Input Devices - INFO 1

Main input of a keyboard:

• Text
• Numbers
• Some cursor movement (arrow keys)

The most common type of keyboard is QWERTY. This is used with most computers as people are familar with them and they are extremely easy to use.

Most instructions can be done with a keyboard

Some systems don't need all of the features of a QWERTY keyboard, and so only have part of one. For example, a cashpoint only has a numeric keypad

Another type of keyboard is the concept keyboard.

A concept keyboard does not contain letters and numbers, but different commands. For example, most restaurants and cafes use a concept keyboard. Instead of having to type of the word 'cheeseburger', there is already an option for this on the keyboard. The user just has to press the button and the data is entered.

This type of keyboard is used as data entry is faster compared to a QWERTY keyboard, and the input is more accurate.

Another keyboard is a braille keyboard - this is similar to a QWERTY keyboard, but has raised dots to represent letters and numbers.

This keyboard is used by those who have difficulty reading the text on a QWERTY keyboard.

The main type of input with a mouse is:

• Cursor movement
• Click/double click
• Drag
• Scroll

The mouse is not the only pointing device, there are several alternatives:

• Trackball
  This mouse has a ball on the top of the mouse, and so only requires little movement from the users fingers. It still has the two buttons
• Trackpad
  The pad is sensitive to finger movement, and so the user is able to use the cursor by moving their finger over the trackpad. For example, on a laptop.

Advantages of using a mouse:

• Most computers use a mouse and so people are familiar with them
• They are designed to fit comfortably in the users hand, and so users find them easy to use for long periods of time
• They are easy for beginners to use with GUI (graphical user interfaces)

Disadvantages of using a mouse:

• Extensive use of a mouse can cause RSI (repetitive strain injury)
• Instructions be slow with a mouse
  For example, when trying to copy and paste an image, it would take at least four clicks of the mouse. Whereas when using a keyboard, 'ctrl+c' and 'ctrl+v' can be used
• Some optical mice have trouble on surfaces - won't pick up the movement of the user
• Wireless mice require batteries to work. When the battery is low, it performance of the mouse will also become low

Main types of input:

• Press
• Drag

Touchscreens are mainly used in public places and are often public devices, such as mp3 players and mobile phones.

User can touch areas on the screen rather than clicking the mouse - both input and output

Advantages of using a touchscreen:

• Correct surface is not required to use the touchscreen, whereas it is for a mouse
• Is straightforward and easy to use for a beginner

Disadvantages of using a touchscreen

• It is difficult to pinpoint small areas, so everything needs to be large and accessible

A scanner uses reflected light to read paper documents and convert them into files on the computer.

The main types of input are:

• Text
• Images

Advantages of using a scanner

• Paper documents can be scanned into the computer so that they can be manipulated and edited

Disadvatages of using a scanner

• Special software is needed to interpret what the scanner reads
• Quality of input depends on the resolution of the scanner

Barcode Scanner

• Barcodes of products can be scanned into retrieve the information about the item.
• Each product has a unique barcode
• Scanning the barcode to retrieve the information takes up far less time than entering each detail about the item the customer wants to buy, this is why they are extremely beneficial in shops

Magnetic Card Readers

• These are used to read the magnetic strips on credit cards and tickets (such as train tickets)
• Like a barcode scanner, it retrieves the stored information and presents it to the user

Sensors

• Sensors are mainly used in control systems to measure data over a period of time
• They do not need human input

Magnetic Ink Character Recognition (MICR)

• MICR is used to read magnetic characters
• These are usually found on cheques
• They make cheque forgery more difficult

Optical Character Recognition (OCR)

• If a document is made up of text, OCR can convert it from written words into text
• One problem is that is doesn't always get it right!

Optical Mark Recognition (OMR)

• This is used to read the marks in multiple choice exam paper or on lottery tickets

Chip and Pin

• This is similar to magnetic strips, but it also holds the pin number in encrypted form

Graphics Tablet

• This is mainly used by artists and designers
• It can be used to trace original drawings or input ones from scratch using a graphics pad and a stylus

Digital Cameras

• These can be connected using a cable to input photos and videos on to your computer
• Some cameras now have a wireless connection to your computer, and can be inputted from anywhere

Webcam/Microphone

• Webcams and microphones can be used to feed videos and sound straight away, rather than uploading and storing them first

All input devices have three main benefits:

• Increased speed of data entry
• Increased accuracy
• Increased ease of data entry

Some input devices may successfully work with some things, but not others