Keyboard QWERTY Ergonomic Concept keyboard Numeric keypad Mouse Trackerball Joystick Touchpad Touch screen Graphics tablet Light pen Microphone Scanner Flat bed Drum Film Hand Magnetic Stripe reader Smart card/pin reader Bar code reader OMR reader OCR reader MICR device Digital camera Webcam Sensors
Keyboard Used to input data into application software. Used for typing in commands to the computer (e.g. Ctrl + P for printing) The keys are arranged into sections: alphabet keys Function or F keys (e.g. F1, F2, F3) Numeric keys Arrow keys Command keys (e.g. insert, delete, home, end) Commonly QWERTY layout, recently Ergonomic keyboards are developed to reduce health-related problems such as repetitive strain injury (RSI).
Keyboard Enable fast entry of new text into a document. Well-tried technology and a well-known method of entry. Easy to use for most of people. Easy to do verification checks as data entered appears on the screen simultaneously. Advantages: Disadvantages: Some people find it difficult to use. It is slow when compared to direct data entry e.g. OMR Needs a valuable desk space to keep.
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 grid so that user can tell what pressing on different areas will do. These are used when fast input is needed and are ideally suited to selecting from a limited range of choices such as fast food restaurants, such as McDonalds. 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 Keyboard
Enable fast data entry. It is waterproof. It is tamper proof, and so are useful in certain applications (e.g. at unmanned airport information kiosks), preventing people from keying in information which could result computer corruption. Advantages: Concept Keyboard
Numeric Keypad Used in ATM to enter pin, amount etc. Also used in telephones. Electronic point of sale (EPOS) terminals have it to use in case barcode reader fails to read. Faster than standard keyboard. Some are small devices like mobile, so easy to carry. Difficult to use due to small keys. Difficult to enter text. Sometimes order of numbers on it is not intuitive. Advantages: Disadvantages:
Mouse To open, close and minimise software. To group, move and delete files. Useful while editing images e.g. controlling size and position of a drawing on a document. Uses: Typical mouse with a ball underneath Optical mouse Cordless mouse Types:
Mouse Advantages: Disadvantages: Fast to select an option rather than a keyboard. Enable rapid navigation through applications and the internet. Small so take little area. People with restricted hand/wrist movement can find it hard to operate a mouse. Can be easily damaged and older type quickly clogs up dirt. Difficult to use if there is no flat surface e.g. on aeroplane. Overuse can lead to RSI
Trackerball Advantages: Disadvantages: It doesn’t need the same fine control as a mouse, so suitable for RSI disability. People with limited hand/wrist movement find it easier to use than a mouse. Pointer can be positioned more accurately on the screen than with a mouse. Takes less desk space than mice since they are stationary. Not supplied with computer as standard, so more expensive. User may need training.
Joystick Uses: Disadvantages: Video/computer games. Used in simulators e.g. flight simulator, to mimic actual controls. More difficult to control on-screen pointer with it than a mouse. Advantages: Easier to navigate round a screen using a joystick rather than a keyboard. Control is in three dimensions.
Touchpad Advantages: Disadvantages: Fast to select an option rather than a keyboard. Enable rapid navigation through applications and the internet. Since it is integrated into laptop, so no need for a separate mouse. Can be used even if no flat surface. People with limited hand/wrist movement can find it hard to operate. More difficult to control pointer as compared to mouse. Difficult to do certain operations like ‘drag and drop’.
Touch screen Uses: For self-service tills, e.g. petrol stations. For selecting options made on screen, e.g. ATM, airport, railway station, tourist office. PDA, mobile phones and satellite navigation systems. Interactive white boards used for education are large touch screens. Used for computer based training (CBT) where selections are made in answering on screen testing.
Touch screen Advantages: Disadvantages: Faster and easy to use - intuitive, don't need much training. No extra peripherals such as a mouse are needed. Software can alter the screen while it is being used, making it more flexible than a concept keyboard which has a permanent overlay. Tamper proof. Limited number of options available. Can lead to health problems like RSI. Screen can get very dirty with constant touching.
