Coffee Payment System Doesn’t Void Your Warranty

Coffee payment system

[Oliver] is back with an update to his recent coffee maker hacks. His latest hack allowed him to add a coffee payment system to an off-the-shelf coffee maker without modifying the coffee maker itself. This project is an update to his previous adventures in coffee maker hacking which logged who was using up all of the coffee.

The payment system begins with an Arduino Uno clone inside of a small project enclosure. The Arduino communicates with the coffee maker via serial using the coffee maker’s service port. This port is easily available from outside the machine, so you won’t have to crack open the case and risk voiding your warranty.

The system also includes an RFID reader and a Bluetooth module. The RFID reader allows each user to have their own identification card. The user can swipe their card over the reader and the system knows how many credits are left in their account. If they have enough credit, the machine will pour a delicious cup of coffee.

The Arduino communicates to an Android phone using the Bluetooth module. [Oliver’s] Android app was built using MIT’s app inventor. It keeps track of the account credits and allows the user to add more. The system can currently keep track of up to forty accounts. [Oliver] also mentions that you can use any Bluetooth terminal program to control the system instead of a smart phone app.

18 thoughts on “Coffee Payment System Doesn’t Void Your Warranty

    1. Because the use of a payment system is activated in the coffeemaker. Although those houshold (fully automated) coffeemakers do not have a MDB interface (where a payment system of a professional coffeemaker would be connected to), the protocol can be used over the service (serial) port. And if the use of a payment system was activated in the coffeemaker, a button press would let the coffeemaker not prepare a coffee, but send a code to the payment system, which then answers “?ok” if there is enough credit.

    1. I would say it has enabled them to more easily ensure that the service of providing coffee does not be a charity but rather a community supported service. Same idea as enabling a soda or “stuff” machine in a hacker space.

  1. So I guess any colleague that figures out the bluetooth commands to delete and re-register a card deserves the free coffee? Or am I reading the code comments wrong (“// 10 EUR standard credit for new cards “)?

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