The present invention relates to a control arrangement for controlling an atmosphere generating device, comprising a control device (102) having a control surface (110), and a control object (104, 106) adapted to be freely-positioned onto the control surface, the control object comprising identification means (116), wherein the control device comprises a control unit (114) adapted to identify the control object, to receive relative positioning information from the control surface relating to the positioning of the control object, and to output control data corresponding to the placement information for controlling the atmosphere generating device. By means of the invention it is provided an intuitive user interface in which the user is provided with a flexible solution in which not only repositioning of the control object onto the surface of the control device influence the atmosphere, but also the identity of the control object.