Input2

CHAPTER 3:

INPUT

Objectives

Describe the four types of input List the characteristics of a keyboard Identify various types of keyboard Identify various types of pointing devices Explain how a mouse works Describe different mouse types Explain how scanners and other reading devices work Identify the purpose of a digital camera Describe the various techniques used for audio and

video input Identify alternative input devices for physically

challenged users.

What is Input?

Input is any data or instructions you enter into the memory of a computer. Once input is on memory, the CPU can access it and process the input into output. Four types of input are data, programs, commands, and user responses.

Data

Is a collection of unorganized facts that can include words, numbers, pictures, sounds, and videos. A computer manipulates and processes data into information, which is useful.

Program

Is a series of instructions that tells a computer how to perform the tasks necessary to process data into information. Programs are kept on storage media such as a floppy disk, hard disk, CD-ROM, or DVD-ROM. Programs respond to commands issued by a user.

Command

Is an instruction given to a computer program.

Can be issued by typing keywords or pressing special keys on the keyboard. A keyword is a specific word, phrase, or code that a program understands as an instruction.

User Response

Is an instruction you issue to the computer by replying to a question posed by a computer program, such as Do you want to save the changes you made? Based on your response, the program performs certain actions. For example, if you answer, Yes, to this question, the program saves your changed file on a storage device.

What are Input Devices?

Is any hardware component that allows you to enter data, programs, commands, and user responses into a computer. Input devices include the keyboard, pointing devices, scanners and reading devices, digital cameras, audio and video input devices, and input devices for physically challenged users.

The Keyboard

You enter data into a computer by pressing the keys on the keyboard.

Includes keys that allow you to type letters of the alphabet, numbers, spaces, punctuation marks, and other symbols such as the dollar sign ($) and asterisk (*).

Contains special keys that allow you to enter data and instructions into the computer.

The Types of Keyboard

1.The standard computer keyboard sometimes is called QWERTY keyboard because of the layout of its typing area. Because of the way the keys are organized, a QWERTY keyboard might limit your typing speed.

Qwerty Keyboard

The Types of Keyboard

2.The Dvorak keyboard (de-VOR-zhak), this type of keyboard places the most frequently typed letters in the middle of the typing area.

Dvorak Keyboard

The Types of Keyboard

3.The wireless keyboard transmits data via infrared light waves. Both computer and the wireless keyboard must have an IrDA port. These IrDA ports must be aligned so that nothing obstructs the path of the infrared light wave.

The Types of Keyboard

4. On laptops and many handheld computers, the keyboard is built into the top of the system unit. The keyboards usually have smaller and fewer keys. To provide all of the functionality of a desktop computer keyboard, many of the keys serve two or three different purposes.

The Types of Keyboard

5.The ergonomic keyboard is designed to minimize the chance of repetitive strain injuries of the wrist. The goal is to incorporate comfort, efficiency, and safety into the design if items and workplace. These keyboard has a rectangular shape with the keys aligned in rows.

Pointing Devices

Allows you to control a pointer on the screen.

Allows you to position the pointer to move or select items on the screen.

Allows you to move the insertion point, select text, graphics and other objects.

Allows you click buttons, icons, links, and menu commands.

Pointing Devices

1. Mouse

2. Track Ball

3. Touchpad

4. Pointing Stick

5. Joystick

6. Touch Screen

7. Light Pen

8. Graphics Tablet

Mouse

The most widely used pointing device on desktop computers.

Takes full advantage of graphical user interface.

Used to control the movement of the mouse pointer on the screen and to make selections from the screen.

Mouse

The top of the mouse has one to four buttons and some also have a small wheel.

The bottom of a mouse is flat and contains a multi-directional mechanism, usually either a small ball or an optical sensor.

Mouse Types

1.The Mechanical Mouse is a mouse that has a rubber or metal ball on its underside.

2.The Optical Mouse uses devices that emit and sense light to detect the mouse’s movement. It is more precise than a mechanical mouse and does not require cleaning.

The newer optical mouse devices can be used on nearly all types of surfaces, eliminating the need for mouse pad.

Mouse Types

3.The Wireless Mouse rely on battery power operating similarly to a television remote control. It uses infrared to communicate with a receiver. It frees up desk space and eliminates the clutter of a cord.

Mouse

Trackball

A stationary pointing device with a ball mechanism on its top.

Has one or more buttons that work just like mouse buttons.

Is not as accurate as a mouse. To move the pointer using a trackball,

you rotate the ball mechanism with your thumb, fingers, or the palm of your hand.

Trackball

Touchpad

Is a small, flat, rectangular pointing device that is sensitive to pressure and motion.

Has one or more buttons around the edge of the pad that works like mouse buttons.

On other touchpad, you tap the pad’s surface to simulate mouse operations such as clicking.

Touchpad

Are found more often on laptop computers.

To move the pointer using a touchpad, you slide your fingertip across the surface of the pad.

Touchpad

Pointing Stick

Is a pressure-sensitive pointing device shaped like a pencil eraser.

Is positioned between keys on the keyboard.

To move the pointer using a pointing stick, you push the pointing stick with your finger. The pointer on the screen moves in the direction that you push the pointing stick.

Pointing Stick

Joystick

Is a vertical lever mounted on a base. Mostly used in game software such as

driving or flight simulation. You move the lever in different

directions to control the actions of a vehicle or a player.

The lever usually includes buttons called triggers that you can press to activate certain events.

Joystick

Touch Screen

Is a monitor that has a touch-sensitive panel on the screen.

Are not used to enter large amounts data because they require a lot of arm movements. Instead, you touch words, pictures, numbers, or locations identified on the screen.

You interact with the computer by touching areas of the screen with your finger, which acts as an input device.

Touch Screen

Often used in kiosks located in stores, hotels, airports, and museums.

A good example of these are the screens used in a fast food chain and ATM machines.

Touch Screen

Light Pen

Is a handheld input device that contains a light source or can detect light.

Some require a specially design monitor while others work with a standard monitor.

Used in applications where desktop space is limited such as in the health-care field or when a wide variety of people use the application, such as electronic voting.

Light Pen

Graphics Tablet

Also called a digitizer or digitizing tablet.

Consists of a flat, rectangular, electronic plastic board used to input drawings, sketches, or other graphical data.

Detects and converts the movements into digital signals that are sent into the computer when you draw on the tablet with either an electronic pen or a puck.

Graphics Tablet

Questions:

1. It is a collection of unorganized facts that can include words, numbers, pictures, sounds, and videos.

Answer: Data

2.This type of keyboard places the most frequently typed letters in the middle of the typing area.

Answer: Dvorak Keyboard

3. Is a monitor that has a touch-sensitive panel on the screen.

Answer: Touch Screen

4. It is a mouse that has a rubber or metal ball on its underside.

Answer: Mechanical Mouse

5. Is any hardware component that allows you to enter data, programs, commands, and user responses into a computer.

Answer: Input Devices

6. It is an instruction you issue to the computer by replying to a question posed by a computer program.

Answer: User Response

7.A stationary pointing device with a ball mechanism on its top.

Answer: Trackball

8. It uses devices that emit and sense light to detect the mouse’s movement.

Answer: Optical Mouse

9. It is a series of instructions that tells a computer how to perform the tasks necessary to process data into information.

Answer: Program

10. It is any data or instructions you enter into the memory of a computer.

Answer: Input