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. Input > Processing > Output. The processing is mainly handled by the Central Processing Unit (CPU).

The most common manual input devices are the mouse and keyboard. Here are some of my favourites:

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 tills in supermarkets and in other shops too. Touch screens are robust, easy to operate and easy to reprogram.

Barcode Readers: 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 the till and on your receipt. The scanning process also assists in stock management, reducing the stock by one each time a product is scanned/sold. This can help with stock levels and crime prevention.

Microphones: Used to input sound. In computing they can be used with voice recognition software and a word processing application to enter text. Webcams commonly have microphones built-in too like ones on a laptop.

Card Readers: 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.

Digital Cameras: 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.

Joystick: Used to be popular with gamers but have slowly been replaced by other types of game controller.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.

Games Controllers: Computer games often demand fast response times and manufactures make special controllers for them. Some games stimulate activities such as driving or flying. For example the Nintendo Wii.