ICT INPUT DEVICES

Input devices An input device is a piece of hardware that is used to enter data into a computer in a computer understand way. Input Devices Manual automatic Key Board. 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:Each key acts as a switch where a binary code for relavant key is entered. 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) Uses 1).Keyboards are used to input text, for example into a word-processed document 2). Ttype commands into a computer 3). type in unusual selections of characters, such as passwords. Advantages: Th ey allow accurate entry of data, in combination with a monitor to check accuracy.quickly Disadvantages. 1.Th ey are not very quick for inputting data compared with direct data entry devices suchas barcode readers, and magnetic ink character recognition (MICR) and optical mark recognition (OMR)devices. 2.Th ey take up more space than other input devices 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' . Uses 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. It consists of,1.a small plastic case, held under the user’s hands 2. a right button (Right clicking brings you up a list of relevant menu items from which you can select a task.) 3.a left button(Left clicking usually lets you put your cursor at a certain point on the page or lets you choose a menu item) 4.. a central wheel (allows you to scroll up and down the page) Advantages Ideal for use with desktop computers Usually supplied as part of a new computer system Most computer users are familiar with them and require little training Works well in conjunction with a keyboard for data entry Disadvantages They need a flat space close to the computer The rollers in mice that use balls can become clogged with grease and grime and lose their accuracy until cleaned. Overuse can lead to RSI Touch Pad A touchpad is an input device which is usually found on a laptop computer. A touchpad can be used in place of a mouse. By dragging your finger over the surface of the touchpad, sensors underneath detect the movement direction and speed . There are usually two buttons next to the touchpad which are used to replace the left and right mouse button. Advantages Useful for laptops when using a mouse isn't practical Very short finger movements are required to move the cursor Disadvantages Takes practice and skill to control the position of the cursor using the touchpad Gloves cannot be worn i.e. in a cleanroom environment Moist, sweaty or calloused fingers can disrupt the signals picked up by the sensors. 5. Joystick Joysticks were originally used by pilots as part of an aeroplane's controls let computer gamers experience a more realistic game environ Joysticks can also be used for controlling machines such as cranes, trucks and powered wheelchairs You can move joysticks in many directions and the joystick tells the computer which direction it has been moved into. They also have one or more buttons whose position when Disadvantages Some people find joysticks more difficult to control than a traditional mouse. Joysticks are not particularly robust and can break easily if too much force is used on them. pushed 7. Touch Screen 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 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. Advantages Easy to use - intuitive, don't need much training No extra peripherals such as a mouse are needed Disadvantages Not suitable for inputting large amounts of data Tiring to use for long periods More expensive than alternatives such as a mouse 8. Scanner Scanners can be used to convert images or text on paper into a digital format that can be used by the computer. There are two types of scanner: Flatbed scanners (They can scan larger images and are more accurate than handheld scanners.) Handheld scanners (are rolled across the document to be scanned. The images produced are generally not as large or as high quality as those captured with a flatbed scanner.) Disadvantages Images can take up a lot of memory space Images lose some quality in the scanning and digitising process 9. Digital Camera A digital camera records images electronically on a memory card rather than on film as did the older models of camera. The images can be downloaded from the memory card onto a computer and then printed, stored or manipulated with a photo editing application. Many digital cameras are now capable of taking short video clips along with sound. Advantages No film is needed, no developing costs to view the pictures Images can be viewed immediately and unwanted images can be deleted Images can be edited, enlarged or enhanced Images can be incorporated into documents or added to web sites Extra memory sticks can be purchased to store images Disadvantages Digital cameras are generally more expensive than ordinary cameras which use film When the memory is full, the images must be downloaded to a computer or deleted before any more can be taken.   11. Microphone A microphone can be used to input sound. The sound is detected by the microphone 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. Automatic input devices 1.Magnetic Ink Character Recognition Bank use a technique called 'Magnetic Ink Character Recognition' (MICR) which enables them to process 300 cheques per minute with 100% accuracy. At the bottom of each cheque are a series of numbers which record: the cheque number the bank or building society sort code the customer's account number written in a special ink which contains iron particles. This ink is magnetised and commonly called 'magnetic ink'. It can be read by a special machine called a Magnetic Ink Character reader (MICR). 2.Optical Mark Reader (OMR) Multiple choice test answers arescanned 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. 3. Optical Character Recognition (OCR) consists of a normal scanner and some special software 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. OCR is used to automatically recognise postcodes on letters at sorting offices Advantages Cheaper, Much faster than someone manually entering large amounts of text. Disadvantages Not 100% accurate, there are likely to be some mistakes made during the process ………..Not worth doing for small amounts of text 4.Barcode Reader Most items that are for sale in shops have a barcode printed somewhere on the packaging. The barcode is a series of vertical bars of varying widths that give information about: the country of manufacture the name of the manufacturer a product code The barcode does NOT contain the price of the item - this is held on the company database. A barcode reader is an automatic input device which is used to scan or 'read' the barcode by using a visible red light. The reflected light is translated into digital data that is interpreted by the computer to identify the product and price from the database. 5. 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 about the card number 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. Advantages Simple to use Cheap to produce Data can be altered if necessary Security has been improved by the use of PIN numbers which must be entered into a machine to confirm that you are the rightful card owner disadvantages Very limited storage capacity for data Data can be easily destroyed by strong magnetic fields Not always secure as thieves can obtain the readers and read the data on the card.