ICT > Hardware
The most widely used input device is a keyboard. This is a set of keys used to operate a PC. Numeric keyboards only have keys to input numbers and few special characters. A QWERTY keyboard may have a numeric keyboard built into the right hand side.Advantages:
- Keyboards are almost always available as an input device. They are widely used at work.
- Many people know how to use a QWERTY keyboard, so help is usually available.
- To use a keyboard efficiently, you need to know the layout and be able to touch-type.
- A hand-held scanner reads the image while being dragged over it.
- In the case of a flatbed scanner, the image is laid flat on the scanner’s surface, and is captured in a similar manner to that of a photocopier.
- A sheet-fed scanner feeds the image in through rollers. The scanner reads the image as the paper goes through. The image must be printed on flexible sheet of paper.
- Scanners quickly convert printed images on paper to electronic form.
- The accuracy of the data input is unlikely to be verified.
- You could see if the weather is suitable for skiing by viewing the webcam in the mountains above Grindelwald in Switzerland.
- You could install a webcam at home for security and view this when you are out at work.
- You could attach a webcam to your computer and contact a friend who has a webcam so that you could both see each other while you are talking.
- You could set up a webcam in a classroom and listen to a teacher from another school. This might be useful if you were learning to speak English and could not find a teacher locally.
- Photos and videos can be recorded in a digital form that can be saved on computer. This makes backup easier, more reliable and more extensive.
- Digital photos and video can be displayed on a wide variety of devices,
- Digital phots and videos can be sent by email.
- Digital video can be broadcast over the Internet so that TV programmes can be available on demand. Disadvantages of webcams:
- Users tend to have more photos and longer videos and this creates a need for more backing storage.
- High-quality photos and videos can be in very large files. When these are sent by email or broadcast over the Internet, this uses bandwidth and slows down the network.
OMR technology is used to interpret pencil marks on a piece of paper. An OMR reader can recognize the position of a mark or set of marks on paper, because the mark is darker than an unmarked area. The computer then records the mark’s position and can analyse it to determine the meaning of the data. Marks made on this kind of form must be very clear or they may not be properly recognized.Advantages:
- There is no requirement to type in the information written on the paper form. Because of this, input is faster and less expensive.
- The person who fills in the form is responsible for the accuracy of the information on it.
- OMR forms must be printed very accurately because the position of the mark on the paper affects the accuracy of the input. Because of this, printing costs more.
- Verification checks on the input are unlikely to be carried out, so mistakes inputting the data are less likely to be detected.
- Text printed on paper can be converted to electronic form and edited. This is especially useful for creating electronic versions of books printed before computers were available.
- Character recognition is not always accurate and the electronic text has to be checked carefully.
A biometric scanner is a pattern recognition which makes a personal identification based on a person’s unique physical characteristics. Biometric scanners can use face recognition, fingerprint matching, iris and retinal scans, voice recognition and hand geometry. Biometric scanners can be built into mobile phones, desktop and laptop computers, and smart cards. They can be used to control entry to buildings and can even replace keys in cars.Advantages:
- There is no need to remember to carry personal identification.
- The person has to be present. This makes identification theft and fraud much less likely.
- Identification using biometric scanners is not yet sufficiently accurate. Permitted users will not be recognized at times, and blocked users will sometimes be permitted.
- They are often used as a form of identification that is small and light and can be carried all the times.
- The data recorded on the magnetic stripe is in electronic form and can be input directly into a computer.
- The data recorded on the magnetic stripe can be affected by electromagnetic radiation, such as that from televisions and computers.
- The data recorded on the magnetic stripe can be copied or deleted. This is an opportunity for determined criminals to commit identity theft and fraud.
- Often used as form of identification that is small and light and can be carried at all times.
- The data recorded on the chip is in electronic form and can be input directly into a computer.
- The data recorded on the chip is more secure than data recorded on a magnetic stripe.
- The data recorded on the chip can be updated during transactions.
- The data recorded on the chip can be affected by electromagnetic radiation.
- The data recorded on the chip can be copied or edited by very determined criminals used for fraud.
Sensors are used to input data about the environment into a computer. There are many types of sensors. They are available in many different shapes and sizes and they have a wide variety of uses. For example, sensors can be used to record light intensity, temperature and pressure. Sensors usually produce a low-voltage which must be converted to a digital signal for the computer using an analogue-to-digital converter (ADC).Advantages:
- Sensors can be placed in dangerous locations where people would be hurt.
- Sensors can continuously and reliably record data whereas to organize this using people could be much more unreliable and expensive.
- Sensors can record data that people do not sense or do not sense accurately, such as humidity.
- The data recorded by sensors can automatically record in a form that can be processed by a computer.
- Data can be collected by a central computer from sensors in remote locations. People do not need to travel and this saves time and allows data to be collected more frequently.
- Sensors cannot interpret the data.
- Sensors detect a very restricted range of the different types of data.