The Hover Pad


Handheld displays are a flexible tool for spatial exploration of information spaces – users can physically navigate through that space to reveal information at specific locations. Having users hold them constantly, however, has several limitations: (1) inaccuracies due to the natural hand tremor; (2) fatigue over time; and (3) exploration limited within arm’s reach. In this paper, we investigate the use of autonomous, self-actuated displays that can freely move and hold their position and orientation in space without the need for users holding them at all times. We illustrate various stages of such a display’s autonomy ranging from manual to fully autonomous, which – depending on the tasks – facilitate the interaction. Further, we discuss possible motion control mechanisms for these displays and present several interaction techniques made possible by such displays. We designed a toolkit – Hover Pad – that enables exploring five degrees of freedom of self-actuated and autonomous displays and the developed control and interaction techniques. We illustrate the utility of our toolkit through five demonstration applications, such as a medical volumetric data explorer.

Handheld displays allow exploring volumetric data sets, yet users have to hold them in their hands at all times (a). Self-actuated and autonomous displays, on the other hand, free handheld displays from this requirement (b). Our prototype is a first realization of a self-actuated display that can autonomously move and hold its position (c).


Hover Pad Toolkit

Hardware Construction Plans

Hover Pad's crane construction allows controlling the position and angle of a tablet computer in space above an (optional) interactive surface. Five degrees of freedom are supported: x-, y-, and z-position, as well as pitch and yaw of the tablet.

The "Inventor" CAD files containing the blueprints and construction information are available for download at:

 Software Toolkit

Along with the hardware plans, we provide the software toolkit components that are necessary to control the tablet's motion in space.

The sources and documentations are available at:

Example Applications - Impressions


Enrico Rukzio


Seifert, Julian; Boring, Sebastian; Winkler, Christian; Schaub, Florian; Schwab, Fabian; Herrdum, Steffen; Maier, Fabian; Mayer, Daniel; Rukzio, Enrico Hover Pad: Interacting with Autonomous and Self-Actuated Displays in Space Proceedings of ACM Symposium on User Interface Software and Technology (UIST) Oktober 2014

DOI: 10.1145/2642918.2647385