Input devices allow users to enter data and interact with computers. Some common input devices are keyboards, mice, touchpads, joysticks, touch screens, scanners, and graphics tablets. Keyboards allow text entry and come in various sizes. Mice control on-screen cursors by detecting finger movement on surfaces. Touchpads are alternatives to mice for laptops. Joysticks are used for game controls. Touch screens are displays that can detect touch input. Scanners digitize images. Graphics tablets enable hand drawing of images and graphics.

3. Input devices
 An input device is a piece of hardware that is used to
enter data into a computer .

4. List of input devices:
 Keyboard.
 Mouse.
 Touchpad.
 Joystick.
 Touch screen.
 Scanner.
 Graphics tablet.
 Micro phone.
 Digital camera.

5. Keyboard
 A keyboard is an input device that allows a person to enter
symbols like letters and numbers into a computer.
 It is the main input device for most computers. There are
different types of keyboards. The most popular type is the
QWERTY design such as typewriter keyboards.

6. keyboard
 Laptop-size
 Handheld
 Multifunctional:
 Common environments for multifunctional keyboards are complex,
high-performance workplaces for financial traders and control
room operators (emergency services, security, air traffic management;
industry, utilities management, etc.).

7. Mouse
 A computer mouse is an input device that is most often used with
a personal computer. Moving a mouse along a flat surface can move the
on-screen cursor to different items on the screen.

8. Mouse
 Optical and laser mice
 The earliest optical mice detected movement on pre-printed mouse pad
surfaces, whereas the modern LED optical mouse works on most opaque
diffuse surfaces; it is usually unable to detect movement on specular surfaces
like polished stone. Laser diodes are also used for better resolution and
precision, improving performance on opaque specular surfaces. Battery
powered, wireless optical mice flash the LED intermittently to save power, and
only glow steadily when movement is detected.
 3D mice:
 USB ,Cordless or wireless:

9. Touchpad
 A touch pad is a device for pointing (controlling input positioning) on
a computer display screen. It is an alternative to the mouse. Originally
incorporated in laptop computers, touch pads are also being made for use with
desktop computers. A touch pad works by sensing the user's finger movement
and downward pressure.
 several layers of material.
 top layer touch.
 electrode layers.

10. Joystick
 A joystick is an input device that allows the user to control
a character or machine in a computer program, such as a
plane in a flight simulator.
 control video games.
 Other common input devices are joysticks, bar code readers, cameras,
fingerprint readers etc.

11. Touch screen
 A touch screen is a computer display screen that is also an input device. The
screens are sensitive to pressure; a user interacts with the computer by
touching pictures or words on the screen.
 Resistive: A resistive touch screen panel is coated with a thin metallic
electrically conductive and resistive layer that causes a change in the
electrical current which is registered as a touch event and sent to the
controller for processing.
 Surface wave:
 ultrasonic waves registers
 Capacitive :
 Electrical charge

12. Scanner
 A scanner is a device that captures images from photographic prints,
posters, magazine pages, and similar sources for computer editing and
display.
 Drum scanner:
 One of the unique features of drum scanners is the ability to control sample
area and aperture size independently. The sample size is the area that the
scanner encoder reads to create an individual pixel. The aperture is the actual
opening that allows light into the optical bench of the scanner. The ability to
control aperture and sample size separately is particularly useful for smoothing
film grain when scanning black-and-white and color negative originals
 CCD scanner:

13. Graphic tablet
 A graphics tablet or digitizer is a computer input device that enables a user to
hand-draw images, animations and graphics, similar to the way a person draws
images with a pencil and paper. These tablets may also be used to capture data
or handwritten signatures.
 Optical tablets:
 Optical tablets operate by a very small digital camera in the stylus