Coin-Operated Vending Machine with LCD Feedback

Introduction

Coin-operated vending machines have been a ubiquitous sight in public spaces for many years. They offer a convenient way to provide products or services in exchange for monetary transactions. In this article, we will explore how to create a coin-operated vending machine with an LCD feedback system using Arduino, making the vending experience more engaging and informative for users.

Working Principle

The principle behind a coin-operated vending machine involves the detection of coins, validating their value, and triggering the dispensing mechanism once the appropriate amount is received. In our project, we'll use an Arduino microcontroller to manage these functions and an LCD screen to provide feedback to the user.

Things We Need

To build this coin-operated vending machine with LCD feedback, you'll need the following components:

1. Arduino Uno or similar microcontroller
2. LCD display (16x2 or similar)
3. Coin acceptor mechanism
4. Solenoid or motor for dispensing
5. Power supply
6. Resistors, capacitors, and wires
7. Enclosure for the vending machine

Circuit Diagram

Here is a simplified circuit diagram for our coin-operated vending machine with LCD feedback:

  Arduino Uno    Coin Acceptor    LCD Display    Dispensing Mechanism
    |                |                 |                    |
    |                |                 |                    |
    |---[Resistor]---|-----[Resistor]---|----[Solenoid/Motor]---
    |                |                 |                    |
    |                |                 |                    |
   GND              GND               GND                 GND

Working of the System with Arduino

1. Coin Detection and Validation:

• When a coin is inserted into the coin acceptor, it sends signals to the Arduino.
• Arduino processes these signals and validates the coin's value.

1. LCD Feedback:

• The LCD display provides feedback to the user, indicating the amount deposited and guiding the user on the next steps.

1. Transaction and Dispensing:

• Arduino keeps track of the amount deposited and compares it with the cost of the item to be vended.
• Once the deposited amount meets or exceeds the item's cost, Arduino triggers the dispensing mechanism (solenoid or motor) to release the item.

Code

Here's a simple Arduino code snippet to demonstrate the logic for this project:

#include <LiquidCrystal.h>
 
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
int coinValue = 0;
int itemCost = 10; // Adjust the cost as needed
int totalDeposited = 0;
 
void setup() {
  lcd.begin(16, 2);
  lcd.print("Welcome to the");
  lcd.setCursor(0, 1);
  lcd.print("Vending Machine");
  delay(3000);
  lcd.clear();
}
 
void loop() {
  // Code for coin detection and validation
  // Update coinValue accordingly
 
  totalDeposited += coinValue;
 
  lcd.clear();
  lcd.print("Deposited: $");
  lcd.print(totalDeposited);
 
  if (totalDeposited >= itemCost) {
    lcd.setCursor(0, 1);
    lcd.print("Press to vend");
    // Trigger dispensing mechanism
  }
}

Please note that the actual coin detection and validation process will vary based on the specific coin acceptor mechanism being used.

Conclusion

Creating a coin-operated vending machine with LCD feedback is a rewarding DIY electronics project that combines microcontroller programming and hardware interfacing. This project can be further expanded by integrating features like item selection, change return, and inventory management. With a bit of creativity and experimentation, you can customize and enhance the vending experience to suit various applications and user preferences. Happy building!