These are the most common form and are used to input hard-copy documents to be converted into an electronic form that can be stored in a computer.

Step 1: Cover is raised, document placed on glass panel, cover is closed

Step 3: Scan head moves across the document, image of the document is produced and then sent to a lens which focuses the document image

Step 4: Focused image falls onto a charge couple device (CCD) which is made up of thousands of light-sensitive elements and each element creates an electric charge when light falls on it. The scanned image is turned into an electric form

Application: Computers that come equipped with OCR (optical character recognition) can allow the scanned text to be turned into text file, where it can be edited using a word processor. 2D scanners are used at airports to scan the image on a passport for facial recognition.

Using a smartphone and the appropriate application, the QR code is scanned. The phone will use its internet connection to retrieve the information portrayed by the Qr code on the screen without typing anything.

It is a very effective method for advertising products in public places and can also hold promotional codes, etc.

Modern digital cameras link to a computer system via a USB port or by using Bluetooth (enabling wireless transfer)

These cameras are controlled by a microprocessor which can: adjust shutter speed, focus images automatically, operate flash automatically, adjust aperture size, adjust size of the image, remove red eye when the flash has been used.

When light passes through the lens it lands onto light sensitive cells made up of many pixels. The number of pixels determines the size and quality of the image. The quality is also dependent on other factors such as light and the type of lens.

Mobile phones have caught up with digital cameras, but are limited by the quality of their lens and storage size.

Selecting items on a screen can be carried out by pointing devices such as mouse, tracker ball, touch pad, or touch screen.

A mouse makes use of a mechanical ball arrangement, the movement of which (along an X and Y plain) is noted and then represented on a computer connected via USB.

An optical mouse makes use of a red LED that can detect movement on a surface. They can be seen as a wireless mouse as well as connected via Bluetooth.

Instead of a mouse, tracker balls use a large ball that is moved for cursor movement. Both tracker balls and mouse have additional buttons for selection and scrolling.

Touch pads use a tactile sensor which allows the user ot move the cursor by moving a finger across the surface of the touch pad. They too have buttons for selection.

This touchscreen is made up of layers of glass that act like a capacitor, creating electric fields between the glass plates in layers. When the top glass layer is touched, the electric current changes and the coordinates where the screen was touched is determined by an on-board microprocessor.

This type of touchscreen makes use of an upper layer of polyester and a bottom layer of glass. When top layer is touched, the top layer and the bottom layer complete a circuit and signals are then sent out which are interpreted by a microprocessor. The calculations determine the coordinates of where the screen was touched.

This type of touchscreen uses glass as the screen material and requires a warm object to carry out an input operation.

It uses glass as the screen material and uses an array of sensors (in the form of a grid). The point of contact is based on which grid coordinate is touched.

Another type of barcode is the QR code, which is made up of a matrix of filled-in dark squares on a light background. Normal barcodes can store up to 30 digits only but QR codes can store over 7000 digits.