INPUT DEVICES

INPUT DEVICES

An input device is a peripheral device through which data are entered or fed and transformed into machine – readable form. Before computer processing, data must be entered into computer by an input device so that they can be translated into a machine – readable form.

EXAMPLES OF INPUT DEVICE

KEYBOARD

One of the most common and familiar input device is the standard keyboard. Computer keyboard are of two sizes 84 keys or 101/102 keys, but now 104 keys or 108 keys. It contains the following sections:

(i)                 Numerical keypad: It is used to enter numeric data or control cursor movement. 

(ii)               Function keys: These are arranged in a row along the top of the keyboard. Each of them has unique meaning and is used for some specific purpose.

(iii)             Special keys such as Enter, shift, Caps lock, Space bar etc.

(iv)             Alphabetic key pads: used to enter letters (A – Z) and digital keys (0 – 9)

(v)               Arrow keys

TYPES OF KEYBOARD

Standard

Standard "full-travel" alphanumeric keyboards have keys that are on three-quarter inch centers (0.750 inches, 19.05 mm), and have a key travel of at least 0.150 inches (3.81 mm). Desktop computer keyboards, such as the 101-key US traditional keyboards or the 104-key Windows keyboards, include alphabetic characters, punctuation symbols, numbers and a variety of function keys.

Laptop-size

Keyboards on laptops and notebook computers usually have a shorter travel distance for the keystroke and a reduced set of keys. They may not have a numerical keypad, and the function keys may be placed in locations that differ from their placement on a standard, full-sized keyboard.

Handheld

Handheld ergonomic keyboards are designed to be held like a game controller, and can be used as such, instead of laid out flat on top of a table surface. Typically handheld keyboards hold all the alphanumeric keys and symbols that a standard keyboard would have, yet only be accessed by pressing two sets of keys at once; one acting as a function key similar to a 'Shift' key that would allow for capital letters on a standard keyboard.

 Thumb-sized

Smaller external keyboards have been introduced for devices without a built-in keyboard, such as PDAs, and smartphones. Small keyboards are also useful where there is a limited workspace.

A chorded keyboard allows users to press several keys simultaneously. For example, the GKOS keyboard has been designed for small wireless devices. Other two-handed alternatives more akin to a game controller, such as the Alpha Grip, are also used to input data and text.

A thumb keyboard (thumb board) is used in some personal digital assistants such as the Palm Treo and BlackBerry and some Ultra-Mobile PCs such as the OQO.

MOUSE

A mouse is a pointing device. It usually contains one, two or three button as the user rolls it on a flat surface, the mouse controls cursor movement on the screen. When the user presses one of the buttons, the mouse either marks a place on the screen or makes selections from the data on the screen. It can be used for many applications ranging from games to designing products with graphics. It can be used as an alternative to keyboard or it can be used in combination with a keyboard to enhance input operations.

TYPES OF MOUSE

1. Traditional mouse

Traditional computer mouse button will be the most affordable, when they make use of a simple construction. They connect to your personal machine utilizing the mouse port, and some mouse for Apple computers use a USB connection. Most mouse include a USB connection for those who love the USB port within the mouse port.

No special application is needed, while you need to reboot after connecting in case you are employing an older version of Windows. This kind of mouse does need to be periodically disassembled for cleaning. You should make use of a lint-free, static-free cloth for cleaning. It will eliminate harm to your mouse preventing any bothersome lint buildup.

2. Optical mouse

Optical mouse have become more commonplace. They exercise efficiently, because they lack the ball found in traditional mouse. The majority are built to be ergonomic, so you are able to make use of them very comfortably.

These mouse are less vulnerable to collecting dust than traditional mouse are and require less cleaning. Most optical mouse hooks up to your computer through the USB port. Special software usually isn’t necessary if you do not need advanced functions enabled for the mouse. You are able to enable any special functions that you want your mouse to accomplish when using the driver CD that had the mouse.

3. Wireless mouse

Wireless mouse provide capability of connecting without cables. That is very useful for gamers as well as others who want room to freely move their mouse. Some newer laptops consist of built-in infrared ports where you can start employing the mouse without special hardware.

These sorts of mouse include the necessary driver software. You’ll normally be capable to start using your brand-new mouse during first minutes. Wireless mouse are optical, taking into account easier movement. Many wireless mouse are purchased plus a wireless keyboard. When you’ve got a large enough monitor, you are able to safely sit well back through the computer and still have the capacity to apply it efficiently.

4. Laptop mouse

Laptop mouse have numerous of identical features as desktop mouse. They give a more compact design that’s well-suited to smaller spaces that laptops are utilized in. These mouse are ideal for laptop users unaccustomed to track pads. Additionally they are useful if your track pad fails and you possess zero chance to change it instantly. Laptop mouse use a retractable cord having a USB connection or may include wireless connection.

 SCANNER

In computing, a scanner is a device that analyzes an image (such as photograph, printed text or handwriting) or an object (such as an ornament) and converts it to a digital image. Most scanners today are variations of the desktop (flatbed) scanner. The flatbed scanner is the most common in offices. Hand – held scanners were moved by hand.

WEBCAM

A web camera (webcam) is a real – time camera whose images can be accessed using the World Wide Web instant messaging, or a PC video calling application. Web – accessing cameras typically involve a digital camera which uploads images to a web server, either continuously or at regular intervals. This may be achieved by a camera attached to a PC, or by deducted hardware.

DIGITAL CAMERA

The photographs are shot on digital media like the RAM and can be transferred to the computer through cable connection that can be either serial or USB. The photograph can be edited with an image editing software like photoshop to add effects and can be printed.

Digital photograph uses a combination of advanced image sensor technology and memory storage, which allows images to be captured in a digital format that is available instantly with no need for a development process.