrasonic sensor (HC-SR04)
Relay module
Small submersible water pump
Water reservoir + dispensing spout
Power supply

Applications

• Public and office water dispensers
• Health-sensitive environments (clinics, hospitals)
• Touchless dispensing for any liquid, not just water

Advantages

• Fully touchless operation improves hygiene in shared spaces
• Simple, low-cost sensor and pump setup
• Adaptable to dispense any pumpable liquid, not just water

Sample Code — Container Detection and Pump Trigger

// Simplified touchless dispenser - Arduino
#define TRIG 9
#define ECHO 10
int pumpRelay = 7;
int containerThresholdCM = 8;

long readDistanceCM() {
  digitalWrite(TRIG, LOW); delayMicroseconds(2);
  digitalWrite(TRIG, HIGH); delayMicroseconds(10);
  digitalWrite(TRIG, LOW);
  return pulseIn(ECHO, HIGH) * 0.034 / 2;
}

void setup() {
  pinMode(TRIG, OUTPUT);
  pinMode(ECHO, INPUT);
  pinMode(pumpRelay, OUTPUT);
}

void loop() {
  long dist = readDistanceCM();
  if (dist < containerThresholdCM) {
    digitalWrite(pumpRelay, HIGH); // container detected - dispense
  } else {
    digitalWrite(pumpRelay, LOW);  // no container - stop
  }
  delay(200);
}

Related Research

• Touchless Water Dispensing System — IJRSI