Input Devices (Grade 12 NSC Matric Computer Application Technology): Revision Notes
Input Devices
Input devices are essential hardware components that allow you to interact with your computer or mobile device. Understanding different types of input devices, their advantages and limitations, will help you choose the right tools for your computing needs and use them safely and efficiently.
What are input devices?
An input device is a piece of hardware that enables you to enter data into a computer or interact with a computer system. These devices allow you to communicate directly with your computer, such as through typing on a keyboard or clicking with a mouse.
Input devices also include equipment where data is saved or transmitted to your computer, like scanners and digital cameras.
The main input devices you'll encounter include keyboards, mice, touch screens, touchpads, digital cameras, webcams, microphones, and scanners. Each serves a specific purpose and comes with its own set of benefits and drawbacks.
Keyboard
The keyboard is the most common and important input device for desktop computers. It consists of various keys that you press to give commands or type letters, numbers, and symbols. Most modern computers use a standard QWERTY keyboard layout.
Advantages and limitations of keyboards
Keyboard Advantages and Limitations
Advantages:
- Enables users to enter information easily with minimal training needed
- Serves as a fast method for entering data
- Keys can be programmed to serve specific functions
- Hotkeys can be used to increase speed and efficiency of various tasks
Limitations:
- Disabled users might find it difficult to enter information using a keyboard
- Easy to make mistakes while typing data
- Programming keys for specific functions requires specialised keyboard and knowledge
- Users need to learn what hotkeys are and how to use them
Ergonomic considerations for keyboards
Preventing Repetitive Strain Injuries
Working with computers for extended periods requires careful attention to how you position your keyboard and hands. Poor ergonomics can lead to serious health problems including carpal tunnel syndrome and tendonitis.
Here are essential ergonomic guidelines for keyboard use:
- Keep your wrists in a neutral (straight) position. Avoid bending your wrists up or down while typing, as this compresses structures in your wrists and causes pain and injuries.
- Adjust your chair height so your elbows are at a 90-degree angle or more. Elbows bent at less than 90 degrees can cause arm and wrist pain.
- Keep your shoulders relaxed and elbows at your side. Your arms should be roughly parallel to the floor.
- Maintain a light touch when typing. The tendons in your fingers connect near your elbow, so hitting keys too hard may cause inflammation.
- Align your body to the keyboard based on which section you use most. If you use letters most, centre the keyboard so the letter B aligns with your belly button. If you use the numeric keypad most, move the keyboard slightly to the left.
- Use keyboard shortcuts or macros for common, repetitive tasks to prevent overusing your hands and wrists.
- Consider buying an ergonomic keyboard if you already suffer from hand, wrist, arm or shoulder pain.
Mouse
The second most common input device is the mouse. A mouse is a pointing device that allows you to move the cursor on your computer screen, as well as point, click and select various programmes and items. The term "mouse" (plural "mice") comes from its resemblance to the small rodent.
Advantages and limitations of computer mice
Mouse Advantages and Limitations
Advantages:
- Easy to use and ideal for desktop and laptop computers
- A standard optical mouse is not very expensive
- They are small and do not take much space
- Enables users to move the cursor and select options faster than using the keyboard
Limitations:
- The mouse requires a flat space close to the computer to operate
- Uneven surfaces might affect the performance of the mouse
- Disabled users might find it difficult to use both a keyboard and mouse
Ergonomic considerations for mice
Preventing Mouse-Related Injuries
Using a computer mouse incorrectly can cause health problems including sore wrists, aching elbows, and shoulder pain. Follow these ergonomic guidelines:
- Choose a mouse that fits comfortably in your hand and is easy to use. Use a symmetrical-shaped mouse rather than a curved one.
- Don't grip the mouse hard. Hold it loosely.
- Hold your mouse correctly by resting your hand over it and placing your index finger on the left button. Rest your thumb and pinkie on the sides.
- Keep your mouse at the correct height and distance from your body, close to the keyboard.
- Make sure your elbow is bent and close to your body.
