Input Devices

Input and Output Devices

Some text here about the topic of discussion

What are input and output devices

Once the data inputted into the computer are processed by the computer the data will be shown in an output device. Output devices show the output of the computer in a form that is understandable by human users.

Output Devices

Input Devices

Input devices are hardwares that allow data to be entered into the computer either by manual entry or direct data entry. Examples of input devices are keyboards, mouse, and sensors.

​Block diagram of computer systems

Input Devices

There are mainly 3 types of input devices:

• Manual input - data is entered by human, e.g. keyboard

• Direct Data Entry - Data is already created, but the device reads the data from it, e.g. QR Code

• Sensors - Gathering data from the surrounding, e.g. temperature sensors

Keyboard

Keyboard is one of the most common input devices for data entry. We see keyboards being used in computers, tablets, and phones. For computers, keyboards are connected to them through USB or wireless connection. For tablets and phones, there are usually virtual keyboards or a type of touchscreen technology.

Keyboard

Keyboard is a slow method of entering data and is prone to error. Frequent use of keyboards can lead to injuries such as repetitive strain injury (RSI) in the hands and wrists. To prevent RSI or injuries an ergonomic keyboard can be used. Ergonomic keyboards have keys arranged differently and are designed to give your wrists and hands more support when typing.

Activity

​Search for an ergonomic keyboard and draw it in your notebook. Give one health benefit of using such keyboard

Keyboard

​Uses of Keyboard	​Advantages	​Disadvantages
Input data into application software	Fast entry of text to document	Can be difficult to use if user has limited arm/wrist use
Typing in commands to the computer	Easy to use	Slow method compared to direct data entry
​	Easier to do verification checks as data is entered	Large device that uses up desk space

Open Ended

The most common keyboard layout is called "QWERTY" named after the first row of keys.

Search if you can find other keyboard layouts.

Numeric Keypad

A numeric keypad is used to enter numbers only

Numeric Keypad

​Uses of Keyboard	​Advantages	​Disadvantages
ATM, where customer can key in their PIN, amount of money	Faster than standard keyboards when entering numeric data	Sometimes have smaller keys which can make input more difficult
Chip and PIN devices when paying by credit cards	Easy to carry around because of its small size	Sometimes the order of numbers on the keypad are not intuitive
Fast entry of numeric data into a spreadsheet	​	​

Pointing Devices

Mouse

User uses a mouse to control the position of a pointer on the screen by moving the mouse around. There are usually two buttons for different functions, the left button for selecting items and the right button to show the drop-down menu. Most mouse have a scroll wheel which helps to move through a document.

Pointing Devices

Mouse

The optical mouse is a type of mouse where movement is detected by light reflected to the mouse. Optical mouse’s advantage is that it does not pick up any dirt and that it does not have any moving parts. Optical mouse and wireless mouse are mouse we use in modern computers.

Mouse

​Uses of Mouse	​Advantages	​Disadvantages
Opening, closing software	Faster to navigate through menu than keyboard	Can be more difficult for people with restricted hand/wrist movement than using a keyboard for data entry
Image editing, for example, controlling size and position of a drawing pasted into a document	Don’t need a large desk area compared to a keyboard	Easy to damage
Controlling the position of a pointer on the screen to allow selection from a menu.	​	Difficult to use if no flat surface available

Pointing Devices

Pointing Devices

Touchpad

Touchpads are used as a pointing device in most laptops. The user uses their finger to control the pointer, tapping the touchpad would simulate the left click on a mouse. Some touchpads also have buttons below for left-click and right-click.

Pointing Devices

Touchpad

​Uses of touchpad	Advantages​	Disadvantages​
Same as mouse	Same as mouse	People with limited hand/wrist movement find the device hard to use
​	No need for a separate mouse when using a laptop	More difficult to use when doing operations such as dragging and dropping

Remote Control

Remote control is used to control other devices using infrared signals. Buttons on the keypad are used for different operations such as TV channels, sound levels, etc.

Open Ended

Most of the remote control required user "point" at the device with the control. Why?

Infrared (light)

Most remote controller use Infrared (a kind of light) to transmit signal, which can be blocked by any opaque objects

Some modern TV remote utilized wireless (radio) technology which is not affect by this

Remote Control

​Uses of Remote Control	​Advantages	​Disadvantages
Alter functions of TV, Blu-ray players	Can be operated from any reasonable distance	People with limited hand/wrist movement find the device hard to use
Control multimedia systems	​	Signals can be blocked easily
Used to remotely control, stop and start industrial machinery	​	​

Joysticks

Joysticks have similar functions to a mouse, the pointer of the screen is controlled by gripping the stick. Buttons are used to make selections.

Joysticks

​Uses of Joysticks	​Advantages	​Disadvantages
Used in video games	Easier to navigate the screen than keyboard	Difficult to control the screen pointer than other devices
Used in simulators	Control is more realistic for some applications compared to a mouse	​

Driving Wheel

Driving (steering) wheel is an example of an input device that is similar to a joystick. The wheels allow you to simulate the turning of a steering wheel, and there are associated devices such as pedals and buttons which allow you to accelerate and brake.

