Input Devices

Keyboard

 The keyboard is a trusty companion to the computer since it's inception.  It provides an efficient way of getting characters representing words, numbers and punctuation (as well as some formatting) into the computer's storage system.

There have been several attempts at improving the layout and shape of the original typewriter keyboard.

Qwerty:  The original layout of the mechanical typewriter was designed to place the most commonly used two letter combinations at opposite ends of they keyboard.  If you press two keys at the same time on a mechanical typewriter the hammers jam i nto each other and that is not good. That layout has remained with us because a change would require retraining of all typists and that seemed a bit expensive.Dvorak: The arrangement of keys to maximize the efficiency of typing has been proved to be 74% more efficient than using a qwerty layout.  This layout has not been widely adopted in spite of the improvement in accuracy and typing speed.We are a fickle bunch..Many adaptations of the keyboard have been developed for people with special needs, these have all altered the layout in order to allow for the specific conditions of the individual user.

Mouse

The mouse was invented at Xerox PARC (Palo Alto Research Centre) in the late 1970's along with the graphical user interface.  The senior executives of Xerox could not see the potential of this technology and as a result allowed other companies like Apple and Microsoft to make loads of money from using their invention. 

Trackball

The trackball was created to be used with a portable computer where a level surface might not be available, it consisted of a small plastic ball protruding from the surface of the device, rotating the ball in any direction resulted in movement of the mouse across the screen.  It was essentially an inverted mouse.

Touch pad

The touch pad came to replace the trackball for portable computers because it has no moving parts and is cheaper to manufacture.  Swipes of the finger across the track pad result in movement of the mouse cursor.  More modern track pads support gestures where several fingers can be placed on the pad at once and different gestures result in more complex actions than simple mouse cursor movement.

Touch screen

The touch screen has been around since the mid 1980's but has recently become very much more popular with the introduction of it on smart phones and tablets.  Prior to this it was used mostly on information kiosks where it simplified the interaction with the user.

Webcam

A small camera connected to a computer system that allows the capture and streaming of video data on that computer.  We have come to expect our laptops to have a webcam built in and our tablets and smart phones to have one or two of these cameras in order to allow us to make video calls.

Microphone

A microphone is seen as standard equipment on all laptops, tablets and smart phones.  It allows the capture and transmission of an audio stream on the device.

Scanner

There are two groups of scanners that we will discuss, the bar code scanner, commonly seen in the point of sale device when you come to pay for items the teller will scan the bar code on the item and that data will be used to search the stock database and calculate the selling price for that item as well as updating the stock on hand field.

The second type of scanner is used to capture an image of a document.  These scanners are usually flat bed but they can also be found as a hand held version where the user must swipe the scanner over the surface of the document to be scanned.  Scanned documents can be passed through an optical character recognition program (OCR) in order to try to re-create the word processor document that can be edited.

Joystick

Designed to replicate the control interface of and areoplane these devices are used to provide input to flight simulator games.  They often have several buttons and levers on them that can be assigned different functions in each game.  Some include force feedback where the stick vibrates when the player's craft is being struck by enemy fire, this force feedback aspect of the joystick is output from the computer.

Gamepad

In a similar way to a joystick the gamepad have evolved from the input devices associated with the TV games of old,  it can be used with a wider variety of games than the joystick.  It is equipped with many buttons many models have a motion sensor in them and they can respond to movements of the gamepad.

Steering wheel/pedals

The steering wheel and pedals combination is an input device set designed for playing driving simulation games, it is not of much use for anything else but severs to heighten the realism while playing such games, these devices are also often equipped with force feedback

Gesture input

Gesture input has been made more popular through the gaming devices like the Nintendo Wii and the Microsoft Xbox Kinect.  Movements of the body can be interpreted by the detected motion of the controllers(in the case of Wii) and a camera pair in the case of the Kinect capturing the movements of the user and converting that into input for the computer (game).

Speciality

Many variations of these devices have been developed over the years in order to allow users who do not have fingers or hands to be able to provide input into the computer system.  These devices are usually tailor made for each situation and tend not to be mass produced.  Steven Hawking has a small motion probe connected to his cheek in order to create input for his speech synthesis computer as well as to do his work on a computer.