input devices [4]
Electronic devices used to transmit data and commands to a computer.
optical mouse 
Mouse in which the ball is replaced by an optical system (light-emitting diode and sensor); it has no movable parts.
optical sensor 
Device that measures the mouse’s movements by analyzing the light rays (emitted by a diode) reflected from its support surface.
wheel mouse 
Mechanical or optical mouse that contains a scroll wheel.
cable 
Flexible cable containing the conductors by which the mouse is attached to the computer.
cordless mouse 
Mechanical or optical mouse connected to the computer by infrared or radio signals.