Input and Output devices

Actuator

(or transducers) takes signals from a computer & convert them into some form of motion e.g. operating motors, pumps, switches & valves)

Lights

* Actuator is connected to the switch which turns the lights on/off * Used in security lights; & in greenhouses to control lighting conditions

Heaters

* Actuators are connected to switches which turn the heater on/off * Used in washing machines, cookers, central heating systems, & in greenhouses to control temperature

Graph Plotter

* Capable of producing highly accurate, very large drawings & posters * Advs - huge printouts at extremely high quality * Disadvs - slow in operation; expensive to buy & maintain

Speakers

* Connected directly to a computer or built in - various uses * Digital data from the computer is converted into analogue form (using a digital to analogue convertor DAC) - signal is then amplified through the speakers

Smart Card Reader

* Data is stored on chips (similar to magnetic stripe cards but have more storage capacity) * Used on loyalty cards, ID cards, smart public transport cards (track customer movements between stations to process payment), electronic passports & driving licences * Advs - some smart cards take payment automatically & reduce the need to carry cash; chip does not need to be in contact with the reader so causes less damage than a magnetic strips card; data is more secure * Disadvs - if the card is lost, it could be used for identity theft

TFT (Thin Film Transistor)

* Main output device - screen is made up of thousands of tiny pixels - each pixel has 3 transistors coloured red, green or blue * Integral part of laptop computers * Advs - lightweight; cheap; reliable; less glare & radiation than old CRT monitors; less power/heat than old CRT monitors * Disadvs - angle of viewing & definition can be an issue; cannot yet be used with light pens in CAD

Webcam

* Many computers have webcams built in although some are connected via USB * Used for online chatting, Skyping, video-conferencing * Advs - can be left on or activated as/when required; allow people to keep in contact without having to travel (particularly useful for elderly, disabled or people who live too far away) * Disadvs - limited features & picture quality can be limited/poor; can be hacked/accessed without the users knowledge

Light Pen

* Pen shaped wand which contains light sensors that send signals to a computer when light changes are detected * screens & for drawing (CAD) * Advs - more accurate than touch-screens; small so easily used where space is an issue; easy to use * Disadvs - problems with lag when drawing; not very accurate when drawing

Laser Printer

* Produce fast high quality volume printing * Used where noise levels need to be kept low (office) * Rely on large buffer memories - data for the whole document is stored before the pages are printed * Advs - fast high quality printing; can handle very large print jobs; consistently high quality; toner cartridges last a long time so can be cost effective * Disadvs - expensive; only fast if more than one copy is being made; colour laser printers are expensive to run; produve ozone & volatile organic compounds linked to health hazards in the office

Inkjet Printer

* Produce good quality hard copies (better than dot matrix but not as good as laser) * No large buffer memory so pages are printed a bit at a time - printing pauses * Used where low output volumes are required - good at producing photo quality printouts * Advs - high quality output; cheaper than laser printers; lightweight; take up little space; do not produce ozone & volatile organic compounds * Disadvs - output is slow; ink cartridges can run out quickly; printing can smudge if the user is not careful; expensive to run if used a lot

3D Inkjet Printer

* Produce solid 3D models using modified inkjet technology (tomography) * Thin layers of fine powder (plaster, resin & starch) are bonded together as a 3D model is slowly built up - known as prototypes * Scale models are produced in colour before the real thing is manufactured * Advs - saves money as making prototypes is cheaper & less time consuming than other methods; physical scale models are produced with working parts which give a better idea of how the end product will look; the powders can be ground up & reused * Disadvs - 3D inkjet printers are expensive; slow at producing the output; end product can sometimes be rough & required further work on it

Bar Code Reader

* Read info from a barcode - e.g. POS terminals in supermarkets or libraries * Handheld scanners or wands are portable (scanning sell-by dates on food products in supermarket) * Advs - a tried & tested technology); fast data entry; automatic stock control; when barcodes are used as a way or recording data, they can improve safety * Disadvs - expensive system as computer & central database is required, along with staff training & every product/book requires a barcode; system is tamper-proof as barcodes can be swapped on items

Touch Screen

* Select by touching the screen (no need for pointing device) * Used in self-service tills, ATMs, public information systems, phones, SatNavs, Interactive Whiteboards * Advs - allow fast entry of data; easy to use; tamper proof * Disadvs - limited options; dirty screens; RSI if used too much

Chip Readers & Pin Pads

* Similar to smart card readers, but used at EFTPOS terminals - e.g. restaurants, supermarkets * Slot card into machine & enter PIN * Advs - provide a secure payment system since the PIN must match that stored on the chip to work * Disadvs - customer need to be careful no-one sees them entering their PIN (fraud)

Buzzer

* Switched on/off by the actuator * Used in cookers & microwaves to tell the user the cooking process is complete * Used in burglar alarm systems to warn if intruders are present