A pointing device used by designers and artists to allow natural hand movements to be input to graphics applications. A stylus is held like a pen and moved over the surface of the tablet. Data about the stylus movements are sent to the computer. Graphics tablet Used to create ‘hand-drawn’ sketches, drawings and computer graphics. In countries where characters are complex (e.g. China, Japan), they are used as a form of input. Used in Computer Aided Design (CAD) work. Uses:
Graphics tablet Advantages: Disadvantages: Possible to modify drawings before they are input. An accurate method of drawing, better than mouse or trackerball. More expensive than other pointing devices, such as mouse.
A light pen is a device used as a pointing device or to ‘write’ on the screen of a computer. Contains sensors that send signals to computer whenever light changes are detected. Only works with Cathode Ray Tube (CRT) monitors. With Thin film Transistor (TFT) monitors, at developmental stage. Light pens are rarely used today since graphics tablets and high-quality touch screens provide similar functionality. Light pen For selecting objects on CRT screen. For drawing on screen (e.g. with CAD packages). Uses:
Advantages: Disadvantages: More accurate than touch screen Is small, so can be used where space is an issue. Easy to use. At the moment, it works with only CRT monitors. Not very accurate while drawing. Light pen
A device that ‘scans’ images, book pages, etc. The scanned image data is passed to the computer. The most common type of scanner is the flat-bed scanner which has a glass plate on which the item to be scanned is placed. The item is illuminated and an image of it is captured by a moving scan ‘head’. Scanned images can be further processed once inside the computer, e.g. OCR of printed text. OCR Types: Flat-bed Drum Hand Film Scanner Film scanner Flat-bed scanner
Advantages: Disadvantages: Images can be stored for editing later. Faster and accurate. Possible to recover damaged documents and photographs by scanning and using appropriate software. Quality can be limited, depending on scanner resolution. Scanner Picture - A drum scanner as it scans an image with a keyboard in the foreground
Many plastic cards, such as credit cards, have a strip of material that can be magnetised on the back. Data can be stored here in the form of magnetised dots. Usually the data stored on this strip is the same data shown on the front of the card (e.g. the credit card number, expiry date and customer name). The stripe allows this data to be input to a computer system faster and more accurately than by typing it in. A magnetic strip/stripe reader is used to read the data from the stripe. This is usually done by ‘swiping’ the card through a slot on the reader. Magnetic Stripe reader
Advantages: Disadvantages: Data entry is faster than keying in using keyboard. Error free system, since no typing. Information is secured. Unaffected by oil, water, moisture etc. If it gets damaged( due to exposure to strong magnetic field or excessive use), data is lost. Card needs to be in close contact with reader, so reader doesn’t work at a distance. Magnetic Stripe reader
Modern credit cards and ID cards don’t use a magnetic strip. Instead have a tiny ‘chip’ of computer memory embedded inside them ( referred to as smart cards). Data can be stored in this memory and read back using a ‘chip’ reader. A card is inserted into the reader where metal contacts connect to the metal pads on the front face of the card. The reader can then access the memory chip and data stored on it. Smart cards can store much more data than magnetic strip cards, e.g. digital image of the person. Many types of card use this system: id cards, phone cards, credit cards, door security cards, etc. Satellite TV decoders use smart cards to store which channels a user has paid for. The data is encrypted so that it is not easy to alter (you can’t add new channels without paying!)encrypted Smart card/chip reader
Advantages: Disadvantages: Some smart cards (e.g. transport tickets) are used instead of money, reducing need to carry cash. Chip on card does not need to be in contact with reader, so there is less damage compared to magnetic stripe reader. Data is more secure than on magnetic stripe. If card is lost, information stored on chip could be used in identity theft. Smart card/chip reader
Advantages: Disadvantages: Scanning barcodes is much faster than keying in data manually and fewer mistakes are made. It is a trusted technology. When an item price is changed, only central database needs to be updated. No need to change prices individually on each item. It is relatively expensive system to administer since every item in shop needs a barcode and an entry in database. This system is not foolproof, barcodes can be swapped around on items. Bar code reader A barcode is simply a numeric code represented as a series of lines.
