See here (AQA)
Probably the most commonly used input device. Inputs characters by pressing them.
Advantages: cheap, widespread, easy to use
Disadvantages: anglophone (foreign characters not shown, especially for oriental languages like Chinese with thousands of characters), can harbour disease, easy to make msitaeks when typing
Used to move a pointer around a screen. Click buttons, icons, menus to activate options.
Advantages: easy & intuitive to use
Disadvantages: can cause RSI if overused
Common on laptop computers, can move mouse around screen by moving finger across it.
Advantages: included on computer
Disadvantages: can be difficult to use, hard to coordinate mouse clicks when using keyboard combinations e.g. Shift/click
A bar code consists of 95 columns, each representing a binary digit in the code. The bar code reader takes a black line as 1 and a white line as 0. The bar code includes a product type code e.g. 0 = standard food item. Five digits follow, each made up of 8 columns; first five digits begin with 0 and have an odd number of 1s; the first five digits represent the manufacturer; they have their own codes to represent decimal digits 0-9. There is a 'center guard' to separate the second set of 5 digits. The second set of five digits begin with a 1 and have an even number of 1s; these represent the product itself. The arrangement of lines on the bar code is designed so that it can be read upside down as well as right side up - obviously a convenience in a shop; the computer identifies the lines from left to right or right to left and adjusts the code accordingly. The last digit is a check digit based on an algorithm that uses modulo arithmetic.
Allow interaction with computer by touching. An output device as well as input. Whiteboard is a tocuh senstive device that needs a projected image calibrated to the touch sensors. Can be used with a stylus. Now common in many devices e.g. photocopier, camera back, Satnav, PDA, mobile phone, portable game console, kiosk systems, tablets. Used in situations where use of a keyboard would be slow and unintuitive e.g. popular in museums and on shopping aracde kiosks.
Early technology used infra-red sensors at edge of screen to detect position of hand/stylus. Next wave of dvelopment is in multitouch technology.
"A resistive touchscreen panel comprises several layers, the most important of which are two thin, transparent electrically-resistive layers separated by a thin space. These layers face each other, with a thin gap between. One resistive layer is a coating on the underside of the top surface of the screen. Just beneath it is a similar resistive layer on top of its substrate. One layer has conductive connections along its sides, the other along top and bottom. When an object, such as a fingertip or stylus tip, presses down on the outer surface, the two layers touch to become connected at that point." (Wikipedia)
"A capacitive touchscreen panel consists of an insulator such as glass, coated with a transparent conductor such as indium tin oxide (ITO).[11][12] As the human body is also an electrical conductor, touching the surface of the screen results in a distortion of the screen's electrostatic field, measurable as a change in capacitance. Different technologies may be used to determine the location of the touch. The location is then sent to the controller for processing. Unlike a resistive touchscreen, one cannot use a capacitive touchscreen through most types of electrically insulating material, such as gloves; one requires a special capacitive stylus, or a special-application glove with an embroidered patch of conductive thread passing through it and contacting the user's fingertip. This disadvantage especially affects usability in consumer electronics, such as touch tablet PCs and capacitive smartphones in cold weather." (Wikipedia)
Uses radio frequency to transfer data from a tag attached to an object for automatic identification and tracking. (Wikipedia)
The tag contains electronically stored information, which can be read from up to several metres away. The tag does not need to be visible and may be embedded in the object (as in a dog's or cow's ear).
RFID is widely used e.g. in the car industry: to track progress of a vehicle along an assembly line. e.g. in a warehouse so items can be tracked through delivery, storage and dispatch to outlets. e.g. to open doors. e.g. to bill motorists for using a particular road, bridge or parking space.
The use of RFID tags has raised privacy issues because they can be embedded and read without a person knowing about it.
How Does RFID Work? RFID in Plain English RFID Demo
Upside-down mouse. Possibly better for avoiding RSI.
Advantages: less RSI
Disadvantages: can be difficult to use
'Air mouse' used in presentations, wireless device that allows entry of button presses and movements when away from the computer. Useful in presentations.
Advantages: can give talk away from computer but still control it
Disadvantages: temperamental
Input movement into games.
Advantages: responsive
Disadvantages: none!
Often found on plastic cards. Store data that is read by a card reader e.g. to open a door, logon to a bank account (replaced by Chip and PIN). Luton Town FC introduced magnetic cards at their ground to exclude non-members but the system was not perfect, fans quickly found that any card with a magnetic stripe would let them in.
Advantages: cheap
Disadvantages: stripe may be faulty, not very secure
Scan pictures and text. Use OCR to scan text. Recognise letters by their shape.
Advantages: can read text and images into computer format
Disadvantages: none
How does it work: use a charge-coupled device (CCD): "In a CCD image sensor, pixels are represented by p-doped MOS capacitors. These capacitors are biased above the threshold for inversion when image acquisition begins, allowing the conversion of incoming photons into electron charges at the semiconductor-oxide interface; the CCD is then used to read out these charges." (Wikipedia)
"A flatbed scanner is usually composed of a glass pane (or platen), under which there is a bright light (often xenon or cold cathode fluorescent) which illuminates the pane, and a moving optical array in CCD scanning. CCD-type scanners typically contain three rows (arrays) of sensors with red, green, and blue filters." (Wikipedia)
Variants: hand scanners: drag across document; drum scanners: these use photomultiplier tubes: the image is wrapped around a drum which rotates at high speed while the pmt's read the information; most modern drum scanners use three sensors for RGB.
Background: pixels, colour models, cameras
Digital cameras are now very popular. Webcam used for security or for messaging and email.
Advantages: compact, take hundreds of images, no film to buy or process, instant results, can discard unwanted images
Disadvantages: batteries run out, images devalued by quantity (takes hundreds etc.)
How they work: How a digital camera works What is a megapixel? How many megapixels? Phase One
Input data into data logging system e.g. temperature, sound, movement, passive infra-red.
Advantages: automatic reading, remote use
Disadvantages: need careful setting up, may not be accurate
Musical Instrument Digital Interface: keyboards and other instruments can be a source of data input, note pitch and length entered by playing keyboard or other instrument. Once entered music can be edited in music software such as a sequencer.
Advantages: can record and playback music electronically, manipulate sounds, correct errors, limitless possibilities
Disadvantages: limitless possibilities (spoiled for choice)