- Use your whole forearm, not just your hand, to move the mouse. Moving only your hand puts strain on your wrist.
- Keep your wrist straight to prevent bending in an unnatural position.
- Don't use a wrist rest, as this doubles the pressure inside the carpal tunnel.
- Don't click too hard; use a soft touch to operate the mouse.
- Adjust the mouse movement speed, double-click timing, and cursor size if you have problems controlling the mouse.
Touch screen
Unlike keyboards and mice, touch screens serve a dual role as both input and output devices. Touch screens allow you to use your fingers or a stylus to directly press buttons and select options that appear on the screen.
The most common example of touch screens can be seen on modern smartphones, from Apple to LG. Each smartphone uses a touch screen to enable easy navigation and use of the phone's various functions.
Advantages and limitations of touch screens
Touch Screen Advantages and Limitations
Advantages:
- Options can be selected faster than would be possible with a keyboard and mouse
- The method of inputting data is very user friendly
- A touch screen allows for more space as a keyboard and mouse is not required
- The screen interface can be changed by updating the software
Limitations:
- There are a limited number of options available when using a touch screen
- It is not suited for entering large amounts of data
- The screen can get damaged and dirty due to constant touching
- Touch screens for computers are more expensive than standard computer screens
Touchpad
The touchpad is a small square or rectangular input device on laptops. It has the same function as a mouse - you use it by moving your finger across the pad to move the cursor on the screen. Like a standard computer mouse, the touchpad also has two buttons for selecting objects and bringing up menus. It also allows you to scroll up and down pages.
Advantages and limitations of touchpads
Whilst touchpads are not the most efficient way to move the mouse cursor, they make it possible to use laptops without needing additional devices.
Touchpad Advantages and Limitations
Advantages:
- Saves space in your laptop bag as you do not need to carry an additional mouse
- Usable when there is no flat surface for a mouse
- Faster to select an option than using a keyboard
Limitations:
- People with hand or wrist injuries might find it difficult to use the touchpad
- Harder to control the pointer than with a mouse
- More difficult to do actions, such as drag and drop
Digital cameras
A digital camera is used to capture photographs and store them on a digital memory card instead of film. Once the image is stored, you can transfer it to your computer, manipulate (edit) the image, and print it or upload it to the internet. Some digital cameras can record video images with sound. An example of this is the camera in your smartphone.
Advantages and limitations of digital cameras
Digital cameras have several advantages over older film-based cameras. The biggest advantage is that you can preview the photo you take and delete the ones you don't want to keep.
Digital Camera Advantages and Limitations
Advantages:
- Easy to use and fast to upload your photos to the computer
- There is no film that needs to be developed
- Easy to delete pictures that you do not like
- Several hundred images can be stored digitally
Limitations:
- Requires the user to be computer literate to make full use of the camera
- With some cheaper digital cameras, the resolution might be slightly worse than pictures taken with a traditional camera
- Images might need to be compressed to reduce the amount of memory used, which reduces the picture quality
- Due to being easy to use, the user might take several photos of one object leading to the memory being filled up quickly
Resolution and image quality
Resolution refers to the amount of detail that a camera can capture. Resolution is measured in megapixels. Generally, the higher the resolution, the clearer the photograph or video will be. A lower pixel count means you can see the sharp edges of each pixel, which makes the image blurry or pixelated.
One of the biggest advantages of digital cameras is that they provide users with a choice of camera resolution and image quality. Although most users will want to take pictures using the high-resolution setting, you should know that there are some advantages to taking lower-resolution pictures.
Images with lower resolution have smaller file sizes and take up less space on storage devices. This saves time when you transfer images and saves money, as you can use devices with smaller storage capacity. On the other hand, high-resolution photos have better image quality, allowing you to crop the image as much as needed with little or no loss of quality.
Webcams
A webcam is a type of digital camera that is connected directly to your computer. It makes it possible for you to stream live videos to, or through, the computer. The camera consists of a lens, image sensor and support electronics. Some webcams include a microphone, allowing you to record sound; others need a separate microphone. Laptops and notebooks have a built-in webcam and in most cases, a built-in microphone as well.
