Locks are mechanical fastening devices used on various kinds of objects like doors and vehicles, and they can be released using a certain type of key. They have a long history, from wood-made Egyptian keys to electronic keys as they are common nowadays, and they are mostly restricted to the basic functionality of selecting one of two states (e.g. locked or unlocked). In many cases however, it would be useful to have the possibility of multistage or even continuous control also, as it is provided by omnipresent turning knobs. In this paper, we propose a novel concept of a handy knob to which we refer to as key knob, which automatically connects to dedicated devices in close proximity, and enables to control them in both discrete and continuous ways in the case of authorization. We present a prototype, point out its potentials with concrete application scenarios, and conclude with an outlook on further improvements of the key knob.