2.1 Input devices

Input devices

How data is processed?

The diagram below represents any computer-based system. Data is input into the system, it processed and an output is produced. For example, a letter is typed into a computer using a keyboard (input) and it is saved onto the hard disk (storage). The letter can then be printed using a printer (output), but a copy is still saved on the disk.Capture

 

 

Analogue and digital data

Computer process digital binary information with the only numbers 0 and 1. This allows many different devices to communicate with each other using the same data. Modern input device now use digital data but some are still using the analogue systems and require a converter. Example of system require a converter are sensor for temperature, pressure, light and measure scale.

Input device:

 

Keyboard: Used to enter text into the computer.

Advantage:

  • Designed for long term repetitive use and widely available.QWERTY_keyboard
  • Function key can be set to preform task or open specific task.

Disadvantage:

  • Data can only be input as fast as it can be typed.
  • Danger of wrist problem after using the keyboard a long period time.

 

Tracker ball: an alternative to a mouse, useful for children or those who have limited movement in their hands.

Advantage:

  • Require very little space to operate.
  • Easier to control than a mouse for those with limited hand movement.SONY DSC

Disadvantage:

  • The tracker ball is often removable and can be lost.

 

Steering wheel: Used in computer games and virtual simulators to steer a vehicle.

Advantage:

  • Accurately represents the steering wheel just like in a real vehicle.
  • Force feedback can be added to provide road resistance. logitech-gt-steering-wheel

Disadvantage

  • limited driving applications due to limited movement.
  •  Adding mechanical elements such as force feedback and gear levers increases manufacturing costs.

 

 Pressure sensor: used to input pres

sure readings to a microprocessor or computer. Found in computer-controlled burglar alarm systems, automatic door, weighing scales etc.

Advantage:

  • Much more accurate than traditional weighing devices; able to detect very small changes in pressure.scale
  • As with other sensors, data does not to read manually.

Disadvantage

  • Any object of suitable weight can incorrectly activate them.
  • As with other sensors , an ADC converter is required.

PIN pads: used to enter data into Automated Teller Machines, Electronic Funds Transfer at Point of sale systems, entry doors and handheld devices.

Advantage:

  • PIN codes help to prevent unauthorized access.
  • Secure entry doors can be accessed without the need for a physical key or card.

Disadvantage:

  • People can be seen entering the PIN code.
  • PIN numbers can be forgotteniPP350-Overview