1. INPUT DEVICES
TYPES OF INPUT DEVICE

2. INPUT DEVICES
An input device is used to convert the input to a form that the C.P.U can understand and process.
The computer is digital and understands machine language.
Words in machine language consists 0’s and 1’s.
For example represent the number 18

3. CATEGORIES OF INPUT DEVICES.
Keyboard entry devices
Terminal entry devices
Pointing devices
Source data entry (SDE) devices
Multimedia input

4. KEYBOARD INPUT The keyboard is the most commonly use input device.
It is used to enter numerical values, alphabetical values and special character.
There are two main type of keyboards:
Alphanumeric keyboard
Specialized keyboard

5. ALPHANUMERIC KEYBOARD
Looks like a type writer
Types of keys
Alphanumeric - ABC, 123
Numeric
Function keys - F1-F12
Toggle keys - CAPS LOCK, NUM LOCK
Modifying keys - SHIFT, CTRL, ALT
Directional Arrow keys

6. SPECIALIZED KEYBOARD These are designed for special applications.
For example:
The retail keyboard – used by fast food restaurants and other retail stores.

7. TERMINAL ENTRY DEVICES
A terminal is an input/output device. Includes a keyboard, a video display unit, and a communication link to send or receive information from a centralized computer system.
The centralized system is usually a minicomputer or mainframe.

8. TYPES OF TERMINAL ENTRY DEVICES
1. Dumb Terminals This terminal doesn’t have a C.P.U (brain). It can’t operate on its own. It can only send and receive data from a central computer system. These can be found in airports, banks etc.

9. 2. Smart terminals: these have a C. P. U
2. Smart terminals: these have a C.P.U. and therefore can do some work on their own. However they rely on a central computer for storage and most of the processing.

10. 3. Intelligent terminals: It accepts data and processes it before sending the information to a main computer. It therefore has its own C.P.U, storage unit and memory.

11. 4. Point of sale (POS)
These are used in stores and super markets to calculate bills and generate receipt. A device is passed over a special tag that is attached to the item to read the relevant information, or it is typed in by the clerk. The terminal will show the description of the product as well as the cost.

12. 5. Automated teller machines (ATM)
ATM’s accepts requests for different transactions such as withdrawal, deposits or bill payments. The request is sent to a main computer for processing and the result sent back to the user.

13. POINTING DEVICES THE MOUSE This is the most popular pointing device.
It is a handheld device that fits comfortably under the palm of your hand.
The mouse is used to control the graphics cursor or the mouse pointer. This cursor normally takes the shape of an arrow, a hand or an I beam.
Whenever the mouse is moved on the surface of a desk or on a mouse pad, the graphics cursor on screen will move in a similar direction.
The mouse is often used in selecting items, highlighting text and icons (icons are pictures of functions).

14. THE MOUSE (cont’d)
A mouse can connect to your computer in several ways. Most have a cable that attaches to a mouse port or a Universal Serial Bus (USB) port on the system unit.
A later invention that is becoming popular is the CORDLESS or WIRELESS mouse. These are battery powered and transmits data using wireless technology such as radio waves or infrared light waves.

15. MOUSE

16. CORDLESS MOUSE

17. TYPES OF MOUSE There a two popular types or mouse
The MECHANICAL mouse – has a rubber or metal ball on its underside and usually has two or more buttons (and maybe a wheel that is used for scrolling) on the top.
Whenever the mouse is moved, the ball underneath rolls thus causing the graphics cursor on the computer screen to move.
A mechanical mouse should always be placed on a mouse pad, as it better protects the ball from getting dirty. A dirty ball will cause the mouse to malfunction.

18. TYPES OF MOUSE (cont’d)
The other type of mouse is the OPTICAL mouse.
This type of mouse has no moving mechanical parts inside. Instead it uses a device to produce and sense light that detect the mouse’s movement.
You can place an optical mouse on almost any surface, thus eliminating the need for a mouse pad.
It is more accurate than a mechanical mouse and does not require any cleaning.

