Building a vending machine requires more attention to designing that usual. In general, we can design a vending machine system with the following parts:

• Machine cabinet
• Product storage
• Central processor machine
• Payment system
• User interface and experience

In this book, we won't explore machine cabinet and product storage for vending machines. You can review vending machine spare parts on this site: https://www.vendingworld.com/vending-machine-parts.

In general, a vending machine model can be described as follows:

A central processing machine can control all the processes in a vending machine. It can control a user's input and deliver the product. We can use Raspberry Pi and Arduino as a central processing machine since these boards provide GPIO for sensor and actuator devices.

Product management addresses product tracking and ensures that the product delivery is correct. In one scenario, if your vending machine is connected to the internet, the machine can inform the administrator about the current product stock.

Payment method is one of the problems in vending machines. We should be able to identify coin types and their value. This has potential problems of fraud. Some vending machines allow payment using debit/credit cards.