Starner elaborates on design principles that modern wearable devices should be focused around. Wearables should be absolutely natural to interact with, and utilize socially acceptable interactions. For example, voice commands might be effective for home assistants inside a house, but talking to your phone to lower the volume when in a subway isn't the same. In the same way that a wristwatch can be used and forgotten about in the span of seconds, modern wearable devices should be accessible within two seconds (Two Second Rule) and completely unobtrusive beforehand and afterwards. The Google Glass project has aimed to integrate all these principles, one example of which is the HUD displayed in front of the user. It should be easily accessed and provide easily digestible information, and at the same time it shouldn't negatively impact the user's ability to see the 'real world' in front of them.
Chris Harrison of Carnegie Mellon University and Disney Research members present technology to enhance touch interfaces with haptic feedback. Touch interface feedback can be tough, as traditional methods like vibration are touch to mechanically implement under a touch interface screen without adding clunkiness or excessive power consumption. However, this team has discovered that by applying a variable AC source across the touch surface, the phenomenon of electrovibration can change the friction of a finger across a surface. The moving a finger across wet rubber causes a strong stuttering motion, while moving a finger across a polished wood surface causes smooth motion. By altering a simple AC source, a single surface can transition between these two qualities. By using finger-tracking software, the friction of a touch surface can be altered to correspond with notable events! Pros: this change is instantaneous and completely uniform across the whole surface, introducing a haptic feedback technology that tackles the problems seen with mechanical haptic feedback. Cons: since these changes are applied uniformly, it's not immediately possible to give different feedback to two fingers simultaneously on the same surface.