Devices for the Hand

Most input devices are designed to be used by hand. Even specialized devices like touch screens enable the user to interact with the system by using his or her fingertips. Unlike keyboards and mice, many of these input devices are highly intuitive and easy to use without special skills or training.

Pens

Pen-based systems -including many-table PCs, personal digital assistants, and other types of handheld computers -use a pen for data input, This device is sometimes called a stylus. You hold the pen in your hand and write on a special pad or directly on the screen. You also can use the pen as a pointing device, like a mouse, to select commands by tapping the screen.

You might think that pen-based systems would be a handy way to enter text into the computer for word processing. In reality, developers have had a great deal of trouble perfecting the technology so that it deciphers people's handwriting with 100 percent reliability. Because handwriting recognition is so complex, pen-based computers are not used generally to enter large amounts of text, although they are used frequently for taking notes, creating short messages, and writing annotations on electronic documents, PDAs and tablet PCs are popular for these kinds of tasks, which do not require keyboarding. To inter Pen-based computers are commonly used for data collection, where the touch of a pen might place a check in a box to indicate a part that must be ordered or a service that has been requested. Another common use is for inputting signatures or messages that are stored and transmitted as a graphic image, such as a fax. When delivery-service drivers make deliveries, they often have recipients sign their names on such a computer-based pad.  As handwriting-recognition technology becomes increasingly reliable, pen-based systems will undoubtedly become more common.

Touch Screens

Touch screens accept input by allowing the user to place a fingertip directly on the computer screen, usually to make a selection from a menu of choices. Most touch-screen computers use sensors on the screen's surface to detect the touch of a finger, but other touch screen technologies are in use, as well. Touch screens work well in environments where dirt or weather would render keyboards and pointing devices useless, and where a simple, intuitive interface is important. They are well-suited for simple applications, such as automated teller machines or public information kiosks. Touch screens have become common in fast-food restaurants, department stores, drugstores, and supermarkets, where they are used for all kinds of purposes, from creating personalized greeting cards to selling lottery tickets.

Game Controllers

You may not think of a game controller as an input device, but it is. Personal computers are widely used as gaming platforms, challenging dedicated video game units like the Sony PlayStation and others. Because PCs of for higher graphics resolution than standard televisions, many gamers believe a well-equipped PC provides a better game-playing experience. If your computer is connected to the Internet, you can play games with people around the world. A game controller can be considered an input device because a computer game is a program, much like a word processor. A game accepts input from the user, processes data, and produces output in the form of graphics and round. As computer games become more detailed and elaborate, more specialized game controllers are being developed to take advantage of their features.

Game controllers generally fall into two broad categories: gamepads and joy. 

Joysticks have been around for a long time and can be used with applications other than games, (Some joystick users actually prefer using a joystick rather than a mouse with some business applications. ) Joysticks enable the user to "fly" or "drive" through a game, directing a vehicle or character. They are popular in racing and flying games. 

A variant of the joystick is the racing game controller, which includes an actual steering wheel; some racing game controllers even include foot pedals and gearshifts. If you have ever used a video gaming system, you are familiar with gamepads. A gamepad is a small, flat device that usually provides two sets of controls - one for each hand. These devices are extremely flexible and are used to control many kinds of games. If you do not have a joystick, you can use a gamepad to control most racing and flying, games. (Many computer games still provide support for a mouse or keyboard, so a dedicated game controller is not always required.