Once a video image is recorded on your computer, you can either save it on the same computer, or upload it to the internet (for example, to YouTube).
Advantages and limitations of webcams
Webcams serve a variety of important functions in today's society. They make it possible for users to make and upload videos to YouTube and other social networks. They also make it possible to have face-to-face conversations with somebody who is far away. This feature is very helpful for business people, as they can have meetings with people in different parts of the world. This is known as video conferencing.
Webcam Advantages and Limitations
Advantages:
- The camera can be left on constantly and activated when the user requires it
- Allows people to have face-to-face conversations without the need to travel
- Can take pictures without the need for film
- Low cost and high convenience
- Compatible with various platforms, such as Windows, Mac, Linux and even some gaming systems, such as Sony PlayStation
Limitations:
- Most webcams produce poor-quality videos
- The webcam needs to be connected to the computer
- Feed when video chatting can be choppy or pixelated
- Webcam-based calls run a greater risk of technological failure due to dropped connections or incompatibility
- Hackers can activate your webcam and watch you without you even knowing it; security information can also be stolen
Microphones
A microphone is an input device that makes it possible for you to record sound, which is then stored on your computer. A variety of sounds can be recorded, including music, ambient sounds and your own voice.
You can use a microphone with a digital camera or webcam to make videos, to have face-to-face meetings, or to have discussions over chat programmes such as Skype.
Advantages and limitations of microphones
Whilst most notebooks and webcams have small built-in microphones, you should buy a specialised microphone if you plan to use your computer to communicate using your voice.
Microphone Advantages and Limitations
Advantages:
- Makes it possible to communicate with other users over the internet in a fast and efficient manner
- Sound can be manipulated using special software
- Makes it possible to use voice-activation software
Limitations:
- Requires an internet connection to communicate with other users
- Sound files can take up a lot of storage space on your computer
- Voice-activation software might not always be as accurate as typing on a keyboard
Voice recognition
Voice recognition (or voice activation) software enables the computer to take verbal commands given by the user, and translate and interpret them. It does this by converting the audio received from the microphone to digital signals that the computer can interpret. The signals are then compared to a database containing words, phrases and actions that should be performed.
Over the last few years, voice recognition has become more common and part of our everyday lives. This can be seen by looking at the artificial assistants that can be found in your smartphone. Apple's Siri and Android's Bixby both work with voice recognition.
Advantages and limitations of voice recognition software
Voice Recognition Advantages and Limitations
Advantages:
- Can learn to recognise your own unique speech pattern
- Works well for people with physical disabilities
- Should catch most spelling and grammar mistakes
- Can capture speech much faster than the average person can type
- Can be used for specialised voice commands
Limitations:
- Speech must be clear and distinct
- Some versions might require training and setup
- Background noise can influence performance
- Alterations to your voice, such as a cold, might cause problems when using the software
- Programmes do not understand the context of language the way humans do, which may lead to misinterpretation
Scanners
A scanner is an input device that works much like a photocopy machine. However, unlike a photocopy machine, a scanner does not produce a printed copy of the scanned document - it produces a digital copy that you can save on your computer. When the document is in digital format, it can be edited and manipulated before you print it.
Examples of scanners include the traditional flatbed scanner, as well as the more modern mouse scanner. The mouse scanner looks almost identical to a traditional computer mouse, but has the advantage that it allows you to have a computer mouse at hand when needed. When the scanner is not needed, the mouse scanner can be used as a traditional computer mouse.
Advantages and limitations of scanners
Scanners are an important part of any office and can also be very useful for private use.
Scanner Advantages and Limitations
Advantages:
- Images and documents can be stored and printed later
- Makes it possible for the user to edit stored documents
- Document quality might be improved by using special editing software
Limitations:
- The quality of the scanned document is limited by the resolution of the scanner, as well as the quality of the original document
- Unable to scan 3D objects
- Prone to wear and tear and, therefore, prone to technical difficulties
Wireless versus wired devices
Over the last 50 years, we have seen many advances in technology. Computers have gone from machines that take up whole rooms, to something the average person can afford and keep on their desk, or even in their pocket. Another advancement was made in the field of wireless technology.
