Cashless payment system

A company I worked for had a coffee machine for which employees could purchase coffee. However, the payment was done by putting coins in a jar.

Not only did this present the obvious risk of theft, this system was also impractical for people not carrying spare change at all time. I decided to solve this issue by designing this cashless payment system.

Here is a video of the system in action:

The system consists of two main parts, the first being a server side application built using NodeJS and a MongoDB database that stores everyone's employee card UUID as well as their current "balance".

The second part is an IoT RFID reader that I designed around an ESP8266 and an mfrc522 RFID reader. When an employee's card is scanned, the UUID is transmitted via WIFI to the server, which is used to check if their is enough balance in the corresponding account. If so, the amount for one coffee is subtracted.

So far, this system has sold for above JPY 100,000 (about USD 1000) worth of coffee.