EMZETT.Input (Input Device)
In short: Umbrella term for devices used to enter data or commands into a system — keyboard, mouse, microphone, scanner, touchscreen.
In more detail: Input devices convert a physical action (a keypress, movement, sound) into a digital signal the computer can process. The counterpart is output devices, which turn digital data back into a form perceivable by humans (image, sound).
In Depth
From physical action to digital signal
Technically, the conversion usually runs via a small controller chip directly in the input device, which samples the physical action (e.g. which key was pressed, how the mouse sensor moved, what light intensity a scanner sensor measures) and produces a standardised digital signal from it, sent to the computer via USB, Bluetooth or another interface. The operating system takes in this signal via a device driver and makes it usable for applications as a structured event (e.g. a “keypress” event with information like which key, how long pressed, with which modifier keys held at the same time).
The variety of input devices
Besides the classic input devices (keyboard, mouse, microphone), input devices also include:
- Touchscreens/graphics tablets: convert touch/pen position into coordinates.
- Scanners/barcode readers: convert optical information (image, printed code) into digital data.
- Sensors in mobile devices: an accelerometer (detects movement/orientation), GPS (location), a fingerprint sensor, a facial-recognition camera.
- Specialised input devices: graphics tablets for digital art, MIDI controllers for music production, joysticks/gamepads for games.
Each of these devices converts a different kind of physical information (touch, light, acceleration, sound) into the same basic format of digital data the computer can process in a unified way.
Combined input/output devices
Some devices are both input and output at once, such as a touchscreen (input via touch, output via image — both functions run technically independently, but appear to the user as a single, merged device) or a microphone-speaker headset (microphone records = input, headphones play sound = output). The counterpart to input is pure output devices, which turn digital data back into a form perceivable by humans (image, sound, print) — input and output together form the complete human-machine interface of a computer system.
Input validation
From a software perspective, it’s especially important that raw input data is never processed without checking it — any software accepting user input has to validate it (checking expected format, length, allowed characters), since malicious or faulty input could otherwise lead to security vulnerabilities (see e.g. SQLi) or program crashes. This principle applies equally, regardless of the physical input device, to keyboard input, uploaded files, or data received via an API.