The Advantage And Disvantage Of Input Devices

 

 

 

An input device is a peripheral---a piece of computer hardware equipment---providing data and control signals to an information processing system. Input devices include scanners, digital and video cameras, keyboards, a mouse, and pointing and reading devices. Input devices serve a purpose but also come with a few disadvantages.

 

 

 

 

 

 

 

 

 

 

Joysticks

 

 

Joysticks are often used for playing computer games such as flight simulators. They can also be used to control the movement of a wheelchair or other machinery.

They input directional data like a mouse but work by switches being closed as the joystick is moved left or right and up or down.

                        Mini finger-controlled joysticks can be used to control a laptop cursor.

 

Advantages:

• Easy to learn to use.  Very simple design so they can be inexpensive.

Disadvantages:

• Control can be a bit crude as the directions in simple joysticks are limited to forward, backwards, left and right.  Better models offer diagonal movement or better.

 

 

 

 

 

 

 

Video digitiser

 

 

 

A video digitiser is used to convert sequences of analogue images into a digital format.The digitised images can then be saved as a file and played back on a monitor to produce a moving image.

Software will allow the video to be edited and special effects added, as well as individual still images to be captured and saved. Digital video cameras digitise the image inside the camera and save the video frames in a digital format. This data can then be transferred directly to the computer via a fast transfer cable and interface such as Firewire.

 

Advantages:

• Digital video is easily edited.  Sections can easily be cut and pasted together and digital effects added.
• The output can be rendered into a wide range of formats ranging from DVD quality down to streaming video suitable for the Internet.

Disadvantages:

• Video files take up a great deal of memory.
• Fast video capture cards may be needed to capture high quality video footage.
• A powerful computer and graphics card is often needed to process video footage

 

  

 

 

Remote control

These emit a beam of infra-red light which carries digital data signals. They are often used to control TV's and VCR's.

More advanced models can be programmed to transmit a series of commands with one button press.


Advantages:

• Each function can have its own button making them very simple to use.

 Disadvantages:

• Only advanced models can be have the buttons reprogrammed so they cannot be used to control anything other than the device they were designed for.

 

MIDI instruments

MIDI stands for Musical Instrument Digital Interface. These are normal musical instruments which have a MIDI port for input into a MIDI interface in the computer.
The notes are converted into digital data and saved as a file on the computer. This data can be converted back into notes or edited by computer software.
The software often has a wide range of special effects or stored sound data from real instruments.

Advantages:

• Data from a musical instrument is easily captured and edited with a computer.
• MIDI files are small.
• MIDI files can be recorded on one type of instrument and played back on another.

 Disadvantages:

• Audio cannot be recorded directly as an audio files such as MP3. 
• The playback depends on the instrument/computer sound card so may not sound the same as the original.
• Only the note and the timing are stored.

 

 

 

 

 

 

 

 

 Digital camera

These are used to take photographs like a normal camera but produce digital images instead of using film.
The light passing through the lens is digitised by special light sensitive sensors. The image is stored on memory chips in the camera and can then be transferred to a computer.
The resolution of such cameras is increasing rapidly and professional models have become standard in photo-journalism. Images are usually compressed as jpeg's to save memory.
Advanced models have removable memory cards to increase the camera's storage capacity. Images can be transferred to a computer by cables or memory card readers.



Advantages:

• No film is needed and there are no film developing costs.
• Unwanted images can be deleted straight away.
• Images are already digital and can easily be transferred to a computer and edited or transferred over the Internet.
• Special image editing software can allow a huge range of adjustments and special effects to be tried.

Disadvantages:

• Images often have to be compressed to avoid using up too much expensive

 

Magnetic Stripe Reader

Magnetic stripes are thin strips of magnetic tape which are usually found on the back of plastic credit and debit cards.
When the card is inserted into a reader (in an Automatic Teller Machine or ATM for example) the tapes slides past a playback head similar to that used in a tape recorder. This reads the data from the stripe and passes it to a computer.


Advantages:

• Simple to use and cheap to produce. The data can be altered if necessary.

Disadvantages:

• Very limited storage capacity. Data easily destroyed by strong magnetic fields.
• Not very secure as thieves can obtain the readers and alter the data.

Standard Keyboard (Further keyboards types)

The standard QWERTY keyboard is the commonest way to enter text and numerical data into a computer.
Each individual key is a switch, which when pressed, sends a digital code to the computer.
For example, pressing the 'A' key produces the binary code 01100001 representing the lower case letter 'a'. Holding down the shift key at the same time produces the binary code 01000001 representing the upper case letter 'A'.
Advantages:

• Reliable for data input of text and numbers.
• Usually supplied with a computer so no additional cost.
• Specialised keyboards are available.

Disadvantages:

Users may be slow for not very accurate typists.

Slow for accessing menus etc. and difficult to use if you want to move objects around the screen.

Difficult for people unable to use keyboards through paralysis or muscular disorder.