The awakening process of artificially respirated patients on intensive care units from unconsciousness is called weaning. In this phase, patients experience difficulties to communicate their basic needs or to meaningfully contact staff and relatives. This means psychological distress for all affected persons - patients themselves, medical/nursing staff and relatives. One major goal of project ACTIVATE is developing and evaluating the innovative, ball-shaped input device BIRDY. It integrates recent technology in terms of sensors, actors, energy supply and wireless communication. Ventilated patients should use BIRDY to interact with the ACTIVATE system that is intended to support communication, provide relevant information and control smart appliances in the room. This quasi-experimental study is part of a larger requirements analysis and aims to show which physical characteristics of BIRDY are relevant for potential users and which values are preferred. In the study, subjects evaluated several everyday objects in a more or less handy form with characteristic values that could be eligible for the design of BIRDY. The subjects were divided into two peer groups: adults and senior adults. The latter was explicitly chosen due to the relatively high average age on intensive care units in Germany. The setting was created as realistic as in the laboratory possible. Participants conducted a pairwise comparison, ranked objects against fixed characteristics and chose a preferred object, which was used to interact with. Within this contribution, the results of the study and derived design proposals for the interaction device BIRDY are described in detail and discussed.