While creating impressive graphics and display systems remains an important part of the VR experience, many researchers feel that developing intuitive devices for user interaction is more crucial. Basic interactive devices like keyboards or joysticks are easy to use, but they also tend to hamper the sense of immersion. Ideally a user would become unaware of the interaction device completely.
Though progress has been slow, there are still some exciting developments in human-machine interfaces (HMI). While many industries help drive developments in graphics technology, not many have a vested interest in exploring new kinds of HMI. Typically, the industries involved in advancing HMI include the entertainment field, academic institutions and small VR firms. Still, there are several interesting HMI devices used in some VR systems. Particularly interesting are the devices designed to be worn by users. These include gloves and bodysuits.
Gloves have played a role in the VR craze from the very beginning, even though the original designers didn't necessarily intend for them to be used in VR systems. Using a wired glove, you can interact with virtual objects by making various hand gestures. Many people call the gloves DataGloves or Power Gloves, though both those terms specifically refer to particular models of gloves and are not generic terms. Not all gloves work the same way, though all share the same purpose: allowing the user to manipulate computer data in an intuitive way.
Some gloves measure finger extension through a series of fiber-optic cables. Light passes through the cables from an emitter to a sensor. The amount of light that makes it to the sensor changes depending on how the user holds his fingers -- if he curls his fingers into a fist, less light will make it to the sensor, which in turn sends this data to the VR system's CPU. In general, these sort of gloves need to be calibrated for each user in order to work properly. The official DataGlove is a fiber-optic glove.
Other gloves use strips of flexible material coated in an electrically conductive ink to measure a user's finger position. As the user bends or straightens his fingers, the electrical resistance along the strips changes. The CPU interprets the changes in resistance and responds accordingly. These gloves are less accurate than fiber-optic gloves, but they also tend to be much less expensive.
Of course, if you want a really accurate and responsive glove, you should use a dexterous hand master (DHM). The DHM uses sensors attached to each finger joint. You attach the sensors to your joints with mechanical links, which means the glove is like an exoskeleton. These gloves are more accurate than either fiber-optic gloves or those using electrically conductive material, but they are also cumbersome and clunky.
In the next section, we'll look at VR input devices.