Introduction to Information Communication Technology, Essays (university) of Information and Communications Technology (ICT)

Download Introduction to Information Communication Technology and more Essays (university) Information and Communications Technology (ICT) in PDF only on Docsity! Introduction An input device is a piece of hardware that is used to enter data into a computer. There are many different kinds of input devices. They are split into two categories - manual input devices and automatic input devices. Keyboard The keyboard is the most common and widely used input device. It is made up of buttons called 'keys'. The keys are arranged into sections:  Alphabet keys  Function or F keys (F1, F2, F3)  Numeric keys (one set above the alphabet keys and a numeric keypad on the right)  Arrow keys  Command keys (insert, delete, home, end, page up/down) Most keyboards are called 'QWERTY' keyboards. This name comes from the first six letters on the top row of the alphabet keys. Using a keyboard for too long can lead to health problems such as repetitive strain injury (RSI). To try to overcome this, different styles of keyboard have been developed, for example, the ergonomic keyboard. They are supposed to put your hands into a much more natural position than a traditional keyboard. Advantages of keyboards Disadvantages of keyboards Most computers come with a keyboard supplied It is easy to make mistakes when typing in data People are used to using keyboards to enter data, they need very little training If you can't touch type, it can be time consuming to enter data A skilled typist can enter data very quickly Keyboards are not suitable for creating diagrams Specialist keyboards are available e.g. ergonomic, gaming keyboards Disabled people often find keyboards difficult to use Excessive use can lead to health problems such as repetitive strain injury (R.S.I.) Mouse Everyone is familiar with a computer mouse; along with the keyboard, it is one of the most common input devices you will use. A mouse is also called a 'pointing device' because it enables you to control what happens on the screen by moving the mouse on your desk and pointing, clicking and selecting items on the screen. A mouse usually has two buttons, a right and left one and also a central wheel which allows you to scroll up and down the page (some mice have up to five buttons). The left and right button have different functions. Left clicking usually lets you put your cursor at a certain point on the page or lets you choose a menu item. Right clicking brings you up a list of relevant menu items from which you can select a task. A touch screen is the only device which works as both an input and an output device. You view the options available to you on the screen (output) and you then use your finger to touch the option that you have chosen (input). Touch screens work particularly well with a menu driven interface. For example, a cashpoint (ATM) at a bank would first of all ask which service you want. You touch the option 'withdraw cash' on the screen. You are then presented with another choice, 'how much cash do you want to withdraw?'. Once you have chosen how much, you then get other options such as 'do you want a receipt?'. Another major use of touch screens are on smart phones and modern tablet computers. Each 'app' is accessed by an icon on the touch screen. Touch screens are easy to use and are often found in public places such as cashpoints at banks, ticket collection terminals at theatres or airports, information centres at museums. Touch screens are not commonly used to input large amounts of data because they are not very accurate and they would be tiring on the hands to use for long periods of time. Advantages of touch screens Disadvantages of touch screens Easy to use - intuitive, don't need much training Not suitable for inputting large amounts of data No extra peripherals such as a mouse are needed Not very accurate - selecting detailed objects can be difficult with fingers Advantages of touch screens Disadvantages of touch screens Software can alter the screen while it is being used, making it more flexible than a concept keyboard which has a permanent overlay. Tiring to use for long periods Touch screen is the main interface on smart phones and tablet computers More expensive than alternatives such as a mouse (unless it is part of the computer \ smartphone in any case) Can make use of finger gestures to make sophisicated actions such as zooming and selecting. Less useful as a control input to a standard computer that makes use of the mouse \ keyboard combination e.g. laptop, desktop pc Excellent for selecting and controlling 'apps' (applications) that have been designed with a touch screen in mind. Concept keyboard A concept keyboard is a flat board that contains a grid of buttons. Each button can be programmed to do whatever you want. An overlay sheet with pictures or symbols is placed on the grid so that the user can tell what pressing on different areas will do. Concept keyboards are used when fast input is needed and are ideally suited to selecting from a limited range of choices such as fast food restaurants. Checkout tills such as McDonalds use symbols to make ordering faster and easier. Primary schools often use them with young children. The overlay image could be a picture of a farmyard. Pressing on an animal would cause the computer to make the right animal noise. Concept keyboards are particularly useful for people who would find using an ordinary keyboard difficult. It is also very handy in locations where an ordinary keyboard might be damaged e.g. by spillage or dust. Concept keyboards are excellent where there is a limited set of things to select and it needs to be done fast e.g. fast food store, pub, skating and other recreation events. Advantages