Jetto: Using Lateral Force Feedback for Smartwatch Interactions


Interacting with media and games is a challenging user experience on smartwatches due to their small screens. We propose using lateral force feedback to enhance these experiences. When virtual objects on the smartwatch display visually collide or push the edge of the screen, we add haptic feedback so that the user also feels the impact. This addition creates the illusion of a virtual object that is physically hitting or pushing the smartwatch, from within the device itself. Using this approach, we extend virtual space and scenes into a 2D physical space. To create realistic lateral force feedback, we first examined the minimum change in force magnitude that is detectable by users in different directions and weight levels, finding an average JND of 49% across all tested conditions, with no significant effect of weight and force direction. We then developed a proof-of-concept hardware prototype called Jetto and demonstrated its unique capabilities through a set of impact-enhanced videos and games. Our preliminary user evaluations indicated the concept was welcomed and is regarded as a worthwhile addition to smartwatch output and media experiences.

In Proceedings of the ACM Conference on Human Factors in Computing Systems (CHI’18)


Smartwatches are beginning to shift from devices that provide quick and convenient access to information, to devices that also consume entertainment (e.g. videos and games) for brief periods of time, particularly in situations when users are on-the-go (e.g. using public transportation). While efforts have begun to accommodate these changes, the user experience is still quite limited due to the small-form factor and accordingly, the limited interaction space common to smartwatches today. Visual and auditory output on smartwatches have improved substantially, but opportunities for smartwatch-enabled haptics in the context of video and gaming applications, similar to those found in console gaming experiences, are yet to be fully explored and realized.


Mechanical Design

The entire mechanical system is composed of 12 components, including gears, connectors, rotary arm, motor holders, decoder holders, and inlet. The following figure demonstrates a teardown of the system structure.


Selected Press Coverage

EurekAlert: Dartmouth College brings smartwatch innovations to CHI2018