19. TRACKBALL
This resembles an upside down mechanical mouse. The ball is on top and is moved by the users palm or finger, thus eliminating the need to move the device.
The ball in most trackballs is about the size of a Ping-Pong ball
A trackball usually has one or more buttons that work similar to those of a mouse
Trackballs must be frequently cleaned because it picks up oils from fingers and dust from the environment.

20. TRACKBALL

21. GLIDEPAD/TOUCHPAD/TRACKPAD
This is a small, flat, rectangular touch sensitive pad that is used in controlling the graphics cursor.
The user slides the finger across the pad and the cursor follows the finger movements.
To make a selection the user may either click buttons that are around the edge of the pad or tap the pad with a finger.
Glide pads are mostly found in laptop computers

22. TOUCHPAD

23. POINTING STICK
This is another device that is popular with laptop computers.
It is a pressure sensitive pointing device that is shaped like a pencil eraser
It is positioned between the keys on the keyboard.
To move the graphics cursor on screen the user pushes the pointing stick with the finger.

24. POINTING STICK

25. JOYSTICK This is a vertical lever that is mounted on a base.
The joystick is mostly used in playing games.
The lever is moved in different directions to control the actions of the user
The lever usually includes buttons (called triggers) that can be pressed to activate certain events in the game.

26. JOYSTICK

27. LIGHT PEN
This is a hand-held, pen shaped device that is connected to the computer using a cable.
Using a special software or a special monitor the light pen detects the presence or absence of light on the computer’s screen.
To select objects, the pen can be pressed against the surface of the screen or you can point the pen at the screen and press a button on the pen.
Light pens are often used by doctors and dentists, as they can slide a protective sleeve over the pen thus keeping their fingers free of contaminants

28. LIGHT PEN

29. TOUCH SCREEN
This is a touch sensitive display. You interact with this device by touching sensitive areas on the screen with your finger.
Touch screens are normally used in situations that only require you to touch words, pictures, numbers or locations that are identified on the screen.

30. TOUCH SCREEN

31. GRAPHICS TABLET/ DIGITIZER/DIGITIZING TABLET
This is a flat, rectangular, electronic plastic board.
Each location on the graphics tablet corresponds to a specific location on the screen.
A pen-like device called a stylus is used to write on the tablet.
Writings or drawings on the tablet are converted to digital signals and are sent into the computer.
Graphics tablets are often used by architects, mapmakers, artists etc.

32. GRAPHICS TABLET

35. SOURCE DATA ENTRY (SDE) or AUTOMATED INPUT DEVICES
These input devices are used to get data into the computer without typing it in.
Using these devices increases the speed of data input and reduces the errors associated with manual input.

36. Examples of SDE devices
Magnetic Ink Character Reader (MICR)
Optical Mark Reader (OMR)
Optical Character Reader (OCR)
Bar Code Reader
Scanner
Sensor

37. MAGNETIC INK CHARACTER READER (MICR)
This device is used in banks to read the magnetised numbers found at the bottom of cheques and deposit slips.
The numbers encode the
cheque number
branch number of the bank
customer’s account number
MICR cheques serve as a deterrent to fraud because those photocopied will not have magnetic ink.

38. MICR

39. OPTICAL MARK READER (OMR)
These devices collect data as hand drawn marks made on pre-printed forms like those used for multiple choice answer sheets or questionnaires.
The master document (such as the answer sheet for the test) is first passed through the OMR so that the correct answers can be recorded.
The remaining documents are then passed through the device and their pattern of light matched against the master document’s pattern.

40. OMR

41. OPTICAL CHARACTER READER (OCR)
This device is used to read typewritten, computer-printed, or handwritten characters from ordinary documents and translating the images into a form that the computer can understand.
Most OCR devices include a small optical scanner for reading characters and sophisticated software for analyzing what is read.
OCR is often used on turn around documents. A turn around document is computer produced output that is ultimately returned to the computer as machine readable input. These documents are normally used by utility companies.

