Chapter 4 -Input and Output devices :)

These are examples of Input Devices: 

Mouse:

Application: Menu Selection

A Mouse is a most widely used pointing device on personal computers. A mechanical Mouse has a rubber ball on its underside to detect movement of the mouse. An optical mouse uses devices that emit and sense light to detect the mouse's movement. A chordless mouse (either mechanical or optical) transmits data using wireless technology such as radio waves or infrarred waves.

 

Trackball:

A trackball is a stationary pointing device with a ball mechanism on its top. A trackball is good for limited desk space because the user does not have to move the entire device.

Touchpad:

Is a small pressure-and motion- sensitive area usually used on a portable computer that you can use to move the mouse pointer. When you move your finger across the pad, the mouse pointer on the screen moves in the same direction. A touchpad is an alternative to a mouse.

 

 

 

Joystick:

Application: Games and simulations

A joystick is a pointing device with a vertical lever mounted on a base. The lever usually includes buttons called triggers, which activate certain events when pressed. Joysticks are mainly used for computer games and ultrasound scanners in hospitals.

An advantage is that a joystick allows fast interactions required in most games.

Bar Code Reader.Application: Point of Sale (POS)

A bar code reader uses laser beams to read bar codes. A bar code reader reads a bar code by using light patterns that pass through the bar code lines of different widths and spaces. A bar code reader represents a set of unique numbers that define a specific product (not the price). These numbers specify the country of origin, the manufacturer, the item's code etc. So the numbers represent different things. 

An advantage of the bar code reader is that the process of data is fast and quite accurate.

While a disadvantage is that the bar code reader may misread a bar code if there is any dirt or even a mark on the code. 

Magnetic Ink Reader.

Application: Bank

A magnetic ink character (MICR) reader can read text printed with magnetic ink. MICR is used most exclusively by the banking industry for processing cheques. The characters represent the check number, the bank number, and the account number of customers. 

An advantage is that - MICR is difficult to forge                               - Documents can still be read when folded or                    written on  

A disadvantage is that- The system can accept only a few different character sets .  

Scanner
Application: Converting hardcopy to machine readable form. 

A scanner is a light-sensing input device that converts printed text and graphics into a digital form that can be further processed by the computer.

There are 2 types of popular scanners, "THE FLATBED SCANNER" & "THE HANDHELD SCANNER". 

The flatbed scanner works like a copy machine. The difference between a copy machine and the flatbed scanner is that the flatbed scanner creates a file of the document rather than a paper-copy. 

 

                                                     

The handheld scanner can be manually passed over the image to be scanned.It is a portable device you can use to copy an image paper to your computer, just like a normal scanner. Hand-held scanners are ideal for capturing small images, such as signatures and logos. A hand-held scanner is smaller, less expensive and also more portable than a flatbed scanner. So most people would rather use a handheld scanner rather than a a flatbed scanner. 

Scanners are mainly used for image processing, which consists of capturing, storing, analysing, displaying, printing, and manipulating images. Many scanners also include optical character recognition (OCR) software, which can convert an image with text included into a text file which one can edit. 

 Advantages of a scanner include: Using the appropriate software, you can edit your photos and insert them.  :)

Disadvantages of a scanner include: A scanner is best for two-dimensional objects only. :(