From MobileDesign

Two-handed devices are those that require two hands to operate. It may be one hand holding and one hand operating, or it may be both hands operating and holding. Of course, it is possible to take a common PDA, put it on the table, and operate it with one hand. We consider the table as acting as an extra hand in this situation (and not a good one!).

[edit] Virtual Keyboards

In the category of two-handed solutions, virtual keyboards are displayed on a touch screen, and the user uses a stylus to select letters from a keyboard. Many devices have a virtual keyboard built in as an alternative to handwriting recognition. All the research we have found suggests that, given how users currently use computers and typewriters, there is no advantage to varying from the QWERTY layout if there is enough room for all the keys. Further, there are learning and skills transfer disadvantages to using different keyboard layouts.

[edit] Standard Keyboards

Most devices use a QWERTY layout. Usability research has shown that this layout is fastest for learning and text entry for modern users. Familiarity and commonality precludes the use of alternative layouts (such as Dvorak).

[edit] TenGO

This is an interesting combination of a virtual keyboard and the sorts of word prediction you will find for 12-button keypads. They have grouped a standard virtual QWERTY keyboard into 6 buttons and use T9-style prediction for a faster typing experience. The buttons have become larger, making them more rapidly accessible than the small buttons. TenGO

[edit] WordLogic

The display shows a standard QWERTY keyboard. When the user begins selecting letters, next likely letters are highlighted on the keyboard, and predicted words or word chunks appear along the left side. "WordChunking" allows the user to construct variations of a word by choosing the root, then continuing to work until the suffix is revealed. The user can easily add new words to the dictionary by tapping the "Add Word" key after the word is typed, or by having the software scan documents on the system. There is no difficulty in typing URLs or words not in the dictionary WordLogic

[edit] Quickwriting

Quickwriting uses a circular keyboard layout, with letters or numbers divided into eight regions in two zones. The location of the letter within its region determines the letter's secondary region. The user drags the stylus from the center to the letter's primary region, through the letter's secondary region, ending back at the center. Special functions, such as shift or backspace, are selected in a similar fashion. Since the user doesn't have to pick the stylus up off the screen, it can be a very fast input method. It is not, however, very fast to learn. A Java demo is available so you can see this in action. NYU Media Research Lab Quickwriting

[edit] Exidias Message-Ease

Message-Ease uses a system of taps and slides to type letters from a compact virtual keyboard. The keyboard is complete, including a full set of character and function keys as well as alphanumeric. Furthermore, the user can program macros to increase typing speed for non-dictionary words. The keyboard also comes in a USB hardware version. This product cannot be found with a simple google search now, so may no longer be available.

[edit] Fitaly

The Fitaly keyboard is designed to be used with one hand and to minimize hand and finger travel. There are two space bars, because the space is the most common character typed. The keys are set up so that the next key is likely to be adjacent to the last key typed. When combined with predictive text, typing speed is further improved. Fitaly

[edit] Handwriting Recognition

[edit] Graffiti

Palm's standard handwriting recognition package for many years, it requires that the user learn unistroke, a special set of handwriting characters. Speed is largely up to the user, and the time they take to learn the language. Wikipedia on Graffiti

A replacement, called Graffiti2 is largely the result of a lengthy lawsuit, but also has characters with more letter-like strokes. While probably slower, its also easier to learn. Wikipedia on Graffiti 2

[edit] SimpliWrite

Unlike Graffiti, SimpliWrite's handwriting recognition does not require that the user learn a special set of characters. Users can start inputting text immediately. SimpliWrite also provides user-programmable "gesture macros". This product was developed by Advanced Recognition and is now owned by Nuance. Nuance SimpliWrite

[edit] Vpen

The Vpen is a laser pen that acts as both stylus and mouse. The handwriting recognition is built inside the pen, so it can be incorporated into any device with Bluetooth support. The laser sensor at the tip can be used on any surface, including the palm of the user's hand. OTM Tech Vpen

[edit] Hardware Keyboards

[edit] Thumboards

Many popular devices have thumboards, popularized by the RIM Blackberry. These keyboards are two to three inches wide and are operated mostly with two thumbs. Users can be quite fast with text entry on these devices, and this size keyboard is perhaps the second best size for a QWERTY keyboard (after full or 3/4 size, of course) because touch typing is not possible on keyboards larger than a thumboard and smaller than a regular keyboard. Some accessory manufacturers are making thumboards that can dock a PDA, so there is only one unit to hold while tying. To the right you see a Handspring Treo 180, with a built-in thumboard.

[edit] Frogpad

Like many virtual keyboards, Frogpad breaks the QWERTY paradigm. Instead of overlaying the right half of a full keyboard on the left half, the most frequently used letters in the alphabet are accessible with a single press. A modifier key gives the user access to the remaining letters using simultaneous keypresses. 86% of the time the user needs to press only one key.

Further, Frogpad has ensured that the most common two-letter combinations in a language are on adjacent keys. The full-sized keys make it possible to learn to touch-type at speeds comparable to standard QWERTY keyboards. The Bluetooth enabled Frogpad allows maximum flexibility in the field. Frogpad