42. OCR

43. SCANNERS
A scanner is a light sensing input device that reads printed text and graphics from paper and then changes result into a form that the computer can use.
Once an object has been scanned it can be displayed on the screen, stored on storage medium, printed, faxed and ed. The resolution (clearness of an image) is measured in dots per inch (dpi).
SCANNERS are used in desktop publishing (creating newsletters or similar documents).

44. TYPES OF SCANNERS
Flatbed – works similar to a photo copy machine except that the results are sent to the computer instead of paper. A paper is placed on a flat scanning surface and a light shines along the length of the document.
Hand held or wand - usually has a scanning width of approximately four inches. It is normally used for copying small images such as signatures, logos, and small photographs.

45. FLATBED SCANNERS

46. HAND HELD SCANNERS

47. BAR CODE READERS This device uses laser beams to read bar codes.
A bar code is an identification code that consists of a series of vertical lines and spaces that vary in width and have numbers and letters printed at the bottom.
They are found on a variety of products example books, clothes and food items and are used to encode information such as price, the name of the product and manufacturer.

48. BARCODE READER

49. SENSORS
Sensors are used to measure mechanical, thermal, electrical and chemical quantities. The measurement is recorded by the sensor and is sent to the CPU where it is analysed and the relevant output given.

50. USES OF A SENSOR regulates temperature
measures and regulates radiation in a nuclear plant
measures and regulate the temperature in a furnace
control traffic light signals
Create characteristics in robots (such as seeing, hearing, feeling etc.
add security to a building (motion sensors)

51. SENSORS
Temperature sensor
Traffic sensor
Temperature sensor

52. MULTIMEDIA INPUT
Multimedia is the presentation of information on a computer using text, graphics, audio and video.
Multimedia input includes:
Voice input
Video input
Sound or audio input

53. VOICE INPUT
This is the process of entering data by speaking into a computer’s microphone. The microphone is attached to the sound card port in the system unit.
A voice recognition system is used to distinguish between spoken words. It can only recognize words pre-programmed in its vocabulary.
Voice recognition systems can either be speaker dependent or speaker independent.

54. SOUND/AUDIO INPUT
This is the process of entering any sound into the computer such as speech, music, and sound effects.
Sound can be entered using a microphone, tape player, Compact disk (CD) player or radio. These devices are attached to the sound card port in the system unit.

55. VIDEO INPUT
Video input or video capture is the process of entering a full-motion recording into a computer and storing it on a storage medium.

56. VIDEO INPUT DEVICES WEB CAM
The output from this camera is displayed on a Web page. It can be used to show weather or traffic information, work in progress or any thing you want to be displayed on the internet.

57. VIDEO INPUT DEVICES (cont’d)
Personal Computer (PC) camera
This is used by home users to record and edit motion or still images. It is also used to make video telephone calls (you are able to see the person as you speak to them). It is plugged in the Universal Serial Bus (USB) port on the system unit and usually sits on top of the monitor.

58. VIDEO INPUT DEVICES (cont’d)
DIGITAL CAMERA
This allows you to take pictures and store them digitally instead of on traditional films. Images can then be transferred to the computer or viewed on the television.
Most digital cameras come with a color Liquid Crystal Display (LCD) screen (similar to those on a laptop computer). You can use the LCD screen to view the photographs taken.

59. VIDEO INPUT DEVICES (cont’d)
DIGITAL VIDEO CAMERA
This allows you to record video in a format that you can save in the computer. Digital videos are more clear and crisp than the traditional videos (analog videos).

60. VOICE RESPONSE UNITS
These units produce computer generated voice output. They provide pre-recorded information for users either with or without request. Interactive Voice Response Units (IVRs) consist of an automated telephone answering system that responds with a voice menu allowing the user to make choices and enter information via the keypad. IVR systems are widely used in call centers as well as a replacement for human switchboard operators.