This slide shows what a generic user interface looks like. As can easily be seen, it references to a washing machine, but in fact it can be anything like a set top box, a healthcare product, a toy… anything with LEDs and keys. First of all, there is the optical feedback to the user. In the case of an LED display, this can be single LEDs, or 7 segment modules. On the other hand, there is the feedback from the user to the machine, which is done by keys, rotary knobs and so forth.

