  Shape-changing interfaces are promising for users to change the physical
properties of common objects. However, prevailing approaches of actuation
devices require either professional equipment or materials that are not
commonly accessible to non-professional users. In this work, we focus on the
controllable soft actuators with inflatable structures because they are soft
thus safe for human computer interaction. We propose a soft actuator design,
called xBalloon, that is workable, inexpensive and easy-to-fabricate. It
consists of daily materials including balloons and plastics and can realize
bending actuation very effectively. For characterization, we fabricated
xBalloon samples with different geometrical parameters and tested them
regarding the bending performance and found the analytical model describing the
relationship between the shape and the bending width. We then used xBalloons to
animate a series of common objects and all can work satisfactorily. We further
verified the user experience about the the fabrication and found that even
those with no prior robotic knowledge can fabricate xBalloons with ease and
confidence. Given all these advantages, we believe that xBalloon is an ideal
platform for interaction design and entertainment applications.