Driving Wheel

​Uses of Driving Wheel	​Advantages	​Disadvantages
Used in video games	Easier to control steering movement as it is more intuitive	Expensive compared to joystick or mouse
Used in simulators to mimic vehicle control	The driving experience is similar to using an actual steering wheel in real life	Movements can be too sensitive
		Unless it is an expensive simulator, feedback to the driving wheel is non-existent

Touch Screens

Users can choose an option on a touch screen by just touching the button on the screen. A pointing device is not necessary during the selection process.

Open Ended

Do you think touch screen is an input or output device? Explain your answer.

Touch Screens

​Uses of Touch Screens	​Advantages	​Disadvantages
ATMs	Faster entry of options compared to keyboard or mouse	Limited number of input options available
Mobile phones, tablets	Easy to use	Lead to problems if an operator has to use the system frequently (straining of arm muscles, RSI)
Can be used as an output device because they also work as flat-screen monitors	Option to expand the size of the display if necessary	Screen can get dirty with constant touching

Scanners

Scanners are used to scan hard copy information into computers. The most common type is a flatbed scanner which is made up of a glass panel and lid. The hard copy documents are scanned by a light source and converted into a computer-readable image.

Scanners

​Uses of Scanners	​Advantages	​Disadvantages
Scan in documents and convert into a format for use in computer programs	Images can be stored for editing	Quality is limited to the resolution the scanner is capable of
Scan in old/valuable/ documents/ books, to archive it and to protect the originals	When use with OCR, much faster and accurate than to type in documents	Can be slow at scanning
​	Possible to recover damaged documents and photographs by scanning into computer and use appropriate software to fix it.	​

Sensors

A sensor is a device that inputs data to the computer. The data is a measurement of the physical quantity that is continuously changing (temperature, light, moisture, etc).

Sensors are used in monitoring and control applications, such as scientific experiments, greenhouse automation.

Sensors

​Uses of Sensors	​Advantages	​Disadvantages
Temperature Sensor	More accurate readings taken compared to human operators	Faulty sensors can give wrong results
Light Sensor	Readings are continuous - no break in the monitoring	Most sensors are analogue, there they require conversion using an Analogue-to-Digital Converter
Sound Sensor	Systems can be automatic, no human intervention needed	​

Digital Cameras

Digital cameras stores images on a memory card, and can be transferred to a computer by:

• directly reading the memory card

• connecting the camera to the computer using a USB port

• Using wireless data transfer

The user can select which photos to upload to the computer or to discard. Images can then be printed out, imported into software, or uploaded to the internet

Digital Cameras

​Uses of Digital Cameras	Advantages​	Disadvantages​
Taking photos	Easier to produce better quality photographs than a traditional camera	Images often need to be compressed to reduce the amount of memory use
Dentists use digital cameras to take photos of patients’ teeth to help them diagnose any problems	Easier and faster to upload pohtos to a computer than traditional method	There is some artistry lost because software now corrects errors in the photographs (incorrect exposure, removal of red eye)
Creation of virtual reality tours around houses, historical buildings	Memory cards can store thousands of photos	Need to be computer literate to use the cameras properly

Microphones

Microphones are either built into the computer or externally connected using USB or Bluetooth. A microphone works by converting sound waves into electric currents.

• When sound is created, the air vibrates.

• A diaphragm in the microphone vibrates with the air

• A copper coil is surrounded by a permanent magnet and the coil is connected to the diaphragm using a cone. As the diaphragm vibrates, it makes a current that flows in the air

• The current is then amplified or sent to a recording device

The electric current output from the microphone can be sent to a computer where a sound card converts the current into a digital signal which can then be stored in the computer

Microphones

​Uses of Microphones	Advantages​	Disadvantages​
Input speech/sounds into presentations, films, music, etc.	Faster to read in text than to type	Sound files can use up a lot of computer memory
Can be used as sensor to pick up sounds	It is possible to manipulate sound in realtime using special software	Voice recognition software is not as accurate as typing in manually
Used in video conferencing	Can be used in voice activation system	​

Light Pens

Light pens are used with the computer as an input device. It can only work with CRT monitors. In an CRT monitor the image is being built up row by row by an electron beam; because of this, the computer is able to determine the pen’s position by noting exactly when the device detected the electron beam passing its tip.

Light Pens

​Uses of Light Pens	Advantages​	Disadvantages​
Selecting objects on CRT screens	Greater accuracy than touch screens	Problems with lag when drawing on screen
Drawing on screen	Small	Only works with CRT monitors
​	Easy to use technology	Outdated technology

Light pen in action​

https://www.youtube.com/watch?v=EBfkiprmoi0

Open Ended

Light pen is an outdated technology that allow "drawing" on screen. Name a modern input device which allows drawing with a pen.

​graphics tablet

tablet computer with stylus