Input & output devices
- 1. Input & Output Devices
- 2. An input device captures data and sends it to a computer system. Input devices convert physical movement, such as key pressing, or environmental data, such as temperature, sound or light into electrical signals. Input Devices There are two types of input device: manual and automatic.
- 3. Manual Input Devices A manual input device requires a human hand to control it… Mouse Scanner Camera
- 4. Keyboard Computer Hardware Servicing Function Keys Alphanumeric key Numeric Key Pad Arrow Keys Back
- 6. Back
- 9. Manual Input Devices Tracker ball Joystick Graphics tablet A manual input device requires a human hand to control it…
- 10. Manual Input Devices Keyboard The most common input device You press keys to input data into the computer The most common type of keyboard is the QWERTY keyboard People are familiar with keyboards, so they don’t need to be trained Skilled typists can work very quickly A lot of different keyboards are available, e.g. ergonomic They are very reliable and cheap Incorrect use or over-use can cause RSI Many people cannot type and look at the screen at the same time, so typing can be time consuming Uses Advantages DisadvantagesDevice
- 11. Manual Input Devices Graphics Tablet A graphics tablet consists of a pad and a special pen The image is instantly converted to digital data User can get much more control, similar to the natural way of drawing The user can zoom in to an area of the drawing for higher accuracy Large models are very expensive Need a large desk area Holding a pen for a long time is more tiring than holding a mouse Uses Advantages DisadvantagesDevice
- 12. Manual Input Devices Mouse Most common pointing device Used to point and click on icons or menus Combines well with a keyboard Fast and accurate Most people are skilled at using a mouse, so no training is needed Prolonged use can lead to RSI Need a flat surface to use them For an optical mouse, the laser does not work well on all surfaces Tracker ball A tracker ball is basically an upside down ball mouse. The user runs their thumb over the ball to control the on-screen pointer User can get great pointing accuracy, without moving the hand Useful where desk space is limited Some people find that the thumb gets painful with prolonged use Ball can get greasy and dirty Uses Advantages DisadvantagesDevice
- 13. Manual Input Devices Uses Advantages DisadvantagesDevice Scanner Used to convert printed images or text into a file of digital data There are two types: handheld and flatbed Even cheap scanners produce quality images Any printed image can be inserted into a document Images can be edited before use The quality of the final image is dependent on the original image Joystick Originally designed for pilots to control aeroplanes Used to control wheelchairs and for playing games They give a more realistic gaming experience when playing games such as flight simulators Many different types available Some people find them difficult to operate,
- 14. Manual Input Devices Digital Camera Used for taking still images which can be uploaded to a computer for permanent storage You can preview the image before pressing the shutter button No film needed or Unwanted images can be deleted When the drive is full, images need to be uploaded to a computer or deleted Touchpad or Fingerpad A pointing device, built into a laptop for convenience Portable - built into the laptop Don’t need to carry extra equipment around Small movements needed to move the cursor Takes practice to master Some people find them very fiddly Fingers need to be clean and free of grease Uses Advantages DisadvantagesDevice
- 15. Automatic Input Devices An automatic input device inputs data without the need for human intervention (once the device has been set up), e.g. MICR, OMR, barcode reader, webcam, microphone, sensor. Microphone Webcam Barcode reader
- 16. Automatic Input Devices MICR Magnetic Ink Character Recognition Banks print important data on the bottom of cheques using magnetic ink This ink is then read by a computer Very quick and accurate processing of data – very low error rate. Humans could not achieve the same accuracy Very secure as any attempt to change the numbers on a cheque will be ignored as the reader only recognises magnetic ink in the same font Banks are the main user – very few other applications Uses Advantages DisadvantagesDevice
- 17. Automatic Input Devices OMR Optical Mark Recognition Used when you mark the numbers with a pencil on a lottery ticket Very fast method of reading data, which reduces queuing time for lottery tickets More accurate than human data entry Sometimes incomplete marks are not read correctly Uses Advantages DisadvantagesDevice OCR Optical Character Recognition Uses a scanner to scan text, then software converts the text into a word processor file Quicker than typing in the text Reduces the cost of posting a letter Sometimes it is not very accurate
- 18. Automatic Input Devices Barcode Readers Used to identify products in shops The code is read by a barcode scanner which identifies the product name, manufacturer and country of origin Very quick and accurate way to enter data – suits busy shops All barcodes need to be programmed into the computer in advance The reader may not be able to read the barcode on wrinkled packaging Uses Advantages DisadvantagesDevice Magnetic Stripe Reader Found on the back of bank cards and store loyalty cards The stripe holds information, such as the account number and the PIN Simple, cheap and effective The data on the card can be altered if needed Magnetic stripe can get scratched Not much data can be stored Thieves can read data on cards then use the cards themselves
