Input Devices | O Level Notes Computer science 2210
Input devices can be described as the peripheral devices that we use to send out signals to the computer system. • A computer system cannot do the processing without receiving some input from the user. • Therefore, these devices are used to send raw data for processing to the system. Types of Input Devices: • Input devices are of two types: • Manual Input Device – Devices like keyboard, mouse, and scanner are manual devices that require the user to manually input the data for processing. • Direct Data Entry Devices (DDE) – Examples include smart cards, optical mark recognition, etc. These devices automatically transfer the data from the source file (e.g. barcode) to the computer system. Different Input Devices: • Mouse • Keyboard • Concept Keyboard • 2D & 3D Scanner • Trackball • Graphic Tablets • Touchscreens • Microphone • QR Code Reader • Digital Camera • Interactive Whiteboard • Barcode Reader 1. Mouse: • It can be wireless or wired and allows the user to control the cursor/pointer’s movement on the screen. • The user can control the cursor coordinates or movement by moving it over a flat surface. • The mouse has two to three buttons. • With the mouse, objects can be clicked/moved, folders can be opened by double-clicking or options of a folder/application can be seen by using the right-click button. • Today, the mouse has become optical i.e. it uses a laser to track the movement however, in the past mouse used to have a small ball inside them for the tracking. 2. Trackball: • Besides mouse, a trackball is also an input device i.e. used to control the cursor movement on the screen. • However, the user keeps the trackball at one position and only moves the ball within it for movement control. • The trackball is best for users with limited hand motor skills and some people prefer it as it gives great control over the movement without demanding a lot of space to use it. • Mouse and Trackball are also known as pointing devices. 3. Keyboard: • It can be wireless or wired. • It is an input device that allows the user to enter commands or data by pressing keys. • When a user presses a key, an ASCII code is sent to the computer system. • A keyboard contains over 100 keys that can be divided into four groups/categories: - Function keys – contains twelve function keys from F1 – F12 that perform special functions. - Numeric keys – contains numeric digits 0 – 9, arithmetic signs of plus, multiplication, division, subtraction, and a decimal point. - Cursor keys – contains arrows for left, right, down and up. - Main Keyboard – contains the alphabets, special characters, etc. 4. Concept Keyboard: • A concept keyboard is a keyboard that has keys that are programmed to perform special tasks and have visual images on them instead of letters/characters/numbers. • For example, a restaurant counter representative may have this keyboard with different meal button, etc. • Today, these keyboards are replaced by virtual concept keyboards or touchscreens. 5. Microphone: • The microphone is like a transducer i.e. it converts energy from one form to another. • It is used to take analog sound waves as an input. • It then converts the sound waves into electrical signals that the computer system can understand. • There are different types of microphones available, but they all have a diaphragm. • A diaphragm is a piece of paper, aluminum, etc. that vibrates when a person speaks into the microphone. • These vibrations are then converted into electrical signals. 6. Digital Camera: • It is used to capture images/videos by sampling light from by time, spatially and tonally, and store on a memory card. - Spatially – sampling the angle of view into a rectangular grid of pixels. - Tonally – sampling the varying tones of brightness. - Time sampling – exposure of a given duration. • Unlike the traditional camera, a digital camera uses an image sensor made of silicon that is sensitive to light. • Digital cameras also contain a display screen with options to change settings. • The display screen also allows the user to view the captured image/video. 7. 2D Scanners: • 2D scanners are input devices that help in converting 2D documents as well as images in a digital format. • 2D scanners can be either handheld or flatbed. • Some printers come with a built-in flatbed scanner with them. • To boost the overall functionality of scanners, users can use it with software like OCR or OMR. • e.g. OCR converts documents into a computer-readable format. #InputDevices #Computerscience
Input devices can be described as the peripheral devices that we use to send out signals to the computer system. • A computer system cannot do the processing without receiving some input from the user. • Therefore, these devices are used to send raw data for processing to the system. Types of Input Devices: • Input devices are of two types: • Manual Input Device – Devices like keyboard, mouse, and scanner are manual devices that require the user to manually input the data for processing. • Direct Data Entry Devices (DDE) – Examples include smart cards, optical mark recognition, etc. These devices automatically transfer the data from the source file (e.g. barcode) to the computer system. Different Input Devices: • Mouse • Keyboard • Concept Keyboard • 2D & 3D Scanner • Trackball • Graphic Tablets • Touchscreens • Microphone • QR Code Reader • Digital Camera • Interactive Whiteboard • Barcode Reader 1. Mouse: • It can be wireless or wired and allows the user to control the cursor/pointer’s movement on the screen. • The user can control the cursor coordinates or movement by moving it over a flat surface. • The mouse has two to three buttons. • With the mouse, objects can be clicked/moved, folders can be opened by double-clicking or options of a folder/application can be seen by using the right-click button. • Today, the mouse has become optical i.e. it uses a laser to track the movement however, in the past mouse used to have a small ball inside them for the tracking. 2. Trackball: • Besides mouse, a trackball is also an input device i.e. used to control the cursor movement on the screen. • However, the user keeps the trackball at one position and only moves the ball within it for movement control. • The trackball is best for users with limited hand motor skills and some people prefer it as it gives great control over the movement without demanding a lot of space to use it. • Mouse and Trackball are also known as pointing devices. 3. Keyboard: • It can be wireless or wired. • It is an input device that allows the user to enter commands or data by pressing keys. • When a user presses a key, an ASCII code is sent to the computer system. • A keyboard contains over 100 keys that can be divided into four groups/categories: - Function keys – contains twelve function keys from F1 – F12 that perform special functions. - Numeric keys – contains numeric digits 0 – 9, arithmetic signs of plus, multiplication, division, subtraction, and a decimal point. - Cursor keys – contains arrows for left, right, down and up. - Main Keyboard – contains the alphabets, special characters, etc. 4. Concept Keyboard: • A concept keyboard is a keyboard that has keys that are programmed to perform special tasks and have visual images on them instead of letters/characters/numbers. • For example, a restaurant counter representative may have this keyboard with different meal button, etc. • Today, these keyboards are replaced by virtual concept keyboards or touchscreens. 5. Microphone: • The microphone is like a transducer i.e. it converts energy from one form to another. • It is used to take analog sound waves as an input. • It then converts the sound waves into electrical signals that the computer system can understand. • There are different types of microphones available, but they all have a diaphragm. • A diaphragm is a piece of paper, aluminum, etc. that vibrates when a person speaks into the microphone. • These vibrations are then converted into electrical signals. 6. Digital Camera: • It is used to capture images/videos by sampling light from by time, spatially and tonally, and store on a memory card. - Spatially – sampling the angle of view into a rectangular grid of pixels. - Tonally – sampling the varying tones of brightness. - Time sampling – exposure of a given duration. • Unlike the traditional camera, a digital camera uses an image sensor made of silicon that is sensitive to light. • Digital cameras also contain a display screen with options to change settings. • The display screen also allows the user to view the captured image/video. 7. 2D Scanners: • 2D scanners are input devices that help in converting 2D documents as well as images in a digital format. • 2D scanners can be either handheld or flatbed. • Some printers come with a built-in flatbed scanner with them. • To boost the overall functionality of scanners, users can use it with software like OCR or OMR. • e.g. OCR converts documents into a computer-readable format. #InputDevices #Computerscience