A portable keyboard (or handheld keyboard) is one that is designed to be used with wireless devices, such as personal digital assistants (PDAs) and smartphones. Earlier means of text entry for handheld devices (such as Palm's Graffiti) are usually thought inadequate for anything more than a few characters of text, precluding most e-mail, for example. The task of adapting a keyboard for mobile use has received a great deal of attention. Because carrying a bulky keyboard would defeat the purpose of handheld devices, portable keyboard manufacturers have resorted to a number of different approaches to making them easier to carry around:
- Smaller keyboard: The simplest approach is to shrink the overall size of the keyboard while maintaining the traditional QWERTY layout. LandWare's GoType is an example of this type of keyboard. According to some reviews, the smaller keyboards take some time to adapt to.
- Car-friendly keyboard: One portable keyboard is specifically designed to be used while traveling by car (although the vendors do not advocate typing while actually driving): Revolve Design's RoadWriter (compatible with PalmIII, PalmVII, Symbol SPT1500, and TRG Pro handhelds), is said to be sturdy enough to be comfortably used in transit.
- Folding keyboard: Another approach is to make a full-size keyboard foldable. The Targus Stowaway (also called the Palm Portable) keyboard is a popular example of this type. According to some reviews, the Stowaway keyboard is similar to a laptop keyboard in use, although it must be used on a flat surface (instead of a lap). The keyboard folds to a size not much bigger than that of the mobile device.
- Rollable keyboard: Some companies, using new technologies such as flexible transistors and smart matter, are exploring potential future keyboards that will be made of plastic or fabric and can be rolled up or folded to fit in a pocket. An early version (that relies on more traditional technology) is the iNPACE Flexi-keyboard: a washable (waterproof) version. On a discussion at Slashdot, users with a propensity for spilling beer in their keyboards were, for the most part, happy with the Flexi-keyboard.