Designing for a Wearing. For wearable computers, one needs to think differently.
Full Paper is available here (PDF 207kb).
A head-mounted display (HMD) may have a relatively low resolution, i.e. 640x480 pixels (VGA), and have to compete with environmental demands, such as bright sunlight, or environmental distractors. To make matters worse, many wearable systems use monocular displays, which raise problems of perception, binocular rivalry and visual fatigue - or in my case a headache. Consequently, we need to ensure that information is displayed in a manner that can be glanced at with minimal demands on the user. Earlier work, on displays for paramedics, suggested that people were quite good at learning to perceive simple patterns in displays. From this, we have designed a nine-dot matrix display, which can be used to visualise basic command data to the wearer. Movement data can be conveyed be illuminating the top or bottom row of dots or the left or right column (the three dots forming each corner can also be used to directions such as north-east).
The interface to our wearable system is a simple three-buttoned car alarm type of keyfob. The user can then press these buttons, which are organised as [up], [Down] and [Switch].
Using a simple pie-menu layout, its is much easier to dertermine the 'mode' in which the user is in. We also added some colour coding to match the segment colour to make it even easier to see what mode we are in. Then the user simply rotates the pie using the [up]/[down] keys until they get what they want then press [switch]. The same is true for other windows widgets, such as combo boxes. We make it so that an action is performed by simply hitting up or down on a button or checkbox and moving to the next is worked by [switch].
We also wanted to cut down on the things displayed, and had to make anything that is displayed really simple. This meant avoiding text and other intricate layouts. Above is an example of our 9-matrix command system. We found that we could flash rows of these nine circles to indicate commands.
Top row for forward, left row for left etc. Its is quite amazing but from only 9 dots, we found that a few dozen commands could be conveyed to the user and that they didn't specifically require the user to look directly at them, they just form a shape. This interface is so simple that it could be implemented with only 9 LED lights and no video display.
This work was presented at ISWC in Japan.
Full Paper is available here (PDF 207kb).