Motors

* Turned on/off by the actuator * Motors are used in many domestic appliances, such as automatic washing machines (to make the drum rotate), cookers (to switch on fans), water pumps in central heating systems & automatic greenhouses to open windows & switch on fans * They are used to control robot arms in industry * They operate fans, disk drives & DVD drives in computers

Multimedia Projector

* Used for teaching, training, advertising & home entertainment systems * Advs - enable a larger audience to see a presentation; display video to audience * Disadvs - image quality can be fuzzy; expensive; set-up can be difficult

Numeric Keypad

* Used in ATMs - customer types in their PIN (personal identification number) * Used in EPOS terminals (Electronic Point of Sale i.e. till)

Magnetic Stripe Reader

* Used to read information (account no., sort code, start/expiry date) on the magnetic strips of bank/credit/other cards * Also used on security cards (entry to buildings & hotel rooms) & travel systems (train/bus tickets) * Advs - fast data entry; error free as no typing involved; info on magnetic stripe is secure; can prevent access to restricted areas; unaffected by oil, water, moisture * Disadvs - data can be lost if stripe is damaged (e.g. strong magnetic field); information is not readable by a human which can be a problem for hotel room keys

Graphical Tablet

* Used with a stylus to produce freehand drawings & then converted & stored as a digital image * Used in computer graphics & computer aided design (CAD) * Advs - accurate method of drawing better than using a mouse; easy to modify drawings * Disadvs - expensive

Concept Keyboard

* Uses icons/phrases instead of letters * Used in restaurants, shops, etc. * Enable fast data entry; waterproof (spillages); tamper-proof

Dot matrix Printer

* a printhead (made up of a matrix of pins) presses against an inked ribbon * Used in noisy environments (e.g. garage workshops) & in applications where print quality is not very important * Multi-part stationary e.g. bill with 3 parts - one for the customer, two for the garage, etc. * Advs - can be used in environments where dust, dirt or moisture is present; carbon copies or multi-part outputs can be produced; cheap to run & maintain; easy to use if continuous stationery is required e.g. long print jobs such as wage slips * Disadvs - very noisy & not good for an office environment; more expensive than an inkjet printer; very slow & poor quality printing

Magnetic Ink Character Recognition (MICR)

* can read characters printed in special ink (characters at the bottom of a bank cheque) * Characters can be converted into a form that the computer can understand & then stored in a file * Banks use MICR to process cheques * Advs - greater security than OCR as the printed characters cannot be altered; errors are reduced as there is no manual input; magnetic ink characters can still be read even if they are written over * Disadvs - equipment is very expensive; only certain characters can be read

Keyboard

* most common input device * Ergonomic keyboards - designed to reduce health-related problems, e.g. RSI

Optical Mark Reader (OMR)

* reads marks written/shaded in pencil/pen on a form, e.g. questionnaires, multiple choice exam paper or lottery tickets * Advs - fast way of inputting results from a survey; more accurate than typing data; more accurate then OCR * Disadvs - forms need to be carefully designed to gather accurate information; problems if forms haven't been filled in properly & sometimes need to be manually checked - time-consuming & expensive

Optical Character Reader (OCR)

* takes scanned text & converts it into a computer readable form * Used in processing passport & ID cards & also when scanning documents so that they can be modified in another SW application like word * Advs - fast data entry; less errors as no manual data entry is required * Disadvs - system has difficulty reading handwriting; accuracy can be a problem

Output Devices

An output device sends the information from the computer

CRT Monitor

Applications where space is not a problem. Applications where more than one user may need to view screen simultaneously such as in design use, e.g. when several designers may need to offer suggestions on a prototype

Temperature Sensors

Automatic washing machines, automatic cookers, central heating controllers, computer-controlled greenhouses, scientific experiments and environmental monitoring

Pressure Sensor

Burglar alarms, automatic washing machines, robotics, production line control, scientific experiments and environmental monitoring

Light Sensors

Computer controlled greenhouses, burglar alarm systems, robotics, production line control, scientific experiments and environmental monitoring

Control Devices

Control devices are another type of output device - use control processes in conjunction with sensor input devices

Input Devices

Input device is used for putting data and information into the computer

Mouse

Mouse controls the position of the pointer on the screen in any computer system

Remote Control

Remote Control is a handheld device which is use to control TVs, PCs, home entertainment system, projectors, etc

Scanner

Scanner is an input device that allow hard copies of images (such as drawings or photographs) or text to be transferred to a computer

Touch Pad

Touch pad is an alternative mouse that was built inside laptops

Tracker ball

Tracker ball is an alternative for a mouse, useful for people with limited motor skills e.g. young children or people with disabilities

Joysticks

Used by a pilot to fly an aeroplane or flight simulator. Used in car driving simulators and for playing games