1. Interacting with computer (Input devices)
Chapter 3
Interacting with computer (Input devices)

2. Using the Keyboard And Mouse
Standard keyboard layout
The Mouse
Variants of the Mouse
Ergonomics and Input Devices

3. 1. The standard keyboard Layout
The Alphanumeric keys (a, b, c,…)
The Modifier keys (Shift, Ctrl, Alt)
The Numeric keypad (1, 2, 3, …)
The Function Keys (F1, F2, F3,…)
The Cursor-Movement keys
Special-Purpose Key (Delete, Esc, …)

4. Allows users to select objects Mechanical mouse
2. The Mouse
Allows users to select objects
Pointer moved by the mouse
Mechanical mouse
Rubber ball determines direction and speed
The ball often requires cleaning
Optical mouse
Wireless Mouse

5. Mouse button configuration
2. The Mouse
Mouse button configuration
Configured for a right-handed user
Can be reconfigured

6. Variants of the Mouse Trackballs Upside down mouse
Hand rests on the ball
User moves the ball
Uses little desk space

7. Variants of the Mouse Trackpad Finger moves across the pad
Popular on laptops

8. Variants of the Mouse TrackPoint Little joystick on the keyboard
Move pointer by moving the joystick
Insider information
The term track point is copyrighted by IBM.

9. Ergonomics and Input Devices
The study of the physical relationship between people and their tools
Study of human and tool interaction
Attempts to improve safety and comfort

10. Ergonomics and Input Devices
Repetitive Strain Injury (RSI)
Caused by continuous misuse of the body
Many professions suffer from RSI
E.g. carpal tunnel syndrome – a wrist or hand injury caused by using a keyboard for long periods of time
Teaching tip
Hairstylists often suffer from carpal tunnel. Bicyclists can suffer from overuse injuries of the knee.
Page 116 of the text has a diagram of the carpal tunnel.

11. Ergonomics and Input Devices
Office hardware suggestions
Office chairs should have
Adjustable armrests and height
Lower back support
Desks should have
Have a keyboard tray
Keep hands at keyboard height
Place the monitor at eye level
(Page 117)

12. Ergonomics and Input Devices
Techniques to avoid RSI
Sit up straight
Have a padded wrist support
Keep your arms straight
Keyboard properly
Take frequent breaks

13. Inputting Data In Other Ways
Devices for the Hand
Pen/Stylus, Touch Screens, Game Controllers
Optical Input Device
Bar code readers, Image scanners, OCR
Audiovisual Input Devices
Microphones, MIDI, Digital cameras

14. 1. Devices for the Hand Pen (Stylus) based input Tablet PCs, PDA
Pen used to write data
Pen used as a pointer
Teaching tip
Microsoft has a demonstration of the tablet PC pen based input. Point your browser to and follow the tours.

15. 1. Devices for the Hand Touch screens
Use sensors to determine where finger points
E.g. fast-food restaurants, supermarket …
Discussion point
Discuss the information kiosks at local malls. Many offer limited Internet access. Have students discuss what could happen to the computers if the malls were to provide keyboards to the mall shoppers.

16. 1. Devices for the Hand Game controllers Enhances gaming experience
Fall into two broad categories
Joystick
Game pad
Teaching tip
Microsoft’s Force Feedback joysticks vibrate. In driving games, when the player hits another car, the joystick will vibrate.

17. Allows the computer to see input Barcode readers
2. Optical Input Devices
Allows the computer to see input
Barcode readers
Converts bar codes to numbers
Works by reflecting light
Scanners
Converts printed media into electronic
Insider information
For more information on the UPC code and a searchable database, visit A working UPC is , which represents a 24 count box of Crayola Crayons.

18. Optical character recognition (OCR)
2. Optical Input Devices
Optical character recognition (OCR)
Converts scanned text into editable text
Each letter is scanned and compared to known letters
Best match is entered into document
Rarely 100% accurate
Teaching tip
Many companies ask for a plaintext resume. This is a resume, typed in Courier or other easy to read font, with no formatting. The intent is to allow the company to scan the resume for future searching. OCR technology makes this possible. For more information, see the website

19. 3. Audiovisual Input Devices
Microphones
Used to record speech
Speech recognition
“Understands” human speech
Allows dictation or control of computer
Insider information
Two common products are IBM’s Via Voice and Scansoft Dragon NaturallySpeaking. More information for ViaVoice can be found at More information regarding Dragon is located at

20. 3. Audiovisual Input Devices
Musical Instrument Digital Interface (MIDI)
Connects musical instruments to computer
Digital recording or playback of music
Musicians can produce professional results

21. Audiovisual Input Devices
Digital cameras
Captures images electronically
Image is stored as a JPG file

22. Thanks