Optical Mark Recognition (OMR) is a technology that allows the data from a multiple-choice type form to be read quickly and accurately into a computer. Special OMR forms are used which have spaces that can be coloured in (usually using a pencil). These marks can then be detected by an OMR scanner. Common uses of OMR are multiple- choice exam answer sheets and lottery number forms. OMR (Optical Mark Recognition) device
Advantages: Disadvantages: Very fast way of inputting the results of a survey. Since there is no typing, it is more accurate than keying in data. OMR is more accurate than OCR. Forms need to be carefully designed to make sure that marks are correctly positioned to gather accurate information. Can be problems if forms haven’t been filled in correctly and sometimes to be checked manually before being read by OMR device. OMR (Optical Mark Recognition) device
Optical Character Recognition (OCR) is a software technology that can convert images of text into an actual text file that can then be edited, e.g. using word-processing software). The result is just as if the text had been typed in by hand. Recently used in processing of passports and identity cards. Advanced OCR software can recognise normal handwriting as well as printed text - this is usually called handwriting recognition. OCR (Optical Character Recognition) device
Advantages: Disadvantages: Faster data entry system manually keying in data. Since no manual data entry, the number of errors is also reduced. System still has difficulty reading handwriting. It is still not a very accurate technique.
MICR device (Magnetic Ink Character Recognition) Optical Character Recognition (OCR) is a software technology that can convert images of text into an actual text file that can then be edited, e.g. using word-processing software). The result is just as if the text had been typed in by hand. Recently used in processing of passports and identity cards. Advanced OCR software can recognise normal handwriting as well as printed text - this is usually called handwriting recognition.
Advantages: Disadvantages: Greater security than OCR since printed characters can’t be altered. No manual input, thus reduces errors. Even if somebody writes over magnetic ink characters, they can still be read. Only certain characters can be read. More expensive method than other methods used in direct data entry. MICR device (Magnetic Ink Character Recognition)
Advantages: Disadvantages: Easier to produce better quality photographs than traditional camera. Faster to upload photographs to a computer than traditional method. No need to develop film and take print; saves money (paper, chemical etc.) Easy to delete an image from memory. Memory card can store several hundred photographs Camera user needs to be computer literate (transferring, storing and manipulating images). Loss of artistry because of clever software availability. Resolution is not yet as good as traditional camera. Digital Camera
Advantages: Disadvantages: Can be left on constantly, only being activated as required. Allow people to keep in contact without the need to travel. Have very limited features and picture is often of poor quality. Need to be connected to computer, though it is less of an issue with laptop when webcam is built into monitor lid. Webcam
An input device that converts sound into a signal that can be fed into a computer. The signal from a microphone is usually analogue so, before it can be processed by a computer, it must be converted into digital data. An Analogue-to-Digital Convertor (ADC) is used for this (usually built into the computer’s sound card)Analogue-to-Digital Convertor (ADC) Many headphones now come with microphones to allow them to be used with chat and phone applications Microphone
Advantages: Disadvantages: Faster to read in text than to type it in using a keyboard. Used in voice activation system, e.g. in car to switch radio station. Sound files can use up a lot of computer memory. Voice recognition software isn’t as accurate as typing in manually. Microphone
Sensors Type of SensorApplications TemperatureAutomatic washing machines, central heating systems, automatic greenhouses, ovens PressureBurglar alarm systems, washing machines, robotics, environmental monitoring LightAutomatic greenhouses, automatic doors, burglar alarm systems, street lighting control SoundBurglar alarm systems, monitoring liquid and powder flow in pipes Humidity / MoistureAutomatic greenhouses, environmental monitoring, factories where moisture levels are crucial (e.g. manufacture of microchips, paint spraying) pHAutomatic greenhouses, chemical processes, environmental monitoring
Advantages: Disadvantages: Readings taken using sensors are generally more accurate than those taken by human operators. Readings are continuous, so there is no break in the monitoring. Because it is a continuous process, any necessary action (control system) or warning (monitoring system) will be initiated immediately. Automatic, so need for human intervention Faulty sensors can give spurious results. Sensors