Input Devices

What is an Input Device?An Input Device is any hardware that can insert data to a computer.Without any Input Devices a computer cannot be commanded. There are dozens of possible Input Devices but the two which are most used are, keyboard and mouse. Every time you press a key or click on the mouse you are ordering the computer to accomplish a specific action. These commands allow you to open files or programs, send messages, drag objects and perform many other functions on your computer.

Some of them are:

external image input+device.jpg

Input Devices:

  • OCR (Optical Character Recognition)
  • OMR (Optical Mark Reader)
  • MICR (Magnetic Ink Character Recognition)
  • VDE (Voice Data Entry)
  • Smart Cards
  • Touchscreen
  • Keyboard
  • Magnetic card
  • Webcam
  • Bar code scanner
  • Microphone
  • Mouse
  • Light pen
  • Scanner
  • Digital Tablet & Stylus
  • Pen Scanner
  • Joystick

Input devices allow us to enter raw data into a computer. The computer processes the data and then produces outputs that we can understand using an output device. Input devices can be manual or automatic.
The processing is mainly handled by the Central Processing Unit (CPU).

Manual input devices

The most common manual input devices are the keyboard and mouse. Other manual input devices include:

Concept keyboard

Each button on a concept keyboard relates to a particular item or function. Buttons can be labelled with text or a picture. Fast food restaurants often use concept keyboards because very little training is needed to operate them and they're efficient - a single button can order an entire meal.


silver trackball with blue ball
silver trackball with blue ball

Used as an alternative to a mouse. To operate it the user rotates the ball which moves the pointer on screen. They are particularly easy to use for those with limited movement in their hands and are often used in Computer Aided Design (CAD) for their increased precision over a mouse.


Joysticks used to be popular with gamers but have slowly been replaced by other types of game controller. In construction, joysticks are used to control machinery such as cranes.

Digital camera

A digital camera takes pictures and can usually record video too. The pictures it takes and the videos it records are stored in files. These files can be copied to a computer and later edited.



Microphones are used to input sound. In computing they can be used with voice recognition software and a word processingapplication to enter text. Webcams commonly have microphones built-in too.

Touch screen

A touch sensitive visual display unit (VDU) or screen has a grid of light beams or fine wires criss-crossing the screen that are used to detect touch. Many mobile phones use touch screens and do away with the keypad entirely. They're often used on cash machines and in shopping centres too. Touch screens are robust, easy to operate and easy to reprogram.

Video digitiser

A video digitiser takes an image from a video camera or television and digitises it so it can be read by, and stored on, a computer. Video sequences captured using a video digitiser are often used in multimedia presentations.


silver scanner with lid open
silver scanner with lid open

A scanner can be used to digitise images. They're similar to a photocopier but they make a digital copy instead of a physical copy. They can also be used with optical character recognition (OCR) software to scan in text that is then editable.

Graphics tablet

A graphics tablet consists of a flat pad (the tablet) on which the user draws with a special pen. As the user draws on the pad the image is created on the screen. Using a graphics tablet a designer can produce very accurate on-screen drawings as if they were drawing on paper.

Automatic input devices


Sensors are often used as part of a feedback cycle. They collect data continuously and are typically linked to a control program that specifies acceptable levels, eg the minimum and maximum temperature in a green house. The control program decides what to do next based on the data it's fed by the sensors.

Barcode reader

Barcodes are represented by black vertical bars and are read by a barcode reader. Barcodes are printed on nearly every product you buy, each product has a unique code. When read, information stored in the shop's database is recalled, such as the product name and price. This information later appears on your receipt.

Magnetic strip (or stripe) reader

Debit card
Debit card

Magnetic stripes are built into many plastic cards such as debit or credit cards and personal identity cards. The magnetic strip on the back of the card can hold the personal details of the card owner and, with the necessary PIN, will allow access to secure information, eg bank account details. Data stored on the strip is scanned and input into a computer system by a magnetic stripe reader.

Magnetic Ink Character Reader (MICR)

Magnetic ink characters appear at the bottom of cheques. Banks use MICR to read the numbers from the bottom of cheques to obtain data such as account numbers and bank sort codes. A particular font is used that makes it easy for the machine to discriminate between characters. The ink is magnetised, this makes it immune to creases and dirty marks.

Optical Mark Reader (OMR)

An OMR reads marks made by pencil on a printed form into the computer. OMR systems are suited to reading pre-printed forms and check boxes such as National Lottery number selection sheets and multiple choice exam papers.