Automatic Lemon Juice Vending Machine

Automatic Lemon Juice Vending Machine

How It Works

• The user inserts a coin (or presses a button, for a simplified demo build) to start a dispense cycle.
• An IR sensor checks a cup is present under the nozzle before the controller allows dispensing to begin.
• The controller runs a sequence of small dosing/peristaltic pumps — juice concentrate, water, and a salt/sugar solution — each for a pre-timed duration, mixing a consistent drink into the cup.
• An indicator LED/buzzer signals when dispensing is complete.

Components

Arduino/microcontroller
Small dosing/peristaltic pumps (x2–3: juice, water, salt/sugar mix)
Relay module
Coin acceptor sensor or push-button trigger
IR cup-presence sensor
Storage reservoirs + dispensing nozzle
Indicator LED/buzzer

Applications

• Public spaces, gyms, and college/campus canteens
• Summer event stalls and outdoor gatherings

Advantages

• Consistent, hygienic, on-demand dispensing without a human vendor
• Measured dosing keeps taste and concentration consistent every time
• Low-cost automation for a simple, high-demand refreshment product

Sample Code — Cup Check and Pump Dosing Sequence

// Simplified cup-check + pump dosing sequence - Arduino
int cupSensorPin = 2;
int juicePumpRelay = 5;
int waterPumpRelay = 6;
int saltSugarPumpRelay = 7;

void dispense() {
  digitalWrite(juicePumpRelay, HIGH);      delay(1500); digitalWrite(juicePumpRelay, LOW);
  digitalWrite(waterPumpRelay, HIGH);      delay(2000); digitalWrite(waterPumpRelay, LOW);
  digitalWrite(saltSugarPumpRelay, HIGH);  delay(500);  digitalWrite(saltSugarPumpRelay, LOW);
}

void setup() {
  pinMode(cupSensorPin, INPUT);
  pinMode(juicePumpRelay, OUTPUT);
  pinMode(waterPumpRelay, OUTPUT);
  pinMode(saltSugarPumpRelay, OUTPUT);
}

void loop() {
  if (digitalRead(cupSensorPin) == HIGH) { // cup detected
    dispense();
    delay(3000); // avoid re-triggering on the same cup
  }
}

Related Research

• IoT Based Smart Automatic Juice Vending Machine — IRJET