- 19. Uses Advantages DisadvantagesDevice Microphone Used to input sound into the computer Very cheap piece of equipment Helpful for people with additional needs or for busy people who need very quick letters Computer can misread voice instructions due to natural variations in people’s voices Generally, the sound quality from a PC microphone is poor Automatic Input Devices Webcam Used to input moving images into the computer for use in online communication Very cheap piece of equipment Enables people to see each other whilst they chat The image quality from most webcams is poor The moving picture tends to flicker due to current limitations in data transfer
- 20. Output Devices
- 21. Output Devices An output device is used to display or use information that comes out of a computer system. Output devices convert electrical signals from a computer system into… Sound (speakers or headphones) Images & Text (screen or printer) Movement (actuator, electric motor)
- 23. Output Devices TFT Monitor Thin Film Transistor monitors are more commonly known as flat screens or LCD screens Take up very little space Run very quietly and produce little heat Use about a third of the energy of a CRT monitor Easy to damage Colour contrast on cheaper models is not as good as CRT monitors Uses Advantages DisadvantagesDevice CRT Monitor Cathode Ray Tube is very old technology. Almost completely replaced by flat screen monitors Robust and difficult to damage Reliable Last for a very long time Large, bulky Can be heavy Produce a lot of heat Old technology
- 24. Output Devices Speakers & Headphones When connected to a computer through a sound card, music can be played Can help blind people use the computer A presentation can be more powerful with sound Games are a lot more involving and realistic with sound Speakers are not useful in a network room, as everyone would disturb each other Headphones can be uncomfortable with extended use Uses Advantages DisadvantagesDevice Plotter These are specialist printers that can produce high quality printouts on large pieces of paper Very high quality printouts Almost any size paper can be used Slower than normal printers Expensive to purchase and run
- 25. Printers There are 3 main types of printer… Dot Matrix Laser Inkjet Uses Advantages DisadvantagesDevice General purpose use for family or home office Cheap to buy Latest models can be very fast Ink cartridges can be very expensive Print quality not always very good Business use for letters, stationery and images Quality printing Good for large areas of colour Quiet & Quick More expensive to buy than inkjets Toner cartridges are expensive Business use for duplicate documents Can make a carbon copy Can print on continuous rolls of paper Noisy and rather old- fashioned technology Poor quality and only prints in black ink
- 26. Drag the input and output devices to the correct side... Input & Output Devices
- 27. Keyword Activity Drag the missing words to the correct place in the sentences…
Editor's Notes
- #8: The Internet is one of the main reasons why a majority of the people use computers these days. Internet keyboards have special keys, called hot keys, which perform functions related to Internet usage. Typical hot keys have functions like back, forward, bookmarks list, e-mail inbox, Google search, YouTube, shopping online, etc.Read more at Buzzle: http://www.buzzle.com/articles/different-types-of-keyboards.html Virtual keyboards are software devices that let you input data just like a hardware keyboard. They open up as an application and can be controlled by a mouse or via a touch screen. They are mainly used in devices which do not necessarily require a keyboard, like a tablet or a smart-phone.Read more at Buzzle: http://www.buzzle.com/articles/different-types-of-keyboards.html Compact keyboards are slim and usually do not have the numeric keypad that is present on the right side of other keyboards. These are typically used in laptops, where sizing issues make it difficult to accommodate a standard keyboard. To make up for the small size, these keyboards rely on the use of multiple keys to carry out functions that would only use a single key on a standard-sized keyboard. Some models also include a touch-pad that can be used instead of the mouse.Read more at Buzzle: http://www.buzzle.com/articles/different-types-of-keyboards.html As the name suggests, gaming keyboards are designed specifically for gamers. They include features meant to enhance gaming experience, as well as provide convenient usage for gamers. They include features like volume control, key lighting, programmable keys, interchangeable keys, touch screens to customize the keyboard, in-built joysticks, fancy lighting, etc.Read more at Buzzle: http://www.buzzle.com/articles/different-types-of-keyboards.html As the name suggests, these keyboards do not need to be connected to the computer via a wire. This makes it very convenient for the user to use the keyboard comfortably. Wireless keyboards use three basic types of connections, Bluetooth, Infrared (IR), and Radio Frequency to connect to the computer.Read more at Buzzle: http://www.buzzle.com/articles/different-types-of-keyboards.html Ergonomics refers to the study of methods that can reduce stress on muscles to avoid repetitive strain injury. It mostly deals with optimizing posture and technique while working, so the work can be carried out in the easiest manner with the least possible strain on any muscle, joint, or organ.Read more at Buzzle: http://www.buzzle.com/articles/different-types-of-keyboards.html
- #16: MICR (magnetic ink character recognition) (Optical Mark Reading)