As a part of my college application 2012 I modified a portafilter coffee machine. There were a few things that really bugged me out. One of them was the constant attention the machine required during the brewing process. More then once I set the kitchen floor under hot coffee. This isn't quite a nice way to start your day. An common way to fix personal clumsiness and a lack of attention is to add an Arduino. In addition to the logic there is now a build-in touchscreen and some sensors.
To keep it simple the new interface offers three cup sizes: small, medium and large. The interfaces says you when the machine demands fresh water. One of the key factor of every brew process is the right boiler temperature. In the original model the temperature was controlled by a simple thermal switch. To be way more accurate, it's now controlled by a thermocouple sensor and some smart algorithms.