A Role for Haptics in Mobile Interaction: Intitial Design Using a Handheld Tactile Display Prototype [CHI Best Paper]

This paper describes haptic technologies that can be formed into tiny skin-stretching tactile displays, enabling a handheld device to provide a range of responses through the tips of the user's fingers grasping it. This offers an alternative to relaying solely on audio or screen graphics to support interaction, and opens up exciting avenues for overcoming size limitations in mobile devices.

Joseph Luk presents a compelling argument for haptic interfaces on mobile devices, where multitasking is the name of the game and users are typically constrained to touching/holding the device anyways.

Application Scenarios
- menu selection
- browsing on small screens
- spatial navigation

The interesting thing about this project is not only that they managed to get together a working handheld prototype that can give your thumb a variety of massages, but they also tested the limits on the number of discernible tactons that such an interface allows. By drawing trends across frequency, amplitude, and duration of the later skin stretch, they isolated a dozen unique tactons.

Question: Have you studied the effectiveness of these tactons under multitasking environments?
Answer: No, that is definitely a direction for future research once we have solidified the base level of what tactons are actually distinguishible.

Question: Is there a reason you favoured lateral skin stretching over other modes of haptic interaction?
Answer: We chose lateral skin stretching because other devices that push or pull into the skin tend to be much larger and more power-hungry.

Question: Have you tested the limits of user's ability to remember/recall kinetic feedback, such as tactons?
Answer: Not yet.

Comment: You could also try combinations of more than one of these lateral skin-stretching devices, in order to increase the number of usable tacton combinations.

The Springboard: Multiple Modes in One Spring-loaded Control

Despite the bad rep that modes have suffered in the usability field, there are ways to circumvent their weaknesses when needed, for instance, through clever design innovations or through the "spring-loaded" model, e.g. a "highlight" option which snaps back to "pen" mode after the user has highlighted one area of interest.

This group proposed an innovate solution to the mode problem through a sort of SpringBoard and SpringOnce approach. They found that the Springboard improves performance for both a local marking menu and for a non-local marking menu (“lagoon”) at the lower left corner of the screen. Despite the round-trip costs incurred to move the pen to a tool lagoon, a keystroke-level analysis of the true cost of each technique reveals the local marking menu is not significantly faster.

The GlobeFish and the GlobeMouse: Two New Six Degree of Freedom Input Devices for Graphics Applications

One cannot really appreciate these devices without experiencing first-hand the multiple degrees of freedom and the different mode switches that each enables. Attend the Interactivity Exhibit. See for yourself.