You type on a keyboard, move a mouse, tap a touchscreen, or speak into a microphone. These are input devices — hardware used to enter data into a computer. Without them, a computer would have no way to receive instructions or information. It would sit there, processing nothing.

Input devices have evolved. Punch cards and paper tape gave way to keyboards and mice. Then came touchscreens, styluses, and voice recognition. Game controllers, scanners, cameras, and sensors are all input devices. Some are specialized, like a barcode scanner at a grocery store or a heart rate monitor in a gym.

Common input devices

• Keyboard: typing text and commands
• Mouse: pointing and clicking
• Touchscreen: direct manipulation
• Microphone: voice input
• Scanner: digitizing documents
• Camera: capturing images and video

Input devices shape how we interact with computers. A keyboard is fast for text. A mouse is precise for graphics. A touchscreen is intuitive for casual use. Voice is hands-free but less private. Each has trade-offs.