of concept keyboards Disadvantages of concept keyboards Much faster for making non-text selections such as menu choices on the till of a fast-food outlet. Poor for text or numeric input - although some keyboards do include a numeric keypad so the operator can enter the amount sold. The keyboard is waterproof which can be useful where there is dirt or Limited to the options shown on the keyboard. Advantages of concept keyboards Disadvantages of concept keyboards the risk of splashes Scanner Scanners can be used to convert images or text on paper into a digital format that can be used by the computer. A scanner works by shining a beam of light onto the surface of the object that you are scanning. This light is then reflected back onto a sensor that detects the colour of the light. This is then used to build up the digital image. Items that are scanned are usually stored in an image format. However, special software - Optical Character Recognition - can be used to convert text on the paper into text which can be edited with a word processor. However, the text doesn't always get converted very well and you could end up with a lot of mistakes. There are three types of scanner:  Flatbed scanners  Handheld scanners  Specialist scanners These forms are scanned by a special piece of equipment called an 'Optical Mark Reader' (OMR). they detect the presence of your pencil mark by reflecting light onto it. Less light is reflected where a mark has been made. The OMR then interprets the pattern of marks and sends the results to the computer for storage, analysis and reporting. Advantages  A fast method of inputting large amounts of data - up to 10,000 forms can be read per hour depending on the quality of the machine used.  Only one computer needed to collect and process the data  OMR is much more accurate than data being keyed in by a person Disadvantages  If the marks don't fill the space completely, or aren't in a dark enough pencil, they may not be read correctly  Only suitable for recording one out of a selection of answers, not suitable for text input  The OMR reader needs the answers to be on the prepared forms which will all be identical to one another. You can't just pick up a blank sheet of paper and mark your answers on it.  Optical Character Recognition (OCR)  An OCR system consists of a normal scanner and some special software. The scanner is used to scan text on a document or piece of paper into the computer. The OCR software then examines the page and changes the letters into a form that can be edited or processed by a normal word processing package.   The ability to scan the characters accurately depends on how clear the writing is.  Scanners have been improved to be able to read different styles and sizes of text as well as neat handwriting.  Although they are often up to 95% accurate, any text scanned with OCR needs careful checking because some letters can be misread.  OCR is used to automatically recognise postcodes on letters at sorting offices.  Advantages of OCR Disadvantages of OCR Cheaper than paying someone to manually enter large amounts of text Not 100% accurate, there are likely to be some mistakes made during the process Much faster than someone manually entering large amounts of text All documents need to be checked over carefully and then manually corrected The latest software can recreate tables and the original layout If the original document is of poor quality or the handwriting difficult to read, more mistakes will occur Not worth doing for small amounts of text Magnetic Stripe Reader Magnetic strips are usually found of the back of most credit cards, cheque guarantee cards, loyalty cards, membership cards etc. The magnetic strip can hold personal details such as account number and name. The strip can contain up to 60 characters, stored magnetically. To read the data on the card, it is 'swiped' through a Magnetic Stripe Reader machine and the data is read and fed back to the computer. A remote control is a hand-held device which is used to control a machine from a short distance away. Remote controls need line-of-sight in order to send their signals to the receiving device, obstacles such as furniture or walls can block the signal. Some remote controls allow text to be typed, for example, making a note of the name of a TV programme which has been recorded. Examples of use for remote controls:  Televisions  Music systems  Lighting systems  Heating systems Microphone A microphone can be used to input sound. The sound is detected by the microphone and an electrical signal is transmitted to the computer. Special hardware is used to convert this analogue data into digital data so it can be stored and manipulated. In the last few years a number of voice recognition systems have been developed. These packages let the user dictate the text into a computer and then convert the speech to text. Dictating like this can be much quicker than typing but the software isn't perfect and it can interpret a word incorrectly. Webcam A webcam is short for 'web camera'. A webcam is an input device because it captures a video image of the scene in front of it. It is either built in to the computer (e.g. laptop) or it is connected through an USB cable. The video signal is made up of a series of individual 'image frames' which are an instant snapshot of the scene in front of it. Each image frame is sent to the computer for further processing by webcam software. If the 'frame rate' is fast enough (more than 25 frames per second) it appears as motion video. Many webcams are also used to catch an image frame every now and then, perhaps every minute or even every hour. Common uses of webcams include: Chatting Webcams are commonly used to allow people to see each other whilst chatting over the internet. Formally this is called 'teleconferencing'