Coin-Operated Airtime Vending Machine

Coin-Operated Airtime Vending Machine

Project Overview

This project is a Coin-Operated Airtime Vending Machine that allows users to purchase airtime for their mobile phones by inserting coins and entering their phone numbers. The system uses an Arduino Uno as the central controller and integrates several components like a coin acceptor, OLED display, keypad, GSM module, and voltage regulator to ensure smooth operation. This system is ideal for environments with limited internet connectivity, providing a simple and reliable way to top up airtime.

Key Components and Functions

1. Coin Acceptor

• Detects and validates the coins inserted by the user.
• Measures the value of the coins and sends the equivalent amount to the Arduino for processing.

1. Keypad

• Allows the user to input their phone number securely.
• Facilitates simple user interaction with the system, such as confirming or canceling a transaction.

1. OLED Display

• Displays instructions to guide the user through the process.
• Shows the amount inserted, entered phone number, and transaction status.

1. GSM Module

• Sends airtime to the entered phone number via SMS or USSD commands.
• Provides real-time communication with the telecom network for airtime distribution.

1. Arduino Uno

• Acts as the brain of the system, coordinating all components.
• Processes input from the coin acceptor and keypad, manages the OLED display, and sends commands to the GSM module.

1. Voltage Regulator

• Ensures stable power supply to the components, especially in areas with fluctuating electricity.

How It Works

1. Insert Coins

• The user starts by inserting coins into the coin acceptor.
• The system calculates and displays the total amount of airtime that can be purchased based on the coins inserted.

1. Enter Phone Number

• The user enters their phone number using the keypad.
• The entered number is displayed on the OLED screen for confirmation.

1. Confirm Transaction

• The user confirms the transaction by pressing a designated key on the keypad.
• The system validates the phone number format and proceeds to send the airtime.

1. Send Airtime

• The Arduino communicates with the GSM module to send the airtime using SMS or USSD.
• A success message is displayed on the OLED screen once the transaction is complete.

1. Error Handling

• If an invalid phone number is entered or insufficient coins are detected, the system prompts the user to correct the issue.

Features and Benefits

• Accessibility: Easy to use for all age groups with a simple and intuitive interface.
• Reliability: Operates offline with GSM connectivity, making it suitable for remote areas.
• Scalability: Can be modified to support multiple denominations or additional features like receipt printing.
• Affordability: Low-cost components make it economically viable for widespread use.

Applications

• Public Locations: Airports, bus stations, and shopping malls.
• Rural Areas: Provides airtime access in areas with limited or no internet access.
• Schools and Universities: Allows students and staff to quickly top up airtime without needing an internet connection.