The Kord® Pad
The Kord® Pad is a 5 key device which fits in the palm of either hand and is operated by pressing single or multiple keys (Figure 1). Graphic buttons on the computer’s screen show the user which fingers on the Kord® Pad to depress in order to produce a particular action. The user interacts with the computer in a very easy and natural way, they find that muscle memory rapidly develops, allowing them to not only make selections far faster than a mouse or stylus, but if needed, totally eyes-free. Additionally, because the Kord® Pad is a digital input device, it is unaffected by vibration or bumping the way pointers (such as a trackball) are. Applications for the Kord® Pad extend to the terrestrial environment. It can be used to control a variety of mobile electronic devices and can be provided in serial, parallel, or keyboard plug models. All units require appropriate Kord® Software to control them.


Figure 1. A hard-bodied Kord® Pad.

Chordic Graphic User Interface 
The CGUI facilitates the wearability and usability of the WetPC® underwater computer. It is based on the principle of “what you see is what you press”, whereby on-screen graphic buttons show what to press. It is based on conventional chording techniques which require the user to press combinations of keys to form a character. However, unlike those techniques, it does not require the user to memorise the various key combinations nor does it just replace the functionality of the QWERTY keyboard (by producing only characters). Instead the user merely looks at the screen to see which fingers he/she needs to depress in order to produce a particular action.

Figure 2: Horizontal proportional buttons

Each button which is displayed on the screen is connected to a particular finger. It is usually activated once the finger has been released, which means that the user can form the chord rather than having to press all the keys simultaneously. The graphic buttons can be used to perform a wide range of functions including typing, pointing, and menu selection. Consequently the interface is applicable not just to computers but also potentially a number of mobile technologies (e.g. phones, Internet devices, video cameras, etc.).

Figure 3: Vertical buttons

Figure 4: "Fingerprints" are used to represent a discontiguous (not continuous) chord combination

The graphic buttons on the screen may take a variety of forms; indeed several different types may be contained in the one interface. Some buttons may be proportional in which case their width and position shows the user which fingers to use (Figure 2).

Proportional buttons are normally laid out horizontally, however in some instances they may also be vertical (Figure 3). Some buttons have “fingerprints” on them which represent discontiguous chord combinations - where consecutive fingers aren’t used to form the chord (Figure 4).

Figure 5: A “stacked” button

Certain functions or commands require using more than one chord combination in which case the buttons may be stacked on one another - the lowest button being activated first - and so on. In Figure 5 the user first presses the thumb and little finger (indicated by “fingerprint”) to access the grey bar and then presses one of the fingers (“singletons”) to activate a camera button (e.g. thumb to activate Camera 1, first finger to activate Camera 2, and so on).

Figure 6: "Iconic" hands indicate which fingers to use

Graphic buttons may also take the form of small iconic hands which show which fingers to use (those which are raised) (Figure 6). The user is left in no doubt as to which keys to press on the Kord® Pad - an extremely important feature for those who have not used a computer before or who may have limited literacy skills.

The generic nature of the interface means that it can have the look and feel of a conventional physical interface and consequently can be used to control a wide range of different mobile technologies (e.g. radio, mobile phone, video camera, etc.) (Figure 7). A number of graphic tools, such as spinners, pop-out menus, radio buttons, have been developed specifically for these types of applications.

Figure 7: A CGUI for a set of circuitbreakers in an underwater swimmer delivery vehicle.
Note to activate the "Nav" button, one activates the grey panel containing the switch, by pressing the thumb, first and second fingers, and then presses the fourth (ring) finger.

Working the Interface 
So how does the CGUI work in practice: let’s understand this better by looking more closely at a particular example. Suppose the interface contains a “Send” button (see Figure 6) with a small iconic hand on it which has the thumb, first, second and third fingers raised. Pressing and releasing the first, second, third and fourth keys on the Kord® Pad simultaneously (one can build the chord) with those fingers, activates that button as if you had clicked it with the mouse. However, it can be vastly faster, because there is no cursor to manoeuvre. Harder to describe than to do, the method is readily learnt and very intuitive. Once they have understood the concept (akin to learning how to operate a mouse) new users are usually confident within minutes and all that is left to learn is the layout of the interface.

There are some basic rules which underlie how the CGUI is interpreted and applied. They are:

• The thumb is ALWAYS on the LEFT (if the button is horizontal) and at the TOP (if vertical)
• Each button is connected to a particular finger
• A button isn’t activated until the fingers are RELEASED; you don’t have to simultaneously depress all keys; and,
• An ACTIVE stacked button takes precedence over all others

On first impressions the CGUI seems limited in the number of things it can do. After all, there are only 31 possible chord combinations using one hand. However, pressing two combinations sequentially to activate buttons - a couplet - multiplies the 31 combinations available from one hand to over 900; sufficient to perform the most complex of tasks. Pressing three combinations sequentially - a triplet - produces over 27,000 different choices!

A Kord® Pad is not required to operate the interface. Chord combinations can also be pressed on a conventional computer keyboard with one or both hands, allowing seamless movement between desktop and handheld computers (a useful feature for training). A further benefit of the technology is that it is compatible with many devices. The Kord® Pad can be plugged into either a serial, parallel, keyboard or PS/2 port. All that is then needed is the software to control the device.

Applications 
The CGUI has distinct advantages over other competing technologies (e.g. pens, voice recognition, trackballs, the mouse), especially when the user is mobile, where the environment may be harsh, where there’s ambient vibration or noise, where the user’s motion is restricted, and where the user can only use one hand or requires a certain amount of eyes-free operation (demos).

The cost of incorporating the interface within existing hardware and software (e.g. Windows 95/98) is relatively small - essentially the cost of the Kord® Pad and the software. Since the Kord® Pad plugs into a number of ports it is backwardly compatible with a large amount of existing hardware. The interface could be used for foreign language character input (e.g. Japanese and Chinese), and a variety of Internet applications (games, chat, web browsing with handheld computers); it could also be used by the front-line soldier for simple messaging, reporting and data entry. The intuitive, and simple yet powerful nature of the interface, may lend itself to a broad range of consumer devices, such as TV remote controls and camcorders. The physically challenged (e.g. people with carpal tunnel syndrome) could also benefit from its ease of use - the interface can be automatically reconfigured where the user may have one or two fingers which are missing or dysfunctional.

Manufacturers are also considering devices to satisfy the growing market for in-vehicle navigation and information systems. Developing world-wide intelligent transportation systems will quite likely lead to an increase of in-vehicle devices with interfaces that will be difficult to operate while driving. A CGUI could be built directly in the steering wheel which might serve as a competitive alternative to devices-such as touch screens, pens, and keyboards-that require users to move the hands from the wheel.