Prof. Dr. Patrick Baudisch

Gesture Output

Eyes-Free Output Using a Force Feedback Touch Surface. Behind gesture output stands the idea to use spatial gestures not only for input but also for output. Analogous to gesture input, gesture output moves the user’s finger in a gesture, which the user then recognizes. A motion path forming a “5”, for example, may inform the user about five unread messages; a heart-shaped path may serve as a message from a close friend.

Figure 1: With our proposed gesture output, the device outputs messages to users using the same gesture language used for input. (a) Here, the user draws an 'N' to check the house number of the upcoming meeting. (b) The device replies by translating the user’s finger along the path of an '8'.

Figure 2: The pocketOuija is self-contained mobile device based on an iPhone. It actuates the user’s fingers by means of a transparent foil overlaid onto the screen using motors located on the back of the device. Contact us if you are interested in obtaining the construction drawings and 3D model to make your own.

We have conducted three user studies, in which participants recognized marking output with 97% accuracy, Graffiti digits with 98.8%, compound pairs of Graffiti digits with 90.5%, and Graffiti letters with 93.4%. Participants previously unfamiliar with Graffiti correctly identified 96.2% of digits and 76.4% of letters, suggesting that properly designed gesture output is guessable. After the experiment, the same participants were able to enter 100% of Graffiti digits by heart and 92.2% of Graffiti letters. This suggests that gesture output teaches gesture input as a side effect.

Figure 3: "Touchy talkie" scenario (a) he sends a heart and (b) when she touches her device, the message is played back by moving her finger along the same heart.

Gesture Ouput on YouTube

Gesture Output is a research project by Anne Roudaut, Pedro Lopes, Christoph Sterz, Andreas Rau and Patrick Baudisch at the Human Computer Interaction Lab at Hasso Plattner Institute.


Roudaut, A., Sterz, C., Rau, A., Plauth, M., Lopes, P. and Baudisch, P. Gesture Output: Eyes-Free Output Using a Force Feedback Touch Surface. In Proceedings of CHI 2013.


All images Copyright © 2013 Hasso-Plattner-Institut.

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In collaboration with Samsung