Wireless devices, such as keyboards and mice, are similar to the standard wired versions. However, there are some factors to consider before you decide which type will work best for you.
Wired input devices
Wired Device Advantages and Limitations
Advantages:
- Usually cheaper than wireless devices
- Requires no batteries to operate
- Little to no delay in communication between the input device and the computer
Limitations:
- Wires take up space and might get tangled
- Wires are not aesthetically pleasing to look at
- The device is less portable
Wireless input devices
Wireless keyboards and mice use a receiver that is plugged into the USB slot on a computer. The input device then communicates with the computer, using a wireless transfer of data.
Wireless Device Advantages and Limitations
Advantages:
- Saves space as there are no wires
- Aesthetically better than wired input devices
- Allows flexibility of use as you can use the device at a distance
Limitations:
- Battery life might be an issue causing the device to stop working
- Potential interference of other Wi-Fi signals might cause a decrease in performance
- There might be some security issues as it is easier to keylog a wireless device
From these comparisons, you can see that both wireless and wired devices are similar, with only a few minor differences. The decision of which to buy ultimately comes down to your own choice and circumstances. If you have limited space or need to be able to work from across the room, wireless will be better. If you are on a budget or want to play games, wired will be better.
Risks associated with input devices
The main function of any input device is allowing you to interact with the computer. Due to this and the fact that most users spend a large amount of time using many of these devices, it is important to note that there are certain risks that you should be aware of.
Security risks
Critical Security Threats
Keystroke logging: This is a method used by hackers to record your keystrokes on the computer. The keystrokes can be used to identify personal information, such as bank details and passwords. Keystroke logging, also known as keylogging, is normally done with malicious software (malware) that is installed on your computer.
Privacy issues: If a webcam and microphone are connected to your computer, a hacker might be able to gain access to them. This will then allow the hacker to gain access to your private images and conversations. This is usually done by malware that is installed on your computer.
Health risks
Physical Health Concerns
Physical injury: The extensive use of a keyboard, mouse, trackpad or touchpad might lead to physical injuries, such as carpal tunnel syndrome, or repetitive strain injury.
Pathogen transmission: If the input devices attached to a computer are used by a large number of people, it might play a role in the transmission of germs and other pathogens.
Integration of input devices
The integration of input devices is a good way to enhance productivity and efficiency. This means that having multiple input methods in a single device can help you become more productive and efficient with what you do.
The mouse scanner is a good example of technology integration, as it combines the traditional computer mouse with scanner technology. The result is a specialised computer mouse that has the ability to scan any size document up to A4, as well as being used as a point-and-click device.
Smartphones use integrated input modes to make users' lives as easy as possible. These methods of input include the following:
Touch screen: The touch screen can be used to play games, type messages and interact with programmes.
Microphone: The microphone can be used to talk to people, record messages and for voice recognition.
Camera: The camera can be used to take pictures and videos, and to scan things like QR codes, as well as facial recognition.
On their own, each of these input devices serves an important function. When you combine them into a single device, you get one of the most popular devices the world has ever seen.
Key Points to Remember:
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Input devices enable interaction: All input devices serve the primary function of allowing you to enter data and interact with your computer system.
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Ergonomics prevent injury: Proper positioning of keyboards and mice is crucial - keep wrists straight, elbows at 90+ degrees, and use light touches to prevent repetitive strain injuries.
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Each device has trade-offs: Every input device has specific advantages and limitations - keyboards are fast for text but difficult for disabled users, mice are precise but need flat surfaces, touch screens are intuitive but limited for large data entry.
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Security awareness is essential: Input devices pose risks including keystroke logging, privacy breaches through webcams/microphones, and pathogen transmission on shared devices.
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Integration improves efficiency: Combining multiple input methods (like smartphone touch screens, cameras, and microphones) creates more powerful and convenient computing experiences.