Nepedia
Back to Discover
Advanced Reader
💻

Input device

technology Maturity 7-9 Next article →

An input device is a piece of equipment used to enter data and control signals into an information processing system. These systems include computers and various other information appliances. Input devices act as the bridge between the physical world and digital systems. They allow humans to provide instructions or information for a computer to process. Without these tools, we could not interact with modern software or hardware.

Input devices function through various mechanical or electronic processes. One way to categorize them is by their modality of output. This refers to whether the device uses mechanical motion, audio, or visual signals. Another way is to look at whether the output is discrete or continuous. A discrete input is a single, distinct action like pressing a specific key. A continuous input involves a constant stream of data, such as a mouse tracking a position. While a mouse movement is digitized into discrete quantities, it is fast enough to be considered continuous.

Logitech Mouse
Logitech Mouse

A keyboard is a common human interface device that uses a matrix of buttons. These buttons, known as keys, allow a user to input alphanumeric characters. They can also be used to call upon specific functions of the computer. Keyboards come in many different form factors to suit different needs. Desktop keyboards are often large and include a numeric keypad or multimedia keys. Laptops and tablets use thinner designs that might compromise on comfort. Different switch technologies are used to make these keys work. Mechanical switches use springs, while scissor switches are common in laptops. Some keyboards use a membrane, and others are virtual or projected.

Pointing devices allow users to input spatial data to a computer. These are often used to navigate a graphical user interface (GUI). A user might move a mouse pointer or touch a screen to select an item. Pointing devices can be classified by whether the input is direct or indirect. Direct input occurs when the input space coincides with the display space. Examples include touchscreens and light pens. Indirect input involves devices like a mouse or a trackball. These devices can also be classified by their positional information. Absolute input, like a touchscreen, knows exactly where you are touching. Relative input, like a mouse, allows you to lift and reposition the device.

Logitech Mouse
Logitech Mouse

Sensors are specialized input devices that produce data based on physical properties. They are very common in mobile devices to detect orientation and acceleration. Some sensors are built using MEMS, which are micro-electromechanical systems. This technology allows sensors to be microscopic in size. An accelerometer is a sensor that detects acceleration. A gyroscope is used to detect spatial orientation. A magnetometer works like a compass to sense magnetic heading. Other sensors include barometers to measure atmospheric pressure and thermometers to measure temperature.

Mobile Device Sensors
Mobile Device Sensors

Some devices provide many degrees of freedom for complex movement. These are often called high-degree of freedom input devices. They are frequently used in virtual reality systems, such as CAVE environments. In these systems, input must register six degrees of freedom. These devices are often used to control camera angles in 3D applications. Many gaming devices are composite devices. A composite device combines different forms of input into one unit. A joystick is a single device that uses a pivoting stick. A gamepad or joypad is a handheld device used for modern video games. Even a mouse is technically a composite device because it tracks movement and provides buttons.

Oculus-Rift-Touch-Controllers-Pair
Oculus-Rift-Touch-Controllers-Pair

Video and audio input devices capture information from the outside world. Video input devices, such as digital cameras and webcams, digitize images or video. Some devices, like the Microsoft Kinect sensor, can even detect human motion visually.

Xbox-360-Kinect-Standalone
Xbox-360-Kinect-Standalone

Audio input devices, like microphones, allow users to send sound to a computer. This can be used for recording voice messages or using speech recognition software. In the 20th century, people used different methods like punched cards and tapes. In those systems, a punched hole represented a one, and its absence represented a zero. Today, we use much more advanced digital tools to communicate with our machines.

674 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (5)
Typing example.ogv
File:Logitech Mouse.JPG
Logitech Mouse.JPG
File:Mobile Device Sensors.png
Mobile Device Sensors.png
File:Oculus-Rift-Touch-Controllers-Pair.jpg
Oculus-Rift-Touch-Controllers-Pair.jpg
File:Xbox-360-Kinect-Standalone.png
Xbox-360-Kinect-Standalone.png
More to explore

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.