Input Devices

Definition of Input Device
Input device is any hardware component that allows a user to enter data and instructions into a computer.
Any peripheral used to provide data and control signals to a computer.
Without any input devices, a computer would only be a display device and not allow users to interact with it. Before computer processing, data must be entered into the computer by an input device so that they can be translated into machine-readable form.
Some input devices include the following:
Keyboard
Mouse
Joy Stick
Light pen
Track Ball
Scanner
Graphic Tablet
Microphone
Magnetic Ink Card Reader (MICR)
Optical Character Reader (OCR)
Bar Code Reader Optical Mark Reader (OMR), etc.

Keyboard
Keyboard is the most common and very popular input device which helps in inputting data to the computer. The keyboard looks very similar to the keyboards of electric typewriters, with some additional keys. Keyboards allow a computer user to input letters, numbers, and other symbols into a computer.

Mouse
The mouse is a device that controls the movement of the cursor or pointer on a display screen. The mouse is important for graphical user interfaces because a user can simply point to options and objects and click a mouse button.

Touchpad
A touchpad is a small, touch-sensitive pad used as a pointing device on some portable computers. By moving a finger or other object along the pad, you can move the pointer on the display screen.

Touch screen
A touch screen is an electronic visual display that can detect the presence and location of a touch within the display area.

Trackball
A trackball is a mouse lying on its back. To move the pointer, you rotate the ball with your thumb, your fingers, or the palm of your hand. It does not require much space to use it.

Light Pen
A light pen is a computer input device in the form of a light-sensitive pen used in conjunction with a computer's CRT display. It allows the user to point to displayed objects or draw on the screen in a similar way to a touch screen but with greater positional accuracy.

Stylus
A stylus is a small pen-shaped instrument that is used to input commands to a computer screen, mobile device or graphics tablet.

Joystick
A joystick allows an individual to move an object in a game such as navigating a plane in a flight simulator.
A gamepad, game controller, joypad, or video game controller is a peripheral device designed to be connected to a computer or console gaming system. It has multiple buttons and may have one or two mini joysticks.

Digital Camera
A camera that stores the pictures or video it takes in electronic format instead of film.

Webcam
A webcam is a camera connected to a computer that allows anyone connected to the Internet to view either still pictures or motion video of a user or other object.

Optical Scanner
An optical scanner is a hardware input device that allows a user to take an image or text and convert it into a digital file, allowing the computer to read or display the scanned object.

Barcode Reader
A barcode reader or scanner is a hardware device capable of reading a barcode and printing out the details of the product or logging that product into a database.

Microphone
A microphone is a hardware peripheral that allows computer users to input audio into their computers.

Structure of the Keyboard
A standard computer keyboard is called a QWERTY keyboard because of the layout of its typing area which is similar to that of a typewriter.

Parts of the Computer Keyboard

Keyboards will vary from manufacturer to manufacturer but generally have the following areas:

Function Keys: These keys are assigned a special task or function. Here is a sample of common function keys and associated tasks.
F1 Get Help or visit Microsoft Office Online
F5 Find and replace
F7 Choose the Spelling command (Review tab)
F8 Usually used with LCD projector/dual monitor device.
F10 Show Key Tips
F12 Choose the Save As command (Microsoft Office Button)
Function keys are also used in combination with the Shift, Alt, and Ctrl keys.
Typewriter Keys or Alphanumeric Keys: letters, numbers, and punctuation keys. Additional keys include the space bar, shift key (for capital letters and top symbol on keys), and Caps Lock key for a series of capital letters. Press the Enter key to begin a new paragraph in a word processor program (also the same as clicking the OK button in a dialogue box. The Spacebar separates a series of letters and/or numbers into Standard English text.
Cursor Control Keys: also called arrow keys, which move your text cursor in the direction of the arrow.
Numeric Keypad: similar to a calculator for entering numbers and doing mathematical operations quickly and easily. (You may also have a calculator shortcut key on your keyboard.)
Arrow or Navigation keys: Arrow keys, Page Up/Page Down, Home, and End are convenient to move your cursor to the desired location.
Combination Keys:
1. Shift Key: The Shift key is used to make capital letters or to access the punctuation and other symbols on the number keys and other keys. (Also used in combination with function and/or ctrl keys.)
2. The Alt key: It is used in combination with the command keys for special functions such as Ctrl+Alt+Dlt for task manager or ALT+F4 Exit Office Word 2007
3. Control key: It is used in combination with other command keys. CTRL+F10 will maximize the document window. . Other Keys include:
i. Windows key: Shortcut for the start menu.
ii. PrtScn/SysRq Print Screen: pressing the print screen will capture the entire screen while pressing the alt key in combination with the print screen will capture the currently selected window.
iii. Esc Escape: shortcut in dialogue boxes for No, Quit, Exit, Cancel, or Abort, as well as a common shortcut key for the Stop button in many web browsers.
iv. Backspace: Erases text to the left of the cursor each time you click on the key.
v. Delete: Erases text to the right of the cursor each time you click on the key. Or click and drag your cursor over a line(s) of text to select the text and click Delete. All the selected text will be deleted.

Types of Mouse
a) Mechanical Mouse: Mechanical mouse contains a rubber or metal ball inside it. The movement of the cursor depends on the movement of the ball. This mouse is normally used on the mouse pad. A mouse pad is a- small flat pad made of rubber or foam to provide easy movement for the mouse. It protects the mouse from dust and dirt.
b) Optical Mouse: Optical mouse contains no ball inside it. It uses a device that emits light to detect mouse movement. An optical sensor or laser is used in these types of mice. It is more expensive than the mechanical mouse.
c) Wireless Mouse: Wireless or cordless mouse is a type of mouse that does not require a wire to work. It transmits data using wireless technology like radio waves or infrared light waves. The receiver is connected to the computer through a serial or USB port.
Parts of a Computer Mouse

The parts of a computer mouse can vary by the type of computer mouse. Below is a general overview of the parts found on most computer mice.
1. Buttons
2. Ball, Laser, or LED
3. Mouse wheel
4. Circuit board
5. Cable or wireless receiver

Functions of the mouse
The primary function of the mouse is to move the mouse cursor on the screen. Others include;
1. To open or execute the program - Once you've moved the cursor to an icon, folder, or other object clicking or double-clicking that object opens the document or executes the program.
2. To select - A mouse also allows you to select text or a file or highlight and select multiple files at once.
3. To drag-and-drop - Once something is selected it can also be moved using the drag-and-drop method.
4. To hover - Moving the mouse cursor over objects with additional hover information can help discover the function of each object on the screen. For example, hover the mouse over the hover link to see an example.
5. To scroll - When working with a long document or viewing a long web page you may need to scroll up or down which can be done using the mouse wheel or clicking and dragging the scroll bar.

Differences between Mouse and Keyboard

Keyboard	Mouse
Used to enter instructions	Used to point and select
Keys are pressed	Buttons are clicked
Combination of keys can be pressed	Left or right button is clicked
Cannot drag and drop text	Drags and drops text
It has keys	It has buttons
Requires no mouse pad	Requires a mouse pad